R2006/823 l 30/06/2009

GHATF shark survey of population abundance and population size composition for target, byproduct and bycatch species

GHATF shark survey of population abundance and population size composition for target, byproduct and bycatch species

J. Matias Braccini, Terence I. Walker and Anne S. Gason

Department of Primary Industries PO Box 114, Queenscliff, Victoria 3225

June 2009

© Australian Fisheries Management Authority and Primary Industries Research Victoria.

This work is copyright. Except as permitted under the Copyright Act 1968 (Cth), no part of this publication may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owners. Neither may information be stored electronically in any form whatsoever without such permission.

ISBN 978‐1‐74217‐386‐3 Preferred way to cite:

Braccini, J. M., Walker, T. I., and Gason, A. S. (2009). GHATF shark survey of population abundance and population size composition for target, byproduct and bycatch species. Final report to Australian Fisheries Management Authority. Project No. R2006/823. June 2009. iv + 123 pp. (Fisheries Research Branch, Department of Primary Industries: Queenscliff, Victoria, Australia).

Published by Department of Primary Industries, Fisheries Research Branch, Queenscliff, Victoria, 3225.

DISCLAIMER The authors do not warrant that the information in this book is free from errors or omissions. The authors do not accept any form of liability, be it contractual, tortious or otherwise, for the contents of this book or for any consequences arising from its use or any reliance placed. upon it The information, opinions and advice contained in this book may not relate to, or be relevant to, a readerʹs particular circumstances. Opinions expressed by the authors are the individual opinions of those persons and are not necessarily those of the publisher or research provider.

GHATF shark survey ii Table of Contents

Non‐technical Summary...... 1

Acknowledgements...... 3

Background ...... 3

Need ...... 4

Objectives ...... 5

Methods ...... 5 Collection of data...... 5 Catch rate comparisons...... 6 Post‐capture mortality...... 7 Estimating length‐frequency and age‐frequency structure of population ...... 8 Estimating total mortality ...... 10

Results/Discussion ...... 10 Sampling summary ...... 10 Catch rate comparisons...... 11 Commercial species...... 11 Bycatch species...... 13 Size‐frequency composition of the catch ...... 14 Retained and discarded species...... 15 Post‐capture mortality...... 15 Age‐frequency composition of the catch...... 15 Wildlife interactions ...... 16 Carcass damage ...... 16 Reproductive sampling ...... 16 Estimating size‐ and age‐structure of commercial shark populations ...... 16 Estimating total mortality of gummy shark and school shark for each sex ...... 17

Benefits / Management Outcomes...... 18

Conclusion ...... 18

References ...... 20

Supplements and Appendices ...... 97 Appendix 1. Fishing sites for 2007–08 shark survey ...... 97 Appendix 2. Catch rate of commercial species caught in each surveys...... 107 Appendix 3. Catch rate of bycatch species caught in each survey...... 121

GHATF shark survey iii List of Tables Table 1. Sampling summary for the 2007–08 survey 21 Table 2. Number of individuals and species caught during the 2007–08 survey 22 Table 3. Number of individuals of each species caught during the 2007–08 survey 23 Table 4. Between-survey comparisons of the number of individuals of commercial species 28 Table 5. Between-survey comparisons of the number of individuals of bycatch species 43 Table 6. Size-frequency composition of species caught in the 2007–08 survey 46 Table 7. Retained and discarded individuals caught in the 2007–08 survey. 53 Table 8. Retained and discarded individuals caught by mesh size in the 2007–08 survey. 54 Table 9. Post-capture mortality for the species caught in the 2007–08 survey 59 Table 10. Wildlife interactions in the 2007–08 survey 61 Table 11. Carcass damage from predation on commercial species 62 Table 12. Number of samples collected for reproduction during 2007–08 survey 63 Table 13. Gillnet relative length selectivity analysis for gummy shark (Mustelus antarcticus) during 1973–76 64 Table 14. Gillnet relative length selectivity analysis for gummy shark (Mustelus antarcticus) during 1986–87 65 Table 15. Gillnet relative length selectivity analysis for gummy shark (Mustelus antarcticus) during 2007–08 66 Table 16. Gillnet relative length selectivity analysis for school shark (Galeorhinus galeus) during 1986–87 67 Table 17. Gillnet relative length selectivity analysis for school shark (Galeorhinus galeus) during 2007–08 68 Table 18. Gillnet relative length selectivity analysis for common sawshark (Pristiophorus cirratus) during 2007–08 69 Table 19. Gillnet relative length selectivity analysis for southern sawshark shark (Pristiophorus nudipinnis) during 2007–08 70 Table 20. Gillnet relative length selectivity analysis for elephant fish (Callorhinchus milii) during 2007–08 71 Table 21. Gillnet relative age selectivity analysis for male gummy shark (Mustelus antarcticus) during 1986–87 72 Table 22. Gillnet relative age selectivity analysis for female gummy shark (Mustelus antarcticus) during 1986–87 73 Table 23. Gillnet relative age selectivity analysis for male school shark (Galeorhinus galeus) during 1986–87 74 Table 24. Gillnet relative age selectivity analysis for female school shark (Galeorhinus galeus) during 1986–87 75 Table 25. Gillnet relative age selectivity analysis for male gummy shark (Mustelus antarcticus) during 2007–08 76 Table 26. Gillnet relative age selectivity analysis for female gummy shark (Mustelus antarcticus) during 2007–08 77 Table 27. Gillnet relative age selectivity analysis for male school shark (Galeorhinus galeus) during 2007–08 78 Table 28. Gillnet relative age selectivity analysis for female school shark (Galeorhinus galeus) during 2007–08 79 Table 29. Summary of length and age at maximum selectivity for gummy and school shark 80 Table 30. Total mortality estimates for male gummy shark (Mustelus antarcticus) 1986–87 81 Table 31. Total mortality estimates for female gummy shark (Mustelus antarcticus) 1986–87 82 Table 32. Total mortality estimates for male school shark (Galeorhinus galeus) 1986–87 83 Table 33. Total mortality estimates for female school shark (Galeorhinus galeus) 1986–87 84 Table 34. Total mortality estimates for male gummy shark (Mustelus antarcticus) 2007–08 85 Table 35. Total mortality estimates for female gummy shark (Mustelus antarcticus) 2007–08 86 Table 36. Summary of total mortality estimates for gummy shark and school shark during 1986–87 and 2006–08 87

List of Figures Figure 1. Size-frequency composition of commercial species caught in the 2007–08 survey 88 Figure 2. Age-frequency composition of gummy and school shark catch 2007–08 93 Figure 3. Wildlife interactions in the 2007–08 survey 95 Figure 4. Percentage-length-frequency distribution for school shark population 96

GHATF shark survey iv

Non‐technical Summary

An industry‐based fishery‐independent fixed‐site survey using five gillnets each 500 m long of 4–8 inch mesh size was designed and carried out to survey the species caught in the Gillnet Hook and Trap Fishery with a particular focus on school shark and, to a lesser extent, gummy shark. The main value of this survey is to establish the starting point of a fishery‐independent time‐series of catch rates for the target, byproduct and key bycatch species caught in the fishery. The three objectives of the project were met completely. The quality of data collected from the 2007–08 survey completed under research quota demonstrates that it is feasible to adopt a fishery‐independent fixed‐site survey undertaken on commercial fishing vessels to provide most of the monitoring data required for the shark fishery. The five adopted mesh‐sizes for the survey fleet of gillnets provide data far superior to tthose tha can be obtained by scientific observers on commercial fishing vessels using 6‐ or 6½‐inch mesh‐size or obtained from port sampling. Not only is it expected that catch rates from the present and any future surveys will provide indices of abundance more robust than fishers’ logbook data as used for assessment in the past, the survey data provide direct measures of recruitment from the small mesh sizes and of surviving breeding stock from the large mesh sizes. For the 2007–08 survey, six different commercial vessels were used during 16 cruises for sampling at 48 sites and 187 stations (106 stations in South Australia, 60 in Bass Strait and 21 in Tasmania) at depths ranging 9–230 m. The catch comprised mostly chondrichthyes (18,983 individuals of 43 species for the experimental nets and 16,314 individuals of 42 species for the commercial nets) and teleosts (4116 individuals of 86 species for the experimental nets and 2840 individuals of 75 species for the commercial nets). Cephalopods, gastropods, bivalves, crinoids, crustaceans, and echinoderms were caught in low numbers, and several seabirds, and marine mammals were caught. Gummy shark, spikey spurdog and school shark accounted for more than three quarters of the chondrichthyan catch (by number). Jackass morwong, blue warehou and bight redfish accounted for almost half of the teleost catch (by number). There was a decline in the overall catch rate of chondrichthyan and teleost species with increased mesh size. There was a significant effect of mesh size for many species; these species showed a pattern of a highest catch (mode) for a particular mesh size. The number of discarded individuals and species in the 2007–08 survey decreased with mesh size. The most commonly discarded species (spikey spurdog, draughtboard shark and Port Jackson shark) have a very low post‐capture mortality probability. Three types of wildlife interactions were recorded with ‘wildlife diving and feeding on discards’ being the most common interaction. Apart from the smallest length classes, all length classes of gummy shark were well represented in survey catches. Small length classes of school shark, common sawshark, southern sawshark, and elephant fish were under‐represented at the sampling sites of the survey. Post‐hoc analyses comparing information from the 2007–08 survey with the earlier surveys of 1973–76, 1986–87, and 1998–01 indicate that many fishing sites among the four survey periods did not overlap and hence reduced power for statistically robust comparisons, particularly for bycatch species. Nevertheless, for the five main commercial species (gummy shark, school shark, southern sawshark, common sawshark, and elephant fish) in specific regions and zones, there were statistically significant differences in catch rate, based on data from selected sites that were considered spatially comparable. For the broad zone of South Australia, there were significant increases in the gummy shark catch rate and the school shark catch rate for 7‐inch mesh and in the elephant fish catch rate for 6‐inch mesh between the 1986–87 survey and the 2007–08 survey.

GHATF shark survey 1

For the broad zone of Bass Strait, there were statistically significant changes in catch rate for all five key commercial species. Gummy shark catch rates for 5‐inch mesh‐size of gillnets were significantly higher during the 2007–08 survey than during the earlier surveys of 1973–76, 1986–87, and 1998–01 suggesting improved recruitment. However, catch rates for 8‐inch mesh were significantly higher during 1973–76 than during the subsequent surveys, suggesting a greater abundance of large animals in the population during the early phase of the gummy shark fishery. Catch rates for 6‐ and 7‐inch mesh were statistically significantly higher during the 1973–76 and 2007–08 surveys than during the 1986–87 and 1998–01 surveys, which is consistent with stock depletion during the 1980s and 1990s from the 1970s and subsequent recovery. School shark catch rates for 6‐, 7‐ and 8‐inch mesh were significantly higher during the 2007–08 survey than during the three earlier surveys, with the proviso that school shark were not adequately surveyed in Bass Strait during 1973–76. Southern sawshark catch rates for 6‐inch mesh were significantly higher during the 1973–76 and 2007–08 surveys than during the 1986–87 and 1998–01 surveys. Common sawshark catch rates for 6‐inch mesh and elephant fish catch rates for 7‐inch mesh, on the other hand, were significantly higher during 1973–76 than the later surveys. The surveys also indicate that the abundances of the bycatch species of draughtboard shark and Port Jackson shark and the byproduct species broadnose sevengill shark have recently increased. The gummy shark estimate of fishing mortality was about double natural mortality during 1986–87, but was about equal to natural mortality during 2007–08. The school shark estimates indicate fishing mortality was about four times natural mortality during 1986–87, for age classes up to age 10 years, suggesting there must have been severe stock depletion during the 1980s. As a general rule, fishing mortality should not exceed natural mortality to maintain the biomass above the level required to produce the maximum sustainable yield.

GHATF shark survey 2

Acknowledgements

The authors are grateful to Kyri Toumazos, Steve Brockwell, J. Maczkowiack, Gary Robinson, M. Larsen, John Doran for their involvement and voluntary participation in the survey, which was crucial for the successful completion of this research. The authors are also grateful to Paul McCoy, Fabian Trinnie, Justin Bell, Jeff Nemec, and Lauren Brown of the Marine and Freshwater Fisheries Research Institute for their participation in the collection of field data. Rory McAuley of the Western Australian Fisheries and Marine Research Laboratories is thanked for providing a program developed in Microsoft EXCEL used for estimation of gillnet selectivity parameters with standard errors.

Background Shark fishing is part of the Gillnet Hook and Trap Fishery (GHATF) of the Southern and Eastern Scalefish and Shark Fishery (SESSF). The SESSF is a complex multi‐species and multi‐sector fishery distributed from SE Queensland to SW Western Australia. From mid‐1920s, Victorian fishers targeted school shark (Galeorhinus galeus) mostly using baited hooks. During the Second World War, the fishery expanded rapidly to include Tasmanian and South Australian fishers (Olsen 1959). During 1964, Victorian fishers began using gillnets and by the early 1970s, most of the catch was taken by this method. During the 1970s, the catch declined following a decline in school shark stocks and a ban on the sale of large school shark due to their mercury content. For the rest of the 1970s, gummy shark (Mustelus antarcticus) replaced school shark as the predominant species (Walker and Gason 2005). School shark became the predominant species again during 1980–87 but their catches have fallen rapidly since 1988 with gummy shark again becoming the main target species. Other species such as common sawshark (Pristiophorus cirratus), southern sawshark (P. nudipinnis), broadnose sevengill shark (Notorynchus cepedianus), and elephant fish (Callorhinchus milii) are commonly landed as byproduct (Walker and Gason 2005). Today, shark is targeted by shark monofilament gillnet. The method of shark demersal longline, deployed as the principal method for targeting shark from the mid‐1920s to the early 1970s, has been almost completely replaced by gillnet. Other methods take only small quantities of shark as byproduct. The industry is limited to the narrow mesh size range of 6–6½ inches. Because of the highly length‐ selective characteristics of gillnets (Kirkwood and Walker 1986), the length‐frequency composition and the age‐frequency composition of the catch are not representative of the length‐frequency composition or age‐frequency composition of the population. Only by using a range of mesh sizes can the length and age profiles of the population be determined accurately. Management of the fishery evolved from an open access fishery to a highly managed fishery. Until 1984, the shark fishery was an open access fishery. During 1984, the Commonwealth began endorsing Commonwealth Fishing Boat Licences (subsequently replaced with Commonwealth Fishing Permits) with ‘shark gillnet endorsements’. By 1988, the use of gillnets was managed under the Southern Shark Fishery Management Plan, providing for reduced effort by limiting gillnet length, the number of meshes deep, and the number of operators. Responsibility for management of the fishery was shared between the Commonwealth Government and the State Governments of Victoria, Tasmania and South Australia. Biological regulations in place at that time included legal minimum lengths, legal minimum (and subsequently maximum) mesh‐size of gillnets, and closed areas. In 2001, the management of the fishery moved from a system of input controls to a system that prioritized output controls, which regulated the annual take of shark using Total Allowable Catches (TACs) and Individual Transferable Quotas (ITQs). That year, ITQs were introduced for gummy shark and school shark. In 2002, ITQs were introduced for sawshark and elephant fish (Walker and Gason 2005).

GHATF shark survey 3

Quantitative assessment of the status of commercial shark species is essential for the determination of TACs of species subject to ITQ management. Current stock assessment for the commercial shark species taken in the GHATF depends on reliable time‐series of relative abundance. Commercial logbooks have been used to determine time‐series of catch‐per‐unit of effort (CPUE), which is used as an indicator of relative abundance. Since adoption of quota management for shark during 2001 and associated retargeting practices, there has been concern about the use of logbook CPUE as a reliable indicator of stock abundance, particularly for school shark dues to it aggregating behaviour and current low TAC. Unreliable CPUEs increase the uncertainty of stock assessments. Therefore, fishery‐independent information on the relative abundance of these species is needed. A programme based on a fixed‐site fishery‐independent sampling survey from commercial fishing vessels was considered by the Southern Shark Fishery Assessment Group (SharkFAG) the most cost‐effective method for collecting information on relative abundance. Also, the use of fixed‐site survey results in stock assessments rather than future commercial CPUEs improves the ability to satisfy the legislative management objective for Australian fisheries of Ecological Sustainable Development (Punt et al. 2002). Catch data are available from fleets of survey gillnets used during 1973–76 and 1986–87. During 1973–76, eight mesh‐sizes (2, 3, 4, 5, 6, 7, 8, and 9‐inch) were used at 73 sites and other configurations of gear (including hooks) at a further 89 sites, and, during 1986–87, four mesh‐sizes (5, 6, 7, and 8‐inch) were used at 144 fishing sites. These data have details of catch rates and length‐frequency composition and, for 1986–87, age composition of catches. In addition, there are data available on target, byproduct and bycatch species for 6‐ and 6½‐inch mesh ‐size used at 153 sites during 1998–01. In the present project, a fishery‐independent fixed‐site survey was designed and conducted to provide reliable indices of abundance for inclusion in stock assessment models, length‐frequency composition and age‐frequency composition of the populations of target and byproduct species taken in thek shar gillnet component of the GHATF. This information simply cannot be obtained by sampling commercial catches. The survey was also aimed at providing data on actual levels of bycatch and length‐frequency profiles for the populations of the main bycatch species. The information produced by this survey is crucial for improving stock assessments of the commercial species and evaluating the effectiveness of school shark stock rebuilding strategies put in place.

Need The Ministerial Direction to AFMA during December 2005 requires fishery‐independent survey of stocks, rehabilitation of overfished stocks of Commonwealth‐managed fisheries, and reduction of bycatch. Stock assessment of shark species presently depends on logbook CPUE data as an index of abundance, which is dependent on catches by highly length‐selective fishing gear. When quota management was adopted for gummy shark and school shark in 2001 and for sawshark and elephant fish in 2002, the time series of CPUE past these dates became unreliable indicators of abundance because of major changes in targeting practices by fishermen. This problem is particularly acute forl schoo shark; the current stock assessment for school shark ignores logbook CPUE for 2001 onwards and uses only catch data. Therefore, fishery‐independent survey of stock abundance using a range of different mesh sizes is needed. In addition to providing essential information related to sustainability of target and byproduct species,s thi project provides essential information for addressing issues of biodiversity conservation and ecosystem structure and function under the Environment Protection and Biodiversity Conservation Act 1999. This is particularly relevant as sharks are proving to be among the most susceptible species to the effects of fishing. Data from the present project provides direct inputs to both stock assessment models and ecosystem models. The present project undertook a fishery‐independent survey during 2007–08 of target (gummy shark), byproduct (principally school shark, common sawshark, southern sawshark, elephant fish, and

GHATF shark survey 4

broadnose sevengill shark) and bycatch stocks harvested by monofilament shark gillnets. The project provides indices of population abundance of target, byproduct and bycatch species, and provides indices of fishery‐wildlife interactions. Indices from selected sites can be compared with indices from previous shark surveys undertaken during 1973–76, 1986–87, and 1998–01. Importantly, it provides baseline data for a widespread rigorously‐designed fishery‐independent survey for ongoing monitoring.

Objectives The aim of the present project was to set the basis for a fishery‐independent fixed‐site survey of species caught in the GHATF with a particular focus on school shark and, to a lesser extent, gummy shark. The main value of this survey is to establish the starting point of an independent time‐series of relative abundance for the main species caught in the fishery. The design provides for comprehensive baseline data for comparison with future surveys. These comparisons will be possible for target, byproduct and bycatch species. There were three specific objectives for the survey. 1. To determine abundance indices and length‐frequency composition of the catch by mesh size and of the population during 2007–08 and calibrate these indices against indices available for 1973–76, 1986– 87, and 1998–01 for target and principal byproduct species. 2. To determine length‐at‐age composition of the gummy shark and school shark catches and populations for 2007–08 and compare them with those available for 1986–87. 3. To compare catches by mesh size and abundance of bycatch species during 2007–08 with those available for 1973–76 and 1998–01.

Methods

Collection of data A detailed description of the experimental design is included in Appendix 1. The design takes account of the location of stations from earlier surveys and covers the most suitable areas for future surveys. Agreement on construction of survey fishing gear and location of survey fishing sites was undertaken in close consultation with industry, the Australian Fisheries Management Authority (AFMA) and the Shark Resource Assessment Group (SharkRAG). The position of the survey sites and sampling time were determined based on careful consideration of the fishing sites sampled during the 1973–76 and 1986–87 surveys and of commercial fishers’ knowledge on areas considered prime school shark and gummy shark grounds. Historic commercial catches were also used as a guide for the selection of the survey sites (SharkRAG Documents 2006/22 and 2007/04). A fleet of monofilament gillnets of five mesh‐sizes was used at 187 stations during 2007 and 2008 in Bass Strait, southern and western Tasmania, and South Australia. By stratifying the sampling, the response variable (e.g. catch rate) variance is reduced as each site is selected given its relatively more homogeneous properties (Rago 2005). Traditional stratified sampling theory where a large area is subdivided into sampling units and random samples are taken within each unit could not be applied because of budget constraints and the spatial extent of the area of interest (i.e. south‐eastern Australia). Hence, an alternative approach was adopted where sites of relatively high school shark and gummy shark production (assumed to be abundance ‘hot‐spots’) were determined to become the basis of the fixed‐site survey. The selected sites were classed as 25 school shark sites, 6 gummy shark sites, and 17 mixed sites.

GHATF shark survey 5

The survey involved the voluntary participation of the shark fishing industry to survey each of the sites. A commercial operator took a scientific observer on board to sample within the specified survey sites. The experimental design had 48 fixed sites with 4 stations per site. The selection of 4 stations per fixed site was a trade‐off between a power analysis undertaken on previous surveys data and the logistical practicality of fishing within the survey sites. Fishers were allowed to determine the location of the four stations within a site with the condition of having the stations at least 2 nm apart. Sampling was conducted during day and night as a standard fishing operation with soak time determined by the skipper. Scientific onboard observers recorded the species, sex, length, condition and degree of damage of the fish captured. Interactions with threatened, endangered and protected (TEP) species were recorded. Postcranial vertebrae were collected from commercial species for ageing studies. A total of 957 school sharks and 999 gummy sharks were aged from vertebrae. Sub‐sampling of the collected vertebrae was according the following design agreed by scientists and AFMA: 250 samples were selected for each sex for each of two broad zones (Bass Strait–Tasmania and South Australia) representing the catch composition by mesh size for each sex x zone groups. For age determination, vertebrae were thawed and removed of soft tissue by first trimming off the skin and flesh with a scalpel followed by immersion in 2% sodium hypochlorite. Gummy shark vertebrae were aged whole whereas school shark vertebrae were aged from sagital sections. For gummy sharks, growth‐increment bands on the surface of the vertebrae were enhanced by staining with an aqueous solution of saturated alizarin red S and 0.1% sodium hydroxide solution in the ratio of 1:9. School shark vertebrae were air dried and embedded in epoxy resin and sectioned with a lapidary saw with a diamond‐impregnated blade. Sections (∼250 μm) were cleaned using ethanol and water, air‐dried and mounted on glass slides using epoxy resin. Gummy and school shark vertebrae were read using a digital image system on a dissecting microscope (8x magnification). Gummy shark growth‐increment bands were distinguished by the alternating pattern of heavy and light staining using reflected light. School shark growth‐increment band consists of an opaque zone and a translucent zone when viewed with reflected light. The total age was calculated as the total number of bands minus one to adjust for the birth mark. A subjective readability score was assigned to each vertebra. All vertebrae were read by a single reader (first reader) and a second reader read a random sub‐sample of vertebrae for evaluation of between‐reader precision. For this, the Average Percentage Error Index (APEI) was calculated.

Catch rate comparisons The current survey was designed to sample areas considered abundance hot‐spots of school shark and to a lesser extent gummy shark. The current survey design also enables various comparisons between the present survey and earlier gillnet surveys. However, these comparisons must be considered within the context of the overall objectives and nature of the earlier surveys. The 1973–76 survey was aimed at estimating gummy shark length‐specific selectivity for gillnets and collecting biological information. Two research vessels were used at 162 stations on the continental shelf between Streaky Bay, South Australia; Gabo Island, Victoria; and Hobart, Tasmania, with most fishing stations (126 stations) located in Bass Strait. Each gillnet was 250 m long and mesh sizes ranged 2–9 inch. The gillnets were set on the seabed mainly between 0400 and 0600 h. Catch composition of commercial, byproduct and bycatch species was recorded (Walker et al. 2005). The 1986–87 survey was aimed at collecting biological information and gillnet length‐specific selectivity of gummy and school sharks. Sampling was conducted on board 11 commercial vessels at 144 stations in South Australia and Bass Strait using four 500‐m long gillnets of 5–8 inch mesh‐size. The fishing gear was set on the seabed duringy da and night. Only catch composition of commercial and byproduct species was recorded; no bycatch information was recorded during this survey (Walker et al. 1989). The 1998–01 survey was aimed at collecting biological information on mainly sawshark and elephant fish and determining the bycatch composition of the shark gillnet fishery. eNin different commercial vessels were used at 153 stations (91 stations in Bass Strait and 62 stations in South Australia). The vessels operated under normal commercial fishing conditions and used 6‐ or 6½‐inch

GHATF shark survey 6

mesh‐size gillnets ~4200 m long. The gear was set on the seabed during day and night. Catch composition of commercial, byproduct and bycatch species was recorded (Walker et al. 2005). Catch rates inevitably exhibit wide variation spatially and temporally which is affected by ‘catchability’ of a species to any specific fishing gear and by the fishing power of a vessel and its operators. Catchability depends on attributes of the species (e.g. diurnal behaviour, response to water temperature, pressure and currents, and habitat) and the fishing gear (e.g. colour, and hanging ratio), whereas fishing power depends on the attributes of the vesseld an its operators (e.g. ability of vessel to stay at sea, navigational aids, and fishers’ knowledge). A fishery‐independent fixed‐site survey‐design attempts to reduce some of this variation by restricting operations spatially and temporally and adopting strict fishing protocols and standardising fishing gear. It is important to recognise, however, when considering the between‐survey comparisons from the post‐hoc analyses that many of these restrictions applied to the 2007–08 survey, but not the earlier surveys. The data were managed and analysed using the statistical package SAS (SAS Institute, North Carolina, USA). Catch rates were statistically tested for the effects of mesh size on the number of individuals of each species per unit of fishing effort caught in the different surveys (70s: 1973–76; 80s: 1986–87; 90s: 1998–01; 00s: 2007–08) pooling the data over all fishing sites. For the comparison of catch rates between surveys, the data were separated into eight sregion (Great Australian Bight Offshore, Great Australian Bight Inshore, Streaky and Venus Bay, South Australia Shelf, Eyre Peninsula, Cape Jaffa, Western Bass Strait, Eastern Bass Strait) and two broader zones (Bass Strait and South Australia). Only comparable stations were used. For the 70s, 80s and 90s surveys, comparable stations were defined as stations located within or adjacent to the sites sampled during the 00s survey. Two sets of analyses were undertaken. In one set of analyses (hereafter referred as ‘defined’), only stations located within the location of the 00s survey sites were used. This criterion was only met by the 80s survey for the comparison of commercial species only. Hence, comparisons were made between the 80s survey and the 00s survey (using data collected by the 5–8 inch mesh‐size gillnets). Based on the assumption that the adjacent stations were located in fishing grounds ‘similar’ to the survey site fishing grounds, in the next set of analyses (hereafter referred as ‘fuzzy’), stations located within and adjacent to the 00s survey sites were used to increase the number of stations used in the comparison. This criterion was met by the 70s, 80s, and 90s surveys. For the commercial species, comparisons were made therefore between the 70s, 80s and 00s surveys using data collected by the 5–8 inch mesh‐size gillnets, and between the 70s, 80s, 90s and 00s surveys using data collected by the 6‐inch mesh‐size gillnet only. For the bycatch species, comparisons were made between the 70s and 00s surveys (using data collected by the 4–8 inch mesh‐size gillnets) and between the 70s, 90s and 00s surveys (using data collected by the 6‐inch mesh‐size gillnets) for stations located in Bass Strait only. Following Walker et al. (2005), an analysis of variance was used to test for the effects of two explanatory variables separately for each species. For each analysis, the variance was tested for homogeneity and the following model was applied:

Catch rate = Explanatory variable(s) + ε. In the model, ε is the error term and catch rate is the number of animals caught divided by the fishing effort and expressed as number per 1000 km‐hour. The explanatory variable in the model varied depending on the analysis. For the mesh‐size effect analysis, the explanatory variable was mesh size; for the among survey‐period analysis, the explanatory variable was period. Bonferroni adjusted means were used to identify those mesh sizes or periods that were significantly different (α<0.05).

Post‐capture mortality Post‐capture mortality (PCM) is composed of immediate mortality caused by injury and acute physiological stress and of delayed mortality caused by physical injury, infection and predation associated with behaviour impairment (Davis 2005). Immediate mortality was determined from direct observation of animals landed on deck either dead or alive. Delayed mortality was determined as the

GHATF shark survey 7

product of a ‘stimuli activity index’, a ‘wounds and bleeding index’, a ‘sea lice damage index’, and a ‘skin damage and surface bruising index’ (see Table 2 in Appendix 1). Each of these indices ranged from 1 to 4 to convert them into a probabilistic framework; i.e. indices with a value of 1, 2, 3, and 4 were assigned a probabilistic value of 0, 0.33 0.66 and 1 respectively. Post‐capture mortality, the product of these indices, therefore ranged between 0 and 1. Three arbitrary PCM categories were determined: low PCM (0–0.33), medium PCM (0.33–0.66) and high PCM (0.66–1.00).

Estimating length‐frequency and age‐frequency structure of population The length‐frequency and age‐frequency compositions of the population cannot be readily obtained by sampling catches from a single mesh size of gillnet. For the present survey, the length‐frequency distribution of the population for each of the key commercial species was obtained from an analysis estimating parameters required to express selectivity as a function of length of shark and mesh size of gillnet. Then for gummy shark and school shark, using length‐at‐age data collected as part of the survey, the age‐frequency distribution of the population was obtained from a similar analysis estimating parameters required to express gillnet relative selectivity as a function of age of shark and mesh size of gillnet. The method adopted for selectivity analysis of the data was originally developed to analyse experimental data for Mustelus antarcticus (Kirkwood and Walker 1986). A review of techniques for determining gillnet selectivity advocated this approach because it simultaneously fits to catches from a range of mesh sizes (Millar 2000). For this method, absolute selectivity of any gillnet for each length of fish is defined as the probability that, if a fish of that size encounters the gillnet, it is captured and retained in the gillnet. These probabilities cannot be readily estimated, so it is necessary to work with relative selectivity, rather than absolute selectivity. Relative selectivity for a particular size of fish is proportional to the absolute selectivity, with the constant of proportionality such that the maximum relative selectivity over all sizes is one. The method is a convenient, flexible, two‐parameter model that can display varying amounts of right skew to account for large fish entangling rather than enmeshing in a net. The model is derived from the probability density function of a gamma distribution with parameters α and β and argument x and has the probability density (xeαβ(/)− x /(Γ+αβ 1)/) (1)α+

2 with a single mode at x = αβ and variance ()αβ+1 . In this expression, Γ(.) is the standard gamma function.

For this method, mi is mesh size of gillnet i , where iI= 1,2,..., for I separate gillnets; l j is mid‐ length of length‐class j , where jJ= 1,2,..., for J separate length‐classes; nij is number of fish from length‐class j caught by gillnet i ; μ j is relative proportion in the population from length‐class j ; Sij is mean relative selectivity for a fish in gillnet mesh size i from length‐class j ; and η j is fishing power at the size of maximum selectivity, relative to the maximum power over all I gillnets. Then for suitably scaled μ j ,

nSij=η iμ j ij .

To model relative selectivity Sij with a maximum of one, this expression is rescaled so that the modal value is one. The model has several simplifying assumptions.

GHATF shark survey 8

1. The gillnets have equal fishing power.

2. The selectivity Sij and the mode and variance of the probability density function can be modelled by

simple functions of mi and l j .

3. For each gillnet i and length‐class j , the catches nij are independent observations from a Poisson

distribution with mean μ jijS .

4. The full set of experimental nets encounter the same population. 5. The catch by a net is not influenced by the presence of any other net.

The log‐likelihood of the whole data set is given by IJ LnSS=−∑∑()ijln(μμ j ij ) j jo ij==11 where IJ ∑ nij ij==1, 1 μ j = IJ . ∑ Sij ij==1, 1

Relative selectivity, μli , expressed as a function of length of fish, l , and mesh size, mi , is given by

αii(/)αβ−l i μαβli = (/lei i ) , where αi and βi are specified in terms of mi and l , and the length at maximum selectivity for gillnet i is proportional to mi such that

αiiβθ= 1m i where θ1 is a constant and the variance θ 2 is constant over different gillnets. These assumptions lead to a quadratic equation for positive βi such that

22 0.5 βθθθiii=−0.5( 11mm − ( + 4 2 ) ) . The catches, adjusted for differences in fishing effort among the various mesh sizes of the experimental gillnets and then rescaled back to the total number of sharks caught across all mesh‐sizes, were pooled into 100‐mm TL classes for each mesh‐size. Five families (four for the 1986–87 survey) of mesh selectivity curve were fitted to the midpoint of each length class for 1973–76, 1986–87, and 2007–08 surveys for mesh‐sizes 4, 5, 6, 7, and 8 inches.

Maximum likelihood estimates of θ 1 and θ 2 were made using the non‐linear optimisation routine in Microsoft Excel (‘Solver’) and 95% confidence intervals on these estimates were determined from bootstrapped datasets. The observed catches for each mesh size were randomly re‐sampled with replacement to generate 1500 bootstrapped datasets of catch such that for each mesh size the bootstrapped sample size was equivalent to observed number. The model was refitted to each bootstrapped dataset by maximising the likelihood function, using randomly starting values for parameters θ 1 and θ 2 . The mean of values of these parameters were calculated and the 95% confidence limits were determined from the 2.5 and 97.5 percentiles of these estimates (McAuley et al. 2007). Any model runs that failed to converge were excluded from these calculations.

GHATF shark survey 9

Although the method was originally designed to determine parameters for expressing relative selectivity as a function of length of shark and mesh size of gillnet, it is applied here to provide also parameters for expressing relative selectivity as a function of age of shark and mesh size. It is recognised that the adopted approach provides only approximate estimates of age‐frequency distribution of a population. Ideally, special models are required for correction of biases in age composition in the sample caused by application of an age‐length key. This is particularly relevant when determining estimates of mortality from cohorts; any bias in age distribution inevitably biases estimates of total mortality based on those distributions. To obtain the appropriate data to undertake this analysis for gummy shark and school shark, in the present survey, a sub‐sample of sharks caught in each mesh size was aged to provide an age‐length key for estimation of age‐frequency composition from length‐frequency composition for the entire catch of each mesh size.

Estimating total mortality Instantaneous total mortality, Z , was calculated from the percentage‐age‐frequency distribution of the population determined by gillnet age selectivity analysis. The method depends on the assumption that the whole population is in a steady state and that the age structure of the population is constant over time. The assumption can be restated that the decline in number in the standing population with increasing age is representative of the decay in number for any cohort of the population, declines exponentially from year to year through total mortality according to the equation

−Zt NNeat++1, 1 = at , where Na is the number in the population of age a years, Na+1 is the number in the population of age a +1 over the period t years. The parameter Z was determined as the gradient of the linear regression of ln(Na ) against a .

Results/Discussion

Sampling summary A summary of sampling conducted during the 2007–08 survey is presented in Table 1. Six different commercial vessels were used during 16 cruises for sampling at 48 sites and 187 stations (106 stations in South Australia, 60 in Bass Strait and 21 in Tasmania) at depths ranging 9–230 m. A summary of the number of individuals and number of species caught in the 00s survey is presented in Table 2. The catch comprised mostly chondrichthyes (18983 individuals of 43 species for the experimental nets and 16314 individuals of 42 species for the commercial nets) and teleosts (4116 individuals of 86 species for the experimental nets and 2840 individuals of 75 species for the commercial nets). Cephalopods, gastropods, bivalves, crinoids, crustaceans, echinoderms, seabirds, and marine mammals were caught in lower numbers. No other taxonomic groups were caught. The total number, catch rate and mesh size effect for each species caught in the 00s survey is presented in Table 3. Overall, the 4–8‐inch mesh‐sized gillnets had much higher catch rates of chondrichthyans than of any other taxonomic group. For chondrichthyans and teleosts, catch rate declined with mesh size. The catch rates varied widely, with three species—gummy shark (32%), spikey spurdog (Squalus megalops) (30%) and school shark (15%)—accounting for more than three quarters of the chondrichthyans caught. Draughtboard shark (Cephaloscyllium laticeps) (8%), Port Jackson shark (Heterodontus portusjacksoni) (5%), and common sawshark (Pristiophorus cirratus) (4%), accounted for most of the rest of the chondrichthyans caught. The catches of teleosts also varied widely among species, where jackass morwong (Nemadactylus macropterus) (17%), blue warehou (Seriolella brama) (15%) and bight redfish (Centroberyx gerrardi) (12%) accounted for almost half those caught.

GHATF shark survey 10

The effect of mesh size was statistically significant for many of the species caught (Table 3). For chondrichthyans and teleosts showing a mesh‐size effect on catch rates and non‐zero catches in any of the mesh sizes, a pattern of a highest catch (mode) for a particular mesh size was observed. For chondrichthyans, the modal catch corresponded to 4‐inch mesh for spikey spurdog and southern sawshark (Pristiophorus nudipinnis); 5‐inch mesh for gummy shark and common sawshark; 6‐inch mesh for whiskery shark (Furgaleus macki) and elephant fish; 7‐inch mesh for school shark, draughtboard shark, broadnose sevengill shark, and bronze whaler (Carcharhinus brachyurus); and 8‐inch mesh for Port Jackson shark and Australian angelshark (Squatina australis). For teleosts, the modal catch corresponded to 4‐inch mesh for bight redfish, barracouta (Thyrsites atun), tiger flathead (Neoplatycephalus richardsoni), red gurnard (Chelidonichthys kumu); 4‐ and 5‐inch mesh for latchet (Pterygotrigla polyommata); 5‐inch mesh for jackass morwong; 6‐inch mesh for blue morwong (Nemadactylus valenciennesi), knifejaw (Oplegnathus woodwardi) and longsnout boarfish (Pentaceropsis recurvirostris); and 6‐ and 7‐inch mesh for snapper (Pagrus auratus). Most species showing no mesh‐size effect had small sample sizes (Table 3), such that the small sample size had insufficient statistical power to detect differences in catch rates among the mesh sizes. For blue warehou and blue mackerel (Scomber australasicus), however, no mesh‐size effect was detected, despite relatively large sample sizes. This was probably due to the high dispersion about the mean catch rate estimates for these species.

Catch rate comparisons The catch rate comparisons among surveys are presented in Table 4 for commercial species and in Table 5 for bycatch species. The mean catch rates of the different surveys used in the comparisons are presented in Appendix 2 for commercial species and Appendix 3 for bycatch species. Overall, the r2 values for the comparisons of commercial and bycatch species were low (<0.60) (with the exception of the gummy shark and school shark comparisons for the 6‐ and 7‐, and 6‐inch mesh, respectively, in the fuzzy region ‘Western Bass Strait’). This indicates that, rather than survey period, the differences in catch rates are mostly attributed to factors other than those included in the model (e.g. spatial heterogeneity within the defined regions and fuzzy regions adopted for the analyses). Also, because of the various surveys had different objectives, many analyses were done using unbalanced (non‐orthogonal) data. For some of the comparisons, only one station was sampled in a particular defined region or fuzzy region in the previous surveys (e.g. ‘Great Australian Bight Inshore’ for the 80s) and the statistical model could not detect significant differences in catch rate even when the mean catch rates of the 00s were much larger than those of the 80s (e.g. catch rates of school sharks taken in the 5‐ 6‐ and 8‐inch mesh‐size gillnets). This must be considered for the interpretation of the among‐survey comparisons reported below.

Commercial species For commercial species, data were selected for analysis within the fuzzy and defined regions and zones. Comparisons were made for each mesh size of gillnets between the 80s and 00s surveys for the defined region and defined zone analyses, and among the 70s, 80s and 00s for the fuzzy region and fuzzy zone analyses. For the six fuzzy regions located in South Australia, there was no information collected during the 70s and only limited data for 6‐inch or 6½‐inch mesh during the 90s (Table 4, Appendix 2). Hence, for these regions, comparisons were made only between the 80s and 00s. Fuzzy regions Significant differences in the catch rate of one or more commercial species between the 80s and 00s were found for all eight fuzzy regions except ‘Streaky and Venus Bay’ (Table 4, Appendix 2). • ‘Great Australian Bight Offshore’ had a significant increase in the catch rate of gummy sharks taken in the 5‐ and 7‐inch mesh and a significant decrease in the catch rate of school sharks taken in the 5‐ and 8‐inch mesh between the 80s and the 00s.

GHATF shark survey 11

• ‘Great Australian Bight Inshore’ had a significant increase in the catch rate of school sharks for 7‐inch mesh between the 80s and the 00s. • ‘Streaky and Venus Bay’ had no significant changes in catch rates for any species between the 80s and the 00s. • ‘South Australia Shelf’ had a significant increase in the catch rate of gummy sharks taken in the 6‐ and 7‐inch mesh between the 80s and the 00s. • ‘Eyre Peninsula’ had a significant increase in the catch rate of gummy sharks, school sharks, and elephant fish taken in the 6‐, 8‐ andh 6‐inc mesh, respectively, between the 80s and the 00s. • ‘Cape Jaffa’ had a significant decrease in the catch rate of gummy sharks taken in the 5‐inch mesh and a significant increase in the catch rate of school sharks taken in the 7‐inch mesh between the 80s and the 00s. • ‘Western Bass Strait’ had significant changes in catch rate for all species. Gummy shark catch rates for 6‐ and 7‐inch mesh were significantly higher during 70s than 80s, 90s and 00s. School shark catch rates for 5‐, 6‐, 7‐ and 8‐inch mesh were significantly higher during 00s than 70s, 80s and 90s. Southern sawshark catch rates for 6‐inch mesh were significantly higher during 80s and 90s than 70s and 00s. Common sawshark catch rates for 5‐inch mesh during the 80s and for 6‐inch mesh during the 70s were significantly higher than during the other survey periods. Elephant fish catch rates for 6‐ and 7‐inch mesh were significantly higher during 70s than 80s, 90s and 00s. • ‘Eastern Bass Strait’ had significant changes in catch rates for all species. Gummy shark catch rates for 5‐, 6‐, 7‐ and 8‐inch mesh were significantly higher during 00s than 70s, 80s and 90s. School shark catch rates for 6‐inch mesh were significantly higher during 70s than 80s, 90s and 00s. Southern sawshark and common sawshark catch rates for 6‐inch mesh were significantly higher during 70s and 00s than 80s dan 90s. Elephant fish catch rates for 6‐inch mesh were significantly higher during 70s than 80s, 90s and 00s. Fuzzy zones Significant differences in the catch rate of some of the commercial species were also found for the fuzzy zones (Table 4, Appendix 2). • ‘South Australia’ had a significant increases in the gummy shark catch rate and school shark catch rate for 7‐inch mesh and in elephant fish catch rate for 6‐inch mesh between the 80s and the 00s. • ‘Bass Strait’ had significant changes in catch rate for all commercial species. Gummy shark catch rates were significantly higher for 5‐inch mesh during 00s than 70s, 80s, and 90s, for 8‐inch mesh during 70s than 80s, 90s and 00s, and for 6‐ and 7‐inch mesh during 70s and 00s than 80s and 90s.

GHATF shark survey 12

School sharks catch rates for 6‐, 7‐ and 8‐inch mesh were significantly higher in during 00s than 70s, 80s, and 90s.

Southern sawshark catch rates for 6‐inch mesh were significantly higher during 70s and 00s than 80s and 90s.

Common sawshark catch rates for 6‐inch mesh were significantly higher during 70s than 80s, 90s, and 00s.

Elephant fish catch rates for 7‐inch mesh were significantly higher during 70s than 80s, 90s, and 00s.

Defined regions and defined zones Overall, the pattern of significant differences in the catch rates for the commercial species in the defined regions dan defined zones was similar to the pattern differences found for the fuzzy‐region and fuzzy‐ zone comparisons (Table 4, Appendix 2). Differences in the pattern are listed as follows. • ‘South Australia Shelf’ defined region had a significant increase in the gummy shark catch rate for 7‐ inch mesh and a significant decrease in the school shark catch rate for 8‐inch mesh between the 80s and 00s. • ‘Eyre Peninsula’ defined region had a significant increase in the gummy shark catch rate for 6‐, 7‐ and 8‐inch mesh between the 80s and 00s. • ‘Western Bass Strait’ defined region had a significant increase in gummy shark and elephant fish catch rates for 6‐inch mesh and in school shark catch rate for 5‐, 6‐, 7‐ and 8‐inch mesh between the 80s and 00s. • ‘Eastern Bass Strait’ defined region had a significant increase in the gummy shark catch rate for 5‐, 6‐ and 7‐inch mesh, a significant decrease in the school shark catch rate of for 7‐inch mesh, and a significant increase in southern sawshark catch rate for 6‐inch mesh between the 80s and 00s. • ‘South Australia’ defined zone had a significant increase in the school shark catch rate for 7‐inch mesh between the 80s and 00s. • ‘Bass Strait’ defined zone had a significant increase in the gummy shark catch rate for 5‐, 6‐ and 7‐ inch mesh and in the school shark catch rate for 6‐inch mesh between the 80s and the 00s.

Bycatch species For bycatch species, comparisons could only be made for fuzzy regions and fuzzy zones in Bass Strait. Comparisons were made between the 70s and 00s for the 4–8 inch mesh gillnets. Comparisons among the 70s, 90s and 00s could only be made for the 6‐inch mesh gillnet. Only species showing a significant change in catch rates are presented in Table 5. All other species showed no significant differences in catch rates between pairs of survey periods. For most species the r2 values were <0.10, indicating very little (i.e. <10%) of the between‐survey variability in catch rate is explained by the survey‐period factor. Hence, for these species the power to detect changes in catch rates between surveys is very low; possible changes may be detected in future surveys with increased power, if future surveys adopt the same sites as the 2007–08 survey. Fuzzy regions Significant differences in the catch rate of some of the bycatch species were found for the two fuzzy regions analysed (Table 5, Appendix 3). • ‘Western Bass Strait’. Broadnose sevengill shark catch rates for 5‐ and h6‐inc mesh were significantly higher during the 00s than 70s and 90s.

GHATF shark survey 13

Spikey spurdog catch rates for 6‐ and 8‐inch mesh were significantly higher during the 90s and 70s, respectively, than in the 00s. Catch rates for Port Jackson sharks (6‐inch mesh), all chondrichthyan species combined (all mesh sizes), and all teleost species combined (5‐inch mesh) were significantly higher during sthe 70 than 90s and 00s. • ‘Eastern Bass Strait’. Broadnose sevengill shark catch rates for 6‐, 7‐ and 8‐inch mesh were significantly higher during the 00s than 70s and 90s. Draughtboard sharks catch rates for 6‐inch mesh were significantly higher during the 00s and 70s than 90s, and the catch rates for 8‐inch mesh were significantly higher during the 00s than 70s. Port Jackson shark catch rates for 6‐inch mesh were significantly higher during the 70s than 90s and 00s. Catch rates for all chondrichthyan species combined (all mesh sizes) were significantly higher during the s00 than 70s and 90s. Catch rates for longsnout boarfish (6‐inch mesh) and all teleost species combined (4‐inch mesh) were significantly higher during the 70s than 90s and 00s. Fuzzy zones Significant differences in the catch rate of some of the bycatch species were found for the two fuzzy zones (Table 5, Appendix 3). • Bass Strait. Broadnose sevengill shark catch rates for 5‐, 6‐, 7‐ and 8‐inch mesh were significantly higher during the 00s than 70s and 90s. Draughtboard shark catch rates for 6‐inch mesh were significantly higher during the 00s and 70s than 90s. Port Jackson shark catch rate for 6‐inch mesh was significantly higher during the 70s than 90s and 00s. Catch rates of chondrichthyan species combined for 4‐, 5‐ and 8‐inch mesh were significantly higher during the 00s than 70s, for 6‐inch mesh were significantly higher during thes 00 and 70s than 90s, and for 7‐inch mesh gillnet were significantly higher during the 70s than 00s. Longsnout boarfish catch rates for 6‐inch mesh were significantly higher during the 70s than 90s and 00s. Catch rates for sand flathead (Platycephalus bassensis) (5‐inch mesh) and teleost species combined (4‐ and 5‐inch mesh) were significantly higher during the 70s than 00s

Size‐frequency composition of the catch The size‐frequency distribution of the catch of each species in the experimental nets in the 00s survey is presented in Table 6. For commercial species, a breakdown of the size‐frequency distribution of males and females separately by experimental mesh‐size is presented in Figure 1. For all species, the larger mesh‐size gillnets caught larger individuals. For male and female gummy shark, the combined‐mesh the length‐frequency distribution ranged from 500 to 1900 and from 600 to 1800 mm TL, respectively. The highest catches of male and female gummy shark were taken by the 5‐ and 4‐inch mesh‐size gillnets (mean size, s.e. and mode: 936 ±5, 900 mm TL, 5 inch and 736 ±4, 700 mm TL, 4 inch for males; 922 ±4, 900 mm TL, 5 inch and 736 ±4, 700 mm TL, 4 inch for females). For male and female school shark, the combined‐meshh the lengt ‐frequency distribution ranged from 500 to 1700 and from 600 to 1800 mm TL, respectively. The highest catches of male and female school shark were taken by the 7‐ and 8‐inch mesh‐ size gillnets (1379 ±7, 1500 mm TL, 7 inch and 1415 ±7, 1500 mm TL, 8 inch for males; 1357 ±6, 1500 mm

GHATF shark survey 14

TL, 7 inch and 1407 ±5, 1500 mm TL, 8 inch for females). For male and female southern sawshark, the combined‐mesh length‐frequency distribution ranged from 700 to 1100 and from 700 to 1400 mm TL, respectively. The highest catches of male and female southern sawshark were taken by the 4‐ and 5‐inch mesh‐size gillnets (934 ±7, 1000 mm TL, 4 inch and 963 ±9, 1000 mm TL, 5 inch for males; 932 ±14, 1000 mm TL, 4 inch and 1009 ±20, 1100 mm TL, 5 inch for females). For male and female common sawshark, the combined‐mesh length‐frequency distribution ranged from 800 to 1400 and from 600 to 1600 mm TL, respectively. The highest catches of male and female common sawshark were taken by the 5‐ and 4‐inch mesh‐size gillnets (1035 ±7, 1100 mm TL, 5 inch and 995 ±6, 1000 mm TL, 4 inch for males; 1130 ±14, 1100 mm TL, 5 inch and 1084 ±18, 1300 mm TL, 4 inch for females). For male and female elephant fish, the combined‐mesh length‐frequency distribution ranged from 500 to 900 and from 500 to 1000 mm TL, respectively. The highest catches of male and female elephant fish were taken by the 6‐ and 5‐inch mesh‐ size gillnets (641 ±44, 600 mm TL, 6 inch and 668 ±31, 800 mm TL, 5 inch for males; 697 ±14, 700 mm TL, 6 inch and 661 ±37, 600 mm TL, 5 inch for females).

Retained and discarded species A summary of the percentages of retained and discarded individuals by mesh size is presented in Table 7. The number of discarded individuals and discarded species decreased with gillnet mesh size. For the 4‐ and 5‐inch mesh‐size gillnets, spikey spurdog was by far the most discarded species. For 6‐ and 7‐inch mesh‐size gillnets, draughtboard shark was the most discarded species, followed by Port Jackson shark, whereas for 8‐inch mesh‐size gillnet, Port Jackson shark was the most discarded species, followed by draughtboard shark. The percentages of retained and discarded individuals of the species caught by the experimental nets in the 00s survey are presented in Table 8. For chondrichthyans, there was a decline in the percentage of discarded individuals with increased mesh‐size; most individuals caught in the 4‐inch mesh gillnet were discarded, whereas most individuals caught in the 6‐, 7‐ and 8‐inch mesh gillnets were retained. For teleosts, the 4‐inch and 5‐inch mesh gillnets had the highest and lowest percent of discarded individuals, respectively. For the other taxonomic groups caught by the different mesh sizes, most individuals were discarded.

Post‐capture mortality The post‐capture mortality (PCM) of the chondrichthyan and teleost species caught in the 00s survey is presented in Table 9. For chondrichthyans, thresher shark (Alopias vulpinus), elephant fish, school shark, smooth hammerhead (Sphyrna zygaena), and whiskery shark had high (>0.66) immediate PCM. No chondrichthyan species had high delayed dPCM an broadnose sevengill shark, bronze whaler, school shark, smooth hammerhead, green‐eyed spurdog (Squalus chloroculus), Ogilbyʹs ghostshark (Hydrolagus ogilbyi), whiskery shark, and shortfin mako (Isurus oxyrinchus) had medium (0.33–0.66) delayed PCM. The most commonly discarded species (spikey spurdog, draughtboard shark and Port Jackson shark) had low‐medium and low delayed PCM. For teleosts, blue warehou, dusky morwong (Dactylophora nigricans), silver drummer (Kyphosus sydneyanus), red gurnard, barracouta, and mulloway (Argyrosomus japonicus) had low‐medium PCM. No teleost species had high delayed PCM and snapper, silver dory (Cyttus australis), western blue groper (Achoerodus gouldii), southern bluespotted flathead (Platycephalus speculator), and western Australian salmon (Arripis truttaceus) had medium delayed PCM.

Age‐frequency composition of the catch For gummy shark, of 999 vertebrae aged, 971 could be used for age determination, the remainder were unreadable. Between‐reader precision was high (mean APEI = 8%). For school shark, of 957 vertebrae aged, 833 could be used for age determination, the remainder were unreadable. Between‐reader precision was high (mean EIAP = 6%). The age‐frequency composition of gummy and school sharks caught by experimental nets in the 00s survey is presented in Figure 2. For gummy shark, the combined‐mesh age‐ frequency composition ranged from 1 to 14 years for males and from 1 to 16 years for females with a

GHATF shark survey 15

mean age of 5.4 ±0.1 years and a mode of 6 years for both sexes. For school shark, the combined‐mesh age‐frequency composition ranged from 1 to 23 years for males and from 1 to 21 years for females with a mean age of 8.2 ±0.2 years and a mode of 7 years for males and a mean of 8.3 ±0.1 years and a mode of 7 years for females.

Wildlife interactions The type and percentages of wildlife interactions recorded in the 00s survey are presented in Figure 3. Three types of wildlife interactions were recorded. The ‘bird flying, contact with vessel or gear’ and ‘wildlife diving and feeding on discards’ interactions were recorded at 51 stations whereas the ‘wildlife entangled in nets’ interaction was recorded in 187 stations (i.e. full survey coverage). A total of 84 interactions were recorded with ‘wildlife diving and feeding on discards’ (mostly seabirds including albatrosses and shearwaters) being the most common interaction (79% of interactions). For gillnet entanglements (7% of interactions), 3 white sharks (Carcharodon carcharias), 2 short‐tailed shearwater (Puffinus tenuirostris), 1 unidentified seal, 1 bottlenose dolphin (Tursiops truncatus), and 2 common dolphins (Delphinus delphis) were caught in the commercial nets whereas 1 Indian Ocean bottlenose dolphin (T. aduncus) was caught in the 5‐inch mesh, 1 unidentified seal was caught in the 7‐inch mesh, and 1 cape petrel (Daption capense), 1 Australian fur‐seal (Arctocephalus pusillus doriferus), and 1 unidentified seal were caught in the 8‐inch mesh (Table 10). The entanglements of white sharks and short‐tailed shearwaters occurred in South Australia. The entanglement of cape petrel, bottlenose dolphin and Australian fur‐seal occurred in Bass Strait. The entanglement of unidentified seals occurred in both South Australia and Bass Strait. The cape petrel and one of the short‐tailed shearwaters were released ‘alive strong’. The white sharks dropped out from the nets before reaching the deck so the released condition of these animals could not be assessed properly; one individual was observed as ‘alive strong’ and another individual as ‘alive weak’. The remainder of the tangled individuals reached the deck dead.

Carcass damage Carcass damage on commercial species is presented in Table 11. All commercial species showed very little damage with less than 4% of any of the species showing extensive damage.

Reproductive sampling The number of reproductive samples collected is presented in Table 12. A total of 1656 samples were collected for 16 chondrichthyan species. Reproductive sampling was done opportunistically and it was not done randomly. Instead, sampling was mostly targeted at mature individuals. Therefore, the per‐ station or per‐cruise proportion of individuals in the different maturity conditions could not be determined. Immature and maturing individuals were collected for all the commercial species but most of the assessed individuals were in mature condition and in different stages of gestation supporting the timing and stages of the reproductive cycle reported for school shark (Walker 2005), gummy shark (Walker 2007), and sawsharks and elephant fish (Walker and Hudson 2005). For school shark, it is worth noting that during cruise 6 (October–November 2007, Head of the Great Australian Bight), a school of large females caught were mostly mature and in different stages of gestation. Of the animals assessed (n=291), 13% were carrying eggs in utero, 1% were carrying near‐term embryos in utero, 82% showed the uteri as a uniformly enlarged tubular structure and largest ovarian follicles < 10 mm in diameter, and 4% showed the uteri as an enlarged tubular structure distended and irrigated and largest ovarian follicles > 10 mm in diameter.

Estimating size‐ and age‐structure of commercial shark populations Summaries of observed and predicted catches (adjusted for differences in fishing effort among mesh sizes), relative selectivity expressed as a function of length of shark and mesh size of gillnet for each mesh size, and parameter estimates are provided for gummy shark, school shark, common sawshark, southern sawshark, and elephant fish for the 2007–08 survey. In addition, similar summaries are provided for the gummy shark 1973–76 and 1986–87 surveys and for the school shark 1986–87 survey (Tables 13–20). For

GHATF shark survey 16

some species, one or more length classes were dropped from the analysis, which is indicated in the tables as ‘trimmed data’. Similar summaries of relative selectivity expressed as a function of age of shark and mesh size of gillnet for each mesh size, and parameter estimates are provided for gummy shark and school shark for the 1986–87 and 2007–08 surveys (Tables 21–28). Mostly, there was good agreement between the parameter estimates from the method providing a single solution using the survey data and the method providing a mean with 95% confidence limits using bootstrapped datasets. These results suggest that the survey coveredl al size classes and all age classes of gummy shark apart from the 0+‐year age‐class and, for females, part of the 1+‐year age‐class; however, the survey tended to cover the large size classes representatively, but not the small size classes of school shark, common sawshark, southern sawshark, and elephant fish. For gummy shark, all size classes were also well represented in the 1973–76 and 1986–87 surveys, and, for school shark, the small size classes were much better represented in the 1986–87 survey. This is partly explained by including special highly productive regions for school shark in the survey where the sharks tended to be large; however, excluding some of these regions from a summary provided very little difference, which suggests an absence of the young age classes overall. Total length (TL) and age at maximum relative selectivity of gummy shark for each mesh size were remarkably similar among the three survey periods (Table 29). For school shark, there was reasonably good agreement in TL at maximum relative selectivity between the 1986–87 and 2007–08 surveys, but not for age at maximum relative selectivity. Because of the 2007–08 results for school shark are different from the other results, the percentage‐age‐frequency distribution for each male and school sharks separately was determined for both periods by adapting the estimated percentage‐length‐frequency distribution using the von Bertalanffy growth function and by application of an age‐length key for the length‐at‐age from pooling data across all mesh sizes (Figure .4) This suggests that the selectivity analysis for each of male and female school shark overestimated the abundance of the oldest age classes. However, these converted distributions were considered too inaccurate to provide meaningful estimates of school shark mortality from the 2007–08 survey.

Estimating total mortality of gummy shark and school shark for each sex It was feasible to estimate total mortality, Z, for gummy shark for each of the 1986–87 and 2007–08 surveys, but only for the 1986–87 survey for school shark from the available age composition data. The survey appears to have sampled all age‐classes over the age of 1 year adequately for gummy shark, but not for school shark. Hence, because the lack of young age‐classes, it was not feasible to estimate Z for school shark for 2007–08. Estimates of Z could not be made for any other species because age composition of the catch was determined only for gummy shark and school shark (Table 30–35). For the 1986–87 survey, gummy shark estimates of Z made for ages 2–12 years of males (Z=0.629, ZSE=0.055, equivalent to 47% annual mortality) (Table 30) were similar to those made for ages 1–12 years of females (Z=0.512, ZSE=0.049, equivalent to 40% annual mortality) (Table 31). School shark estimates of Z for ages 2–13 years of males (Z=0.605, ZSE=0.070, equivalent to 45% annual mortality) (Table 32) were similar to estimates for ages 1–14 years of females (Z=0.532, ZSE=0.054, equivalent to 41% annual mortality) (Table 33). Similarly, for the 2007–08 survey, gummy shark estimates of Z made for ages 1–12 years of males (Z=0.453, ZSE=0.021, equivalent to 36% annually) (Table 34) were similar to those made for ages 2–12 years of females (Z=0.453, ZSE=0.021, equivalent to 35% annually) (Table 35). The reduction in total mortality for gummy shark from 1986–87 to 2007–08 is consistent with the reduced fishing effort between these periods. For both sexes of gummy shark, total mortality is higher for the young sharks than for older sharks (Table 36), which is consistent with, although it does not prove, assumptions adopted for modelling gummy shark stocks where natural mortality on juveniles is allowed to be density dependent and higher than that applied to the older animals. The differences in the 2007–08 age‐profiles between those shown for male school shark in Table 27 and female school shark in Table 28 and those shown in Figure 4 are different. Given the 2007–08 θ1 values

GHATF shark survey 17

appears uncertain (i.e. θ1 = 1.00 for every bootstrapped data set for both males and females) and are less than the 1986–87 values of θ1 of 1.29 for each of the males (Table 23) and females (Table 24), the abundance of the oldest age classes (~13–16 years) are likely to be overestimated. The gummy shark estimates indicate fishing mortality was about double natural mortality during 1986– 87, but was about equal to natural mortality during 2007–08. The school shark estimates indicate fishing mortality was about four times natural mortality during 1986–87, for age classes up to age 10 years, suggesting there must have been severe stock depletion during the 1980s. As a general rule, fishing mortality should not exceed natural mortality to maintain the biomass above the level required to produce the maximum sustainable yield.

Benefits / Management Outcomes This project meets the requirement to begin fishery‐independent monitoring of the Shark Gillnet Sector of the Gillnet Hook and Trap Fishery as prescribed by the Ministerial Direction to AFMA. It provides a basis for measuring bycatch levels, which are required to be reduced under the Ministerial Direction. Results from the survey feed into stock assessment processes, which urgently require indices of abundance for reliable update of assessment of the severely depleted school shark. Without good monitoring data it is not possible to determine whether school shark stocks are continuing to trend downwards, stabilise, or recover. Similarly, relative abundance indices are available for the target species (gummy shark), other byproduct species, and the bycatch species for use in stock assessment and ecosystem modelling.

Conclusion 1. The conduct of and quality of data from the 2007–08 survey completed under research quota demonstrates that it is feasible to adopt a fixed‐site fishery‐independent survey undertaken on commercial fishing vessels to provide most of the required monitoring data for the shark fishery. The five adopted mesh sizesr fo the survey fleet of gillnets provide data far superior to those that can be obtained by scientific observers on commercial fishing vessels using 6‐ or 6½‐inch mesh‐size or obtained from port sampling. Not only is it expected that catch rates from the present and any future surveys will provide indices of abundance more robust than fishers’ logbook data, the survey data provide direct measures of recruitment from the small mesh sizes and of surviving breeding stock from the large mesh sizes 2. The most significant cost of the survey over and above those for an onboard monitoring program is the cost for construction and maintenance of a fleet of gillnets. 3. Most difficulties conducting the survey related to the timing, which is dependent on weather conditions, availability of a suitable commercial vessel and skipper, and timely repair to the survey gillnets when damaged. 4. The 2007–08 survey catch comprised mostly species of chondrichthyes followed by teleostei; cephalopods, gastropods, bivalves, crinoids, crustaceans, and echinoderms were caught in low numbers. For chondrichthyes, gummy shark, spikey spurdog, and school shark accounted for more than three quarters of the chondrichthyan catch. For teleostei, jackass morwong, blue warehou, and bight redfish accounted for almost ehalf th teleost catch. Overall, there was a decline in the number of fish caught with increasing mesh size for both chondrichthyes and teleostei. 5. There was a significant effect of mesh size for many species caught; these species showed a pattern of a highest catch (mode) for a particular mesh size.

GHATF shark survey 18

6. The number of discarded individuals and species decreased with mesh size. 7. The most commonly discarded species (spikey spurdog, draughtboard shark and port jackson shark) have a very low post‐capture mortality probability. 8. Three types of wildlife interactions were recorded with ‘wildlife diving and feeding on discards’ being the most common interaction. 9. Post‐hoc analyses comparing information from the 2007–08 survey with the earlier surveys of 1973– 76, 1986–87, and 1998–01 indicate that many of fishing sites among the four survey periods did not overlap and hence reduced power for statistically robust comparisons, particularly for bycatch species. Nevertheless, for eth five main commercial species (gummy shark, school shark, southern sawshark, common sawshark, and elephant fish) in specific regions and zones there were significant differences in catch rate, based on data from selected sites that were considered spatially comparable. In South Australia, there were significant increases in the gummy shark catch rate and the school shark catch rate for 7‐inch mesh and in the elephant fish catch rate for 6‐inch mesh between the 1986– 87 survey and the 2007–08 survey. In Bass Strait, gummy shark recruitment during the 2007–08 survey improved since earlier surveys, but the abundance of large animals in the population was higher during the early phase of the gummy shark fishery. Catch rates for 6‐ and 7‐inch mesh were consistent with stock depletion during the 1980s and 1990s from the 1970s and subsequent recovery. School shark catch rates for 6‐, 7‐ and 8‐inch mesh were significantly higher during the 2007–08 survey than during the three earlier surveys, with the proviso that school shark were not adequately surveyed in Bass Strait during 1973–76 and there was a general absence of small fish during the 2007– 08 survey. Southern sawshark catch rates for 6‐inch mesh were significantly higher during 1970s and 2000s than during the 1980s and late 1990s. Common sawshark catch rates for 6‐inch mesh and elephant fish catch rates for 7‐inch mesh, on the other hand, were significantly higher during 1973–76 than the later surveys. The surveys also indicate that the abundance of the bycatch species of draughtboard shark and Port Jackson shark and the byproduct species broadnose sevengill shark recently increased. 10. Apart from the smallest size classes, all size classes of gummy shark were well represented in the survey catches. Small size classes of school shark, common sawshark, southern sawshark, and elephant fish, however, appear to be under‐represented at the sampling sites of the survey. This can be partly addressed by excluding special school shark regions from the analyses and minor adjustment to the sampling design. 11. Applying available length‐frequency and age‐frequency composition data from both the 1986–87 and 2007–08 surveys, total mortality estimates could be made for each of male and female gummy shark for both surveys, but only for the 1986–87 survey for school shark. Total mortality estimates could not be made for the 2007–08 survey, because of and increase in the number of sharks present with increasing age. There is a clear absence of young school sharks in the 2007–08 survey, but it is likely that the abundance of the ~13–16‐year age‐classes relative to the younger age classes are overestimated. 12. The gummy shark estimates of total mortality indicate fishing mortality was double natural mortality during 1986–87, but was about equal to natural mortality during 2007–08. 13. The school shark estimates of total mortality indicate fishing mortality was about four times natural mortality during 1986–87, for age classes <10 years, suggesting there must have been severe stock depletion during the 1980s.

GHATF shark survey 19

References

Davis, M. W. (2005). Behaviour impairment in captured and released sablefish: ecological consequences and possible substitute measures for delayed discard mortality. Journal of Fish Biology 66, 254–265. Kirkwood, G. P. and Walker, T. I. (1986). Gill net mesh selectivities for Gummy shark, Mustelus antarcticus Günther, taken in South‐eastern Australian Waters. Australian Journal of Marine and Freshwater Research 37, 689–697. McAuley, R. B., Simpfendorfer, C. A. and Wright, I. W. (2007). Gillnet mesh selectivity of the sandbar shark (Carcharhinus plumbeus): implications for fisheries management. ICES Journal of Marine Science 64, 1702–1709. Millar, R. B. (2000). Untangling the confusion surrounding gillnet selectivity. Canadian Journal of Fisheries and Aquatic Sciences 57, 507–511. Olsen, A. M. (1959). The status of the school shark fishery in south‐eastern Australian waters. Marine and Freshwater Research 10, 150–176. Punt, A. E., Walker, T. I. and Prince, J. D. (2002). Assessing the management‐related benefits of fixed‐ station fishery‐independent surveys in Australiaʹs Southern Shark Fishery. Fisheries Research 55, 281– 295. Rago, P. J. (2005). Fishery independent sampling: survey techniques and data analyses. In ʹManagement techniques for elasmobranch fisheriesʹ. (Eds J. A. Musick and R. Bonfil.) pp. 201–215. (FAO: Rome.) Walker, T. I. and Gason, A. S. (2005). GHATF monitoring database management 2004/05. Australian Fisheries Management Authority, Canberra, ACT, Australia, Final report for Project No R03/1383, Queenscliff, Victoria. Walker, T. I. and Hudson, R. J. (2005). Sawshark and elephant fish assessment and bycatch evaluation in the Southern Shark Fishery. Fisheries Research and Development Corporation, Project No 1999/103. Walker, T. I., Hudson, R. J. and Gason, A. S. (2005). Catch evaluation of target, by‐product and by‐catch species taken by gillnets and longlines in the shark fishery of south‐eastern Australia. Journal of Northwest Atlantic fishery science 35, 505–530. Walker, T. I., Moulton, P. L.,, Dow N. G. and Saddlier, S. R. (1989). Southern shark assessment project. Marine Science Laboratories, Final FIRTA report Queenscliff, Victoria.

GHATF shark survey 20

Table 1. Sampling summary for the 2007–08 survey Number of vessels, cruises, sites, stations, and depth range.

Region No. of No. of No. of No. of Depth vessels cruises sites stations range (m)

South Australia 2 8 28 106 9–230 Bass Strait 3 6 15 60 18–195 Tasmania 1 2 5 21 78–161

Total 6 16 48 187 9–230

GHATF shark survey 21

Table 2. Number of individuals and species caught during the 2007–08 survey Number of individuals and number of species caught in the experimental and commercial nets.

Taxonomic group Number of individuals Number of species Experimental Commercial Experimental Commercial

Chondrichthyes 18983 16314 43 42 Teleostei 4116 2840 86 75 Cephalopoda 26 6 3 2 Gastropoda 0 3 0 2 Bivalvia 1 0 1 0 Crinoidea 1 1 1 1 Crustacea 30 29 6 3 Aves 1 1 1 1 Mammalia 4 4 3 3 Echinoidea 1 0 1 0

Total 23163 19198 145 129

GHATF shark survey 22

Table 3. Number of individuals of each species caught during the 2007–08 survey Total number of individuals of each species caught by mesh‐size per 1000 km‐hour for the experimental nets used in the 2007–08 survey. P = probability for effect of mesh size; *P < 0.05, **P < 0.01, ***P < 0.001.

Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n P 4-inch 5-inch 6-inch 7-inch 8-inch

Fishing effort (km-hour) 783 811 799 802 783 Number of stations 187 187 187 187 187 Chondrichthyes Gummy shark Mustelus antarcticus 2259 (617) 2729 (476) 1732 (191) 835 (78) 380(49) 6010 .0000*** Piked spurdog Squalus megalops 5985 (940) 2458 (365) 359 (70) 92 (71) 21(10) 5655 .0000*** School shark Galeorhinus galeus 119 (20) 431 (64) 657 (107) 1015 (173) 922(144) 2814 .0000*** Draughtboard shark Cephaloscyllium laticeps 36 (10) 263 (82) 584 (97) 856 (141) 276(55) 1463 .0000*** Port Jackson shark Heterodontus portusjacksoni 27 (7) 112 (25) 334 (68) 255 (49) 383(127) 976 .0009*** Common sawshark Pristiophorus cirratus 315 (49) 356 (59) 180 (29) 126 (35) 71(14) 826 .0000*** Broadnose sevengill shark Notorynchus cepedianus 6 (3) 34 (8) 72 (16) 100 (19) 89(18) 247 .0000*** Southern sawshark Pristiophorus nudipinnis 149 (32) 95 (29) 43 (12) 3 (2) 2(2) 214 .0000*** Whitespotted dogfish Squalus acanthias 97 (33) 111 (43) 50 (26) 37 (29) 4(3) 154 .0667 Whiskery shark Furgaleus macki 14 (5) 28 (8) 41 (10) 35 (9) 12(6) 109 .0391* Bronze whaler Carcharhinus brachyurus 5 (2) 21 (6) 14 (6) 43 (10) 22(7) 101 .0022** Smooth hammerhead Sphyrna zygaena 6 (3) 34 (12) 15 (5) 16 (6) 18(6) 78 .0802 Elephant fish Callorhinchus milii 9 (5) 27 (9) 55 (14) 10 (5) 6(3) 76 .0001*** Rusty carpetshark Parascyllium ferrugineum 79 (16) 1 (1) 5 (4) 0 0 64 .0000*** Southern eagle ray Myliobatis australis 1 (1) 3 (2) 6 (3) 19 (7) 42(26) 53 .0947 Australian angelshark Squatina australis 2 (2) 7 (4) 7 (3) 25 (10) 26(7) 48 .0057** Sparsely-spotted stingaree Urolophus paucimaculatus 2 (2) 1 (1) 5 (3) 6 (3) 2(2) 13 .4914 Ogilby's ghostshark Hydrolagus ogilbyi 0 0 2 (2) 4 (3) 3(3) 9 .5249 Thresher shark Alopias vulpinus 0 5 (3) 2 (2) 3 (2) 0 7 .1278 Spotted wobbegong Orectolobus maculatus 0 2 (2) 3 (2) 1 (1) 3(2) 7 .6967

GHATF Green-eyed spurdog Squalus chloroculus 0 0 7 (7) 1 (1) 0 7 .4495 Shortfin mako Isurus oxyrinchus 0 2 (2) 2 (1) 1 (1) 2(2) 5 .8097 Varied catshark Parascyllium variolatum 6 (4) 0 0 0 0 5 .0346*

shark Green-backed stingaree Urolophus viridis 0 1 (1) 2 (2) 3 (2) 2(2) 5 .7055

survey 23

24 GHATF Table 3 (Number of individuals caught continued)

shark Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n P

4-inch 5-inch 6-inch 7-inch 8-inch survey Cobbler wobbegong Sutorectus tentaculatus 0 0 2 (2) 1 (1) 2(2) 4 .4933 Ornate angelshark Squatina tergocellata 0 0 0 0 5(2) 4 .0029**

Ornate wobbegong Orectolobus halei 0 0 1 (1) 1 (1) 0 3 .3655 Gulf catshark Asymbolus vincenti 5 (5) 0 0 0 0 3 .4066 Grey spotted catshark Asymbolus analis 7 (4) 0 0 0 0 3 .0217* Melbourne skate Dipturus whitleyi 0 1 (1) 0 1 (1) 1(1) 3 .7209 Western spotted catshark Asymbolus occiduus 3 (2) 0 0 0 0 2 .1180 Pencil shark Hypogaleus hyugaensis 2 (2) 0 0 1 (1) 0 2 .5412 Longnose skate Dipturus confusus 0 0 0 1 (1) 1(1) 2 .5552 Bluntnose sixgill shark Hexanchus griseus 0 0 1 (1) 0 0 1 .4066 Whitefined swell shark Cephaloscyllium albipinnus 0 0 0 1 (1) 0 1 .4066 Brier shark Deania calcea 0 0 0 0 1(1) 1 .4066 Southern dogfish Centrophorus zeehaani 0 0 0 0 2(2) 1 .4066 Western shovelnose ray Aptychotrema vincentiana 0 0 0 2 (2) 0 1 .4066 Skates Rajidae 0 0 0 0 1(1) 1 .4066 Peacock skate Pavoraja nitida 0 0 0 1 (1) 0 1 .4066 Sandyback stingaree Urolophus bucculentus 0 1 (1) 0 0 0 1 .4066 Banded stingaree Urolophus cruciatus 0 0 0 2 (2) 0 1 .4066 Western shovelnose stingaree Trygonoptera mucosa 0 0 0 1 (1) 0 1 .4066 Sub-total Chondrichthyes 9134 (1121) 6724 (622) 4182 (277) 3499 (272) 2300(215) 18983 .0000*** Teleostei Jackass morwong Nemadactylus macropterus 399 (91) 588 (157) 66 (23) 10 (4) 9(5) 683 .0000*** Blue warehou Seriolella brama 151 (69) 351 (172) 147 (127) 64 (43) 78(66) 598 .3247 Bight redfish Centroberyx gerrardi 266 (66) 187 (43) 126 (30) 59 (23) 37(12) 512 .0002*** Blue mackerel Scomber australasicus 210 (205) 1 (1) 0 44 (44) 0 244 .4423 Blue morwong Nemadactylus valenciennesi 11 (5) 46 (12) 91 (19) 50 (10) 26(10) 171 .0001*** Knifejaw Oplegnathus woodwardi 26 (12) 62 (17) 96 (36) 11 (6) 1(1) 167 .0017** Barracouta Thyrsites atun 285 (95) 8 (5) 4 (2) 6 (4) 3(3) 162 .0000*** Ocean jacket Nelusetta ayraudi 91 (25) 104 (34) 9 (5) 2 (2) 0 150 .0000*** Snapper Pagrus auratus 5 (3) 23 (8) 56 (13) 57 (13) 34(9) 144 .0008*** Longsnout boarfish Pentaceropsis recurvirostris 5 (3) 26 (7) 60 (11) 33 (7) 17(5) 115 .0000*** Tiger flathead Neoplatycephalus richardsoni 78 (21) 15 (7) 7 (3) 4 (2) 7(3) 81 .0000***

Table 3 (Number of individuals caught continued)

Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n P 4-inch 5-inch 6-inch 7-inch 8-inch Latchet Pterygotrigla polyommata 34 (9) 34 (12) 13 (5) 21 (8) 6(3) 75 .0483* Western australian salmon Arripis truttaceus 56 (54) 25 (18) 0 0 0 75 .4455 Silver dory Cyttus australis 11 (5) 40 (17) 28 (13) 15 (8) 8(3) 67 .1846 Red gurnard Chelidonichthys kumu 59 (17) 8 (3) 3 (2) 9 (5) 1(1) 63 .0000*** Leatherjackets Monacanthidae 42 (29) 30 (14) 1 (1) 0 0 63 .1075 Western blue groper Achoerodus gouldii 3 (2) 20 (7) 29 (14) 10 (4) 6(3) 51 .1032 Silver warehou Seriolella punctata 31 (14) 25 (15) 16 (13) 0 13(12) 49 .4272 Dusky morwong Dactylophora nigricans 3 (2) 13 (6) 21 (7) 7 (3) 7(4) 45 .0533 Pink ling Genypterus blacodes 29 (16) 34 (13) 6 (5) 0 2(2) 40 .0298* Striped trumpeter Latris lineata 2 (1) 4 (2) 35 (18) 14 (8) 0 40 .0258* Red cod Pseudophycis bachus 22 (8) 33 (13) 1 (1) 0 4(3) 35 .0016** Magpie perch Cheilodactylus nigripes 0 6 (3) 12 (5) 5 (2) 9(4) 30 .0952 Swallowtail Centroberyx lineatus 8 (4) 7 (5) 5 (4) 12 (12) 8(5) 29 .9628 Bearded rock cod Pseudophycis barbata 17 (7) 14 (6) 3 (2) 0 1(1) 26 .0068** Southern whiptail Caelorinchus australis 45 (14) 2 (2) 0 1 (1) 0 26 .0000*** Common gurnard perch Neosebastes scorpaenoides 27 (10) 5 (4) 0 0 1(1) 26 .0003*** Blackspot boarfish Zanclistius elevatus 1 (1) 2 (2) 10 (5) 8 (3) 8(4) 22 .1634 Deepwater flathead Neoplatycephalus conatus 13 (7) 15 (7) 3 (2) 1 (1) 1(1) 21 .0647 Sergeant baker Aulopus purpurissatus 25 (12) 0 3 (2) 0 0 20 .0026** Redfish Centroberyx affinis 19 (13) 1 (1) 1 (1) 1 (1) 0 18 .0999 Thetis fish Neosebastes thetidis 19 (9) 2 (2) 1 (1) 0 0 15 .0046** Flatheads Platycephalidae 18 (9) 0 0 5 (3) 0 15 .0122* Bluethroat wrasse Notolabrus tetricus 2 (2) 18 (9) 2 (2) 2 (2) 0 15 .0072** Speckled stargazer Kathetostoma canaster 0 5 (2) 3 (2) 5 (2) 5(3) 15 .4008 Giant boarfish Paristiopterus labiosus 0 1 (1) 6 (3) 5 (3) 5(4) 13 .3483 Gemfish Rexea solandri 27 (24) 6 (5) 0 0 0 13 .3184 Blue grenadier Macruronus novaezelandiae 0 13 (6) 1 (1) 0 6(5) 12 .0405* Silver trevally Pseudocaranx dentex 1 (1) 4 (3) 10 (10) 1 (1) 0 12 .5520 Moonlighter Vinculum sexfasciatum 0 5 (4) 5 (3) 2 (2) 2(2) 12 .5073

GHATF Sweep Scorpis lineolatus 3 (2) 7 (5) 2 (2) 0 0 11 .2470 Tusk Dannevigia tusca 5 (3) 7 (7) 1 (1) 0 1(1) 10 .5509 Reef ocean perch Helicolenus percoides 13 (5) 0 2 (2) 0 1(1) 10 .0008***

shark Mulloway Argyrosomus japonicus 1 (1) 3 (2) 1 (1) 3 (3) 2(1) 9 .9516

survey 25

26 GHATF Table 3 (Number of individuals caught continued)

shark Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n P

4-inch 5-inch 6-inch 7-inch 8-inch survey Silver drummer Kyphosus sydneyanus 1 (1) 0 8 (5) 0 0 8 .1249 Zebrafish Girella zebra 6 (5) 2 (2) 1 (1) 0 0 8 .3488

Yellowspotted boarfish Paristiopterus gallipavo 0 0 1 (1) 9 (3) 1(1) 8 .0021** Brownstriped leatherjacket Meuschenia australis 1 (1) 6 (4) 0 0 0 7 .0668 Gulf gurnard perch Neosebastes pantica 5 (4) 3 (2) 0 0 0 5 .2982 Bastard trumpeter Latridopsis forsteri 0 6 (3) 1 (1) 0 0 5 .0589 Parrotfishes Scaridae 1 (1) 0 5 (5) 0 0 5 .4753 Dusky flathead Platycephalus fuscus 7 (5) 0 0 0 0 4 .0896 Sea sweep Scorpis aequipinnis 1 (1) 0 5 (5) 0 0 4 .4844 Short boarfish Parazanclistius hutchinsi 0 1 (1) 1 (1) 1 (1) 1(1) 4 .8859 Sixspine leatherjacket Meuschenia freycineti 3 (2) 0 0 0 0 4 .1033 Hapuku Polyprion oxygeneios 0 2 (2) 1 (1) 1 (1) 0 3 .6870 Wrasses Labridae 4 (4) 0 0 0 0 3 .4066 Smoothspine leatherjacket Cantheschenia longipinnis 3 (2) 0 0 0 0 3 .0179* Butterfly gurnard Lepidotrigla vanessa 2 (2) 0 0 0 0 2 .1558 Toothy flathead Neoplatycephalus aurimaculatus 2 (1) 0 0 0 0 2 .0933 Southern bluespotted flathead Platycephalus speculator 1 (1) 1 (1) 0 0 0 2 .5570 Skipjack trevally Pseudocaranx wrighti 2 (2) 0 0 0 0 2 .4066 Butterfish Scatophagus sp. 0 1 (1) 1 (1) 0 0 2 .5573 Snook Sphyraena novaehollandiae 2 (1) 0 0 0 0 2 .1020 Rosy wrasse Pseudolabrus psittaculus 3 (2) 0 0 0 0 2 .1005 Rock ling Genypterus tigerinus 0 0 0 2 (2) 0 1 .4066 Mirror dory Zenopsis nebulosus 0 0 0 0 1(1) 1 .4066 Pipefishes Syngnathidae 0 0 0 1 (1) 0 1 .4066 Scorpionfishes Sebastidae 1 (1) 0 0 0 0 1 .4066 Sand flathead Platycephalus bassensis 1 (1) 0 0 0 0 1 .4066 Harlequin fish Othos dentex 1 (1) 0 0 0 0 1 .4066 King george whiting Sillaginodes punctata 2 (2) 0 0 0 0 1 .4066 Samsonfish Seriola hippos 0 0 1 (1) 0 0 1 .4066 White trevally Pseudocaranx georgianus 0 0 1 (1) 0 0 1 .4066 Rusty Jobfish Aphareus rutilans 0 1 (1) 0 0 0 1 .4066 Bluespotted goatfish Upeneichthys vlamingii 1 (1) 0 0 0 0 1 .4066 Bigscale bullseye Pempheris multiradiatus 2 (2) 0 0 0 0 1 .4066

Table 3 (Number of individuals caught continued)

Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n P 4-inch 5-inch 6-inch 7-inch 8-inch Old wife Enoplosus armatus 1 (1) 0 0 0 0 1 .4066 Rock cale Crinodus lophodon 0 1 (1) 0 0 0 1 .4066 Banded morwong Cheilodactylus spectabilis 0 0 0 0 1(1) 1 .4066 Foxfish Bodianus frenchii 0 0 0 1 (1) 0 1 .4066 Southern bluefin tuna Thunnus maccoyii 0 2 (2) 0 0 0 1 .4066 Blue-eye trevalla Hyperoglyphe antarctica 2 (2) 0 0 0 0 1 .4066 Toothbrush leatherjacket Acanthaluteres vittiger 1 (1) 0 0 0 0 1 .4066 Velvet leatherjacket Meuschenia scaber 0 0 1 (1) 0 0 1 .4066 Starry toadfish Arothron firmamentum 0 2 (2) 0 0 0 1 .4066 Sub-total Teleostei 2121 (298) 1826 (256) 916 (152) 481 (86) 312(75) 4116 .0000*** Crustacea Southern rocklobster Jasus edwardsii 0 8 (6) 6 (3) 0 5(2) 17 .2906 Crabs undiferentiated crab 0 3 (3) 9 (6) 1 (1) 0 8 .2126 Spider crabs Homolidae 0 0 0 0 3(3) 2 .4066 Anomurans Anomura 0 0 1 (1) 0 0 1 .4066 King crabs Lithodidae 0 0 0 0 1(1) 1 .4066 Giant crab Pseudocarcinus gigas 0 0 1 (1) 0 0 1 .4066 Sub-total Crustacea 0 11 (7) 17 (7) 1 (1) 9(4) 30 .0730

Cephalopoda Gould squid Nototodarus gouldi 30 (10) 0 1 (1) 0 0 22 .0000*** Octopuses Octopoda 1 (1) 0 0 0 4(3) 3 .2736 Squid Eucleoteuthis luminosa 2 (2) 0 0 0 0 1 .4066 Sub-total Cephalopoda 32 (10) 0 1 (1) 0 4(3) 26 .0000***

Bivalvia Scallops Pectinidae 0 0 1 (1) 0 0 1 .4066 Sub-total Bivalvia 0 0 1 (1) 0 0 1 .4066

Echinoidea Sea urchins Echinoidea 0 1 (1) 0 0 0 1 .4066 Sub-total Echinoidea 0 1 (1) 0 0 0 1 .4066 GHATF Crinoidea Crinoids Crinoidea 0 0 2 (2) 0 0 1 .4066

shark Sub-total Crinoidea 0 0 2 (2) 0 0 1 .4066

survey 27

28 GHATF

Table 4. Between‐survey comparisons of the number of individuals of commercial species shark A) ‘Fuzzy analysis’ and B) ‘defined analysis’, comparing the number of individuals for each commercial species caught per 1000 km‐hour by 5–8‐inch mesh

survey gillnets during the 1973–76 (70s), 1986–87 (80s), 1998–01 (90s), and 2007–08 (00s) surveys, where all four surveys are included in the ‘fuzzy analysis’, but only the s80s and 00 surveys are included in the ‘defined analysis’; r2, correlation coefficient squared; P, probability of differences; *P < 0.05, **P < 0.01, ***P < 0.001;

—, insufficient data. A) Region Fuzzy region: Great Australian Bight Offshore Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.219 0.003** —————— 6‐inch 0.023 0.357 —————— 7‐inch 0.196 0.005** —————— 8‐inch 0.010 0.542 ——————

School shark Galeorhinus galeus 5‐inch 0.146 0.016* —————— 6‐inch 0.091 0.062 —————— 7‐inch 0.054 0.154 —————— 8‐inch 0.148 0.015* —————— Southern sawshark Pristiophorus nudipinnis 5‐inch 0.015 0.453 —————— 6‐inch 0.053 0.160 —————— 7‐inch ———————— 8‐inch ————————

Common sawshark Pristiophorus cirratus 5‐inch 0.047 0.187 —————— 6‐inch 0.026 0.327 —————— 7‐inch 0.004 0.688 —————— 8‐inch 0.004 0.704 ——————

Elephant fish Callorhinchus milii 5‐inch 0.013 0.487 —————— 6‐inch ———————— 7‐inch ———————— 8‐inch ————————

Table 4 (Commercial species ‘fuzzy region analysis’ continued)

Fuzzy region: Great Australian Bight Inshore Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.133 0.165 —————— 6‐inch 0.220 0.067 —————— 7‐inch 0.104 0.224 —————— 8‐inch 0.139 0.156 ——————

School shark Galeorhinus galeus 5‐inch 0.202 0.081 —————— 6‐inch 0.207 0.076 —————— 7‐inch 0.268 0.040* —————— 8‐inch 0.215 0.071 —————— Southern sawshark Pristiophorus nudipinnis 5‐inch —— — — — — — — 6‐inch —— — — — — — — 7‐inch —— — — — — — — 8‐inch —— — — — — — —

Common sawshark Pristiophorus cirratus 5‐inch 0.186 0.096 —————— 6‐inch —— — — — — — — 7‐inch —— — — — — — — 8‐inch —— — — — — — —

Elephant fish Callorhinchus milii 5‐inch —— — — — — — — 6‐inch —— — — — — — — 7‐inch —— — — — — — — 8‐inch —— — — — — — — GHATF

shark

survey 29

30 GHATF

Table 4 (Commercial species ‘fuzzy region analysis’ continued)

shark

Fuzzy region: Streaky Bay and Venus Bay

survey Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons

size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.025 0.546 —————— 6‐inch 0.000 0.980 —————— 7‐inch 0.013 0.660 —————— 8‐inch 0.004 0.802 ——————

School shark Galeorhinus galeus 5‐inch 0.070 0.304 —————— 6‐inch 0.070 0.304 —————— 7‐inch 0.000 0.991 —————— 8‐inch 0.070 0.304 ——————

Southern sawshark Pristiophorus nudipinnis 5‐inch —— — — — — — — 6‐inch —— — — — — — — 7‐inch —— — — — — — — 8‐inch —— — — — — — —

Common sawshark Pristiophorus cirratus 5‐inch —— — — — — — — 6‐inch —— — — — — — — 7‐inch —— — — — — — — 8‐inch —— — — — — — —

Elephant fish Callorhinchus milii 5‐inch —— — — — — — — 6‐inch —— — — — — — — 7‐inch —— — — — — — — 8‐inch 0.056 0.362 ——————

Table 4 (Commercial species ‘fuzzy region analysis’ continued)

Fuzzy region: South Australia Shelf Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.086 0.116 —————— 6‐inch 0.163 0.027* —————— 7‐inch 0.185 0.018* —————— 8‐inch 0.064 0.176 ——————

School shark Galeorhinus galeus 5‐inch 0.055 0.213 —————— 6‐inch 0.035 0.320 —————— 7‐inch 0.057 0.205 —————— 8‐inch 0.115 0.067 ——————

Southern sawshark Pristiophorus nudipinnis 5‐inch 0.069 0.161 —————— 6‐inch —— — — — — — — 7‐inch 0.017 0.489 —————— 8‐inch 0.069 0.161 ——————

Common sawshark Pristiophorus cirratus 5‐inch 0.044 0.269 —————— 6‐inch 0.000 0.974 —————— 7‐inch 0.010 0.593 —————— 8‐inch 0.006 0.673 ——————

Elephant fish Callorhinchus milii 5‐inch 0.017 0.489 —————— 6‐inch 0.017 0.489 —————— 7‐inch —— — — — — — — 8‐inch —— — — — — — — GHATF

shark

survey 31

32 GHATF

Table 4 (Commercial species ‘fuzzy region analysis’ continued)

shark

Fuzzy region: Eyre Peninsula

survey Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons

size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.225 0.055 —————— 6‐inch 0.292 0.025* —————— 7‐inch 0.222 0.056 —————— 8‐inch 0.054 0.371 ——————

School shark Galeorhinus galeus 5‐inch 0.026 0.539 —————— 6‐inch 0.029 0.515 —————— 7‐inch 0.099 0.219 —————— 8‐inch 0.247 0.043* ——————

Southern sawshark Pristiophorus nudipinnis 5‐inch 0.111 0.192 —————— 6‐inch 0.000 0.961 —————— 7‐inch 0.044 0.420 —————— 8 ‐inch —— — — — — — —

Common sawshark Pristiophorus cirratus 5‐inch 0.009 0.719 —————— 6‐inch 0.044 0.420 —————— 7‐inch 0.044 0.420 —————— 8‐inch —— — — — — — —

Elephant fish Callorhinchus milii 5‐inch 0.001 0.924 —————— 6‐inch 0.290 0.026* —————— 7‐inch 0.044 0.420 —————— 8‐inch —— — — — — — —

Table 4 (Commercial species ‘fuzzy region analysis’ continued)

Fuzzy region: Cape Jaffa Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.313 0.047* —————— 6‐inch 0.122 0.241 —————— 7‐inch 0.002 0.885 —————— 8‐inch 0.290 0.058 ——————

School shark Galeorhinus galeus 5‐inch 0.250 0.082 —————— 6‐inch 0.088 0.325 —————— 7‐inch 0.311 0.048* —————— 8‐inch 0.046 0.481 ——————

Southern sawshark Pristiophorus nudipinnis 5‐inch —— — — — — — — 6‐inch 0.037 0.529 —————— 7‐inch —— — — — — — — 8‐inch 0.081 0.347 ——————

Common sawshark Pristiophorus cirratus 5‐inch 0.130 0.226 —————— 6‐inch 0.124 0.238 —————— 7‐inch 0.037 0.529 —————— 8‐inch 0.081 0.347 ——————

Elephant fish Callorhinchus milii 5‐inch —— — — — — — — 6‐inch —— — — — — — — 7‐inch —— — — — — — — 8‐inch —— — — — — — — GHATF

shark

survey 33

34 GHATF

Table 4 (Commercial species ‘fuzzy region analysis’ continued)

shark

Fuzzy region: Western Bass Strait

survey Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons

size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.056 0.562 0.872 — 1.000 — 1.000 — 6‐inch 0.765 <.001*** <.001*** <.001*** <.001*** 1.000 0.118 0.144 7‐inch 0.665 <.001*** <.001*** — <.001*** — 1.000 — 8‐inch 0.124 0.324 0.420 — 0.742 — 1.000 —

School shark Galeorhinus galeus 5‐inch 0.396 0.007** 1.000 — 0.024* — 0.009** — 6‐inch 0.624 <.001*** 0.950 0.661 0.003** 1.000 <.001*** <.001*** 7‐inch 0.463 0.003** 1.000 — 0.025* — 0.003** — 8‐inch 0.418 0.010* 1.000 — 0.091 — 0.011* —

Southern sawshark Pristiophorus nudipinnis 5‐inch 0.159 0.177 0.317 — 0.288 — 1.000 — 6‐inch 0.239 0.040* 1.000 0.144 1.000 0.412 1.000 0.101 7‐inch 0.081 0.448 1.000 — 0.634 — 1.000 — 8‐inch ————————

Common sawshark Pristiophorus cirratus 5‐inch 0.266 0.045* 0.279 — 1.000 — 0.060 — 6‐inch 0.265 0.025* 0.023* 0.094 0.069 1.000 1.000 1.000 7‐inch 0.037 0.699 1.000 — 1.000 — 1.000 — 8‐inch 0.102 0.401 0.634 — 1.000 — 1.000 —

Elephant fish Callorhinchus milii 5‐inch 0.190 0.121 0.168 — 0.269 — 1.000 — 6‐inch 0.320 0.008** 0.009** 0.012* 0.053 1.000 1.000 1.000 7‐inch 0.302 0.033* 0.041* — 0.082 — 1.000 — 8‐inch 0.296 0.051 0.058 — 0.095 — 1.000 —

Table 4 (Commercial species ‘fuzzy region analysis’ continued)

Fuzzy region: Eastern Bass Strait Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.338 <.001*** 1.000 — <.001*** — <.001*** — 6‐inch 0.279 <.001*** 0.003** 0.392 0.164 0.387 <.001*** <.001*** 7‐inch 0.226 <.001*** 0.014* — 0.559 — <.001*** — 8‐inch 0.129 0.009** 0.010* — 0.775 — 0.245 —

School shark Galeorhinus galeus 5‐inch 0.056 0.120 0.286 — 1.000 — 0.291 — 6‐inch 0.081 0.034* 0.119 0.047* 0.105 1.000 1.000 1.000 7‐inch 0.063 0.092 0.314 — 0.102 — 1.000 — 8‐inch 0.027 0.391 1.000 — 1.000 — 0.521 —

Southern sawshark Pristiophorus nudipinnis 5‐inch 0.048 0.165 1.000 — 0.178 — 0.558 — 6‐inch 0.129 0.003** 0.020* 0.055 1.000 1.000 0.041* 0.094 7‐inch 0.032 0.310 1.000 — 1.000 — 0.383 — 8‐inch 0.017 0.555 1.000 — 1.000 — 0.893 —

Common sawshark Pristiophorus cirratus 5‐inch 0.012 0.651 1.000 — 1.000 — 1.000 — 6‐inch 0.084 0.029* 0.021* 0.110 0.565 1.000 1.000 1.000 7‐inch 0.057 0.119 0.223 — 0.192 — 1.000 — 8‐ inch 0.053 0.154 0.180 — 1.000 — 1.000 —

Elephant fish Callorhinchus milii 5‐inch 0.012 0.644 1.000 — 1.000 — 1.000 — 6‐inch 0.092 0.020* 0.095 1.000 0.227 0.124 1.000 0.325 7‐inch 0.032 0.304 1.000 — 0.372 — 1.000 — 8‐inch 0.024 0.437 0.959 — 1.000 — 0.888 — GHATF

shark

survey 35

36 GHATF

Table 4 (Commercial species ‘fuzzy zone analysis’ continued)

shark A) Zones

survey Fuzzy zone: South Australia Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons

size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.003 0.569 —————— 6‐inch 0.015 0.167 —————— 7‐inch 0.039 0.023* —————— 8‐inch 0.001 0.777 ——————

School shark Galeorhinus galeus 5‐inch 0.006 0.359 —————— 6‐inch 0.015 0.164 —————— 7‐inch 0.058 0.005** —————— 8‐inch 0.024 0.073 —————— Southern sawshark Pristiophorus nudipinnis 5‐inch 0.019 0.115 —————— 6‐inch 0.000 0.871 —————— 7‐inch 0.002 0.588 —————— 8‐inch 0.020 0.106 ——————

Common sawshark Pristiophorus cirratus 5‐inch 0.021 0.098 —————— 6‐inch 0.027 0.062 —————— 7‐inch 0.002 0.608 —————— 8‐inch 0.002 0.620 ——————

Elephant fish Callorhinchus milii 5‐inch 0.005 0.415 —————— 6‐inch 0.032 0.040* —————— 7‐inch 0.007 0.334 —————— 8‐inch 0.007 0.334 ——————

Table 4 (Commercial species ‘fuzzy zone analysis’ continued)

Fuzzy zone: Bass Strait Common name Scientific name Mesh r2 P values for between‐survey post‐hoc comparisons size All periods 70s vs 80s 70s vs 90s 70s vs 00s 80s vs 90s 80s Vs 00s 90s vs 00s

Gummy shark Mustelus antarcticus 5‐inch 0.225 <.001*** 1.000 — <.001*** — <.001*** — 6‐inch 0.256 <.001*** <.001*** 0.006** 1.000 0.634 <.001*** <.001*** 7‐inch 0.199 <.001*** <.001*** — 1.000 — <.001*** — 8‐inch 0.116 0.004** 0.004** — 0.316 — 0.345 —

School shark Galeorhinus galeus 5‐inch 0.029 0.246 0.310 — 1.000 — 1.000 — 6‐inch 0.127 <.001*** 0.422 0.245 0.444 1.000 0.001** <.001*** 7‐inch 0.091 0.011* 1.000 — 0.108 — 0.009** — 8‐inch 0.088 0.017* 1.000 — 0.087 — 0.018* —

Southern sawshark Pristiophorus nudipinnis 5‐inch 0.011 0.589 0.915 — 1.000 — 1.000 — 6‐inch 0.080 0.010** 0.031* 0.138 1.000 1.000 0.106 0.357 7‐inch 0.031 0.228 1.000 — 0.699 — 0.266 — 8‐inch 0.014 0.531 1.000 — 1.000 — 0.818 —

Common sawshark Pristiophorus cirratus 5‐inch 0.002 0.893 1.000 — 1.000 — 1.000 — 6‐inch 0.109 0.001** <.001*** 0.014* 0.060 1.000 1.000 1.000 7‐inch 0.006 0.769 1.000 — 1.000 — 1.000 — 8‐inch 0.054 0.086 0.091 — 0.834 — 0.922 —

Elephant fish Callorhinchus milii 5‐inch 0.017 0.445 1.000 — 0.637 — 1.000 — 6‐inch 0.079 0.010* 0.007** 0.068 0.082 1.000 1.000 1.000 7‐inch 0.066 0.039* 0.051 — 0.108 — 1.000 — 8‐inch 0.039 0.174 0.249 — 0.291 — 1.000 — GHATF

shark

survey 37

Table 4 (Commercial species ‘defined region analysis’ continued)

B) Regions Great Australian Bight Offshore Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.264 0.004 *** 6-inch 0.146 0.041 * 7-inch 0.171 0.026 * 8-inch 0.030 0.371 * School shark Galeorhinus galeus 5-inch 0.259 0.005 ** 6-inch 0.120 0.065 7-inch 0.050 0.242 8-inch 0.139 0.047 * * Southern sawshark Pristiophorus nudipinnis 5-inch 0.044 0.275 6-inch 0.044 0.275 7-inch — — 8-inch — — * Common sawshark Pristiophorus cirratus 5-inch 0.061 0.196 6-inch 0.011 0.584 7-inch 0.001 0.862 8-inch 0.003 0.787 * Elephantfish Callorhinchus milii 5-inch — — 6-inch — — 7-inch — — 8-inch ——

Great Australian Bight Inshore Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.133 0.165 6-inch 0.220 0.067 7-inch 0.104 0.224 8-inch 0.139 0.156 * School shark Galeorhinus galeus 5-inch 0.202 0.081 6-inch 0.207 0.076 7-inch 0.268 0.040 * 8-inch 0.215 0.071 * Southern sawshark Pristiophorus nudipinnis 5-inch — — 6-inch — — 7-inch — — 8-inch — — * Common sawshark Pristiophorus cirratus 5-inch 0.186 0.096 6-inch — — 7-inch — — 8-inch — — * Elephantfish Callorhinchus milii 5-inch — — 6-inch — — 7-inch — — 8-inch ——

GHATF shark survey 38

Table 4 (Commercial species ‘defined region analysis’ continued)

Streaky and Venus Bay Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.060 0.419 6-inch 0.001 0.927 7-inch <0.001 0.946 8-inch 0.078 0.354 * School shark Galeorhinus galeus 5-inch 0.052 0.453 6-inch 0.052 0.453 7-inch 0.017 0.672 8-inch 0.052 0.453 * Southern sawshark Pristiophorus nudipinnis 5-inch — — 6-inch — — 7-inch — — 8-inch — — * Common sawshark Pristiophorus cirratus 5-inch — — 6-inch — — 7-inch — — 8-inch — — * Elephantfish Callorhinchus milii 5-inch — — 6-inch — — 7-inch — — 8-inch ——

South Australia Shelf Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.063 0.208 6-inch 0.115 0.084 7-inch 0.150 0.046 * 8-inch 0.041 0.309 * School shark Galeorhinus galeus 5-inch 0.034 0.360 6-inch 0.061 0.214 7-inch 0.058 0.226 8-inch 0.162 0.038 * * Southern sawshark Pristiophorus nudipinnis 5-inch 0.110 0.091 6-inch — — 7-inch 0.013 0.564 8-inch 0.110 0.091 * Common sawshark Pristiophorus cirratus 5-inch 0.030 0.392 6-inch 0.007 0.682 7-inch 0.009 0.643 8-inch 0.013 0.564 * Elephantfish Callorhinchus milii 5-inch 0.013 0.564 6-inch 0.013 0.564 7-inch — — 8-inch ——

GHATF shark survey 39

Table 4 (Commercial species ‘defined region analysis’ continued)

Eyre Peninsula Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.281 0.062 6-inch 0.329 0.040 * 7-inch 0.416 0.017 * 8-inch 0.386 0.023 * * School shark Galeorhinus galeus 5-inch 0.047 0.477 6-inch 0.022 0.632 7-inch 0.067 0.392 8-inch 0.192 0.134 * Southern sawshark Pristiophorus nudipinnis 5-inch 0.141 0.206 6-inch 0.071 0.377 7-inch — — 8-inch — — * Common sawshark Pristiophorus cirratus 5-inch 0.018 0.664 6-inch — — 7-inch 0.097 0.300 8-inch — — * Elephantfish Callorhinchus milii 5-inch 0.018 0.664 6-inch 0.243 0.087 7-inch 0.097 0.300 8-inch ——

Cape Jaffa Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.313 0.047 * 6-inch 0.122 0.241 7-inch 0.002 0.885 8-inch 0.290 0.058 * School shark Galeorhinus galeus 5-inch 0.250 0.082 6-inch 0.088 0.325 7-inch 0.311 0.048 * 8-inch 0.046 0.481 * Southern sawshark Pristiophorus nudipinnis 5-inch — — 6-inch 0.037 0.529 7-inch — — 8-inch 0.081 0.347 * Common sawshark Pristiophorus cirratus 5-inch 0.130 0.226 6-inch 0.124 0.238 7-inch 0.037 0.529 8-inch 0.081 0.347 * Elephantfish Callorhinchus milii 5-inch — — 6-inch — — 7-inch — — 8-inch ——

GHATF shark survey 40

Table 4 (Commercial species ‘defined region analysis’ continued)

Western Bass Strait Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.005 0.811 6-inch 0.371 0.026 * 7-inch 0.180 0.149 8-inch <0.001 0.990 * School shark Galeorhinus galeus 5-inch 0.309 0.049 * 6-inch 0.529 0.005 ** 7-inch 0.383 0.024 * 8-inch 0.345 0.035 * * Southern sawshark Pristiophorus nudipinnis 5-inch 0.240 0.089 6-inch 0.233 0.098 7-inch 0.071 0.377 8-inch — — * Common sawshark Pristiophorus cirratus 5-inch 0.280 0.063 6-inch 0.001 0.926 7-inch 0.004 0.845 8-inch 0.143 0.202 * Elephantfish Callorhinchus milii 5-inch — — 6-inch 0.566 0.003 ** 7-inch 0.173 0.158 8-inch 0.097 0.300

Eastern Bass Strait Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.226 0.003 ** 6-inch 0.422 <0.001 *** 7-inch 0.359 <0.001 *** 8-inch 0.017 0.440 * School shark Galeorhinus galeus 5-inch 0.068 0.113 6-inch 0.048 0.186 7-inch 0.141 0.020 * 8-inch 0.080 0.085 * Southern sawshark Pristiophorus nudipinnis 5-inch 0.029 0.307 6-inch 0.124 0.030 * 7-inch 0.058 0.144 8-inch 0.020 0.401 * Common sawshark Pristiophorus cirratus 5-inch 0.040 0.229 6-inch 0.039 0.238 7-inch 0.009 0.566 8-inch 0.001 0.861 * Elephantfish Callorhinchus milii 5-inch 0.020 0.392 6-inch 0.011 0.531 7-inch 0.020 0.401 8-inch 0.020 0.401

GHATF shark survey 41

Table 4 (Commercial species ‘defined zone analysis’ continued)

B) Zones South Australia Common name Scientifc name Mesh P values r2 Year Period * Gummy shark Mustelus antarcticus 5-inch <0.001 0.830 6-inch 0.016 0.193 7-inch 0.033 0.058 8-inch 0.000 0.983 * School shark Galeorhinus galeus 5-inch <0.001 0.922 6-inch 0.008 0.347 7-inch 0.054 0.014 * 8-inch 0.024 0.106 * Southern sawshark Pristiophorus nudipinnis 5-inch 0.016 0.183 6-inch 0.004 0.509 7-inch 0.007 0.394 8-inch 0.035 0.051 * Common sawshark Pristiophorus cirratus 5-inch 0.026 0.091 6-inch 0.017 0.176 7-inch 0.001 0.742 8-inch <0.001 0.907 * Elephantfish Callorhinchus milii 5-inch <0.001 0.906 6-inch 0.027 0.088 7-inch 0.012 0.245 8-inch ——

Bass Strait Common name Scientifc name Mesh P values Period r2 Year * Gummy shark Mustelus antarcticus 5-inch 0.143 0.006 ** 6-inch 0.321 <0.001 *** 7-inch 0.225 <0.001 *** 8-inch 0.009 0.511 * School shark Galeorhinus galeus 5-inch 0.016 0.373 6-inch 0.090 0.032 * 7-inch 0.065 0.072 8-inch 0.057 0.092 * Southern sawshark Pristiophorus nudipinnis 5-inch 0.008 0.542 6-inch 0.074 0.054 7-inch 0.052 0.106 8-inch 0.016 0.383 * Common sawshark Pristiophorus cirratus 5-inch 0.002 0.729 6-inch 0.022 0.300 7-inch <0.001 0.906 8-inch 0.021 0.311 * Elephantfish Callorhinchus milii 5-inch 0.016 0.380 6-inch 0.070 0.061 7-inch 0.002 0.729 8-inch 0.010 0.487

GHATF shark survey 42

Table 5. Between‐survey comparisons of the number of individuals of bycatch species ‘Fuzzy analysis’ comparing the number of individuals for each of several bycatch species caught per 1000 km‐hour in Bass Strait by 5–8‐inch mesh gillnets during the 1973–76 and 2007–08 surveys, and by 6‐inch mesh gillnets during the 1973–76 (70s), 1998–01 (90s), and 2007–08 (00s) surveys; r2, correlation coefficient squared; P, probability of differences; *P < 0.05, **P < 0.01, ***P < 0.001; —, insufficient data.

Region Fuzzy region: Western Bass Strait Mesh 70s vs 00s 70s vs 90s vs 00s

Common name Scientific name size r2 P value r2 P values for between‐survey post‐hoc comparisons All periods 70s vs 90s 70s vs 00s 90s vs 00s

Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 4‐inch ——————— 5‐inch 0.240 0.106 ————— 6‐inch —— 0.460 0.002** 1.000 0.009** 0.003** 7‐inch 0.009 0.785 ————— 8‐inch 0.001 0.941 —————

Spikey spurdog Squalus megalops 4‐inch 0.131 0.248 ————— 5‐inch 0.014 0.718 ————— 6‐inch —— 0.197 0.111 1.000 0.765 0.115 7‐inch ——————— 8‐inch 0.250 0.170 —————

Draughtboard shark Cephaloscyllium laticeps 4‐inch ——————— 5 ‐inch 0.258 0.092 ————— 6‐inch —— 0.076 0.454 1.000 0.742 0.916 7‐inch 0.066 0.447 ————— 8‐inch 0.038 0.614 —————

Port Jackson shark Heterodontus portusjacksoni 4‐inch ——————— 5‐inch 0.090 0.344 ————— 6‐inch —— 0.383 0.008** 0.010** 0.023* 1.000 7‐inch 0.123 0.289 ————— 8‐inch 0.217 0.206 —————

Total Chondrichthyes 4‐inch 0.336 0.048* ————— 5‐inch 0.205 0.140 ————— 6‐inch —— 0.513 <.001*** <.001*** 0.107 0.147 7‐inch 0.087 0.378 ————— 8‐inch 0.080 0.460 —————

Teleostei Long‐snouted boarfish Pentaceropsis recurvirostris 4‐inch ——————— 5‐inch ——————— 6‐inch —— 0.139 0.224 0.375 0.355 1.000 7‐inch 0.120 0.297 ————— 8‐inch —— —————

Sand flathead Platycephalus bassensis 4‐inch 0.180 0.170 ————— 5‐inch 0.311 0.060 ————— 6‐inch —— 0.087 0.401 0.873 1.000 0.785 7‐inch ——————— 8‐inch ———————

Total Teleostei 4‐inch 0.177 0.173 ————— 5‐inch 0.511 0.009** ————— 6‐inch —— 0.021 0.806 1.000 1.000 1.000 7‐inch 0.120 0.297 ————— 8‐inch 0.063 0.516 —————

GHATF shark survey 43

Table 5 (Bycatch species ‘fuzzy region analysis’ continued)

Fuzzy region: Eastern Bass Strait Mesh 70s vs 00s 70s vs 90s vs 00s

Common name Scientific name size r2 P value r2 P values for between‐survey post‐hoc comparisons All periods 70s vs 90s 70s vs 00s 90s vs 00s

Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 4‐inch ——————— 5‐inch ——————— 6‐inch —— 0.276 <.001*** 1.000 <.001*** <.001*** 7‐inch 0.279 0.001** ————— 8‐inch 0.188 0.017* —————

Spikey spurdog Squalus megalops 4‐inch 0.000 0.899 ————— 5‐inch 0.004 0.717 ————— 6‐inch —— 0.030 0.391 0.526 1.000 1.000 7‐inch ——————— 8‐inch ———————

Draughtboard shark Cephaloscyllium laticeps 4‐inch 0.012 0.512 ————— 5‐inch 0.071 0.117 ————— 6‐inch —— 0.245 <.001*** 0.009** 0.704 <.001*** 7‐inch 0.051 0.190 ————— 8‐inch 0.132 0.048* —————

Port Jackson shark Heterodontus portusjacksoni 4‐inch 0.038 0.235 ————— 5‐inch 0.014 0.490 ————— 6‐inch —— 0.128 0.014* 0.015* 0.103 1.000 7‐inch 0.049 0.201 ————— 8‐inch 0.011 0.580 —————

Total Chondrichthyes 4‐inch 0.203 0.004** ————— 5‐inch 0.308 <.001*** ————— 6‐inch —— 0.238 <.001*** 0.003** 1.000 <.001*** 7‐inch 0.003 0.772 ————— 8‐inch 0.086 0.116 —————

Teleostei Long‐snouted boarfish Pentaceropsis recurvirostris 4‐inch ——————— 5‐inch 0.066 0.129 ————— 6‐inch —— 0.112 0.025* 0.034* 0.090 1.000 7‐inch 0.009 0.595 ————— 8‐inch 0.030 0.359 —————

Sand flathead Platycephalus bassensis 4‐inch 0.055 0.151 ————— 5‐inch 0.035 0.274 ————— 6‐inch —— 0.035 0.330 0.509 0.699 1.000 7‐inch 0.051 0.192 ————— 8‐inch ———————

Total Teleostei 4‐inch 0.109 0.040* ————— 5‐inch 0.108 0.050 ————— 6‐inch —— 0.044 0.248 0.339 0.626 1.000 7‐inch 0.040 0.247 ————— 8‐inch 0.001 0.850 —————

GHATF shark survey 44

Table 5 (Bycatch species ‘fuzzy zone analysis’ continued) Zone Fuzzy zone: Bass Strait Mesh 70s vs 00s 70s vs 90s vs 00s

Common name Scientific name size r2 P value r2 P values for between‐survey post‐hoc comparisons All periods 70s vs 90s 70s vs 00s 90s vs 00s

Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 4‐inch ——————— 5‐inch 0.060 0.093 ————— 6‐inch —— 0.309 <.001*** 1.000 <.001*** <.001*** 7‐inch 0.115 0.021* ————— 8‐inch 0.077 0.088 —————

Spikey spurdog Squalus megalops 4‐inch 0.011 0.460 ————— 5‐inch 0.001 0.795 ————— 6‐inch —— 0.019 0.439 1.000 0.659 0.928 7‐inch ——————— 8‐inch 0.034 0.261 —————

Draughtboard shark Cephaloscyllium laticeps 4‐inch 0.011 0.457 ————— 5‐inch 0.005 0.650 ————— 6‐inch —— 0.184 <.001*** 0.017* 0.611 <.001*** 7‐inch 0.039 0.186 ————— 8‐inch 0.089 0.065 —————

Port Jackson shark Heterodontus portusjacksoni 4‐inch 0.026 0.255 ————— 5‐inch 0.024 0.293 ————— 6‐inch —— 0.164 <.001*** <.001*** 0.007** 1.000 7‐inch 0.057 0.110 ————— 8‐inch 0.045 0.197 —————

Total Chondrichthyes 4‐inch 0.078 0.047* ————— 5‐inch 0.160 0.005** ————— 6‐inch —— 0.269 <.001*** <.001*** 1.000 <.001*** 7‐inch 0.003 0.701 ————— 8‐inch 0.007 0.601 —————

Teleostei Long‐snouted boarfish Pentaceropsis recurvirostris 4‐inch ——————— 5‐inch 0.047 0.141 ————— 6‐inch —— 0.113 0.006** 0.009** 0.026* 1.000 7‐inch 0.028 0.270 ————— 8‐inch 0.020 0.386 ————— Sand flathead Platycephalus bassensis 4‐inch 0.073 0.054 ————— 5‐inch 0.084 0.045* ————— 6‐inch —— 0.029 0.288 0.428 0.604 1.000 7‐inch 0.042 0.174 ————— 8‐inch ———————

Total Teleostei 4‐inch 0.114 0.015* ————— 5‐inch 0.187 0.002** ————— 6‐inch —— 0.036 0.210 0.283 0.507 1.000 7‐inch 0.058 0.108 ————— 8‐inch 0.000 0.949 —————

GHATF shark survey 45

46 GHATF Table 6. Size‐frequency composition of species caught in the 2007–08 survey

shark Size‐frequency compositions by sex (teleosts were not sexed) for individuals caught in the experimental nets. ML: mantle length; CL: carapace length; TL: total length; FL; fork length; DW: disc width; SL: standard length; size class 200: 200–299; etc. n: number.

survey Common name Scientifc name Size Size class (mm) n type <200 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300

Chondrichthyes

Gummy shark Mustelus antarcticus TL Female 15 390 360 628 595 398 297 193 172 97 61 15 2 3223 Male 1 12 349 287 440 393 307 353 214 82 27 2 1 2468 Unknown 2485147821 51 Spikey spurdog Squalus megalops TL Female 20 568 2563 311 3 3465 Male 10 62 10 1 1 1 85 Unknown 5 41 147 19 212 School shark Galeorhinus galeus TL Female 2 6 15 31 30 58 164 270 369 539 236 30 7 1757 Male 1 1 4 4 23 20 14 28 60 92 227 349 139 5 967 Unknown 1 213351 16 Draughtboard shark Cephaloscyllium laticeps TL Female 3 23 67 173 286 82 4 2 640 Male 8501362837051 553 Unknown 12211142 32 Port Jackson shark Heterodontus portusjacksoni TL Female 1 14 56 105 105 82 51 12 1 427 Male 2 14 84 184 104 61 42 5 496 Unknown 12223 10 Common sawshark Pristiophorus cirratus TL Female 1 10 17 36 75 72 128 78 22 3 442 Male 1 7 95 147 53 5 1 309 Unknown 1 242 9 Broadnose sevengill shark Notorynchus cepedianus TL Female 2 7 14 12 20 23 16 10 4 7 5 2 1 2 125 Male 2 2 15 19 5 15 11 8 6 6 1 4 1 1 96 Unknown 13 1 5

Table 6 (Size‐frequency composition continued)

Common name Scientifc name Size Size class (mm) n type <200 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 Southern sawshark Pristiophorus nudipinnis TL Female 2 104232333 95 Male 1 1 20 67 23 112 Unknown 11 2 Whitespotted dogfish Squalus acanthias TL Female 81520313 77 Male 16 40 1 57 Unknown 125 8 Whiskery shark Furgaleus macki TL Female 3 12285 1 22 Male 1 1 4 3 10 27 33 2 81 Unknown 123 6 Bronze whaler Carcharhinus brachyurus TL Female 128461392111 39 Male 1 211113894334 1 60 Unknown 11 2 Smooth hammerhead Sphyrna zygaena TL Female 13587243121 37 Male 4116764511 36 Unknown 11 1 2 5 Elephant fish Callorhinchus milii FL Female 13241541 48 Male 282102 24 Rusty carpetshark Parascyllium ferrugineum TL Female 2492 53 Male 25 7 Unknown 1 1 Southern eagle ray Myliobatis australis DW Female 25 5 3 2 1 18 Male 11089 28 Australian angelshark Squatina australis TL Female 11324431 19 GHATF Male 132125 23 Unknown 1 1

shark

survey

47

48 GHATF Table 6 (Size-frequency composition continued)

Common name Scientifc name Size Size class (mm) n

shark type <200 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 Ogilby's ghostshark Hydrolagus ogilbyi TL

survey Female 41 5 Male 12 3 Sparsely-spotted stingaree Urolophus paucimaculatus DW Male 5 5 Unknown 1 2 3 Green-eyed spurdog Squalus chloroculus TL Female 1 1 Male 23 5 Unknown 1 1 Thresher shark Alopias vulpinus TL Female 11 1 1 1 5 Male 112 Spotted wobbegong Orectolobus maculatus TL Female 112 Male 1113 Unknown 11 Shortfin mako Isurus oxyrinchus FL Female 112 Male 11 1 3 Varied carpetshark Parascyllium variolatum TL Female 4 4 Male 1 1 Cobbler wobbegong Sutorectus tentaculatus TL Female 111 3 Male 1 1 Green-backed stingaree Urolophus viridis DW Female 1 1 Male 12 3 Ornate angelshark Squatina tergocellata TL Female 1 1 Male 2 2 Unknown 1 1

Table 6 (Size-frequency composition continued)

Common name Scientifc name Size Size class (mm) n type <200 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300

Grey spotted catshark Asymbolus analis TL Female 1 1 Male 1 1 Unknown 1 1 Gulf catshark Asymbolus vincenti TL Female 1 1 Unknown 2 2 Longnose skate Dipturus confusus TL Male 2 2 Melbourne skate Dipturus whitleyi DW Female 11 Male 1 1 Ornate wobbegong Orectolobus halei TL Male 11 2 Pencil shark Hypogaleus hyugaensis TL Male TL 2 2 Western spotted catshark Asymbolus occiduus TL Female 1 1 Unknown 1 1 Bluntnose sixgill shark Hexanchus griseus TL Male 1 1 Brier shark Deania calcea TL Female TL 1 1 Peacock skate Pavoraja nitida TL Male 1 1 Sandyback stingaree Urolophus bucculentus TL Male 1 1 Southern dogfish Centrophorus zeehaani TL Female TL 1 1 Western shovelnose ray Aptychotrema vincentiana TL Male 1 1 Western shovelnose stingaree Trygonoptera mucosa DW GHATF Unknown 1 1 Whitefined swell shark Cephaloscyllium albipinnus TL Female 1 1

shark

survey

49

50 GHATF Table 6 (Size-frequency composition continued)

Common name Scientifc name Size Size class (mm) n

shark type <200 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 Teleostei

Jackass morwong Nemadactylus macropterus FL 42 299 146 2 489 survey Blue warehou Seriolella brama FL 7 166 286 7 466 Bight redfish Centroberyx gerrardi FL 2 173 162 55 12 1 405 Blue mackerel Scomber australasicus FL 2 174 66 1 243 Knifejaw Oplegnathus woodwardi TL 1 35 102 16 1 155 Ocean jacket Nelusetta ayraudi TL 13 122 13 148 Blue morwong Nemadactylus valenciennesi FL 1 15 39 36 22 17 1 131 Snapper Pagrus auratus FL 11 33 37 26 6 113 Longsnout boarfish Pentaceropsis recurvirostris FL 2 27 58 7 2 96 Barracouta Thyrsites atun FL 1 34 45 3 83 Tiger flathead Neoplatycephalus richardsoni TL 1 21 38 14 1 75 Silver dory Cyttus australis TL 11 31 15 2 1 60 Western australian salmon Arripis truttaceus FL 1 33 21 55 Western blue groper Achoerodus gouldii TL 1 12 16 14 5 1 49 Silver warehou Seriolella punctata FL 15 30 2 47 Leatherjackets Monacanthidae FL 7 37 1 45 Dusky morwong Dactylophora nigricans FL 1 4 13 14 7 4 43 Pink ling Genypterus blacodes TL 1 12 9 9 4 1 36 Latchet Pterygotrigla polyommata FL 1 20 11 3 35 Striped trumpeter Latris lineata FL 1 3 8 14 3 29 Red cod Pseudophycis bachus TL 3 12 12 1 28 Bearded rock cod Pseudophycis barbata TL 4 12 8 24 Common gurnard perch Neosebastes scorpaenoides TL 9132 24 Magpie perch Cheilodactylus nigripes FL 3164 23 Deepwater flathead Neoplatycephalus conatus TL 6 6 6 3 21 Blackspot boarfish Zanclistius elevatus TL 269 3 20 Southern whiptail Caelorinchus australis TL 4 11 2 1 18 Swallowtail Centroberyx lineatus FL 16 16 Sergeant baker Aulopus purpurissatus FL 1 9 5 15 Thetis fish Neosebastes thetidis TL 8 7 15 Bluethroat wrasse Notolabrus tetricus TL 2 11 1 14 Red gurnard Chelidonichthys kumu TL 283 13 Giant boarfish Paristiopterus labiosus TL 1 1 4 5 1 1 13 Speckled stargazer Kathetostoma canaster TL 3 8 2 13 Flatheads Platycephalidae TL 5 5 2 12 Moonlighter Vinculum sexfasciatum TL 9 3 12 Tusk Dannevigia tusca TL 1 5 4 10 Silver trevally Pseudocaranx dentex FL 118 10 Blue grenadier Macruronus novaezelandiae SL 5 2 2 9 Reef ocean perch Helicolenus percoides TL 2 7 9 Mulloway Argyrosomus japonicus TL 1 1 1 2 3 1 9

Table 6 (Size‐frequency composition continued)

Common name Scientifc name Size Size class (mm) n type <200 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 Gemfish Rexea solandri FL 4 2 3 9 Zebrafish Girella zebra FL 8 8 Redfish Centroberyx affinis FL 6 1 7 Silver drummer Kyphosus sydneyanus FL 3 4 7 Brownstriped leatherjacket Meuschenia australis TL 6 1 7 Sweep Scorpis lineolatus FL 3 3 6 Yellowspotted boarfish Paristiopterus gallipavo TL 3 3 6 Gulf gurnard perch Neosebastes pantica TL 3 2 5 Parrotfishes Scaridae FL 5 5 Dusky flathead Platycephalus fuscus TL 4 4 Short boarfish Parazanclistius hutchinsi FL 4 4 Bastard trumpeter Latridopsis forsteri FL 4 4 Sixspine leatherjacket Meuschenia freycineti TL 3 1 4 Hapuku Polyprion oxygeneios TL 2 1 3 Sea sweep Scorpis aequipinnis TL 2 1 3 Wrasses Labridae TL 3 3 Smoothspine leatherjacket Cantheschenia longipinnis TL 2 1 3 Butterfly gurnard Lepidotrigla vanessa TL 1 1 2 Toothy flathead Neoplatycephalus aurimaculatus TL 1 1 2 Southern bluespotted flathead Platycephalus speculator FL 2 2 Skipjack trevally Pseudocaranx wrighti FL 2 2 Butterfish Scatophagus sp. FL 2 2 Snook Sphyraena novaehollandiae FL 1 1 2 Rosy wrasse Pseudolabrus psittaculus FL 2 2 Rock ling Genypterus tigerinus FL 1 1 Mirror dory Zenopsis nebulosus FL 1 1 Scorpionfishes Sebastidae TL 1 1 Harlequin fish Othos dentex FL 1 1 King george whiting Sillaginodes punctata TL 1 1 Samsonfish Seriola hippos TL 1 1 White trevally Pseudocaranx georgianus FL 1 1 Rusty Jobfish Aphareus rutilans TL 1 1 Bluespotted goatfish Upeneichthys vlamingii TL 1 1 Bigscale bullseye Pempheris multiradiatus FL 1 1 Old wife Enoplosus armatus FL 1 1 Rock cale Crinodus lophodon FL 1 1 Banded morwong Cheilodactylus spectabilis FL 1 1 Foxfish Bodianus frenchii FL 1 1 Southern bluefin tuna Thunnus maccoyii FL 1 1 Blue-eye trevalla Hyperoglyphe antarctica FL 1 1

GHATF Toothbrush leatherjacket Acanthaluteres vittiger TL 1 1 Velvet leatherjacket Meuschenia scaber TL 1 1 Starry toadfish Arothron firmamentum TL 1 1

shark

survey

51

52 GHATF Table 6 (Size‐frequency composition continued)

shark Common name Scientifc name Size Size class (mm) n type <200 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300

survey Cephalopoda Gould squid Nototodarus gouldi ML 19 2 21

Crustacea Southern rocklobster Jasus edwardsii CL 10 10 King crabs Lithodidae CL 1 1 Giant crab Pseudocarcinus gigas CL 1 1

Table 7. Retained and discarded individuals caught in the 2007–08 survey. Summary of total catch as retained or discarded number of individuals and of top three discarded species caught by the different mesh‐sizes in the 2007–08 survey.

Mesh Retained Discarded Discarded Species Individuals % Individuals % Number Top three % 4-inch 1473 21 5680 79 72 Spikey spurdog 61 Gummy shark 18 Blue mackerel 4 5-inch 3741 60 2447 40 62 Spikey spurdog 68 Draughtboard shark 7 Gummy shark 7 6-inch 2742 68 1264 32 52 Draughtboard shark 34 Port Jackson shark 24 Spikey spurdog 19 7-inch 2072 64 1158 36 48 Draughtboard shark 54 Port Jackson shark 20 Spikey spurdog 5 8-inch 1353 66 690 34 44 Port Jackson shark 47 Draughtboard shark 28 Southern eagle ray 4 Commercial 12874 67 6237 33 100 Draughtboard shark 27 Port Jackson shark 26 Spikey spurdog 22

GHATF shark survey 53

54 GHATF Table 8. Retained and discarded individuals caught by mesh size in the 2007–08 survey.

shark Breakdown of experimental net catch as retained and discarded individuals (in percentages) for each species caught in the 2007–08 survey. R: percent retained; D: percent discarded; U: percent unknown; n: number.

survey 4-inch 5-inch 6-inch 7-inch 8-inch Common name Scientifc name RDUn RDUn RDUn RDUn RDUn

Chondrichthyes Gummy shark Mustelus antarcticus 34 62 4 1659 91 9 0 2042 97 3 1 1364 98 2 0 656 97 3 0 290 Spikey spurdog Squalus megalops 0 95 5 3660 0 99 1 1676 0 100 0 242 0 100 0 63 0 100 0 14 School shark Galeorhinus galeus 82 16 2 90 97 2 1 394 99 1 1 619 100 0 0 927 97 1 2 784 Draughtboard shark Cephaloscyllium laticeps 0 100 0 24 0 100 0 178 0 100 0 437 0 100 0 629 0 100 0 195 Port Jackson shark Heterodontus portusjacksoni 0 100 0 21 0 100 0 93 0 100 0 308 0 100 0 230 0 100 0 324 Common sawshark Pristiophorus cirratus 91 8 0 247 94 6 0 277 93 6 1 150 94 6 0 95 91 9 0 57 Broadnose sevengill shark Notorynchus cepedianus 75 25 0 4 77 23 0 31 61 28 11 54 91 8 1 86 93 7 0 72 Southern sawshark Pristiophorus nudipinnis 90 8 2 111 88 12 0 67 94 6 0 31 100 0 0 3 100 0 0 2 Whitespotted dogfish Squalus acanthias 0 100 0 52 0 98 2 55 7 93 0 27 0 100 0 18 0 100 0 2 Whiskery shark Furgaleus macki 91 9 0 11 100 0 0 23 97 3 0 37 100 0 0 28 100 0 0 10 Bronze whaler Carcharhinus brachyurus 100 0 0 5 100 0 0 20 100 0 0 15 97 3 0 39 91 0 9 22 Smooth hammerhead Sphyrna zygaena 100 0 0 6 97 3 0 30 100 0 0 15 100 0 0 13 71 29 0 14 Elephant fish Callorhinchus milii 75 25 0 4 50 50 0 18 50 50 0 44 67 33 0 6 50 50 0 4 Rusty carpetshark Parascyllium ferrugineum 0 100 0 59 0 100 0 1 0 100 0 4 0 0 0 0 0 0 0 0 Southern eagle ray Myliobatis australis 0 100 0 1 0 100 0 2 0 100 0 5 0 100 0 16 0 100 0 29 Australian angelshark Squatina australis 0 100 0 1 0 100 0 4 20 80 0 5 6 94 0 18 10 90 0 20 Sparsely-spotted stingaree Urolophus paucimaculatus 0 100 0 2 0 100 0 1 0 100 0 4 0 100 0 5 0 100 0 1 Ogilby's ghostshark Hydrolagus ogilbyi 0 0 0 0 0 0 0 0 50 50 0 2 0 100 0 4 0 100 0 3 Green-eyed spurdog Squalus chloroculus 0 0 0 0 0 0 0 0 0 100 0 6 0 100 0 1 0 0 0 0 Spotted wobbegong Orectolobus maculatus 0 0 0 0 100 0 0 2 50 0 50 2 100 0 0 1 100 0 0 2 Thresher shark Alopias vulpinus 0 0 0 0 50 50 0 4 100 0 0 1 50 50 0 2 0 0 0 0 Green-backed stingaree Urolophus viridis 0 0 0 0 0 100 0 1 0 100 0 1 0 100 0 2 0 100 0 1 Shortfin mako Isurus oxyrinchus 0 0 0 0 100 0 0 1 50 50 0 2 0 100 0 1 100 0 0 1 Varied carpetshark Parascyllium variolatum 010005 0000 0000 0000 0000 Cobbler wobbegong Sutorectus tentaculatus 0000 0000 100002 100001100001 Ornate angelshark Squatina tergocellata 0000 0000 0000 0000 257504 Gulf catshark Asymbolus vincenti 010003 0000 0000 0000 0000 Grey spotted catshark Asymbolus analis 33 67 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Melbourne skate Dipturus whitleyi 0 0 0 0 0 100 0 1 0 0 0 0 0 100 0 1 0 100 0 1

Table 8 (Retained and discarded continued)

4-inch 5-inch 6-inch 7-inch 8-inch Common name Scientifc name RDUn RDUn RDUn RDUn RDUn Ornate wobbegong Orectolobus halei 0000 0000 100001 100002 0000 Longnose skate Dipturus confusus 0000 0000 0000 010001 010001 Pencil shark Hypogaleus hyugaensis 100001000000001000010000 Western spotted catshark Asymbolus occiduus 010002 0000 0000 0000 0000 Bluntnose sixgill shark Hexanchus griseus 0000 0000 100001 0000 0000 Brier shark Deania calcea 0000 0000 0000 0000 100001 Peacock skate Pavoraja nitida 0000 0000 0000 010001 0000 Sandyback stingaree Urolophus bucculentus 0000 010001 0000 0000 0000 Southern dogfish Centrophorus zeehaani 0000 0000 0000 0000 010001 Western shovelnose ray Aptychotrema vincentiana 0000 0000 0000 010001 0000 Western shovelnose stingaree Trygonoptera mucosa 0000 0000 0000 001001 0000 Whitefined swell shark Cephaloscyllium albipinnus 0000 0000 0000 010001 0000 Sub-total Chondrichthyes 17 79 4 5971 54 45 0 4922 66 33 1 3379 64 36 0 2853 65 34 1 1856 Teleostei Jackass morwong Nemadactylus macropterus 49 50 1 256 91 8 1 368 98 2 0 46 25 63 13 8 100 0 0 5 Blue warehou Seriolella brama 40 25 35 112 90 10 1 248 43 14 43 122 72 11 17 47 20 6 74 69 Bight redfish Centroberyx gerrardi 30 65 5 194 89 11 1 148 85 10 5 92 74 22 4 50 64 36 0 28 Blue mackerel Scomber australasicus 0 100 0 203 100 0 0 1 0 0 0 0 0 100 0 40 0 0 0 0 Blue morwong Nemadactylus valenciennesi 67 33 0 9 94 6 0 36 90 7 3 67 98 3 0 40 100 0 0 19 Knifejaw Oplegnathus woodwardi 33 67 0 21 91 9 0 56 90 7 2 81 75 25 0 8 100 0 0 1 Barracouta Thyrsites atun 3 97 0 148 0 100 0 4 0 100 0 3 20 80 0 5 0 100 0 2 Ocean jacket Nelusetta ayraudi 82 6 12 66 92 5 3 75 71 0 29 7 100 0 0 2 0 0 0 0 Snapper Pagrus auratus 100 0 0 4 65 35 0 20 73 27 0 41 60 40 0 53 69 31 0 26 Longsnout boarfish Pentaceropsis recurvirostris 100 0 0 4 96 4 0 23 100 0 0 50 100 0 0 26 100 0 0 12 Tiger flathead Neoplatycephalus richardsoni 5243558881308406005505004336706 Latchet Pterygotrigla polyommata 39 61 0 23 65 35 0 23 56 44 0 9 25 75 0 16 75 25 0 4 Western australian salmon Arripis truttaceus 100 0 0 49 100 0 0 26 0 0 0 0 0 0 0 0 0 0 0 0 Silver dory Cyttus australis 14 86 0 7 83 17 0 24 78 22 0 18 82 18 0 11 86 14 0 7 Leatherjackets Monacanthidae 3 97 0 37 76 24 0 25 0 0 100 1 0 0 0 0 0 0 0 0 GHATF Red gurnard Chelidonichthys kumu 496048010006 010002 17830 6 010001 Western blue groper Achoerodus gouldii 67 33 0 3 0 100 0 14 37 63 0 19 100 0 0 9 33 67 0 6 Silver warehou Seriolella punctata 80 13 7 15 75 19 6 16 100 0 0 9 0 0 0 0 100 0 0 9

shark

survey 55

56 GHATF Table 8 (Retained and discarded continued)

shark 4-inch 5-inch 6-inch 7-inch 8-inch Common name Scientifc name RDUn RDUn RDUn RDUn RDUn

survey Dusky morwong Dactylophora nigricans 0 100 0 3 0 100 0 13 0 100 0 18 0 100 0 6 0 100 0 5 Pink ling Genypterus blacodes 79 14 7 14 95 5 0 20 100 0 0 5 0 0 0 0 100 0 0 1 Striped trumpeter Latris lineata 100 0 0 2 100 0 0 3 100 0 0 25 90 10 0 10 0 0 0 0

Red cod Pseudophycis bachus 9 91 0 11 57 43 0 21 0 100 0 1 0 0 0 0 100 0 0 2 Magpie perch Cheilodactylus nigripes 0 0 0 0 60 40 0 5 29 57 14 14 80 20 0 5 50 50 0 6 Swallowtail Centroberyx lineatus 0 67 33 6 0 100 0 5 0 100 0 3 0 100 0 9 0 83 17 6 Bearded rock cod Pseudophycis barbata 8 92 0 12 36 64 0 11 50 50 0 2 0 0 0 0 0 100 0 1 Common gurnard perch Neosebastes scorpaenoides 5 95 0 22 0 100 0 3 0 0 0 0 0 0 0 0 0 100 0 1 Southern whiptail Caelorinchus australis 0 100 0 24 0 100 0 1 0 0 0 0 0 100 0 1 0 0 0 0 Blackspot boarfish Zanclistius elevatus 100 0 0 1 100 0 0 1 100 0 0 8 83 17 0 6 83 17 0 6 Deepwater flathead Neoplatycephalus conatus 67 11 22 9 88 13 0 8 100 0 0 2 100 0 0 1 0 100 0 1 Sergeant baker Aulopus purpurissatus 18 82 0 17 0 0 0 0 33 67 0 3 0 0 0 0 0 0 0 0 Redfish Centroberyx affinis 40 60 0 15 0 100 0 1 0 100 0 1 0 100 0 1 0 0 0 0 Bluethroat wrasse Notolabrus tetricus 0 100 0 1 17 83 0 12 0 100 0 1 0 100 0 1 0 0 0 0 Flatheads Platycephalidae 92 8 0 12 0 0 0 0 0 0 0 0 0 100 0 3 0 0 0 0 Speckled stargazer Kathetostoma canaster 0 0 0 0 25 75 0 4 0 67 33 3 20 80 0 5 67 33 0 3 Thetis fish Neosebastes thetidis 0 100 0 13 0 100 0 1 0 100 0 1 0 0 0 0 0 0 0 0 Gemfish Rexea solandri 100 0 0 10 100 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 Giant boarfish Paristiopterus labiosus 0 0 0 0 100 0 0 1 100 0 0 4 100 0 0 4 100 0 0 4 Blue grenadier Macruronus novaezelandiae 0 0 0 0 50 38 13 8 100 0 0 1 0 0 0 0 33 67 0 3 Moonlighter Vinculum sexfasciatum 0 0 0 0 100 0 0 4 80 20 0 5 100 0 0 2 100 0 0 1 Silver trevally Pseudocaranx dentex 0 0 100 1 67 33 0 3 100 0 0 7 100 0 0 1 0 0 0 0 Sweep Scorpis lineolatus 050502574307 10000 2 0 0 00 0 000 Reef ocean perch Helicolenus percoides 63 38 0 8 0 0 0 0 100 0 0 1 0 0 0 0 100 0 0 1 Tusk Dannevigia tusca 80 20 0 5 100 0 0 3 100 0 0 1 0 0 0 0 100 0 0 1 Mulloway Argyrosomus japonicus 0 100 0 1 100 0 0 3 100 0 0 1 100 0 0 2 100 0 0 2 Silver drummer Kyphosus sydneyanus 0 100 0 1 0 0 0 0 0 100 0 7 0 0 0 0 0 0 0 0 Yellowspotted boarfish Paristiopterus gallipavo 0000 0000 100001 100006100001 Zebrafish Girella zebra 040605010002 10000 1 0 0 00 0 000 Brownstriped leatherjacket Meuschenia australis 100001831706000000000000 Bastard trumpeter Latridopsis forsteri 0 0 0 0 100 0 0 4 100 0 0 1 0 0 0 0 0 0 0 0 Gulf gurnard perch Neosebastes pantica 0 100 0 3 0 100 0 2 0 0 0 0 0 0 0 0 0 0 0 0

Table 8 (Retained and discarded continued)

4-inch 5-inch 6-inch 7-inch 8-inch Common name Scientifc name RDUn RDUn RDUn RDUn RDUn Parrotfishes Scaridae 0 100 0 1 0 0 0 0 0 100 0 4 0 0 0 0 0 0 0 0 Dusky flathead Platycephalus fuscus 010004 0000 0000 0000 0000 Sea sweep Scorpis aequipinnis 010001 0000 100003 0000 0000 Short boarfish Parazanclistius hutchinsi 0000 010001 100001 100001100001 Sixspine leatherjacket Meuschenia freycineti 010004 0000 0000 0000 0000 Hapuku Polyprion oxygeneios 0 0 0 0 100 0 0 1 100 0 0 1 100 0 0 1 0 0 0 0 Smoothspine leatherjacket Cantheschenia longipinnis 010003 0000 0000 0000 0000 Wrasses Labridae 0 100 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Butterfish Scatophagus sp. 000001000100100100000000 Butterfly gurnard Lepidotrigla vanessa 50 50 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Rosy wrasse Pseudolabrus psittaculus 010002 0000 0000 0000 0000 Skipjack trevally Pseudocaranx wrighti 010002 0000 0000 0000 0000 Snook Sphyraena novaehollandiae 010002 0000 0000 0000 0000 Southern bluespotted flathead Platycephalus speculator 100 0 0 1 100 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 Toothy flathead Neoplatycephalus aurimaculatus 010002 0000 0000 0000 0000 Banded morwong Cheilodactylus spectabilis 0000 0000 0000 0000 010001 Bigscale bullseye Pempheris multiradiatus 001001 0000 0000 0000 0000 Blue-eye trevalla Hyperoglyphe antarctica 001001 0000 0000 0000 0000 Bluespotted goatfish Upeneichthys vlamingii 010001 0000 0000 0000 0000 Foxfish Bodianus frenchii 0000 0000 0000 0010010000 Harlequin fish Othos dentex 1000010000000000000000 King george whiting Sillaginodes punctata 1000010000000000000000 Mirror dory Zenopsis nebulosus 0000 0000 0000 0000100001 Old wife Enoplosus armatus 010001 0000 0000 0000 0000 Pipefishes Syngnathidae 0000 0000 0000 010001 0000 Rock cale Crinodus lophodon 0000 010001 0000 0000 0000 Rock ling Genypterus tigerinus 0000 0000 0000 100001 0000 Rusty Jobfish Aphareus rutilans 0000 010001 0000 0000 0000 Samsonfish Seriola hippos 0000 0000 100001 0000 0000

GHATF Scorpionfishes Sebastidae 0 100 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Southern bluefin tuna Thunnus maccoyii 0000 100001 0000 0000 0000 Starry toadfish Arothron firmamentum 0000 010001 0000 0000 0000

shark

survey 57

58 GHATF Table 8 (Retained and discarded continued)

shark 4-inch 5-inch 6-inch 7-inch 8-inch Common name Scientifc name RDUn RDUn RDUn RDUn RDUn

survey Toothbrush leatherjacket Acanthaluteres vittiger 010001 0000 0000 0000 0000 Velvet leatherjacket Meuschenia scaber 0000 0000 010001 0000 0000 White trevally Pseudocaranx georgianus 0000000010000100000000

Sub-total Teleostei 32 63 5 1491 83 16 1 1284 72 18 10 704 62 35 3 393 56 23 21 243 Crustacea Southern rocklobster Jasus edwardsii 0 0 0 0 0 100 0 7 0 100 0 4 0 0 0 0 0 100 0 6 Crabs undiferentiated crab 0 0 0 0 0 100 0 1 0 100 0 6 0 100 0 1 0 0 0 0 Spider crabs Homolidae 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 2 Giant crab Pseudocarcinus gigas 0000 0000 010001 0000 0000 King crabs Lithodidae 0000000000000000100001 Sub-total Crustacea 0 0 0 0 0 100 0 8 0 100 0 11 0 100 0 1 11 89 0 9 Cephalopoda Gould squid Nototodarus gouldi 10 90 0 21 0 0 0 0 100 0 0 1 0 0 0 0 0 0 0 0 Octopuses Octopoda 0 0 100 1 0 0 0 0 0 0 0 0 0 0 0 0 100 0 0 2 Sub-total Cephalopoda 13 83 4 22 0 0 0 0 100 0 0 1 0 0 0 0 100 0 0 2 Bivalvia Scallops Pectinidae 0000 0000 010001 0000 0000 Sub-total Bivalvia 0000 0000 010001 0000 0000 Echinoidea Sea urchins Echinoidea 0000010001000000000000 Sub-total Echinoidea 0000 010001 0000 0000 0000 Crinoidea Crinoids Crinoidea 0000 0000 010001 0000 0000 Sub-total Crinoidea 0000 0000 010001 0000 0000

Table 9. Post‐capture mortality for the species caught in the 2007–08 survey Immediate and delayed post‐capture mortality probability for the species caught in the 2007–08 survey where the number of observations is ≥5 per species. ND: no data.

Common name Scientifc name Number Immediate Delayed Mean s.e. Mean s.e.

Chondrichthyes Green-backed stingaree Urolophus viridis 15 0 0 0 0 Cobbler wobbegong Sutorectus tentaculatus 6 0 0 0.06 0.06 Spotted wobbegong Orectolobus maculatus 50000 Draughtboard shark Cephaloscyllium laticeps 1975 0 0 0.02 <0.01 Port Jackson shark Heterodontus portusjacksoni 1448 0.01 0 0.01 <0.01 Sparsely-spotted stingaree Urolophus paucimaculatus 26 0.04 0.04 0.01 0.01 Southern eagle ray Myliobatis australis 133 0.05 0.02 0.05 0.01 Ogilby's ghostshark Hydrolagus ogilbyi 23 0.09 0.06 0.58 0.06 Spikey spurdog Squalus megalops 1154 0.09 0.01 0.04 <0.01 Rusty carpetshark Parascyllium ferrugineum 24 0.13 0.07 0.03 0.03 Whitespotted dogfish Squalus acanthias 52 0.13 0.05 0.09 0.03 Varied carpetshark Parascyllium variolatum 5 0.20 0.20 0.14 0.14 Common sawshark Pristiophorus cirratus 538 0.21 0.02 0.21 0.01 Australian angelshark Squatina australis 56 0.25 0.06 0.14 0.04 Broadnose sevengill shark Notorynchus cepedianus 197 0.31 0.03 0.33 0.03 Southern sawshark Pristiophorus nudipinnis 104 0.37 0.05 0.14 0.03 Bronze whaler Carcharhinus brachyurus 150 0.37 0.04 0.34 0.03 Shortfin mako Isurus oxyrinchus 8 0.38 0.18 0.61 0.13 Green-eyed spurdog Squalus chloroculus 5 0.40 0.24 0.48 0.24 Gummy shark Mustelus antarcticus 3546 0.56 0.01 0.26 0.01 Thresher shark Alopias vulpinus 9 0.67 0.17 0.53 0.27 Elephant fish Callorhinchus milii 63 0.68 0.06 0.29 0.08 School shark Galeorhinus galeus 1308 0.72 0.01 0.41 0.02 Smooth hammerhead Sphyrna zygaena 122 0.89 0.03 0.43 0.10 Whiskery shark Furgaleus macki 221 0.93 0.02 0.59 0.07 Teleostei Thetis fish Neosebastes thetidis 14 0 0 0 0 Banded morwong Cheilodactylus spectabilis 90000 Blackspot boarfish Zanclistius elevatus 24 0 0 0.01 0.01 Speckled stargazer Kathetostoma canaster 20 0 0 0.02 0.02 Zebrafish Girella zebra 5 0 0 0.11 0.11 Moonlighter Vinculum sexfasciatum 11 0 0 0.20 0.09 Southern bluespotted flathead Platycephalus speculator 6 0 0 0.54 0.12 Knifejaw Oplegnathus woodwardi 134 0.01 0.01 0.01 0.01 Magpie perch Cheilodactylus nigripes 34 0.03 0.03 0.10 0.04 Longsnout boarfish Pentaceropsis recurvirostris 116 0.04 0.02 0.16 0.03 Leatherjackets Monacanthidae 42 0.05 0.03 0.08 0.03 Sweep Scorpis lineolatus 19 0.05 0.05 0.04 0.03 Tiger flathead Neoplatycephalus richardsoni 52 0.10 0.04 0.03 0.02 Bight redfish Centroberyx gerrardi 493 0.10 0.01 0.05 0.01 Jackass morwong Nemadactylus macropterus 17 0.12 0.08 0.20 0.05 Bluethroat wrasse Notolabrus tetricus 8 0.13 0.13 0 0 Short boarfish Parazanclistius hutchinsi 15 0.13 0.09 0.08 0.06 Rock ling Genypterus tigerinus 6 0.17 0.17 0 0

GHATF shark survey 59

Table 9 (Post‐capture mortality continued)

Common name Scientifc name Number Immediate Delayed Mean s.e. Mean s.e. Marblefish Aplodactylus arctidens 6 0.17 0.17 0 0 Blue morwong Nemadactylus valenciennesi 124 0.18 0.03 0.28 0.03 Yellowspotted boarfish Paristiopterus gallipavo 14 0.29 0.13 0.27 0.11 Latchet Pterygotrigla polyommata 35 0.31 0.08 0.15 0.06 Striped trumpeter Latris lineata 20 0.35 0.11 0.08 0.06 Snapper Pagrus auratus 144 0.38 0.04 0.37 0.03 Giant boarfish Paristiopterus labiosus 9 0.44 0.18 0.13 0.13 Sergeant baker Aulopus purpurissatus 14 0.50 0.14 0.21 0.13 Silver dory Cyttus australis 14 0.50 0.14 0.43 0.10 Western australian salmon Arripis truttaceus 14 0.57 0.14 0.65 0.13 Ocean jacket Nelusetta ayraudi 8 0.63 0.18 ND ND Swallowtail Centroberyx lineatus 19 0.63 0.11 0 0 Western blue groper Achoerodus gouldii 38 0.63 0.08 0.46 0.09 Blue warehou Seriolella brama 48 0.69 0.07 0.28 0.09 Dusky morwong Dactylophora nigricans 73 0.70 0.05 0.28 0.07 Silver drummer Kyphosus sydneyanus 15 0.73 0.12 ND ND Red gurnard Chelidonichthys kumu 29 0.90 0.06 ND ND Barracouta Thyrsites atun 19 0.95 0.05 ND ND Mulloway Argyrosomus japonicus 22 0.95 0.05 ND ND

GHATF shark survey 60

Table 10. Wildlife interactions in the 2007–08 survey Number of marine mammals, seabirds and other protected species caught by the different mesh‐sizes in the 2007–08 survey.

Common name or effort Scientifc name No. of individuals 4-inch 5-inch 6-inch 7-inch 8-inch Commercial Fishing effort (km- hour) 783 811 799 802 783 4249 Chondrichthyes White shark Carcharodon carcharias 00 0 00 3 Aves Short-tailed shearwater Puffinus tenuirostris 00 0 00 2 Cape Petrel Daption capense 00 0 01 0 Mammalia Australian fur-seal Arctocephalus pusillus doriferus 00 0 01 0 Seals Otariidae - undifferentiated 0 0 0 1 1 1 Bottlenose dolphin Tursiops truncatus 00 0 00 1 Common dolphin Delphinus delphis 00 0 00 2 Indian Ocean bottlenose dolphin Tursiops aduncus 01 0 00 0 Total 0 1 0 1 3 9

GHATF shark survey 61

Table 11. Carcass damage from predation on commercial species Percentage of carcass damage from predation on commercial species. 0, nil damage; 1, negligible damage (<3% loss of carcass); 2, minor damage (3–9% loss of carcass); 3, extensive damage (>9% loss of carcass).

Common name Scientifc name Number Damage 0123 Gummy shark Mustelus antarcticus 12011 96.8 0.2 0.1 2.8 School shark Galeorhinus galeus 5907 98.4 0.1 0.0 1.5 Common Sawshark Pristiophorus cirratus 1701 96.8 0 0.2 2.9 Southern Sawshark Pristiophorus nudipinnis 350 96.6 0 0 3.4 Elephantfish Callorhinchus milii 234 98.7 0 0 1.3

GHATF shark survey 62

Table 12. Number of samples collected for reproduction during 2007–08 survey Number of reproductive samples collected for each species.

Common name Scientifc name Number

Gummy shark Mustelus antarcticus Female 561 Male 163 School shark Galeorhinus galeus Female 505 Male 99 Common sawshark Pristiophorus cirratus Female 156 Male 12 Whiskery shark Furgaleus macki Female 13 Male 54 Southern sawshark Pristiophorus nudipinnis Female 28 Male 9 Broadnose sevengill shark Notorynchus cepedianus Female 5 Male 11 Bronze whaler Carcharhinus brachyurus Female 4 Male 10 Elephant fish Callorhinchus milii Female 5 Male 2 Smooth hammerhead Sphyrna zygaena Female 2 Male 3 Port Jackson shark Heterodontus portusjacksoni Male 4 Spikey spurdog Squalus megalops Female 3 Australian angelshark Squatina australis Female 1 Male 1 Pencil shark Hypogaleus hyugaensis Male 2 Bluntnose sixgill shark Hexanchus griseus Male 1 Brier shark Deania calcea Female 1 Ornate angelshark Squatina tergocellata Female 1 Total 1656

GHATF shark survey 63

64 GHATF Table 13. Gillnet relative length selectivity analysis for gummy shark (Mustelus antarcticus) during 1973–76 Across 73 fishing sites of southern Australia (mainly Bass Strait); ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived

shark parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

survey Total length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 400–499 450 0.0 0.0 0.125 0.002 0.000 0.000 0.000 0.025 0.0 0.0 0.0 0.0 0.0 0.0 0 500–599 550 12.3 0.0 0.0 0.0 0.0 12.3 12.3 0.0 0.0 0.0 0.0 12.3 0.454 0.031 0.000 0.000 0.000 0.097 11.5 0.8 0.0 0.0 0.0 12.3 6 600–699 650 37.8 0.0 0.0 0.0 0.0 37.8 37.8 0.0 0.0 0.0 0.0 37.8 0.851 0.186 0.005 0.000 0.000 0.209 30.9 6.7 0.2 0.0 0.0 37.8 9 700–799 750 57.3 25.1 0.0 0.0 0.0 82.3 57.3 25.1 0.0 0.0 0.0 82.3 0.999 0.535 0.054 0.001 0.000 0.318 51.8 27.7 2.8 0.0 0.0 82.3 13 800–899 850 50.1 76.2 21.3 0.0 0.0 147.6 50.1 76.2 21.3 0.0 0.0 147.6 0.824 0.898 0.243 0.011 0.000 0.395 61.6 67.1 18.2 0.8 0.0 147.6 19 900–999 950 24.5 50.2 35.8 3.0 0.0 113.5 24.5 50.2 35.8 3.0 0.0 113.5 0.517 0.990 0.605 0.079 0.002 0.439 26.8 51.2 31.3 4.1 0.1 113.5 13 1000–1099 1050 13.3 41.1 56.0 13.0 3.0 126.5 13.3 41.1 56.0 13.0 3.0 126.5 0.261 0.781 0.934 0.299 0.018 0.459 14.4 43.1 51.5 16.5 1.0 126.5 14 1100–1199 1150 5.1 36.1 29.0 28.1 5.0 103.3 5.1 36.1 29.0 28.1 5.0 103.3 0.110 0.468 0.975 0.669 0.107 0.466 4.9 20.8 43.3 29.7 4.7 103.3 11 1200–1299 1250 1.0 12.0 16.4 35.1 19.1 83.7 1.0 12.0 16.4 35.1 19.1 83.7 0.040 0.223 0.735 0.962 0.355 0.463 1.4 8.1 26.5 34.8 12.8 83.7 9 1300–1399 1350 0.0 2.0 3.9 13.0 10.0 28.9 0.0 2.0 3.9 13.0 10.0 28.9 0.013 0.088 0.420 0.953 0.727 0.440 0.2 1.2 5.5 12.5 9.6 28.9 3 1400–1499 1450 0.0 2.0 1.0 3.0 5.0 11.0 0.0 2.0 1.0 3.0 5.0 11.0 0.004 0.029 0.190 0.686 0.982 0.378 0.0 0.2 1.1 4.0 5.7 11.0 1 1500–1599 1550 0.0 0.0 0.0 2.0 3.0 5.0 0.0 0.0 0.0 2.0 3.0 5.0 0.001 0.008 0.070 0.374 0.925 0.276 0.0 0.0 0.3 1.4 3.4 5.0 1 1600–1699 1650 0.0 0.0 0.0 0.0 3.0 3.0 0.0 0.0 0.0 0.0 3.0 3.0 0.000 0.002 0.021 0.160 0.636 0.164 0.0 0.0 0.1 0.6 2.3 3.0 1 1700–1799 1750 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1800–1899 1850 0.0 0.0 Total 201.5 244.8 163.3 97.3 48.2 755.0 201.5 244.8 163.3 97.3 48.2 755.0 1.050 1.060 1.063 1.048 0.938 1.032 203.4 226.9 180.7 104.3 39.6 755.0 100

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 20 Solver Mean 95% CL 1.0 4-inch estimates Lower Upper mesh-size θ1 185.2 185.4 179.1 192.1 0.8 5678 θ2 29431 30241 18564 46697 15 ML 1817 1808 1672 1948 0.6 Mesh Size (inch) 45678 10 Derivations from EXCEL Solver parameter estimates α 19.6 30.1 42.9 58.1 75.6 0.4 β 37.8 30.8 25.9 22.3 19.6 A 5 αβ 741 926 1111 1297 1482 Population frequency (%) .

Gillnet relative selectivity . selectivity relative Gillnet 0.2 Derivations from bootstrap parameter estimates α 19.1 29.4 41.9 56.7 73.7 β 38.7 31.5 26.5 22.9 20.1 0.0 0 αβA 742 927 1113 1298 1483 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 550 650 750 850 950 1050 1150 1250 1350 1450 1550 1650 No. boostrapped datasets 980 Total length (mm) Total length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm)

Table 14. Gillnet relative length selectivity analysis for gummy shark (Mustelus antarcticus) during 1986–87 Across 144 fishing sites of southern Australia ; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Total length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 400–499 450 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.006 0.000 0.000 0.000 0.001 0.0 0.0 0.0 0.0 0.0 0 500–599 550 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.073 0.001 0.000 0.000 0.015 0.0 0.0 0.0 0.0 0.0 0 600–699 650 32.0 3.0 0.0 0.0 35.0 32.0 3.0 0.0 0.0 35.0 0.335 0.019 0.000 0.000 0.071 8.9 0.5 0.0 0.0 9.4 3 700–799 750 161.9 9.1 0.0 0.0 171.0 161.9 9.1 0.0 0.0 171.0 0.755 0.136 0.004 0.000 0.179 70.6 12.7 0.3 0.0 83.6 12 800–899 850 325.8 71.7 1.0 0.0 398.5 325.8 71.7 1.0 0.0 398.5 0.996 0.459 0.042 0.001 0.299 186.0 85.6 7.8 0.1 279.5 24 900–999 950 178.9 150.5 20.7 0.0 350.1 178.9 150.5 20.7 0.0 350.1 0.868 0.857 0.214 0.010 0.390 133.2 131.5 32.9 1.5 299.1 19 1000–1099 1050 98.9 124.2 41.3 8.9 273.4 98.9 124.2 41.3 8.9 273.4 0.542 0.996 0.581 0.076 0.439 63.5 116.6 68.0 8.9 257.1 15 1100–1199 1150 49.0 51.5 50.2 23.7 174.4 49.0 51.5 50.2 23.7 174.4 0.258 0.786 0.933 0.306 0.457 19.3 58.8 69.7 22.9 170.7 9 1200–1299 1250 26.0 22.2 40.3 31.6 120.2 26.0 22.2 40.3 31.6 120.2 0.098 0.449 0.967 0.697 0.442 5.3 24.2 52.2 37.6 119.4 7 1300–1399 1350 5.0 14.1 13.8 15.8 48.7 5.0 14.1 13.8 15.8 48.7 0.031 0.195 0.693 0.981 0.380 0.8 5.0 17.7 25.1 48.6 3 1400–1499 1450 1.0 10.1 3.0 11.9 25.9 1.0 10.1 3.0 11.9 25.9 0.008 0.067 0.362 0.914 0.270 0.2 1.3 6.9 17.5 25.9 2 1500–1599 1550 1.0 2.0 2.0 6.9 11.9 1.0 2.0 2.0 6.9 11.9 0.002 0.019 0.144 0.596 0.152 0.0 0.3 2.2 9.3 11.9 2 1600–1699 1650 0.0 1.0 3.0 3.0 6.9 0.0 1.0 3.0 3.0 6.9 0.000 0.004 0.045 0.284 0.067 0.0 0.1 0.9 5.9 6.9 3 1700–1799 1750 0.0 0.0 0.000 0.001 0.011 0.103 0.023 0.0 0.0 0.0 0.0 0.0 0 1800–1899 1850 0.0 0.0 Total 879.5 459.6 175.1 101.8 1616.0 879.5 459.6 175.1 101.8 1616.0 0.993 0.997 0.999 0.992 0.796 487.8 436.6 258.8 128.9 1312.1 100

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 4-inch Solver Mean 95% CL 1.0 25 estimates Lower Upper mesh-size 5678 θ1 172.6 173.3 169.3 177.1 20 θ2 25805 26548 18084 35913 0.8 ML 5262 5258 5033 5531 0.6 15 Mesh Size (inch) 45678

Derivations from EXCEL Solver parameter estimates 10 α 19.4 29.8 42.6 57.6 74.9 0.4 β 35.5 28.9 24.3 21.0 18.4 αβA 691 863 1036 1208 1381 Population frequency (%) . 5 Gillnet relative selectivity . selectivity relative Gillnet 0.2 Derivations from bootstrap parameter estimates α 19.1 29.3 41.7 56.4 73.4 β 36.4 29.6 24.9 21.5 18.9 0.0 0 αβA 693 867 1040 1213 1387 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 450 550 650 750 850 950 1050 1150 1250 1350 1450 1550 1650 1750 No. boostrapped datasets 394 Total length (mm) Total length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm) GHATF

shark

survey

65

66 GHATF Table 15. Gillnet relative length selectivity analysis for gummy shark (Mustelus antarcticus) during 2007–08 Across 187 fishing sites of southern Australia ; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

shark

Total length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn

survey Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 400–499 450 1.0 0.0 0.0 0.0 0.0 1.0 1.0 0.0 0.0 0.0 0.0 1.0 0.096 0.001 0.000 0.000 0.000 0.019 1.0 0.0 0.0 0.0 0.0 1.0 0 500–599 550 26.5 2.0 1.0 0.0 0.0 29.5 26.5 2.0 1.0 0.0 0.0 29.5 0.416 0.020 0.000 0.000 0.000 0.087 28.1 1.3 0.0 0.0 0.0 29.5 2

600–699 650 728.8 21.6 5.0 1.0 0.0 756.4 728.8 21.6 5.0 1.0 0.0 756.4 0.843 0.152 0.003 0.000 0.000 0.200 639.2 115.1 2.1 0.0 0.0 756.4 22 700–799 750 461.7 194.8 3.0 0.0 1.0 660.6 461.7 194.8 3.0 0.0 1.0 660.6 0.996 0.504 0.037 0.000 0.000 0.308 428.0 216.5 16.0 0.1 0.0 660.6 13 800–899 850 279.3 698.7 82.9 4.0 2.0 1066.9 279.3 698.7 82.9 4.0 2.0 1066.9 0.785 0.897 0.208 0.006 0.000 0.379 441.8 504.5 117.1 3.4 0.0 1066.9 17 900–999 950 96.8 529.4 344.6 20.9 3.1 994.8 96.8 529.4 344.6 20.9 3.1 994.8 0.452 0.983 0.582 0.059 0.001 0.415 216.5 471.0 279.0 28.0 0.3 994.8 14 1000–1099 1050 20.4 252.9 330.6 94.5 10.2 708.6 20.4 252.9 330.6 94.5 10.2 708.6 0.202 0.732 0.938 0.266 0.011 0.430 66.7 241.4 309.2 87.6 3.7 708.6 10 1100–1199 1150 12.2 150.6 266.7 192.1 33.6 655.2 12.2 150.6 266.7 192.1 33.6 655.2 0.074 0.397 0.961 0.655 0.084 0.434 22.3 119.9 290.1 197.6 25.3 655.2 9 1200–1299 1250 5.1 55.1 134.8 137.3 76.4 408.8 5.1 55.1 134.8 137.3 76.4 408.8 0.023 0.166 0.676 0.968 0.326 0.432 4.3 31.4 128.1 183.4 61.7 408.8 6 1300–1399 1350 5.1 19.7 69.9 92.5 68.3 255.5 5.1 19.7 69.9 92.5 68.3 255.5 0.006 0.055 0.346 0.931 0.722 0.412 0.7 6.9 42.9 115.5 89.5 255.5 4 1400–1499 1450 0.0 10.8 21.0 54.7 37.7 124.2 0.0 10.8 21.0 54.7 37.7 124.2 0.001 0.015 0.135 0.618 0.989 0.352 0.1 1.1 9.5 43.7 69.9 124.2 2 1500–1599 1550 0.0 3.0 10.0 21.9 28.5 63.4 0.0 3.0 10.0 21.9 28.5 63.4 0.000 0.004 0.041 0.298 0.893 0.247 0.0 0.2 2.1 15.3 45.8 63.4 2 1600–1699 1650 0.0 0.0 2.0 3.0 10.2 15.2 0.0 0.0 2.0 3.0 10.2 15.2 0.000 0.001 0.010 0.109 0.560 0.136 0.0 0.0 0.2 2.4 12.5 15.2 1 1700–1799 1750 0.0 0.0 0.0 2.0 0.0 2.0 0.0 0.0 1.0 2.0 0.0 3.0 0.000 0.000 0.002 0.031 0.255 0.058 0.0 0.0 0.0 0.3 2.6 3.0 0 1800–1899 1850 0.0 0.0 1.0 0.0 0.0 1.0 Total 1636.9 1938.6 1272.5 623.9 271.1 5743.0 1636.9 1938.6 1272.5 623.9 271.1 5743.0 0.974 0.982 0.985 0.985 0.960 0.977 1848.7 1709.3 1196.3 677.4 311.3 5743.0 100

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 25 Solver Mean 95% CL 1.0 4-inch estimates Lower Upper mesh-size θ1 184.2 184.3 181.8 186.8 78 20 θ2 25133 25217 20627 30973 0.8 56 ML 25951 25983 25522 26418 0.6 15 Mesh Size (inch) 45678

Derivations from EXCEL Solver parameter estimates 10 α 22.6 34.7 49.6 67.1 87.4 0.4 β 32.7 26.5 22.3 19.2 16.9 αβA 737 921 1105 1289 1474 Population frequency (%) . 5 Gillnet relative selectivity . selectivity relative Gillnet 0.2 Derivations from bootstrap parameter estimates α 22.5 34.6 49.5 67.0 87.2 β 32.8 26.6 22.4 19.3 16.9 0.0 0 αβA 737 922 1106 1290 1474 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 450 550 650 750 850 950 1050 1150 1250 1350 1450 1550 1650 1750 No. boostrapped datasets 1094 Total length (mm) Total length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm)

Table 16. Gillnet relative length selectivity analysis for school shark (Galeorhinus galeus) during 1986–87 Across 144 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Total length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 400–499 450 1.0 1.0 0.0 0.094 0.006 0.000 0.000 0.020 0.0 0.0 0.0 0.0 0.0 0 500–599 550 1.0 1.0 2.0 2.0 0.0 0.0 1.0 3.0 0.300 0.042 0.002 0.000 0.069 0.8 0.1 0.0 0.0 0.9 1 600–699 650 74.0 74.0 74.0 0.0 0.0 0.0 74.0 0.605 0.164 0.017 0.001 0.157 25.3 6.9 0.7 0.0 32.9 11 700–799 750 96.0 22.0 1.0 2.0 121.0 96.0 22.0 1.0 2.0 121.0 0.879 0.404 0.079 0.006 0.273 45.5 20.9 4.1 0.3 70.8 14 800–899 850 99.0 35.0 1.0 135.0 99.0 35.0 1.0 0.0 135.0 0.998 0.701 0.238 0.034 0.394 48.4 34.0 11.6 1.6 95.6 13 900–999 950 52.0 40.0 12.0 5.0 109.0 52.0 40.0 12.0 5.0 109.0 0.938 0.932 0.499 0.124 0.498 33.1 32.9 17.6 4.4 87.9 9 1000–1099 1050 31.0 40.0 11.0 3.0 85.0 31.0 40.0 11.0 3.0 85.0 0.756 0.998 0.782 0.315 0.570 19.8 26.1 20.4 8.2 74.5 7 1100–1199 1150 16.0 22.0 25.0 7.0 70.0 16.0 22.0 25.0 7.0 70.0 0.539 0.897 0.969 0.587 0.598 11.6 19.4 20.9 12.7 64.7 6 1200–1299 1250 13.0 15.0 31.0 17.0 76.0 13.0 15.0 31.0 17.0 76.0 0.346 0.697 0.985 0.850 0.576 8.7 17.5 24.8 21.4 72.4 7 1300–1399 1350 6.0 17.0 31.0 21.0 75.0 6.0 17.0 31.0 21.0 75.0 0.203 0.478 0.849 0.991 0.504 5.9 13.8 24.5 28.6 72.8 8 1400–1499 1450 14.0 16.0 28.0 30.0 88.0 14.0 16.0 28.0 30.0 88.0 0.111 0.295 0.634 0.961 0.400 4.8 12.7 27.3 41.5 86.3 11 1500–1599 1550 8.0 13.0 19.0 25.0 65.0 8.0 13.0 19.0 25.0 65.0 0.057 0.166 0.418 0.794 0.287 2.5 7.4 18.7 35.5 64.1 12 1600–1699 1650 1.0 3.0 6.0 10.0 1.0 1.0 4.0 6.0 12.0 0.027 0.086 0.248 0.570 0.186 0.3 1.1 3.2 7.3 11.9 3 1700–1799 1750 1.0 1.0 2.0 0.0 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0 1800–1899 1850 0.0 0.0 Total 412.0 221.0 163.0 117.0 913.0 412.0 221.0 163.0 117.0 913.0 1.463 1.466 1.430 1.308 1.134 206.7 192.8 173.9 161.5 734.9 100

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 4-inch Solver Mean 95% CL 1.0 15 estimates Lower Upper mesh-size 5678 θ1 172.7 173.4 166.1 181.5 θ2 58557 61700 36795 82871 0.8 ML 1991 2039 1923 2176 10 0.6 Mesh Size (inch) 45678

Derivations from EXCEL Solver parameter estimates α 9.0 13.7 19.3 25.9 33.6 0.4 5 β 76.3 63.2 53.7 46.6 41.2 αβA 691 863 1036 1209 1382 Population frequency (%) .

Gillnet relative selectivity . selectivity relative Gillnet 0.2 Derivations from bootstrap parameter estimates α 8.7 13.1 18.5 24.8 32.2 β 79.8 66.1 56.3 48.9 43.1 0.0 0 αβA 694 867 1040 1214 1387 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 450 550 650 750 850 950 1050 1150 1250 1350 1450 1550 1650 No. boostrapped datasets 1032 Total length (mm) Total length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm)

GHATF

shark

survey

67

68 GHATF Table 17. Gillnet relative length selectivity analysis for school shark (Galeorhinus galeus) during 2007–08 Across 187 fishing sites of southern Australia ; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating

shark relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Total length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size

survey No. in popn Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 300–399 350 0.0 0.0 0.0 0.0 1.0 1.0 0.939 0.484 0.103 0.008 0.000 0.307 6.2 3.2 0.7 0.0 0.0 10.2 1 400–499 450 1.0 0.0 0.0 0.0 0.0 1.0 0.997 0.773 0.284 0.042 0.002 0.420 18.0 14.0 5.1 0.8 0.0 38.0 2

500–599 550 6.1 0.0 0.0 0.0 0.0 6.1 0.898 0.964 0.554 0.144 0.014 0.515 18.0 19.3 11.1 2.9 0.3 51.6 2 600–699 650 9.2 0.0 1.0 0.0 0.0 10.2 9.2 0.0 1.0 0.0 0.0 10.2 0.711 0.990 0.822 0.344 0.062 0.586 10.6 14.7 12.2 5.1 0.9 43.6 1 700–799 750 17.3 16.7 4.0 0.0 0.0 38.0 17.3 16.7 4.0 0.0 0.0 38.0 0.509 0.872 0.981 0.614 0.184 0.632 14.1 24.1 27.2 17.0 5.1 87.5 3 800–899 850 7.1 26.5 14.0 3.0 1.0 51.6 7.1 26.5 14.0 3.0 1.0 51.6 0.335 0.676 0.979 0.862 0.399 0.650 23.1 46.6 67.5 59.4 27.5 224.0 6 900–999 950 4.1 20.6 15.9 3.0 0.0 43.6 4.1 20.6 15.9 3.0 0.0 43.6 0.205 0.472 0.842 0.992 0.667 0.636 23.5 54.1 96.5 113.7 76.4 364.3 11 1000–1099 1050 5.1 25.5 42.9 10.9 3.1 87.5 5.1 25.5 42.9 10.9 3.1 87.5 0.119 0.302 0.639 0.964 0.896 0.584 24.4 61.9 131.2 197.9 184.0 599.5 19 1100–1199 1150 6.1 35.4 79.7 80.4 22.4 224.0 6.1 35.4 79.7 80.4 22.4 224.0 0.065 0.179 0.435 0.810 0.998 0.498 23.5 64.2 156.4 291.1 358.6 893.8 34 1200–1299 1250 2.0 36.3 96.7 153.9 75.3 364.3 2.0 36.3 96.7 153.9 75.3 364.3 0.034 0.099 0.270 0.601 0.945 0.390 6.7 19.2 52.3 116.3 182.9 377.3 18 1300–1399 1350 12.2 67.8 116.6 206.6 196.3 599.5 12.2 67.8 116.6 206.6 196.3 599.5 0.017 0.052 0.155 0.399 0.776 0.280 0.4 1.3 3.9 10.0 19.5 35.1 2 1400–1499 1450 11.2 105.1 165.5 304.9 307.2 893.8 11.2 105.1 165.5 304.9 307.2 893.8 0.009 0.026 0.082 0.241 0.562 0.184 0.1 0.2 0.6 1.8 4.3 7.0 1 1500–1599 1550 7.1 33.4 66.8 106.3 163.8 377.3 7.1 33.4 66.8 106.3 163.8 377.3 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1600–1699 1650 1.0 3.9 7.0 9.9 13.2 35.1 1.0 3.9 7.0 9.9 13.2 35.1 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1700–1799 1750 0.0 0.0 2.0 3.0 2.0 7.0 0.0 0.0 2.0 3.0 2.0 7.0 Total 89.5 371.2 612.1 881.9 785.3 2740.0 82.4 371.2 612.1 881.9 784.3 2731.9 1.210 1.472 1.537 1.505 1.377 1.420 168.6 322.9 564.7 816.1 859.6 2731.9 100

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 35 Solver Mean 95% CL 1.0 4-inch estimates Lower Upper mesh-size 5678 θ1 183.0 183.0 176.9 188.3 30 θ2 64749 65764 53023 80676 0.8 ML 10103 9945 9712 10181 25 0.6 Mesh Size (inch) 4 5 6 7 8 20

Derivations from EXCEL Solver parameter estimates 15 α 9.2 13.9 19.6 26.3 34.1 0.4 β 79.8 66.0 56.1 48.7 43.0 10 αβA 732 915 1098 1281 1464 Population frequency (%) .

Gillnet relative selectivity . selectivity relative Gillnet 0.2 Derivations from bootstrap parameter estimates 5 α 9.0 13.7 19.3 25.9 33.6 β 80.9 67.0 56.9 49.4 43.6 0.0 0 αβA 732 915 1098 1281 1464 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 650 750 850 950 1050 1150 1250 1350 1450 1550 1650 1750 No. bootstrapped sets 707 Total length (mm) Total length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm)

Table 18. Gillnet relative length selectivity analysis for common sawshark (Pristiophorus cirratus) during 2007–08 Across 187 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Total length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 400–499 450 0.0 0.0 0.0 0.0 0.0 0.0 0.0 500–599 550 0.0 1.0 0.0 0.0 0.0 1.0 0.0 600–699 650 0.0 0.0 0.0 0.0 0.0 0.0 0.0 700–799 750 8.1 2.0 0.0 0.0 1.0 11.1 8.1 2.0 0.0 0.0 1.0 11.1 0.929 0.975 0.670 0.271 0.058 0.581 71.0 74.5 51.2 20.7 4.5 221.8 30 800–899 850 16.3 6.9 1.0 0.0 1.0 25.2 16.3 6.9 1.0 0.0 1.0 25.2 0.821 0.999 0.842 0.442 0.132 0.647 32.1 39.1 32.9 17.3 5.2 126.6 15 900–999 950 65.2 50.1 8.0 4.0 4.1 131.4 65.2 50.1 8.0 4.0 4.1 131.4 0.692 0.953 0.957 0.633 0.250 0.697 27.2 37.5 37.6 24.9 9.8 137.0 15 1000–1099 1050 74.3 88.5 34.9 15.9 8.1 221.8 74.3 88.5 34.9 15.9 8.1 221.8 0.560 0.855 1.000 0.808 0.410 0.727 12.5 19.0 22.2 18.0 9.1 80.8 9 1100–1199 1150 23.4 49.2 31.9 13.9 8.1 126.6 23.4 49.2 31.9 13.9 8.1 126.6 0.437 0.729 0.971 0.935 0.594 0.733 2.6 4.4 5.8 5.6 3.6 22.1 2 1200–1299 1250 31.6 29.5 35.9 29.8 10.2 137.0 31.6 29.5 35.9 29.8 10.2 137.0 0.332 0.594 0.886 0.996 0.771 0.716 0.3 0.5 0.7 0.8 0.7 3.0 0 1300–1399 1350 5.1 18.7 24.0 21.9 11.2 80.8 5.1 18.7 24.0 21.9 11.2 80.8 0.245 0.465 0.764 0.985 0.910 0.674 0.0 0.0 0.0 0.0 0.0 0.0 0 1400–1499 1450 3.1 3.9 4.0 5.0 6.1 22.1 3.1 3.9 4.0 5.0 6.1 22.1 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1500–1599 1550 0.0 1.0 0.0 0.0 2.0 3.0 0.0 1.0 0.0 0.0 2.0 3.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1600–1699 1650 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1700–1799 1750 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1800–1899 1850 0.0 0.0 0.0 0.0 1.0 1.0 0.0 Total 227.1 250.7 139.7 90.5 53.0 761.0 227.1 249.7 139.7 90.5 51.9 759.0 1.004 1.392 1.522 1.267 0.781 1.193 145.7 174.9 150.6 87.3 32.8 591.3 72

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 30 Solver Mean 95% CL 1.0 7 estimates Lower Upper 4-inch 56 mesh-size 8 θ1 226.3 229.6 212.5 264.0 25 0.8 θ2 150053 175146 67760 456972 ML 1835 1868 1740 1984 20 0.6 Mesh Size (inch) 45678 15 Derivations from EXCEL Solver parameter estimates 0.4 α 6.3 9.4 13.2 17.7 22.8 10 β 143.2 119.9 102.8 89.7 79.4 αβA 905 1131 1358 1584 1810 Population frequency (%) . Gillnet relative selectivity . selectivity relative Gillnet 0.2 5 Derivations from bootstrap parameter estimates α 5.7 8.4 11.8 15.7 20.2 β 162.1 136.4 117.2 102.5 90.9 0.0 0 αβA 918 1148 1377 1607 1837 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 750 850 950 1050 1150 1250 1350 1450 1550 1650 No. boostrapped datasets 1026 Total length (mm) Total length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm)

GHATF

shark

survey

69

70 GHATF Table 19. Gillnet relative length selectivity analysis for southern sawshark shark (Pristiophorus nudipinnis) during 2007–08 Across 187 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating

shark relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Total length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size

survey No. in popn Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 400–499 450 0.0 0.0 0.503 0.124 0.012 0.000 0.000 0.128 2.4 0.6 0.1 0.0 0.0 3.0 4 500–599 550 0.0 0.0 0.705 0.253 0.039 0.002 0.000 0.200 0.7 0.3 0.0 0.0 0.0 1.0 1

600–699 650 1.0 1.0 1.0 0.0 0.0 3.0 1.0 1.0 1.0 0.0 0.0 3.0 0.870 0.425 0.099 0.010 0.000 0.281 19.4 9.5 2.2 0.2 0.0 31.3 19 700–799 750 1.0 0.0 0.0 0.0 0.0 1.0 1.0 0.0 0.0 0.0 0.0 1.0 0.971 0.616 0.202 0.030 0.002 0.364 58.2 37.0 12.1 1.8 0.1 109.2 52 800–899 850 26.4 3.9 1.0 0.0 0.0 31.3 26.4 3.9 1.0 0.0 0.0 31.3 1.000 0.792 0.349 0.075 0.007 0.445 25.0 19.8 8.7 1.9 0.2 55.6 21 900–999 950 64.9 31.3 10.9 0.0 2.0 109.2 64.9 31.3 10.9 0.0 2.0 109.2 0.965 0.923 0.525 0.156 0.022 0.518 3.3 3.2 1.8 0.5 0.1 8.9 3 1000–1099 1050 18.3 25.5 10.9 1.0 0.0 55.6 18.3 25.5 10.9 1.0 0.0 55.6 0.881 0.991 0.704 0.278 0.055 0.582 0.0 0.0 0.0 0.0 0.0 0.0 0 1100–1199 1150 1.0 0.0 2.0 0.0 0.0 3.0 1.0 2.9 4.0 1.0 0.0 8.9 0.769 0.993 0.857 0.436 0.117 0.634 0.0 0.0 0.0 0.0 0.0 0.0 0 1200–1299 1250 0.0 2.0 0.0 1.0 0.0 2.9 0.0 0.645 0.938 0.959 0.610 0.216 0.674 0.0 0.0 0.0 0.0 0.0 0.0 0 1300–1399 1350 0.0 1.0 2.0 0.0 0.0 3.0 0.0 0.523 0.841 0.999 0.776 0.353 0.698 0.0 0.0 0.0 0.0 0.0 0.0 0 1400–1499 1450 0.0 0.0 0.411 0.722 0.978 0.907 0.516 0.707 0.0 0.0 0.0 0.0 0.0 0.0 0 1500–1599 1550 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1600–1699 1650 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1700–1799 1750 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1800–1899 1850 0.0 Total 112.6 64.6 27.8 2.0 2.0 209.0 112.6 64.6 27.8 2.0 2.0 209.0 2.060 1.905 1.431 0.820 0.322 1.307 109.0 70.3 25.0 4.4 0.4 209.0 100

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates Solver Mean 95% CL 1.0 25 4-inch estimates Lower Upper 56 mesh-size θ1 260.5 264.8 233.6 322.7 20 θ2 172248 265 84788 485399 0.8 ML 441 265 423 464 7 0.6 15 Mesh Size (inch) 45678 8 Derivations from EXCEL Solver parameter estimates 10 α 7.2 10.8 15.1 20.3 26.2 0.4 β 145.1 121.0 103.4 90.0 79.6 αβA 1042 1303 1563 1824 2084 Population frequency (%) . 5 Gillnet relative selectivity . 0.2 Derivations from bootstrap parameter estimates α 4237.7 6620.9 9533.6 12975.9 16947.9 β 0.2 0.2 0.2 0.1 0.1 0.0 0 αβA 1059 1324 1589 1854 2118 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 650 750 850 950 1050 1150 No. boostrapped datasets 862 Total length (mm) Total length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm)

Table 20. Gillnet relative length selectivity analysis for elephant fish (Callorhinchus milii) during 2007–08 Across 187 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Fork length (mm) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn Range Mid-point 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 400–499 450 0.0 0.0 3.0 0.0 0.0 3.0 0.0 0.0 3.0 0.0 0.0 3.0 0.988 0.718 0.312 0.073 0.008 0.420 1.4 1.0 0.4 0.1 0.0 3.0 7 500–599 550 0.0 4.9 4.0 1.0 1.0 11.0 0.0 4.9 4.0 1.0 1.0 11.0 0.945 0.968 0.664 0.277 0.064 0.584 3.5 3.6 2.5 1.0 0.2 11.0 18 600–699 650 2.0 3.0 17.0 3.0 1.0 26.0 2.0 3.0 17.0 3.0 1.0 26.0 0.743 0.972 0.939 0.608 0.242 0.701 5.5 7.2 7.0 4.5 1.8 26.0 35 700–799 750 2.0 6.9 14.0 1.0 1.0 25.0 2.0 6.9 14.0 1.0 1.0 25.0 0.507 0.792 0.990 0.902 0.551 0.749 3.4 5.3 6.6 6.0 3.7 25.0 31 800–899 850 0.0 1.0 5.0 0.0 0.0 6.0 0.0 1.0 5.0 0.0 0.0 6.0 0.311 0.552 0.839 0.999 0.859 0.712 0.5 0.9 1.4 1.7 1.4 6.0 8 900–999 950 0.0 0.0 1.0 0.0 0.0 1.0 0.0 0.0 1.0 0.0 0.0 1.0 0.176 0.340 0.599 0.881 0.999 0.599 0.1 0.1 0.2 0.3 0.3 1.0 2 1000–1099 1050 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1100–1199 1150 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1200–1299 1250 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1300–1399 1350 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1400–1499 1450 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1500–1599 1550 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1600–1699 1650 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1700–1799 1750 0.0 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.0 0.0 0.0 0.0 0.0 0.0 0 1800–1899 1850 0.0 Total 4.1 15.8 44.1 5.0 3.1 72.0 4.1 15.8 44.1 5.0 3.1 72.0 0.917 1.086 1.086 0.935 0.681 0.941 14.4 18.2 18.1 13.7 7.5 72.0 100

Parameter estimates Gillnet relative selectivity against length of shark by mesh-size Estimated percentage-length-frequency distribution for shark population Parameter EXCEL Bootstrap estimates Solver Mean 95% CL 1.0 4-inch 35 8 estimates Lower Upper mesh-size 56 7 θ1 120.1 120.8 116.3 126.4 30 θ2 45959 48740 25902 87261 0.8 ML 25 26 15 40 25 0.6 Mesh Size (inch) 45678 20

Derivations from EXCEL Solver parameter estimates 15 α 5.9 8.7 12.2 16.3 21.0 0.4 β 81.7 68.7 59.0 51.5 45.7 10 αβA 480 601 721 841 961 Population frequency (%) . Gillnet relative selectivity . 0.2 Derivations from bootstrap parameter estimates 5 α 5.6 8.4 11.7 15.6 20.1 β 85.7 72.1 62.0 54.2 48.0 0.0 0 αβA 483 604 725 846 966 400 500 600 700 800 900 1000 450 550 650 750 850 950 No. boostrapped datasets 866 Fork length (mm) Fork length mid-point of 100-mm range (mm) ALength at maximum selectivity (mm)

GHATF

shark

survey

71

72 GHATF Table 21. Gillnet relative age selectivity analysis for male gummy shark (Mustelus antarcticus) during 1986–87 Across 144 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating

shark relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

survey Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5

1.5 2.5 53.5 1.0 54.5 53.5 1.0 0.0 0.0 54.5 0.260 0.041 0.002 0.000 0.000 0.061 51.4 3.1 0.1 0.0 54.5 58 3.5 102.6 27.5 130.1 102.6 27.5 0.0 0.0 130.1 0.641 0.225 0.037 0.003 0.000 0.181 110.6 18.2 1.3 0.0 130.1 23 4.5 144.0 71.0 1.0 216.0 144.0 71.0 0.0 1.0 216.0 0.933 0.560 0.184 0.030 0.002 0.342 155.8 51.3 8.3 0.6 216.0 13 5.5 53.0 38.4 2.2 1.5 95.0 53.0 38.4 2.2 1.5 95.0 0.993 0.874 0.478 0.146 0.023 0.503 54.6 29.9 9.1 1.4 95.0 3 6.5 24.3 26.3 13.3 3.9 67.9 24.3 26.3 13.3 3.9 67.9 0.858 1.000 0.801 0.398 0.112 0.634 29.4 23.5 11.7 3.3 67.9 1 7.5 14.7 11.3 18.3 2.0 46.3 14.7 11.3 18.3 2.0 46.3 0.639 0.917 0.985 0.718 0.324 0.717 14.4 15.5 11.3 5.1 46.3 1 8.5 8.6 1.3 10.3 3.0 23.1 8.6 1.3 10.3 3.0 23.1 0.426 0.712 0.961 0.951 0.630 0.736 5.1 6.8 6.8 4.5 23.1 0 9.5 5.4 1.3 10.3 2.5 19.5 5.4 1.3 10.3 2.5 19.5 0.261 0.486 0.783 0.990 0.899 0.684 3.0 4.8 6.1 5.6 19.5 0 10.5 1.4 1.0 5.7 3.0 11.0 1.4 1.0 5.7 3.0 11.0 0.149 0.300 0.552 0.850 1.000 0.570 1.2 2.3 3.5 4.1 11.0 0 11.5 0.0 7.0 1.0 8.0 0.0 0.0 7.0 1.0 8.0 0.080 0.170 0.346 0.623 0.908 0.425 0.7 1.4 2.4 3.6 8.0 0 12.5 0.0 2.4 1.0 3.4 0.0 0.0 2.4 1.0 3.4 0.041 0.090 0.197 0.401 0.696 0.285 0.2 0.5 1.0 1.7 3.4 0 13.5 1.0 1.0 14.5 0.0 15.5 0.0 16.5 0.0 Total 407.6 180.1 69.6 18.7 676.0 407.6 179.1 69.6 18.7 675.0 426.4 157.3 61.5 29.8 675.0 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 60 Solver Mean 95% CL 1.0 5 6 7 estimates Lower Upper 4-inch 8 θ1 1.31 1.23 1.08 1.41 mesh-size 50 0.8 θ2 5.16 7.03 3.61 12.95 ML 1863 1769 1659 1902 40 0.6 Mesh Size (inch) 45678 30 Derivations from EXCEL Solver parameter estimates 0.4 α 6.2 9.2 12.9 17.3 22.3 20 β 0.8 0.7 0.6 0.5 0.5 αβA 5.2 6.6 7.9 9.2 10.5 Population frequency (%) . (%) frequency Population

Gillnet relative selectivity . relative selectivity Gillnet 0.2 10 Derivations from bootstrap parameter estimates α 4.2 6.2 8.6 11.4 14.6 0.0 β 1.2 1.0 0.9 0.8 0.7 0 αβA 4.9 6.1 7.4 8.6 9.8 012345678910111213141516 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 No. boostrapped datasets 447 Age (years) Age (years) AAge at maximum selectivity (mm)

Table 22. Gillnet relative age selectivity analysis for female gummy shark (Mustelus antarcticus) during 1986–87 Across 144 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5 1.5 3.8 2.1 5.8 3.8 2.1 0.0 0.0 5.8 0.051 0.002 0.000 0.000 0.000 0.011 5.7 0.1 0.0 0.0 5.8 57 2.5 61.7 5.5 0.0 67.2 61.7 5.5 0.0 0.0 67.2 0.358 0.069 0.005 0.000 0.000 0.087 62.5 4.7 0.1 0.0 67.2 22 3.5 132.5 40.6 0.0 173.1 132.5 40.6 0.0 0.0 173.1 0.792 0.348 0.074 0.007 0.000 0.244 140.4 29.8 2.7 0.1 173.1 10 4.5 146.2 74.0 4.8 224.9 146.2 74.0 4.8 0.0 224.9 0.998 0.752 0.325 0.071 0.007 0.431 146.4 63.2 13.9 1.4 224.9 5 5.5 79.8 80.8 21.0 4.7 186.3 79.8 80.8 21.0 4.7 186.3 0.900 0.988 0.708 0.296 0.065 0.592 89.4 64.1 26.8 5.9 186.3 2 6.5 25.7 30.9 20.1 14.5 91.3 25.7 30.9 20.1 14.5 91.3 0.651 0.932 0.972 0.662 0.266 0.696 30.0 31.3 21.3 8.6 91.3 1 7.5 22.0 26.7 16.0 19.5 84.2 22.0 26.7 16.0 19.5 84.2 0.402 0.694 0.958 0.949 0.613 0.723 18.2 25.1 24.9 16.1 84.2 1 8.5 6.8 12.2 16.2 9.8 45.0 6.8 12.2 16.2 9.8 45.0 0.220 0.433 0.736 0.978 0.921 0.658 6.4 10.8 14.4 13.5 45.0 0 9.5 1.1 6.7 12.0 13.2 33.0 1.1 6.7 12.0 13.2 33.0 0.110 0.236 0.467 0.778 0.991 0.516 3.1 6.2 10.4 13.2 33.0 0 10.5 3.2 2.5 6.4 10.9 23.0 3.2 2.5 6.4 10.9 23.0 0.051 0.115 0.254 0.504 0.818 0.348 1.6 3.5 6.9 11.1 23.0 0 11.5 0.0 5.2 7.1 12.3 0.0 0.0 5.2 7.1 12.3 0.022 0.051 0.122 0.276 0.543 0.203 0.6 1.5 3.4 6.7 12.3 0 12.5 0.0 2.1 1.0 3.2 0.0 0.0 2.1 1.0 3.2 0.009 0.021 0.053 0.131 0.301 0.103 0.1 0.3 0.8 1.9 3.2 0 13.5 1.0 2.0 1.2 4.2 0.0 1.0 2.0 1.2 4.2 0.004 0.008 0.021 0.055 0.143 0.046 0.2 0.4 1.0 2.6 4.2 0 14.5 0.0 1.5 1.5 0.0 0.0 0.0 1.5 1.5 0.001 0.003 0.008 0.021 0.060 0.019 0.0 0.1 0.3 1.0 1.5 0 15.5 1.0 0.0 1.0 0.001 0.001 0.003 0.007 0.022 0.007 16.5 1.1 1.1 0.000 0.000 0.001 0.002 0.007 0.002 Total 482.7 283.0 106.9 84.5 957.0 482.7 283.0 105.9 83.4 954.9 504.8 241.1 126.9 82.1 954.9 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 60 Solver Mean 95% CL 1.0 4-inch 5 6 78 estimates Lower Upper mesh-size θ1 1.16 1.10 1.07 1.13 50 0.8 θ2 3.73 4.84 4.10 5.74 ML 2715 2576 2530 2622 40 0.6 Mesh Size (inch) 45678 30 Derivations from EXCEL Solver parameter estimates 0.4 α 6.6 9.9 13.8 18.5 23.9 20 β 0.7 0.6 0.5 0.4 0.4 A 4.6 5.8 6.9 8.1 9.2 αβ Gillnet relative selectivity . 0.2 . (%) frequency Population 10 Derivations from bootstrap parameter estimates α 4.8 7.1 9.8 13.1 16.8 β 0.9 0.8 0.7 0.6 0.5 0.0 0 αβA 4.4 5.5 6.6 7.7 8.8 012345678910111213141516 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 No. boostrapped datasets 1102 Age (years) Age (years) AAge at maximum selectivity (mm) GHATF

shark

survey

73

74 GHATF Table 23. Gillnet relative age selectivity analysis for male school shark (Galeorhinus galeus) during 1986–87 Across 144 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

shark

Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size

survey No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5 1.5 0.0 0.0 0.050 0.003 0.000 0.000 0.000 0.011 0.0 0.0 0.0 0.0 0.0 0

2.5 40.8 0.0 0.0 0.0 40.8 40.8 0.0 0.0 0.0 40.8 0.303 0.058 0.005 0.000 0.000 0.073 37.7 3.1 0.1 0.0 40.8 61 3.5 65.8 18.6 0.0 0.0 84.4 65.8 18.6 0.0 0.0 84.4 0.682 0.270 0.054 0.005 0.000 0.202 69.2 13.9 1.3 0.0 84.4 24 4.5 31.4 24.6 0.0 0.0 56.1 31.4 24.6 0.0 0.0 56.1 0.948 0.610 0.230 0.046 0.004 0.368 38.4 14.5 2.9 0.3 56.1 6 5.5 21.4 18.6 5.2 2.0 47.2 21.4 18.6 5.2 2.0 47.2 0.990 0.900 0.535 0.189 0.036 0.530 25.6 15.2 5.4 1.0 47.2 3 6.5 19.6 17.5 8.3 1.0 46.4 19.6 17.5 8.3 1.0 46.4 0.854 1.000 0.839 0.460 0.151 0.661 18.9 15.9 8.7 2.9 46.4 2 7.5 5.6 11.2 10.3 2.0 29.1 5.6 11.2 10.3 2.0 29.1 0.643 0.908 0.993 0.768 0.388 0.740 8.6 9.4 7.3 3.7 29.1 1 8.5 2.9 3.8 11.5 5.6 23.8 2.9 3.8 11.5 5.6 23.8 0.437 0.710 0.952 0.969 0.691 0.752 5.1 6.8 6.9 5.0 23.8 1 9.5 6.2 2.4 5.0 6.6 20.2 6.2 2.4 5.0 6.6 20.2 0.275 0.493 0.775 0.982 0.930 0.691 3.1 4.9 6.2 5.9 20.2 1 10.5 0.0 5.3 5.1 2.0 12.4 0.0 5.3 5.1 2.0 12.4 0.162 0.312 0.553 0.836 0.998 0.572 1.4 2.5 3.8 4.6 12.4 0 11.5 0.0 3.8 5.7 3.6 13.2 0.0 3.8 5.7 3.6 13.2 0.091 0.183 0.355 0.617 0.891 0.427 1.2 2.3 4.0 5.8 13.2 1 12.5 3.0 1.0 2.2 2.6 8.8 3.0 1.0 2.2 2.6 8.8 0.049 0.100 0.208 0.404 0.683 0.289 0.6 1.3 2.6 4.3 8.8 1 13.5 0.0 4.8 1.0 5.8 0.0 0.0 4.8 1.0 5.8 0.025 0.052 0.113 0.239 0.459 0.178 0.3 0.8 1.6 3.1 5.8 1 14.5 0.0 1.6 1.6 0.0 0.013 0.026 0.058 0.130 0.277 0.101 15.5 1.1 3.5 4.5 0.0 0.006 0.012 0.028 0.066 0.151 0.053 16.5 1.6 5.1 6.7 0.0 0.003 0.006 0.013 0.031 0.076 0.026 Total 196.7 106.9 60.9 36.6 401.0 196.7 106.9 58.2 26.4 388.1 210.2 90.6 50.8 36.5 388.1 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 60 Solver Mean 95% CL 1.0 4-inch 5 6 7 8 estimates Lower Upper mesh-size θ1 1.29 1.21 1.14 1.28 50 0.8 θ2 5.57 7.57 5.94 9.68 ML 698 638 613 663 40 0.6 Mesh Size (inch) 45678 30 Derivations from EXCEL Solver parameter estimates 0.4 α 5.7 8.4 11.8 15.7 20.2 20 β 0.9 0.8 0.7 0.6 0.5 αβA 5.2 6.5 7.8 9.1 10.4 Population frequency (%) . (%) frequency Population

Gillnet relative selectivity . relative selectivity Gillnet 0.2 10 Derivations from bootstrap parameter estimates α 3.9 5.7 7.8 10.4 13.3 0.0 β 1.2 1.1 0.9 0.8 0.7 0 αβA 4.8 6.0 7.2 8.5 9.7 012345678910111213141516 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 No. boostrapped datasets 1495 Age (years) Age (years) AAge at maximum selectivity (mm)

Table 24. Gillnet relative age selectivity analysis for female school shark (Galeorhinus galeus) during 1986–87 Across 144 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5 1.5 5.8 0.0 5.8 5.8 0.0 0.0 0.0 5.8 0.100 0.012 0.001 0.000 0.000 0.022 47.5 5.6 0.3 0.0 0.0 53.3 44 2.5 23.0 0.0 0.0 1.0 24.0 23.0 0.0 0.0 1.0 24.0 0.399 0.115 0.017 0.001 0.000 0.107 71.6 20.6 3.1 0.2 0.0 95.6 17 3.5 77.1 18.2 1.2 1.0 97.5 77.1 18.2 1.2 1.0 97.5 0.747 0.370 0.111 0.019 0.002 0.250 145.0 71.9 21.6 3.6 0.3 242.5 18 4.5 35.7 22.3 6.5 2.1 66.6 35.7 22.3 6.5 2.1 66.6 0.961 0.689 0.331 0.099 0.017 0.420 56.3 40.4 19.4 5.8 1.0 122.9 5 5.5 25.0 11.8 5.6 4.0 46.3 25.0 11.8 5.6 4.0 46.3 0.991 0.925 0.627 0.288 0.084 0.583 23.9 22.3 15.1 6.9 2.0 70.2 2 6.5 16.0 19.9 9.5 3.1 48.5 16.0 19.9 9.5 3.1 48.5 0.882 1.000 0.879 0.562 0.246 0.714 15.9 18.1 15.9 10.1 4.4 64.5 2 7.5 9.6 7.9 8.6 5.2 31.2 9.6 7.9 8.6 5.2 31.2 0.706 0.926 0.996 0.824 0.496 0.790 6.8 8.9 9.6 7.9 4.8 38.0 1 8.5 5.4 7.7 15.9 8.8 37.7 5.4 7.7 15.9 8.8 37.7 0.523 0.764 0.961 0.979 0.764 0.798 5.7 8.3 10.5 10.7 8.3 43.4 1 9.5 3.6 8.5 6.2 8.6 27.0 3.6 8.5 6.2 8.6 27.0 0.364 0.577 0.819 0.985 0.950 0.739 3.0 4.7 6.6 8.0 7.7 29.9 1 10.5 8.5 5.1 11.7 8.2 33.5 8.5 5.1 11.7 8.2 33.5 0.242 0.405 0.632 0.868 0.998 0.629 2.8 4.7 7.3 10.0 11.5 36.3 1 11.5 4.3 5.1 5.4 8.2 23.1 4.3 5.1 5.4 8.2 23.1 0.154 0.268 0.449 0.687 0.912 0.494 1.5 2.7 4.5 6.8 9.1 24.6 1 12.5 2.1 4.9 10.0 8.0 25.1 2.1 4.9 10.0 8.0 25.1 0.095 0.169 0.299 0.497 0.743 0.361 1.4 2.5 4.4 7.3 10.9 26.5 1 13.5 3.7 7.1 8.3 19.1 0.0 3.7 7.1 8.3 19.1 0.057 0.102 0.187 0.333 0.549 0.246 0.9 1.7 3.1 5.4 9.0 20.1 2 14.5 2.1 4.8 6.9 0.0 0.0 2.1 4.8 6.9 0.033 0.060 0.112 0.209 0.373 0.158 0.3 0.5 1.0 1.9 3.4 7.2 1 15.5 6.0 3.8 9.8 0.0 0.0 6.0 3.8 9.8 0.019 0.034 0.064 0.124 0.236 0.095 0.4 0.7 1.4 2.7 5.1 10.3 2 16.5 2.5 3.3 5.8 0.0 0.0 2.5 3.3 5.8 0.011 0.019 0.035 0.070 0.140 0.055 0.2 0.4 0.8 1.5 3.1 6.0 2 Total 216.2 115.2 98.4 78.3 508.0 216.2 115.2 98.4 78.3 508.0 383.3 213.9 124.4 89.1 80.6 891.3 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 60 Solver Mean 95% CL 1.0 4-inch 5 6 7 8 estimates Lower Upper mesh-size θ1 1.29 1.19 1.14 1.26 50 0.8 θ2 7.47 8.90 6.80 11.75 ML 834 784 751 818 40 0.6 Mesh Size (inch) 45678 30 Derivations from EXCEL Solver parameter estimates 0.4 α 4.4 6.4 8.9 11.9 15.2 20 β 1.2 1.0 0.9 0.8 0.7 αβA 5.2 6.5 7.7 9.0 10.3 Population frequency (%) . (%) frequency Population

Gillnet relative selectivity . relative selectivity Gillnet 0.2 10 Derivations from bootstrap parameter estimates α 3.3 4.8 6.6 8.7 11.2 0.0 β 1.4 1.2 1.1 1.0 0.9 0 αβA 4.8 6.0 7.2 8.4 9.6 012345678910111213141516 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 No. boostrapped datasets 1491 Age (years) Age (years) AAge at maximum selectivity (mm) GHATF

shark

survey

75

76 GHATF Table 25. Gillnet relative age selectivity analysis for male gummy shark (Mustelus antarcticus) during 2007–08 Across 187 fishing sites of southern Australia. ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

shark

Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size

survey No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5 0.0 0.0 0.004 0.000 0.000 0.000 0.000 0.001 0.0 0.0 0.0 0.0 0.0 0.0 0 1.5 158.1 19.1 14.0 191.3 158.1 19.1 14.0 0.0 0.0 191.3 0.138 0.021 0.001 0.000 0.000 0.032 164.8 24.8 1.7 0.1 0.0 191.3 48

2.5 258.1 88.7 14.3 6.7 367.8 258.1 88.7 14.3 6.7 0.0 367.8 0.482 0.166 0.032 0.003 0.000 0.137 259.0 89.5 17.5 1.8 0.1 367.8 22 3.5 210.2 168.6 50.8 6.5 436.1 210.2 168.6 50.8 6.5 0.0 436.1 0.823 0.468 0.171 0.037 0.005 0.301 238.7 135.7 49.5 10.8 1.3 436.1 12 4.5 40.6 180.8 97.6 13.4 332.4 40.6 180.8 97.6 13.4 0.0 332.4 0.989 0.786 0.440 0.163 0.038 0.483 136.1 108.1 60.6 22.4 5.2 332.4 6 5.5 50.8 127.6 62.3 33.4 274.0 50.8 127.6 62.3 33.4 0.0 274.0 0.966 0.974 0.745 0.407 0.150 0.648 81.6 82.3 63.0 34.4 12.7 274.0 3 6.5 37.1 119.6 83.6 56.4 29.4 326.1 37.1 119.6 83.6 56.4 29.4 326.1 0.821 0.984 0.952 0.700 0.371 0.766 69.9 83.8 81.1 59.6 31.6 326.1 3 7.5 6.5 70.7 112.9 48.2 0.0 238.2 6.5 70.7 112.9 48.2 0.0 238.2 0.632 0.861 0.996 0.924 0.653 0.813 37.0 50.5 58.3 54.1 38.3 238.2 2 8.5 5.4 38.4 59.9 47.8 20.0 171.5 5.4 38.4 59.9 47.8 20.0 171.5 0.452 0.677 0.897 1.000 0.891 0.783 19.8 29.6 39.3 43.8 39.0 171.5 2 9.5 8.2 24.1 21.0 15.3 68.6 0.0 8.2 24.1 21.0 15.3 68.6 0.306 0.488 0.719 0.928 0.997 0.688 6.1 9.8 14.4 18.5 19.9 68.6 1 10.5 6.8 13.5 10.9 7.9 39.1 0.0 6.8 13.5 10.9 7.9 39.1 0.197 0.330 0.526 0.761 0.953 0.553 2.8 4.7 7.4 10.8 13.5 39.1 1 11.5 5.9 6.7 7.9 20.5 0.0 0.0 5.9 6.7 7.9 20.5 0.123 0.211 0.356 0.564 0.801 0.411 1.2 2.1 3.6 5.6 8.0 20.5 0 12.5 3.5 3.3 6.9 0.0 0.0 3.5 3.3 0.0 6.9 0.074 0.129 0.226 0.385 0.604 0.284 0.4 0.6 1.1 1.9 2.9 6.9 0 13.5 7.4 3.2 10.5 0.043 0.076 0.136 0.244 0.416 0.183 14.5 5.7 3.6 9.3 0.025 0.043 0.078 0.146 0.265 0.111 15.5 0.0 0.014 0.024 0.043 0.083 0.158 0.064 16.5 0.0 0.008 0.013 0.023 0.045 0.089 0.035 Total 766.8 834.3 549.7 261.2 80.5 2492.5 766.8 828.6 542.4 254.4 80.5 2472.6 1017.5 621.5 397.3 263.9 172.5 2472.6 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 50 Solver Mean 95% CL 1.0 5 6 78 estimates Lower Upper 4-inch θ1 1.21 1.22 1.14 1.31 mesh-size 0.8 40 θ2 7.08 7.25 4.78 10.96 ML 8396 8436 8248 8631 0.6 30 Mesh Size (inch) 45678

Derivations from EXCEL Solver parameter estimates 0.4 20 α 4.1 6.0 8.3 11.1 14.2 β 1.2 1.0 0.9 0.8 0.7 αβA 4.8 6.1 7.3 8.5 9.7 Population frequency (%) . (%) frequency Population

Gillnet relative selectivity . relative selectivity Gillnet 0.2 10 Derivations from bootstrap parameter estimates α 4.1 6.0 8.2 10.9 14.0 0.0 β 1.2 1.0 0.9 0.8 0.7 0 αβA 4.9 6.1 7.3 8.5 9.7 012345678910111213141516 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 No. boostrapped datasets 1293 Age (years) Age (years) AAge at maximum selectivity (mm)

Table 26. Gillnet relative age selectivity analysis for female gummy shark (Mustelus antarcticus) during 2007–08 Across 187 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.007 0.000 0.000 0.000 0.000 0.002 1.5 118.1 49.6 4.5 172.3 118.1 49.6 4.5 0.0 0.0 172.3 0.198 0.040 0.004 0.000 0.000 0.049 140.6 28.5 3.0 0.2 0.0 172.3 32 2.5 355.4 191.4 52.3 3.0 0.0 602.1 355.4 191.4 52.3 3.0 0.0 602.1 0.583 0.247 0.064 0.010 0.001 0.181 387.9 164.3 42.8 6.5 0.5 602.1 30 3.5 230.5 213.2 92.0 17.3 0.0 553.1 230.5 213.2 92.0 17.3 0.0 553.1 0.895 0.587 0.266 0.078 0.014 0.368 269.0 176.5 79.8 23.5 4.3 553.1 13 4.5 80.2 184.1 64.0 39.8 11.9 380.0 80.2 184.1 64.0 39.8 11.9 380.0 1.000 0.879 0.578 0.269 0.084 0.562 135.2 118.8 78.1 36.4 11.4 380.0 6 5.5 29.5 188.6 168.4 36.9 19.2 442.5 29.5 188.6 168.4 36.9 19.2 442.5 0.925 0.998 0.860 0.561 0.265 0.722 113.4 122.4 105.4 68.8 32.5 442.5 5 6.5 14.6 140.6 128.5 76.2 40.6 400.4 14.6 140.6 128.5 76.2 40.6 400.4 0.754 0.944 0.994 0.838 0.541 0.814 74.2 92.8 97.7 82.4 53.2 400.4 4 7.5 35.6 68.8 110.5 60.3 25.2 300.4 35.6 68.8 110.5 60.3 25.2 300.4 0.563 0.784 0.960 0.987 0.815 0.822 41.1 57.3 70.2 72.2 59.6 300.4 3 8.5 0.0 33.1 61.4 59.4 29.1 183.0 0.0 33.1 61.4 59.4 29.1 183.0 0.392 0.590 0.810 0.973 0.978 0.749 19.2 28.8 39.6 47.5 47.8 183.0 2 9.5 6.1 26.3 15.8 43.1 20.4 111.7 6.1 26.3 15.8 43.1 20.4 111.7 0.260 0.412 0.616 0.835 0.983 0.621 9.3 14.8 22.1 30.0 35.4 111.7 2 10.5 8.5 19.9 15.9 11.3 55.6 0.0 8.5 19.9 15.9 11.3 55.6 0.165 0.270 0.430 0.641 0.858 0.473 3.9 6.4 10.1 15.1 20.2 55.6 1 11.5 5.6 6.0 11.4 22.9 0.0 0.0 5.6 6.0 11.4 22.9 0.101 0.169 0.281 0.450 0.667 0.334 1.4 2.3 3.9 6.2 9.2 22.9 1 12.5 0.0 3.0 0.0 3.0 0.0 0.0 0.0 3.0 0.0 3.0 0.060 0.101 0.173 0.293 0.470 0.220 0.2 0.3 0.5 0.8 1.3 3.0 0 13.5 0.0 0.0 0.0 0.0 14.5 0.0 0.0 7.4 7.4 15.5 3.9 3.9 16.5 2.0 10.2 12.2 Total 870.1 1104.3 722.8 362.8 190.6 3250.5 870.1 1104.3 722.8 360.8 169.1 3226.9 1195.4 813.3 553.4 389.6 275.2 3226.9 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 1.0 4-inch 50 Solver Mean 95% CL 5 6 7 8 estimates Lower Upper mesh-size θ1 1.13 1.13 1.11 1.15 0.8 40 θ2 6.91 6.95 6.39 7.62 ML 11695 11698 11632 11746 0.6 30 Mesh Size (inch) 45678

Derivations from EXCEL Solver parameter estimates 0.4 20 α 3.7 5.4 7.5 9.9 12.7 β 1.2 1.0 0.9 0.8 0.7 αβA 4.5 5.6 6.8 7.9 9.0

0.2 . Population frequency (%) 10 Gillnet relative selectivity . Derivations from bootstrap parameter estimates α 3.7 5.4 7.5 9.9 12.7 0.0 0 β 1.2 1.0 0.9 0.8 0.7 αβA 4.5 5.6 6.8 7.9 9.0 012345678910111213141516 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 No. boostrapped datasets 1500 Age (years) Age (years) ALength at maximum selectivity (mm)

GHATF

shark

survey

77

78 GHATF Table 27. Gillnet relative age selectivity analysis for male school shark (Galeorhinus galeus) during 2007–08 Across 187 fishing sites of southern Australia; ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating

shark relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

survey Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5 0.0 0.0 0.007 0.000 0.000 0.000 0.000 0.002 0.0 0.0 0.0 0.0 0.0 0.0 0 1.5 14.7 0.0 0.0 0.0 0.0 14.7 14.7 0.0 0.0 0.0 0.0 14.7 0.234 0.049 0.005 0.000 0.000 0.058 12.0 2.5 0.3 0.0 0.0 14.7 2 2.5 16.0 17.3 0.0 0.0 0.0 33.3 16.0 17.3 0.0 0.0 0.0 33.3 0.678 0.315 0.089 0.014 0.001 0.220 20.6 9.6 2.7 0.4 0.0 33.3 1 3.5 1.3 5.6 23.4 9.4 0.0 39.7 1.3 5.6 23.4 9.4 0.0 39.7 0.966 0.712 0.363 0.120 0.024 0.437 17.5 12.9 6.6 2.2 0.4 39.7 1 4.5 0.0 19.4 8.5 3.3 2.7 33.9 0.0 19.4 8.5 3.3 2.7 33.9 0.971 0.968 0.732 0.395 0.144 0.642 10.3 10.2 7.7 4.2 1.5 33.9 0 5.5 3.3 9.3 13.5 24.7 14.6 65.4 3.3 9.3 13.5 24.7 14.6 65.4 0.794 0.972 0.970 0.745 0.417 0.780 13.3 16.3 16.3 12.5 7.0 65.4 1 6.5 0.0 2.8 29.1 29.6 23.2 84.8 0.0 2.8 29.1 29.6 23.2 84.8 0.566 0.798 0.973 0.971 0.753 0.812 11.8 16.7 20.3 20.3 15.7 84.8 1 7.5 3.3 12.9 22.9 77.3 51.1 167.4 3.3 12.9 22.9 77.3 51.1 167.4 0.365 0.568 0.801 0.974 0.972 0.736 16.6 25.8 36.4 44.3 44.2 167.4 2 8.5 0.0 9.0 27.8 35.1 52.7 124.7 0.0 9.0 27.8 35.1 52.7 124.7 0.219 0.363 0.568 0.802 0.974 0.585 9.4 15.5 24.2 34.2 41.5 124.7 2 9.5 0.0 14.8 34.9 56.8 37.7 144.3 0.0 14.8 34.9 56.8 37.7 144.3 0.124 0.213 0.359 0.567 0.802 0.413 8.7 14.9 25.1 39.6 56.0 144.3 3 10.5 0.0 6.9 18.2 20.5 14.1 59.7 0.0 6.9 18.2 20.5 14.1 59.7 0.067 0.117 0.207 0.354 0.565 0.262 3.1 5.3 9.4 16.1 25.7 59.7 2 11.5 10.2 7.2 7.7 13.6 29.0 67.6 10.2 7.2 7.7 13.6 29.0 67.6 0.035 0.061 0.110 0.201 0.350 0.152 3.1 5.4 9.9 17.9 31.2 67.6 4 12.5 0.0 0.0 9.8 10.8 23.1 43.7 0.0 0.0 9.8 10.8 23.1 43.7 0.018 0.030 0.055 0.104 0.195 0.081 1.9 3.3 6.0 11.3 21.2 43.7 5 13.5 0.0 0.0 6.3 10.8 18.4 35.5 0.0 0.0 6.3 10.8 18.4 35.5 0.009 0.015 0.026 0.051 0.099 0.040 1.6 2.6 4.7 9.0 17.7 35.5 8 14.5 0.0 3.8 7.9 12.4 10.9 35.0 0.0 3.8 7.9 12.4 10.9 35.0 0.004 0.007 0.012 0.023 0.047 0.019 1.6 2.5 4.5 8.7 17.6 35.0 16 15.5 0.0 0.0 0.0 2.8 2.5 5.3 0.0 0.0 0.0 2.8 2.5 5.3 0.002 0.003 0.005 0.010 0.021 0.008 0.3 0.4 0.7 1.3 2.7 5.3 6 16.5 0.0 4.1 2.6 0.0 12.1 18.8 0.0 4.1 2.6 0.0 12.1 18.8 0.001 0.001 0.002 0.004 0.009 0.003 1.0 1.5 2.4 4.6 9.4 18.8 47 Total 48.8 113.3 212.6 307.1 292.2 974.0 48.8 113.3 212.6 307.1 292.2 974.0 132.7 145.5 177.2 226.6 292.0 974.0 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 5 6 7 8 50 Solver Mean 95% CL 1.0 4-inch estimates Lower Upper mesh-size 45 θ1 1.00 1.00 1.00 1.00 0.8 40 θ2 4.87 4.88 4.36 5.48 ML 1899 1918 1875 1960 35 0.6 30 Mesh Size (inch) 4 5 6 7 8 25 Derivations from EXCEL Solver parameter estimates 0.4 α 4.1 6.0 8.3 11.0 14.1 20 β 1.00.80.70.60.6 15 αβA 4.05.06.07.08.0

Gillnet relative selectivity . 0.2 Population frequency (%) . (%) frequency Population 10 Derivations from bootstrap parameter estimates 5 α 4.1 6.0 8.3 11.0 14.1 0.0 β 1.00.80.70.60.6 0 αβA 4.05.06.07.08.0 0 1 2 3 4 5 6 7 8 9 10111213141516 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5 No. boostrapped datasets 1485 Age (years) Age (years) AAge at maximum selectivity (mm)

Table 28. Gillnet relative age selectivity analysis for female school shark (Galeorhinus galeus) during 2007–08 Across all 187 fishing sites of southern Australia ML, maximum likelihood; θ1 and θ2 are estimated parameters and α and β are derived parameters relating relative selectivity to mesh‐size and length of shark in the Kirkwood and Walker (1986) gillnet selectivity model.

Age (years) Observed catch adjusted for effort by mesh-size (all data) Catch adjusted for effort by mesh-size (trimmed data) Relative selectivity for each mesh-size Predicted catch for each mesh-size No. in popn 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total 4-inch 5-inch 6-inch 7-inch 8-inch Total (%) 0.5 0.0 0.0 0.043 0.005 0.000 0.000 0.000 0.010 0.0 0 1.5 8.1 5.7 0.0 2.0 0.0 15.9 8.1 5.7 0.0 2.0 0.0 15.9 0.395 0.152 0.039 0.007 0.001 0.119 10.5 4.1 1.1 0.2 0.0 15.9 2 2.5 3.1 27.8 11.0 0.0 0.0 41.8 3.1 27.8 11.0 0.0 0.0 41.8 0.780 0.486 0.227 0.077 0.018 0.318 20.5 12.8 6.0 2.0 0.5 41.8 2 3.5 2.3 13.4 19.7 10.1 10.6 56.1 2.3 13.4 19.7 10.1 10.6 56.1 0.978 0.809 0.537 0.277 0.108 0.542 20.3 16.8 11.1 5.7 2.2 56.1 2 4.5 1.7 27.7 32.6 35.7 7.3 105.0 1.7 27.7 32.6 35.7 7.3 105.0 0.981 0.980 0.826 0.570 0.312 0.734 28.1 28.1 23.6 16.3 8.9 105.0 2 5.5 1.7 17.2 25.7 60.9 56.1 161.6 1.7 17.2 25.7 60.9 56.1 161.6 0.863 0.983 0.981 0.836 0.592 0.851 32.8 37.3 37.3 31.8 22.5 161.6 3 6.5 1.7 25.3 51.0 59.1 51.7 188.9 1.7 25.3 51.0 59.1 51.7 188.9 0.695 0.869 0.983 0.982 0.844 0.875 30.0 37.5 42.5 42.4 36.4 188.9 4 7.5 2.3 29.2 59.1 89.1 82.9 262.5 2.3 29.2 59.1 89.1 82.9 262.5 0.526 0.702 0.872 0.984 0.983 0.814 33.9 45.3 56.3 63.5 63.4 262.5 6 8.5 0.0 23.6 52.0 83.3 55.1 214.0 0.0 23.6 52.0 83.3 55.1 214.0 0.380 0.531 0.707 0.875 0.984 0.695 23.4 32.7 43.5 53.8 60.6 214.0 5 9.5 8.1 32.5 37.2 76.3 42.0 196.2 8.1 32.5 37.2 76.3 42.0 196.2 0.264 0.381 0.533 0.709 0.876 0.553 18.8 27.1 37.8 50.3 62.2 196.2 6 10.5 3.1 25.4 28.2 46.6 61.9 165.2 3.1 25.4 28.2 46.6 61.9 165.2 0.179 0.262 0.380 0.534 0.710 0.413 14.3 21.0 30.4 42.7 56.8 165.2 7 11.5 2.7 10.7 29.0 39.2 39.1 120.8 2.7 10.7 29.0 39.2 39.1 120.8 0.118 0.175 0.259 0.378 0.533 0.292 9.8 14.4 21.4 31.2 44.0 120.8 7 12.5 0.015.219.932.518.786.30.015.219.932.518.786.30.076 0.113 0.170 0.255 0.375 0.198 6.7 9.9 14.8 22.2 32.7 86.3 8 13.5 3.1 0.0 14.3 13.7 26.6 57.6 3.1 0.0 14.3 13.7 26.6 57.6 0.049 0.071 0.108 0.164 0.250 0.128 4.4 6.4 9.7 14.8 22.5 57.6 8 14.5 0.0 4.1 5.7 4.1 17.6 31.5 0.0 4.1 5.7 4.1 17.6 31.5 0.031 0.044 0.066 0.102 0.159 0.080 2.4 3.5 5.2 8.0 12.4 31.5 7 15.5 3.1 0.0 3.9 6.4 12.2 25.6 3.1 0.0 3.9 6.4 12.2 25.6 0.019 0.027 0.040 0.062 0.097 0.049 2.0 2.8 4.2 6.5 10.2 25.6 9 16.5 0.0 0.0 10.2 15.8 10.2 36.1 0.0 0.0 10.2 15.8 10.2 36.1 0.012 0.016 0.024 0.036 0.057 0.029 2.9 4.0 5.9 9.0 14.3 36.1 22 Total 40.7 257.9 399.4 574.8 492.1 1765.0 40.7 257.9 399.4 574.8 492.1 1765.0 1.597 1.652 1.688 1.712 1.725 1.675 260.6 303.5 350.7 400.4 449.8 1765.0 100

Parameter estimates Gillnet relative selectivity against age of shark by mesh-size Estimated percentage-age-frequency distribution for shark population Parameter EXCEL Bootstrap estimates 5 6 7 8 25 Solver Mean 95% CL 1.0 4-inch estimates Lower Upper mesh-size θ1 1.00 1.00 1.00 1.00 0.8 20 θ2 8.48 8.47 7.42 9.76 ML 4259 4310 4257 4368 0.6 15 Mesh Size (inch) 45678

Derivations from EXCEL Solver parameter estimates 0.4 α 2.6 3.7 5.1 6.6 8.4 10 β 1.5 1.3 1.2 1.1 0.9 αβA 4.0 5.0 6.0 7.0 8.0

Gillnet relative selectivity . selectivity relative Gillnet 0.2 Population frequency (%) . 5 Derivations from bootstrap parameter estimates α 2.6 3.7 5.1 6.7 8.4 0.0 β 1.5 1.3 1.2 1.1 0.9 0 αβA 4.0 5.0 6.0 7.0 8.0 012345678910111213141516 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5 No. boostrapped datasets 1500 Age (years) Age (years) A

GHATF Age at maximum selectivity (mm)

shark

survey

79

Table 29. Summary of length and age at maximum selectivity for gummy and school shark

Species Sex Period Total length (mm) or age (y) at maximum selectivity 4-inch 5-inch 6-inch 7-inch 8-inch

Length at maximum selectivity Gummy shark Combined 1973–76 741 926 1111 1297 1482 1986–87 691 863 1036 1208 1381 2007–08 737 921 1105 1289 1474 School shark Combined 1986–87 691 863 1036 1209 1382 2007–08 732 915 1098 1281 1464 Age at maximum selectivity Gummy shark Male 1986–87 5.2 6.6 7.9 9.2 10.5 2007–08 4.8 6.1 7.3 8.5 9.7

Gummy shark Female 1986–87 4.6 5.8 6.9 8.1 9.2 2007–08 4.5 5.6 6.8 7.9 9.0

School shark Male 1986–87 5.2 6.5 7.8 9.1 10.4 2007–08 4.0 5.0 6.0 7.0 8.0

School shark Female 1986–87 5.2 6.5 7.7 9.0 10.3 2007–08 4.0 5.0 6.0 7.0 8.0

GHATF shark survey 80

Table 30. Total mortality estimates for male gummy shark (Mustelus antarcticus) 1986–87 Across 144 fishing sites of southern Australia Obs, observed; exp, expected; res, residual; N, number of sharks, Z, total mortality.

Age (y) N(%) Ln(N) Obs Ages 2–12 y Ages 2–8 y Ages 8–12 y Exp Res Exp Res Exp Res

2.5 58 4.06 3.41 0.65 4.03 0.04 3.5 23 3.13 2.78 0.35 3.15 -0.02 4.5 13 2.56 2.15 0.41 2.27 0.29 5.5 3 1.07 1.52 -0.46 1.39 -0.32 6.5 1 0.31 0.90 -0.58 0.51 -0.20 7.5 1 -0.31 0.27 -0.58 -0.37 0.06 8.5 0 -1.11 -0.36 -0.75 -1.25 0.15 -1.06 -0.04 9.5 0 -1.25 -0.99 -0.26 -1.32 0.07 10.5 0 -1.66 -1.62 -0.04 -1.58 -0.09 11.5 0 -1.70 -2.25 0.54 -1.83 0.13 12.5 0 -2.16 -2.88 0.72 -2.09 -0.07

5.00 Total mortality estimation 4.00 3.00 2.00 1.00

Ln(N) 0.00 -1.00 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 -2.00 -3.00 -4.00 Age (years)

Age range Annual Annual Z Z Z % (y) SE SE survival mortality 2–12 0.629 0.055 8.8 % 53% 47% 2–8 0.880 0.043 4.8 % 41% 59% 8–12 0.256 0.035 13.6 % 77% 23%

GHATF shark survey 81

Table 31. Total mortality estimates for female gummy shark (Mustelus antarcticus) 1986–87 Across 144 fishing sites of southern Australia; Obs, observed; exp, expected; res, residual; N, number of sharks, Z, total mortality.

Age (y) N(%) Ln(N) Obs Ages 2–12 y Ages 2–8 y Ages 8–12 y Exp Res Exp Res Exp Res

1.5 57 4.04 3.19 0.82 3.80 0.21 2.5 22 3.10 2.68 0.39 3.06 0.00 3.5 10 2.30 2.17 0.10 2.33 -0.06 4.5 5 1.57 1.66 -0.12 1.60 -0.06 5.5 2 0.80 1.14 -0.37 0.87 -0.10 6.5 1 -0.23 0.63 -0.89 0.14 -0.40 7.5 1 -0.44 0.12 -0.59 -0.59 0.12 8.5 0 -1.01 -0.39 -0.65 -1.32 0.28 -0.93 -0.12 9.5 0 -1.11 -0.90 -0.24 -1.11 -0.03 10.5 0 -1.09 -1.41 0.29 -1.28 0.16 11.5 0 -1.19 -1.93 0.71 -1.46 0.24 12.5 0 -1.86 -2.44 0.54 -1.64 -0.25

5.00 Total mortality estimation 4.00

3.00

2.00

1.00 Ln(N) 0.00 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 -1.00

-2.00

-3.00 Age (years)

Age range Annual Annual Z Z Z % (y) SE SE survival mortality 2–12 0.512 0.049 9.7 % 60% 40% 2–8 0.731 0.035 4.8 % 48% 52% 8–12 0.177 0.074 41.7 % 84% 16%

GHATF shark survey 82

Table 32. Total mortality estimates for male school shark (Galeorhinus galeus) 1986–87 Across 144 fishing sites of southern Australia; Obs, observed; exp, expected; res, residual; N, number of sharks, Z, total mortality.

Age (y) N(%) Ln(N) Obs Ages 1–9 y Exp Res

2.5 61 4.11 3.40 0.39 3.5 24 3.19 2.79 -0.41 4.5 6 1.78 2.19 -0.60 5.5 3 0.99 1.58 -0.40 6.5 2 0.58 0.98 -0.48 7.5 1 -0.11 0.37 -0.16 8.5 1 -0.39 -0.23 0.33 9.5 1 -0.51 -0.84 0.61 10.5 0 -0.84 -1.44 0.00 11.5 1 -0.49 12.5 1 -0.52 13.5 1 -0.46

Total mortality estimation 4.00

3.00

2.00 Ln(N) 1.00

0.00 0.0 3.0 6.0 9.0 12.0 15.0 -1.00 Age (years)

Age range Annual Annual Z Z Z % (y) SE SE survival mortality 2–10 0.605 0.070 11.6 % 55% 45%

GHATF shark survey 83

Table 33. Total mortality estimates for female school shark (Galeorhinus galeus) 1986–87 A across 144 fishing sites of southern Australia; Obs, observed; exp, expected; res, residual; N, number of sharks, Z, total mortality.

Age (y) N(%) Ln(N) Obs Ages 1–9 y Exp Res

1.5 44 3.78 3.47 0.32 2.5 17 2.80 2.93 -0.13 3.5 18 2.88 2.40 0.48 4.5 5 1.69 1.87 -0.18 5.5 2 0.80 1.34 -0.54 6.5 2 0.51 0.81 -0.30 7.5 1 -0.12 0.28 -0.40 8.5 1 0.00 -0.26 0.26 9.5 1 -0.29 -0.79 0.49 10.5 1 0.06 0.00 0.00 11.5 1 -0.09 0.00 0.00 12.5 1 0.30 0.00 0.00 13.5 2 0.41 0.00 0.00 14.5 1 -0.17 0.00 0.00

4.00 Total mortality estimation

3.00

2.00 Ln(N) 1.00

0.00 0.0 3.0 6.0 9.0 12.0 15.0

-1.00 Age (years)

Age range Annual Annual Z Z Z % (y) SE SE survival mortality 1–9 0.532 0.054 10.2 % 59% 41%

GHATF shark survey 84

Table 34. Total mortality estimates for male gummy shark (Mustelus antarcticus) 2007–08 Across 187 fishing sites of southern Australia; Obs, observed; exp, expected; res, residual; N, number of sharks, Z, total mortality.

Age (y) N(%) Ln(N) Obs Ages 1–12 y Ages 1–5 y Ages 6–12 y Exp Res Exp Res Exp Res

1.5 48 3.88 3.47 0.41 3.80 0.07 2.5 22 3.07 3.01 0.06 3.14 -0.06 3.5 12 2.46 2.56 -0.10 2.47 -0.01 4.5 6 1.71 2.11 -0.39 1.80 -0.09 5.5 3 1.23 1.65 -0.43 1.14 0.09 6.5 3 1.23 1.20 0.03 1.33 -0.09 7.5 2 0.86 0.75 0.11 0.85 0.01 8.5 2 0.57 0.29 0.27 0.38 0.19 9.5 1 -0.22 -0.16 -0.06 -0.09 -0.12 10.5 1 -0.56 -0.61 0.05 -0.57 0.01 11.5 0 -0.91 -1.07 0.15 -1.04 0.13 12.5 0 -1.63 -1.52 -0.11 -1.52 -0.12

5.00 Total mortality estimation

4.00

3.00

2.00

Ln(N) 1.00

0.00 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 -1.00

-2.00 Age (years)

Age range Annual Annual Z Z Z % (y) SE SE survival mortality 1–12 0.453 0.021 4.7 % 64% 36% 1–5 0.666 0.029 4.4 % 51% 49% 6–12 0.474 0.025 5.4 % 62% 38%

GHATF shark survey 85

Table 35. Total mortality estimates for female gummy shark (Mustelus antarcticus) 2007–08 Across 187 fishing sites of southern Australia; Obs, observed; exp, expected; res, residual; N, number of sharks, Z, total mortality.

Age (y) N(%) Ln(N) Obs Ages 1–12 y Ages 2–4 y Ages 5–11 y Exp Res Exp Res Exp Res

1.5 31.84 3.46 3.57 -0.11 2.5 29.84 3.40 3.14 0.25 3.40 0.00 3.5 13.48 2.60 2.71 -0.11 2.60 0.00 4.5 6.06 1.80 2.28 -0.48 1.80 0.00 5.5 5.50 1.70 1.85 -0.14 1.83 -0.13 6.5 4.41 1.48 1.41 0.07 1.47 0.02 7.5 3.28 1.19 0.98 0.21 1.11 0.08 8.5 2.19 0.78 0.55 0.24 0.74 0.04 9.5 1.61 0.48 0.12 0.36 0.38 0.10 10.5 1.05 0.05 -0.32 0.37 0.02 0.03 11.5 0.62 -0.48 -0.75 0.27 -0.34 -0.14 12.5 0.12 -2.10 -1.18 -0.92

4.00 Total mortality estimation 3.00 2.00 1.00

Ln(N) 0.00 -1.00 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 -2.00 -3.00 Age (years)

Age range Annual Annual Z Z Z % (y) SE SE survival mortality 1–12 0.432 0.034 7.8 % 65% 35% 2–4 0.797 0.001 0.1 % 45% 55% 5–11 0.362 0.020 5.5 % 70% 30%

GHATF shark survey 86

Table 36. Summary of total mortality estimates for gummy shark and school shark during 1986–87 and 2006–08

Species Sex Period Age-range Z ZSE ZSE Annual Annual (y) (y-1)(y-1)(y-1) survival mortality Gummy shark Male 1986–87 2–12 0.629 0.055 8.8% 53% 47% 2–8 0.880 0.043 4.8% 41% 59% 8–12 0.256 0.035 13.6% 77% 23% 2007-08 1–12 0.453 0.021 4.7% 64% 36% 1–5 0.666 0.029 4.4% 51% 49% 6–12 0.474 0.025 5.4% 62% 38% Gummy shark Female 1986–87 2–12 0.512 0.049 9.7% 60% 40% 2–8 0.731 0.035 4.8% 48% 52% 8–12 0.177 0.074 41.7% 84% 16% 2007-08 1–12 0.432 0.034 7.8% 65% 35% 2–4 0.797 0.001 0.1% 45% 55% 5–11 0.362 0.020 5.5% 70% 30% School shark Male 1986–87 2–10 0.605 0.070 11.6% 55% 45% School shark Female 1986–87 1–9 0.532 0.054 10.2% 59% 41%

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Figure 1. Size‐frequency composition of commercial species caught in the 2007–08 survey Size‐frequency composition by experimental mesh‐size for male and female gummy and school sharks, southern and common sawsharks, and elephant fish.

450 Female gummy shark 400 4-inch 350 5-inch 6-inch 300 7-inch 250 8-inch

200 Numbers

150

100

50

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

450 Male gummy shark 400 4-inch 350 5-inch 6-inch 300 7-inch 250 8-inch

200 Numbers

150

100

50

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

GHATF shark survey 88

Figure 1 (continued) 200 Female school shark 180 4-inch 160 5-inch 140 6-inch 7-inch 120 8-inch 100

Numbers 80

60

40

20

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

200 Male school shark 180 4-inch 160 5-inch 140 6-inch 7-inch 120 8-inch 100

Numbers 80

60

40

20

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

GHATF shark survey 89

Figure 1 (continued)

50 Female southern sawshark 4-inch 40 5-inch 6-inch 7-inch 30 8-inch

Numbers 20

10

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

50 Male southern sawshark 4-inch 40 5-inch 6-inch 7-inch 30 8-inch

Numbers 20

10

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

GHATF shark survey 90

Figure 1 (continued)

70 Female common sawshark 60 4-inch 5-inch 50 6-inch 7-inch 40 8-inch

Numbers 30

20

10

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

70 Male common sawshark 60 4-inch 5-inch 50 6-inch 7-inch 40 8-inch

Numbers 30

20

10

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Total length (mm)

GHATF shark survey 91

Figure 1 (continued)

20 Female elephant fish 18 4-inch 16 5-inch 14 6-inch 7-inch 12 8-inch 10

Numbers 8

6

4

2

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Fork length (mm)

20 Male elephant fish 18 4-inch 16 5-inch 14 6-inch 7-inch 12 8-inch 10

Numbers 8

6

4

2

0 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Fork length (mm)

GHATF shark survey 92

Figure 2. Age‐frequency composition of gummy and school shark catch 2007–08

Age‐frequency composition by experimental mesh‐size for male and female gummy and school sharks.

35 Female gummy shark 30 4-inch 5-inch 25 6-inch 7-inch 20 8-inch

Numbers 15

10

5

0 12345678910111213141516 Age (years)

35 Male gummy shark 30 4-inch 5-inch 25 6-inch 7-inch 20 8-inch

Numbers 15

10

5

0 12345678910111213141516 Age (years)

GHATF shark survey 93

Figure 2 (continued)

25 Female school shark 4-inch 20 5-inch 6-inch 7-inch 15 8-inch

Numbers 10

5

0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 Age (years)

25 Male school shark 4-inch 20 5-inch 6-inch 7-inch 15 8-inch

Numbers 10

5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Age (years)

GHATF shark survey 94

Figure 3. Wildlife interactions in the 2007–08 survey Pie chart detailing the percentage of interactions that occurred with marine mammals, seabirds and other protected species in the 2007–08 survey.

4% 17%

Bird flying, contact with vessel or gear (sampled stations= 51)

Wildlife diving for and feeding on discards (sampled stations= 51)

Wildlife entangled in nets (sampled stations= 187)

79%

GHATF shark survey 95

Figure 4. Percentage‐length‐frequency distribution for school shark population

Estimated percentage-length-frequency distribution for Estimated percentage-length-frequency distribution for shark population shark population 35 35 1986–87 2006–07

30 30

25 25

20 20

15 15 Population frequency (%) . (%) Population frequency Population frequency (%) . (%) frequency Population 10 10

5 5

0 0 550 650 750 850 950 1050 1150 1250 1350 1450 1550 1650 1750 550 650 750 850 950 1050 1150 1250 1350 1450 1550 1650 1750 Total length mid-point of 100-mm range (mm) Total length mid-point of 100-mm range (mm)

Percentage-length-frequency distribution for shark Percentage-length-frequency distribution for shark population converted by von Bertalanffy function population converted by von Bertalanffy function 16 16

1986–87 2006–07

12 12

8 8

Population frequency (%) . (%) Population frequency 4 Population frequency (%) . (%) frequency Population 4

0 0 012345678910111213141516 012345678910111213141516 Age (years) Age (years)

Percentage-length-frequency distribution for shark Percentage-length-frequency distribution for shark population converted by age-length key population converted by age-length key 20 20 1986–87 2006–07

16 16

12 12

8 8 Population frequency (%) . (%) frequency Population Population frequency (%) . (%) Population frequency

4 4

0 0 12345678910111213141516 1 2 3 4 5 6 7 8 9 10111213141516 Age (years) Age (years)

GHATF shark survey 96

Supplements and Appendices

Appendix 1. Fishing sites for 2007–08 shark survey

Introduction Catch data are available from fleets of survey gillnets used during 1973–76 and 1986–87. Eight mesh‐sizes (2, 3, 4, 5, 6, 7, 8, and 9‐inch) were used during 1973–76 at 73 sites and other configurations of gear (including hooks) at a further 89 sites and four mesh‐sizes (5,d 6, 7, an 8‐inch) were used at each 144 fishing sites during 1986–87. These data have details on length‐frequency composition and, for 1986–87, age composition of catches. Using a range of mesh‐sizes together, provides data for determining both the size (and age where collected) composition of the catch and of the population of target, byproduct and bycatch species. In addition, there are data on bycatch for 6 and 6½‐inch mesh‐size during 1998–01. For the present survey, design and construction of the nets and the experimental design of the survey (including the fishing sites) were agreed to by industry, AFMA managers and scientists through SharkRAG. Design and construction of shark survey gillnets The present concept was to construct five gillnets of standard length (500 m), standard height (2.4 m), standard hanging coefficient (0.6), and standard colour (green) of varying mesh‐size of 4, 5, 6, 7, and 8 inches that can be compared with similar nets constructed during 1973–76 and 1986–87. Experimental design for shark survey The experimental design of the current fishery‐independent survey of shark involved using a fleet of monofilament gillnets of five mesh‐sizes (4, 5, 6, 7, and 8‐inch) at ~200 sites during 2007 and early 2008, to provide indices of abundance and length‐frequency composition and, for five species, samplesr fo determining age‐frequency composition of the populations of target, byproduct and bycatch. The survey covered the regions of Bass Strait, southern Tasmania, western Tasmania, western Victoria, and South Australia. The present concept was to undertake a survey at 48 sites (Table A1, Maps A1–A5) with 4 stations per site, whereh eac site was a 15 x 20 for depths <130 m or 10 x 30 nautical miles rectangle for deeper water sites on the edge of the continental shelf (>130 m). The experimental design covered shots from earlier surveys and areas most suitable for future surveys as areas of comparatively hhig catch in the past, particularly for school shark.

Research quota and research permit Research quota for fish caught during the fishery‐independent survey was designed to offset the costs of operating at fishing sites fishers might not otherwise choose to fish. Research quota also served to offset the costs associated with loading and unloading the gillnets on shark drum‐winches, with setting and hauling gillnets of 7‐ and 8‐inch mesh‐size, which took lower catches, and with setting and hauling 4‐ and 5‐inch mesh‐size, which required handling additional bycatch. Research permits were issued by AFMA to authorise participants to deploy the 2500 m of survey gillnets (4‐, 5‐, 6‐, 7‐, and 8‐inch mesh size) in addition to the 4200 m gillnet limit and to retain and sell undersized fish taken during the survey shots. Concession holders participating in the survey were permitted to keep and sell the catch. All SESSF quota species caught by the surveyd nets an commercial nets were deducted from research quota, which means that no participating operator’s personal quota holdings was affected. Field operations A fleet of five survey gillnets were loaded onto the drum winch of each commercial shark fishing vessel participating in the survey. As for past surveys, the survey fleet of gillnets was periodically repaired to ensure the gear did not lose fishing power from fish swimming through damaged meshes.

GHATF shark survey 97

At‐sea operations when hauling the fishing gear required recording for each mesh‐size of the survey nets and commercial nets, the species, sex of chondrichthyans, and size of every fish captured. In addition, the condition (live strong, live weak, dead) and degree of damage to sharks (percentage by mass) from predation by sea lice, other fish, and seals was recorded. Four indices (stimuli activity, wounds and bleeding, sea lice damage, and skin damage and surface bruising) (see Table 2 for definition of indices values) were used as indicators of the immediate and delayed post‐capture mortality of sharks and teleosts. When possible, the following reproductive information was recorded: ovary condition, diameter of largest ovarian follicle, uterus condition, and approximate mean length of embryos for females and seminal vesicle, testis and clasper condition for males. A sample of 4–6 postcranial vertebrae was collected from gummy shark, school shark, common sawshark, and southern sawshark and the dorsal spine from elephant fish caught by the experimental nets. Vertebrae samples were stored frozen at –20 °C. All interactions with TEP species were recorded. The start and end times of setting and hauling the gear and start and end positions of the gear were recorded. Data management and analysis Data were initially entered into an EXCEL spreadsheet and then uploaded to MAFFRI’s Southern and Eastern Scalefish and Shark Fishery Data Integration Management Summary and Analysis System (SESSF‐DIMSAS) and MAFFRI’s SAS‐based Chondrichthyan Data Management and Analysis System (Chondrichthyan Database) for processing biological and gear selectivity data. The data were used for revised estimates of gillnet selectivity and calculating the profile of the length‐frequency for the population following Walker and Kirkwood (1986). Age‐frequency profiles were used to determine total mortality for school shark and gummy shark. Population abundance indices were determined for 1973– 76, 1986–87, and 2007–08 for target dan key byproduct species and trends in catches and abundance of bycatch species for 1973–76, 1998–01, and 2007–08 were also presented and made available for stock assessment.

GHATF shark survey 98

Table A1. Site specifications for Shark Fixed‐site Survey

Region Site name Site code Site position Depth Shots Repeat Period Species (m) Past New Sum Trip New

SA Far west Shoulder Hill Shoulder-H Grid 4 0 4 Repeat Oct–Nov 2007 Sch–Gum Head of GAB1 GAB-Hd1 Grid 0 4 4 New Oct–Nov 2007 Sch–Gum Head of GAB2 GAB-Hd2 Grid 0 4 4 New Oct–Nov 2007 Sch–Gum Head of GAB3 GAB-Hd3 Grid 0 4 4 New Oct–Nov 2007 Sch–Gum Head of GAB4 GAB-Hd4 Grid 0 4 4 20 New Oct–Nov 2007 Sch–Gum

GAB Western Australia GAB-WA Grid >80 5 -1 4 Repeat Aug 2008 School GAB Offshore West GAB-OW Grid >80 6 -2 4 Repeat Aug 2008 School GAB Offshore Middle GAB-OM Grid >80 4 0 4 Repeat Aug 2008 School GAB Offshore East GAB-OE Grid >80 3 1 4 16 Repeat Aug 2008 School

SA West Streaky Streaky Grid 6 -2 4 Repeat Sep 2008 Gummy Venus Venus Grid 2 2 4 Repeat Sep 2008 Sch–Gum Eyre West1 Eyre-W1 Grid 2 2 4 Repeat Aug 2008 School Eyre West2 Eyre-W2 Grid 0 4 4 16 New Aug 2008 Sch–Gum

SA Eyre GAB Shelf GAB-Shelf Grid >130 2 2 4 Repeat Jul 2008 School Eyre Shelf Eyre-Shelf Grid >130 2 2 4 Repeat Mar 2007 School Eyre South West Eyre-SW Grid 5 -1 4 Repeat Jul 2008 Sch–Gum Eyre South Eyre-S Grid 4 0 4 16 Repeat Jul 2008 Sch–Gum

SA Central South-west Kangaroo Shelf KI SW-Shelf Grid >130 2 2 4 Repeat Mar 2007 School South Kangaroo Shelf KI S-Shelf Grid >130 2 2 4 Repeat Mar 2007 School West Kangaroo Inshore KI W-Inshore Grid 0 4 4 New Feb 2008 School South-west Kangaroo Inshore KI SW-Inshore Grid 0 4 4 New Feb 2008 School South-east Kangaroo Inshore KI SE-Inshore Grid 0 4 4 New Feb 2008 School South Kangaroo Mid KI S-Mid Grid 0 4 4 24 New Mar 2007 School

SA East South Kangaroo Offshore KI S-Offshore Grid 2 2 4 Repeat Mar 2007 Sch–Gum Murray mouth MurrayM Grid 0 4 4 New Sep 2008 Gummy Coral Patch CoralP Grid 1 3 4 Repeat Sep 2008 School South Coral Patch S-CoralP Grid 0 4 4 New Sep 2008 Sch–Gum Cape Jaffa JaffaC Grid 11 -7 4 20 Repeat Sep 2008 Gummy GHATF

Total South Australia 59 45 112 112

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survey 99

100 GHATF Table A1. Site specifications for Shark Fixed‐site Survey (continued)

shark Region Site name Site code Site position Depth Shots Repeat Period Species (m) Past New Sum Trip New

survey West Tas–Vic West Victoria1 VicW1 Grid 0 4 4 New Aug–Oct 2007 School (deep water) West Victoria2 VicW2 Grid >130 0 4 4 New Aug–Oct 2007 School King North West1 KingNW1 Grid >130 0 4 4 8 New Aug–Oct 2007 School

King North West2 KingNW2 Grid 0 4 4 4 New Aug–Oct 2007 School Tasmania North West2 TasNW2 Grid 0 4 4 New Feb–Mar 2008 School Tasmania North West3 TasNW3 Grid 0 4 4 8 New Feb–Mar 2008 School West Tas1 TasW1 Grid 0 4 4 New Apr–May 2007 School West Tas 2 TasW2 Grid 0 4 4 New Apr–May 2007 School South Tas 1 TasS1 Grid 0 4 4 New Apr–May 2007 School South Tas 2 TasS2 Grid 0 4 4 New Apr–May 2007 School South Tas 3 TasS3 Grid 0 4 4 20 New Apr–May 2007 School

King Island King North East KingNE Grid 9 -5 4 Repeat Feb 2008 Sch–Gum King North KingN Grid 4 0 4 8 Repeat Feb 2008 Sch–Gum Tasmania North West1 TasNW1 Grid 1 3 4 4 Repeat Feb–Mar 2008 Sch–Gum

Eastern Kent North KentN Grid 7 -3 4 4 Repeat Apr–May 2008 Gummy Bass Strait East Vic EastVic Grid 4 0 4 Repeat Apr–May 2008 Sch–Gum Far East FarEast Grid 3 1 4 8 Repeat Apr–May 2008 Sch–Gum

Flinders Flinders West FlinW Grid 1 3 4 Repeat Apr 2008 Gummy Island Flinders North FlinN Grid 1 3 4 Repeat Apr 2008 Gummy Flinders North East FlinNE Grid 7 -3 4 12 Repeat Apr 2008 Sch–Gum

Total Bass Strait 37 39 76 76

Table A2. Definition of indices used to determine post‐capture mortality

Index Value Description

Stimuli activity 1 Strong and lively, flopping around on deck, shark can tightly clench jaws, no stiffness 2 Weaker movement but still lively, response if stimulated or provoked, shark can clench jaws no stiffness 3 Intermittent movement, physical activity limited to fin ripples or twitches, little response to stimuli, body appears limp but not in rigor mortis some stiffness 4 Shark in rigor mortis, stiff and lifeless, no physical activity or response to stimuli, jaws hanging open

Wounds bleeding 1 No cuts or bleeding observed 2 1-3 small cuts or lacerations not deep only on skin, some bleeding but not flowing profusely, no exposed or damaged organs 3 >3 small cuts or one severe cut or wound, exposed organs but undamaged, some bleeding but not flowing profusely 4 Extensive small cuts or very severe wounds or missing body parts, excessive bleeding, blood flowing freely and continuously in large quantities, internal organs exposed and damaged, may be protruding

Sea lice damage 1 No penetration of body by sea lice, body is intact 2 No penetration of body by sea lice, sea lice may be present on body but not attached to 3 Minor penetration of body, sea lice only on cloaca area 4 Extensive penetration of body via eyes, cloaca, gills, and/or skin, sea lice ate tissue

Skin damage and 1 0% of skin body damage and no redness or hemorrhagia on surface surface bruising 2 <5% of skin body damage or bruises or redness 3 5-40% of skin body damage or bruises or redness 4 >40% of skin body damage or bruises or redness

GHATF shark survey 101

Map A1. Western South Australia Each of the large boxes represents a sampling site done during the 00s survey. The colour of the box represents a primarily gummy shark, school shark or mixed fishing grounds. Also presented is the location of stations surveyed during the 70s, 80s and 90s.

Shoulder-H Gummy GAB-Hd1 GAB-Hd2 School GAB-Hd4 Mixed GAB-Hd3 Streaky 70s GAB-WA GAB-OM GAB-OE Eyre-W1 80s GAB-OW Venus 90s Eyre-W2

GAB-Shelf Eyre-SW

129 130 131 132 133 134 135 136

GHATF shark survey 102

Map A2. Eastern South Australia

Gummy

School

Mixed

70s

80s

90s

MurrayM KI W-Inshore Eyre-Shelf KI SW-Inshore CoralP KI SE-Inshore KI SW-Shelf KI S-Mid KI S-Offshore S-CoralP KI S-Shelf JaffaC

135 136 137 138 139 140

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Map A3. Western Bass Strait

VicW1 KingNE

VicW2 King NW2 Gummy King NW1 KingN School

Mixed TasNW1 70s

80s TasNW2 90s TasNW3

142 143 144 145 146

GHATF shark survey 104

Map A4. Eastern Bass Strait

East Vic KentN Far east Gummy FlinN FlinNE School

FlinW Mixed

70s

80s

90s

146 147 148

GHATF shark survey 105

Map A5. Tasmania

Gummy

TasW1 School Mixed TasW2

70s

TasS2 TasS1 80s

90s TasS3

145 146 147 148 149 150

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Appendix 2. Catch rate of commercial species caught in each surveys Catch rate caught by mesh‐size per 1000 km‐hour used in the comparative analysis between the 1973–76, 1986–87, 1998–2001, and 2007–08 surveys. A) Fuzzy analysis; B) defined analysis; —: no data; n= number.

A) Regions Great Australian Bight Offshore Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 1986–87 Fishing effort (km-hour) 0 81 78 536 85 Number of stations 0 26 26 26 26 Gummy shark Mustelus antarcticus — 147 (53) 185 (110) 1 (1) 32 (19) 25 School shark Galeorhinus galeus — 634 (177) 324 (113) 155 (65) 489 (129) 176 Southern sawshark Pristiophorus nudipinnis — 8 (8) 0 0 0 1 Common sawshark Pristiophorus cirratus — 213 (80) 239 (105) 10 (4) 45 (31) 48 Elephant fish Callorhinchus milii — 57 (57) 0 0 0 1 1998–2001 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 2007–08 Fishing effort (km-hour) 48 48 48 48 48 Number of stations 13 13 13 13 13 Gummy shark Mustelus antarcticus 70 (38) 561 (148) 373 (182) 130 (62) 55 (38) 54 School shark Galeorhinus galeus 15 (15) 0 15 (15) 19 (19) 21 (21) 4 Southern sawshark Pristiophorus nudipinnis 145 (68) 23 (23) 32 (32) 0 0 8 Common sawshark Pristiophorus cirratus 104 (66) 55 (40) 88 (39) 14 (14) 27 (27) 14 Elephant fish Callorhinchus milii 0000 00

GHATF shark survey 107

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Great Australian Bight Inshore Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 1986–87 Fishing effort (km-hour) 0 16 16 123 17 Number of stations 0 4 4 4 4 Gummy shark Mustelus antarcticus — 0 42 (42) 5 (5) 0 2 School shark Galeorhinus galeus — 82 (82) 107 (107) 30 (19) 121 (121) 9 Southern sawshark Pristiophorus nudipinnis — 000 00 Common sawshark Pristiophorus cirratus — 458 (458) 0 0 0 1 Elephant fish Callorhinchus milii — 000 00 1998–2001 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 2007–08 Fishing effort (km-hour) 71 71 71 72 71 Number of stations 12 12 12 12 12 Gummy shark Mustelus antarcticus 52 (22) 787 (303) 1285 (353) 639 (281) 367 (138) 200 School shark Galeorhinus galeus 115 (33) 1041 (286) 1758 (486) 2907 (717) 2957 (817) 583 Southern sawshark Pristiophorus nudipinnis 0000 00 Common sawshark Pristiophorus cirratus 0 17 (17) 0 0 0 1 Elephant fish Callorhinchus milii 0000 00

GHATF shark survey 108

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Streaky and Venus Bay Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 0000 0 Fishing effort (km-hour) 0 0 0 0 0 Number of stations ———— —— Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 1986–87 Fishing effort (km-hour) 0 28 28 27 27 Number of stations 0 9 9 9 9 Gummy shark Mustelus antarcticus — 2200 (1490) 1655 (819) 885 (361) 1012 (402) 101 School shark Galeorhinus galeus — 0 0 90 (90) 0 2 Southern sawshark Pristiophorus nudipinnis — 000 00 Common sawshark Pristiophorus cirratus — 000 00 Elephant fish Callorhinchus milii — 0 0 0 23 (23) 1 1998–2001 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 2007–08 Fishing effort (km-hour) 38 38 39 38 40 Number of stations 8 8 8 8 8 Gummy shark Mustelus antarcticus 112 (73) 1124 (764) 1688 (1035) 1244 (749) 834 (587) 197 School shark Galeorhinus galeus 0 34 (34) 29 (29) 88 (88) 18 (18) 5 Southern sawshark Pristiophorus nudipinnis 0000 00 Common sawshark Pristiophorus cirratus 0000 00 Elephant fish Callorhinchus milii 0000 00

GHATF shark survey 109

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

South Australia Shelf Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 1986–87 Fishing effort (km-hour) 0 47 50 364 48 Number of stations 0 10 10 10 10 Gummy shark Mustelus antarcticus — 255 (78) 105 (105) 0 19 (19) 13 School shark Galeorhinus galeus — 552 (196) 312 (142) 49 (28) 269 (109) 69 Southern sawshark Pristiophorus nudipinnis — 37 (37) 0 0 35 (35) 2 Common sawshark Pristiophorus cirratus — 20 (20) 49 (34) 5 (3) 13 (13) 6 Elephant fish Callorhinchus milii — 000 00 1998–2001 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 2007–08 Fishing effort (km-hour) 66 60 66 64 67 Number of stations 20 20 20 20 20 Gummy shark Mustelus antarcticus 339 (91) 827 (244) 693 (169) 261 (73) 100 (40) 146 School shark Galeorhinus galeus 33 (24) 276 (118) 184 (55) 174 (66) 92 (37) 46 Southern sawshark Pristiophorus nudipinnis 21 (14) 0 0 11 (11) 0 3 Common sawshark Pristiophorus cirratus 40 (23) 136 (71) 48 (28) 21 (21) 34 (34) 21 Elephant fish Callorhinchus milii 0 14 (14) 11 (11) 0 0 2

GHATF shark survey 110

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Eyre Peninsula Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 1986–87 Fishing effort (km-hour) 0 32 32 54 35 Number of stations 0 10 10 10 10 Gummy shark Mustelus antarcticus — 774 (297) 674 (150) 392 (240) 230 (173) 66 School shark Galeorhinus galeus — 218 (136) 119 (83) 80 (33) 12 (12) 15 Southern sawshark Pristiophorus nudipinnis — 294 (131) 41 (41) 56 (56) 0 9 Common sawshark Pristiophorus cirratus — 72 (60) 41 (41) 6 (6) 0 5 Elephant fish Callorhinchus milii — 49 (49) 0 54 (54) 0 2 1998–2001 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 2007–08 Fishing effort (km-hour) 30 47 29 32 27 Number of stations 7 7 7 7 7 Gummy shark Mustelus antarcticus 1390 (279) 1696 (314) 1500 (338) 1144 (267) 457 (160) 207 School shark Galeorhinus galeus 60 (39) 108 (72) 207 (106) 23 (23) 217 (111) 19 Southern sawshark Pristiophorus nudipinnis 338 (98) 72 (47) 38 (38) 0 0 16 Common sawshark Pristiophorus cirratus 36 (36) 43 (43) 0 0 0 2 Elephant fish Callorhinchus milii 0 43 (43) 88 (43) 0 0 4

GHATF shark survey 111

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Cape Jaffa Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 1986–87 Fishing effort (km-hour) 0 45 61 215 47 Number of stations 0 9 9 9 9 Gummy shark Mustelus antarcticus — 1634 (369) 1626 (569) 259 (84) 469 (86) 223 School shark Galeorhinus galeus — 319 (108) 325 (171) 17 (7) 92 (37) 39 Southern sawshark Pristiophorus nudipinnis — 0 22 (22) 0 43 (28) 3 Common sawshark Pristiophorus cirratus — 185 (94) 108 (56) 4 (4) 42 (28) 17 Elephant fish Callorhinchus milii — 000 00 1998–2001 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 2007–08 Fishing effort (km-hour) 15 16 15 16 14 Number of stations 4 4 4 4 4 Gummy shark Mustelus antarcticus 196 (72) 338 (180) 498 (399) 238 (97) 161 (97) 23 School shark Galeorhinus galeus 0 0 52 (52) 122 (73) 152 (95) 5 Southern sawshark Pristiophorus nudipinnis 0000 00 Common sawshark Pristiophorus cirratus 0000 00 Elephant fish Callorhinchus milii 0000 00

GHATF shark survey 112

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Western Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 8 7 7 7 4 Number of stations 6 6 5 5 3 Gummy shark Mustelus antarcticus 3603 (3003) 2436 (1171) 4756 (979) 1820 (488) 280 (280) 100 School shark Galeorhinus galeus 1140 (326) 419 (294) 1322 (472) 1063 (397) 247 (247) 39 Southern sawshark Pristiophorus nudipinnis 3342 (2346) 2491 (1968) 0 103 (103) 0 45 Common sawshark Pristiophorus cirratus 1339 (654) 985 (624) 1956 (1051) 467 (310) 0 43 Elephant fish Callorhinchus milii 2523 (1793) 3258 (2582) 7435 (4822) 10237 (6805) 3643 (3643) 197 1986–87 Fishing effort (km-hour) 0 36 154 38 37 Number of stations 0 11 11 11 11 Gummy shark Mustelus antarcticus — 1310 (505) 146 (37) 100 (56) 63 (43) 68 School shark Galeorhinus galeus — 391 (165) 188 (68) 543 (358) 174 (100) 72 Southern sawshark Pristiophorus nudipinnis — 403 (120) 38 (15) 48 (33) 0 23 Common sawshark Pristiophorus cirratus — 2030 (321) 337 (96) 710 (239) 448 (172) 169 Elephant fish Callorhinchus milii — 0 7 (7) 0 0 1 1998–2001 Fishing effort (km-hour) 0 0 580 0 0 Number of stations 0 0 12 0 0 Gummy shark Mustelus antarcticus —— 204 (41) ——99 School shark Galeorhinus galeus —— 48 (14) ——22 Southern sawshark Pristiophorus nudipinnis —— 102 (36) ——49 Common sawshark Pristiophorus cirratus —— 650 (120) ——338 Elephant fish Callorhinchus milii —— 305 (145) ——151 2007–08 Fishing effort (km-hour) 28 29 27 21 20 Number of stations 6 6 6 6 6 Gummy shark Mustelus antarcticus 1819 (1207) 1627 (694) 1325 (487) 275 (100) 98 (63) 161 School shark Galeorhinus galeus 197 (85) 2813 (1062) 4807 (1395) 5580 (1864) 3028 (1233) 465 Southern sawshark Pristiophorus nudipinnis 0 43 (43) 0 0 0 1 Common sawshark Pristiophorus cirratus 95 (95) 533 (374) 397 (290) 1108 (869) 226 (226) 45 Elephant fish Callorhinchus milii 0 0 723 (208) 130 (94) 56 (56) 22

GHATF shark survey 113

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Eastern Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 33 29 31 29 21 Number of stations 23 20 20 19 14 Gummy shark Mustelus antarcticus 655 (321) 786 (421) 991 (497) 387 (144) 0 116 School shark Galeorhinus galeus 331 (212) 169 (108) 525 (301) 298 (172) 94 (65) 50 Southern sawshark Pristiophorus nudipinnis 238 (113) 257 (145) 272 (108) 108 (75) 41 (41) 33 Common sawshark Pristiophorus cirratus 91 (71) 81 (56) 488 (252) 336 (158) 0 35 Elephant fish Callorhinchus milii 876 (301) 1520 (666) 3373 (1145) 1452 (475) 573 (136) 266 1986–87 Fishing effort (km-hour) 0 174 901 188 177 Number of stations 0 42 42 42 42 Gummy shark Mustelus antarcticus — 3372 (526) 491 (144) 442 (103) 195 (50) 993 School shark Galeorhinus galeus — 1855 (775) 127 (49) 112 (34) 111 (38) 389 Southern sawshark Pristiophorus nudipinnis — 441 (88) 39 (14) 151 (52) 75 (37) 141 Common sawshark Pristiophorus cirratus — 728 (203) 142 (51) 179 (44) 130 (42) 210 Elephant fish Callorhinchus milii — 426 (380) 37 (28) 179 (113) 97 (63) 183 1998–2001 Fishing effort (km-hour) 0 0 1017 0 0 Number of stations 0 0 29 0 0 Gummy shark Mustelus antarcticus —— 1805 (280) ——1671 School shark Galeorhinus galeus —— 39 (19) ——39 Southern sawshark Pristiophorus nudipinnis —— 52 (20) ——51 Common sawshark Pristiophorus cirratus —— 266 (54) ——265 Elephant fish Callorhinchus milii —— 421 (160) ——405 2007–08 Fishing effort (km-hour) 64 61 65 62 61 Number of stations 16 16 16 16 16 Gummy shark Mustelus antarcticus 17059 (5974) 16060 (4010) 5549 (1041) 2016 (280) 405 (121) 2558 School shark Galeorhinus galeus 126 (92) 42 (31) 25 (17) 0 22 (22) 14 Southern sawshark Pristiophorus nudipinnis 1039 (256) 730 (284) 271 (115) 16 (16) 14 (14) 128 Common sawshark Pristiophorus cirratus 973 (331) 1155 (456) 402 (203) 123 (99) 71 (34) 177 Elephant fish Callorhinchus milii 0 0 12 (12) 0 0 1

GHATF shark survey 114

Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Zones South Australia Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 1986–87 Fishing effort (km-hour) 0 251 264 1318 257 Number of stations 0 68 68 68 68 Gummy shark Mustelus antarcticus — 715 (220) 622 (156) 210 (68) 245 (71) 430 School shark Galeorhinus galeus — 403 (81) 236 (55) 94 (28) 248 (58) 310 Southern sawshark Pristiophorus nudipinnis — 52 (23) 9 (7) 8 (8) 11 (6) 15 Common sawshark Pristiophorus cirratus — 146 (43) 119 (43) 6 (2) 25 (13) 77 Elephant fish Callorhinchus milii — 29 (23) 0 8 (8) 3 (3) 4 1998–2001 Fishing effort (km-hour) 0 0 0 0 0 Number of stations 0 0 0 0 0 Gummy shark Mustelus antarcticus ———— —— School shark Galeorhinus galeus ———— —— Southern sawshark Pristiophorus nudipinnis ———— —— Common sawshark Pristiophorus cirratus ———— —— Elephant fish Callorhinchus milii ———— —— 2007–08 Fishing effort (km-hour) 268 279 268 269 268 Number of stations 64 64 64 64 64 Gummy shark Mustelus antarcticus 308 (65) 867 (144) 940 (168) 523 (120) 276 (83) 827 School shark Galeorhinus galeus 42 (12) 298 (79) 420 (122) 624 (191) 623 (205) 662 Southern sawshark Pristiophorus nudipinnis 73 (22) 13 (7) 11 (8) 3 (3) 0 27 Common sawshark Pristiophorus cirratus 38 (16) 62 (25) 33 (12) 9 (7) 16 (12) 38 Elephant fish Callorhinchus milii 0 9 (6) 13 (6) 0 0 6

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Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1973–76 Fishing effort (km-hour) 41 37 38 36 25 Number of stations 29 26 25 24 17 Gummy shark Mustelus antarcticus 1440 (658) 1731 (573) 3650 (935) 1528 (386) 521 (122) 366 School shark Galeorhinus galeus 499 (189) 227 (106) 684 (263) 457 (168) 121 (66) 89 Southern sawshark Pristiophorus nudipinnis 880 (517) 773 (476) 218 (89) 107 (62) 34 (34) 78 Common sawshark Pristiophorus cirratus 796 (287) 832 (349) 1184 (446) 404 (128) 0 159 Elephant fish Callorhinchus milii 594 (396) 814 (617) 1877 (1066) 2399 (1548) 643 (643) 232 1986–87 Fishing effort (km-hour) 0 210 1055 226 215 Number of stations 0 53 53 53 53 Gummy shark Mustelus antarcticus — 2936 (442) 418 (115) 370 (84) 168 (41) 1061 School shark Galeorhinus galeus — 1546 (616) 140 (41) 203 (81) 124 (36) 461 Southern sawshark Pristiophorus nudipinnis — 433 (73) 39 (11) 129 (42) 59 (29) 164 Common sawshark Pristiophorus cirratus — 1004 (188) 184 (46) 292 (67) 196 (51) 379 Elephant fish Callorhinchus milii — 336 (300) 30 (22) 141 (90) 77 (50) 184 1998–2001 Fishing effort (km-hour) 0 0 1597 0 0 Number of stations 0 0 41 0 0 Gummy shark Mustelus antarcticus —— 1336 (229) ——1770 School shark Galeorhinus galeus —— 42 (14) ——61 Southern sawshark Pristiophorus nudipinnis —— 67 (18) ——100 Common sawshark Pristiophorus cirratus —— 379 (58) ——603 Elephant fish Callorhinchus milii —— 387 (120) ——556 2007–08 Fishing effort (km-hour) 92 90 92 83 81 Number of stations 22 22 22 22 22 Gummy shark Mustelus antarcticus 12903 (4564) 12123 (3217) 4397 (864) 1541 (265) 321 (94) 2719 School shark Galeorhinus galeus 145 (70) 798 (382) 1329 (585) 1522 (721) 842 (429) 479 Southern sawshark Pristiophorus nudipinnis 755 (210) 543 (215) 197 (87) 12 (12) 10 (10) 129 Common sawshark Pristiophorus cirratus 733 (254) 986 (347) 401 (164) 392 (252) 113 (64) 222 Elephant fish Callorhinchus milii 0 0 206 (88) 36 (27) 15 (15) 23

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Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

B) Region Great Australian Bight Offshore Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 50 48 328 52 Number of stations 0 16 16 16 16 Gummy shark Mustelus antarcticus — 101 (58) 19 (19) 0 18 (18) 8 School shark Galeorhinus galeus — 325 (95) 380 (170) 88 (49) 416 (170) 95 Southern sawshark Pristiophorus nudipinnis — 000 00 Common sawshark Pristiophorus cirratus — 224 (110) 167 (125) 12 (7) 18 (18) 21 Elephant fish Callorhinchus milii — 000 00 2007–08 Fishing effort (km-hour) 48 48 48 48 48 Number of stations 13 13 13 13 13 Gummy shark Mustelus antarcticus 70 (38) 561 (148) 373 (182) 130 (62) 55 (38) 54 School shark Galeorhinus galeus 15 (15) 0 15 (15) 19 (19) 21 (21) 4 Southern sawshark Pristiophorus nudipinnis 145 (68) 23 (23) 32 (32) 0 0 8 Common sawshark Pristiophorus cirratus 104 (66) 55 (40) 88 (39) 14 (14) 27 (27) 14 Elephant fish Callorhinchus milii 0000 00

Great Australian Bight Inshore Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 16 16 123 17 Number of stations 0 4 4 4 4 Gummy shark Mustelus antarcticus — 0 42 (42) 5 (5) 0 2 School shark Galeorhinus galeus — 82 (82) 107 (107) 30 (19) 121 (121) 9 Southern sawshark Pristiophorus nudipinnis — 000 00 Common sawshark Pristiophorus cirratus — 458 (458) 0 0 0 1 Elephant fish Callorhinchus milii — 000 00 2007–08 Fishing effort (km-hour) 71 71 71 72 71 Number of stations 12 12 12 12 12 Gummy shark Mustelus antarcticus 52 (22) 787 (303) 1285 (353) 639 (281) 367 (138) 200 School shark Galeorhinus galeus 115 (33) 1041 (286) 1758 (486) 2907 (717) 2957 (817) 583 Southern sawshark Pristiophorus nudipinnis 0000 00 Common sawshark Pristiophorus cirratus 0 17 (17) 0 0 0 1 Elephant fish Callorhinchus milii 0000 00

Streaky and Venus Bay Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 12 12 12 12 Number of stations 0 5 5 5 5 Gummy shark Mustelus antarcticus — 3038 (2679) 1836 (1082) 1317 (542) 1674 (560) 79 School shark Galeorhinus galeus — 0 0 162 (162) 0 2 Southern sawshark Pristiophorus nudipinnis — 000 00 Common sawshark Pristiophorus cirratus — 000 00 Elephant fish Callorhinchus milii — 000 00 2007–08 Fishing effort (km-hour) 38 38 39 38 40 Number of stations 8 8 8 8 8 Gummy shark Mustelus antarcticus 112 (73) 1124 (764) 1688 (1035) 1244 (749) 834 (587) 197 School shark Galeorhinus galeus 0 34 (34) 29 (29) 88 (88) 18 (18) 5 Southern sawshark Pristiophorus nudipinnis 0000 00 Common sawshark Pristiophorus cirratus 0000 00 Elephant fish Callorhinchus milii 0000 00

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Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

South Australia Shelf Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 32 34 248 33 Number of stations 0 7 7 7 7 Gummy shark Mustelus antarcticus — 283 (86) 150 (150) 0 28 (28) 11 School shark Galeorhinus galeus — 503 (239) 373 (200) 33 (22) 327 (151) 40 Southern sawshark Pristiophorus nudipinnis — 53 (53) 0 0 50 (50) 2 Common sawshark Pristiophorus cirratus — 29 (29) 70 (47) 4 (4) 0 4 Elephant fish Callorhinchus milii — 000 00 2007–08 Fishing effort (km-hour) 66 60 66 64 67 Number of stations 20 20 20 20 20 Gummy shark Mustelus antarcticus 339 (91) 827 (244) 693 (169) 261 (73) 100 (40) 146 School shark Galeorhinus galeus 33 (24) 276 (118) 184 (55) 174 (66) 92 (37) 46 Southern sawshark Pristiophorus nudipinnis 21 (14) 0 0 11 (11) 0 3 Common sawshark Pristiophorus cirratus 40 (23) 136 (71) 48 (28) 21 (21) 34 (34) 21 Elephant fish Callorhinchus milii 0 14 (14) 11 (11) 0 0 2

Eyre Peninsula Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 21 21 37 22 Number of stations 0 6 6 6 6 Gummy shark Mustelus antarcticus — 683 (379) 550 (196) 254 (141) 0 26 School shark Galeorhinus galeus — 263 (213) 127 (127) 64 (41) 20 (20) 10 Southern sawshark Pristiophorus nudipinnis — 228 (114) 0 0 0 4 Common sawshark Pristiophorus cirratus — 20 (20) 0 10 (10) 0 2 Elephant fish Callorhinchus milii — 82 (82) 0 89 (89) 0 2 2007–08 Fishing effort (km-hour) 30 47 29 32 27 Number of stations 7 7 7 7 7 Gummy shark Mustelus antarcticus 1390 (279) 1696 (314) 1500 (338) 1144 (267) 457 (160) 207 School shark Galeorhinus galeus 60 (39) 108 (72) 207 (106) 23 (23) 217 (111) 19 Southern sawshark Pristiophorus nudipinnis 338 (98) 72 (47) 38 (38) 0 0 16 Common sawshark Pristiophorus cirratus 36 (36) 43 (43) 0 0 0 2 Elephant fish Callorhinchus milii 0 43 (43) 88 (43) 0 0 4

Cape Jaffa Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 45 61 215 47 Number of stations 0 9 9 9 9 Gummy shark Mustelus antarcticus — 1634 (369) 1626 (569) 259 (84) 469 (86) 223 School shark Galeorhinus galeus — 319 (108) 325 (171) 17 (7) 92 (37) 39 Southern sawshark Pristiophorus nudipinnis — 0 22 (22) 0 43 (28) 3 Common sawshark Pristiophorus cirratus — 185 (94) 108 (56) 4 (4) 42 (28) 17 Elephant fish Callorhinchus milii — 000 00 2007–08 Fishing effort (km-hour) 15 16 15 16 14 Number of stations 4 4 4 4 4 Gummy shark Mustelus antarcticus 196 (72) 338 (180) 498 (399) 238 (97) 161 (97) 23 School shark Galeorhinus galeus 0 0 52 (52) 122 (73) 152 (95) 5 Southern sawshark Pristiophorus nudipinnis 0000 00 Common sawshark Pristiophorus cirratus 0000 00 Elephant fish Callorhinchus milii 0000 00

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Appendix 2. Catch rate of commercial species caught in the different surveys (continued)

Western Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 23 92 24 24 Number of stations 0 7 7 7 7 Gummy shark Mustelus antarcticus — 1367 (777) 161 (54) 79 (79) 99 (65) 45 School shark Galeorhinus galeus — 579 (232) 295 (83) 854 (540) 273 (148) 71 Southern sawshark Pristiophorus nudipinnis — 318 (131) 44 (22) 41 (41) 0 12 Common sawshark Pristiophorus cirratus — 1710 (416) 427 (140) 931 (350) 668 (232) 119 Elephant fish Callorhinchus milii — 000 00 2007–08 Fishing effort (km-hour) 28 29 27 21 20 Number of stations 6 6 6 6 6 Gummy shark Mustelus antarcticus 1819 (1207) 1627 (694) 1325 (487) 275 (100) 98 (63) 161 School shark Galeorhinus galeus 197 (85) 2813 (1062) 4807 (1395) 5580 (1864) 3028 (1233) 465 Southern sawshark Pristiophorus nudipinnis 0 43 (43) 0 0 0 1 Common sawshark Pristiophorus cirratus 95 (95) 533 (374) 397 (290) 1108 (869) 226 (226) 45 Elephant fish Callorhinchus milii 0 0 723 (208) 130 (94) 56 (56) 22

Eastern Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 100 573 97 101 Number of stations 0 22 22 22 22 Gummy shark Mustelus antarcticus — 4608 (811) 769 (251) 621 (170) 296 (80) 742 School shark Galeorhinus galeus — 2010 (1029) 163 (86) 166 (58) 165 (66) 239 Southern sawshark Pristiophorus nudipinnis — 435 (129) 42 (23) 157 (79) 37 (21) 77 Common sawshark Pristiophorus cirratus — 574 (234) 163 (85) 181 (47) 82 (51) 98 Elephant fish Callorhinchus milii — 721 (707) 50 (50) 81 (81) 109 (109) 136 2007–08 Fishing effort (km-hour) 64 61 65 62 61 Number of stations 16 16 16 16 16 Gummy shark Mustelus antarcticus 17059 (5974) 16060 (4010) 5549 (1041) 2016 (280) 405 (121) 2558 School shark Galeorhinus galeus 126 (92) 42 (31) 25 (17) 0 22 (22) 14 Southern sawshark Pristiophorus nudipinnis 1039 (256) 730 (284) 271 (115) 16 (16) 14 (14) 128 Common sawshark Pristiophorus cirratus 973 (331) 1155 (456) 402 (203) 123 (99) 71 (34) 177 Elephant fish Callorhinchus milii 0 0 12 (12) 0 0 1

GHATF shark survey 119

Appendix 2. Catch rate of commercial species caught in the different surveys (continued) Zones South Australia Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 176 191 963 183 Number of stations 0 47 47 47 47 Gummy shark Mustelus antarcticus — 800 (306) 609 (185) 223 (81) 278 (94) 349 School shark Galeorhinus galeus — 287 (60) 272 (75) 66 (24) 221 (66) 195 Southern sawshark Pristiophorus nudipinnis — 37 (19) 4 (4) 0 16 (9) 9 Common sawshark Pristiophorus cirratus — 158 (56) 88 (44) 7 (3) 14 (8) 45 Elephant fish Callorhinchus milii — 10 (10) 0 11 (11) 0 2 2007–08 Fishing effort (km-hour) 268 279 268 269 268 Number of stations 64 64 64 64 64 Gummy shark Mustelus antarcticus 308 (65) 867 (144) 940 (168) 523 (120) 276 (83) 827 School shark Galeorhinus galeus 42 (12) 298 (79) 420 (122) 624 (191) 623 (205) 662 Southern sawshark Pristiophorus nudipinnis 73 (22) 13 (7) 11 (8) 3 (3) 0 27 Common sawshark Pristiophorus cirratus 38 (16) 62 (25) 33 (12) 9 (7) 16 (12) 38 Elephant fish Callorhinchus milii 0 9 (6) 13 (6) 0 0 6

Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch 1986–87 Fishing effort (km-hour) 0 124 665 122 125 Number of stations 0 29 29 29 29 Gummy shark Mustelus antarcticus — 3826 (689) 622 (196) 491 (137) 248 (64) 787 School shark Galeorhinus galeus — 1664 (786) 195 (69) 332 (142) 191 (61) 310 Southern sawshark Pristiophorus nudipinnis — 407 (102) 42 (18) 129 (61) 28 (16) 89 Common sawshark Pristiophorus cirratus — 848 (220) 227 (75) 362 (106) 224 (81) 217 Elephant fish Callorhinchus milii — 547 (537) 38 (38) 62 (62) 82 (82) 136 2007–08 Fishing effort (km-hour) 92 90 92 83 81 Number of stations 22 22 22 22 22 Gummy shark Mustelus antarcticus 12903 (4564) 12123 (3217) 4397 (864) 1541 (265) 321 (94) 2719 School shark Galeorhinus galeus 145 (70) 798 (382) 1329 (585) 1522 (721) 842 (429) 479 Southern sawshark Pristiophorus nudipinnis 755 (210) 543 (215) 197 (87) 12 (12) 10 (10) 129 Common sawshark Pristiophorus cirratus 733 (254) 986 (347) 401 (164) 392 (252) 113 (64) 222 Elephant fish Callorhinchus milii 0 0 206 (88) 36 (27) 15 (15) 23

GHATF shark survey 120

Appendix 3. Catch rate of bycatch species caught in each survey Catch rate caught by mesh‐size per 1000 km‐hour used in the comparative analysis between the 1973–76, 1998–2001, and 2007–08 surveys (fuzzy analysis only). —: no data; n= number.

Regions Western Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch

1973–76 Fishing effort (km-hour) 8 7 7 7 4 Number of stations 6 6 5 5 3 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 0 0 0 238 (238) 280 (280) 3 Spikey spurdog Squalus megalops 2836 (1775) 1468 (521) 305 (196) 0 1233 (1233) 270 Draughtboard shark Cephaloscyllium laticeps 0 1118 (600) 113 (113) 207 (207) 280 (280) 10 Port Jackson shark Heterodontus portusjacksoni 0 1742 (1414) 1409 (621) 2543 (2002) 1681 (1681) 56 Total Chondrichthyes 14782 (5160) 13918 (3384) 17297 (5924) 16678 (8490) 7644 (5574) 767 Teleostei Long-snout boarfish Pentaceropsis recurvirostris 0 0 191 (191) 365 (365) 0 3 Sand flathead Platycephalus bassensis 3756 (2537) 1046 (492) 0 0 0 116 Total Teleostei 4606 (2728) 1301 (402) 191 (191) 365 (365) 0 193

1998–2001 Fishing effort (km-hour) 0 0 580 0 0 Number of stations 0 0 12 0 0 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus —— 17 (7) ——9 Spikey spurdog Squalus megalops —— 476 (149) ——228 Draughtboard shark Cephaloscyllium laticeps —— 407 (119) ——209 Port Jackson shark Heterodontus portusjacksoni —— 248 (70) ——121 Total Chondrichthyes —— 2493 (363) ——1245 Teleostei Long-snout boarfish Pentaceropsis recurvirostris —— 26 (11) ——13 Sand flathead Platycephalus bassensis —— 4 (3) ——2 Total Teleostei —— 201 (71) ——95

2007–08 Fishing effort (km-hour) 28 29 27 21 20 Number of stations 6 6 6 6 6 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 0 198 (111) 247 (97) 173 (81) 306 (195) 23 Spikey spurdog Squalus megalops 569 (514) 2214 (1936) 0 0 0 62 Draughtboard shark Cephaloscyllium laticeps 0 0 1197 (1197) 1780 (1780) 755(602) 48 Port Jackson shark Heterodontus portusjacksoni 0 316 (255) 233 (83) 448 (405) 137 (86) 27 Total Chondrichthyes 2822 (1261) 7772 (1796) 8930 (1076) 9495 (1006) 4606 (922) 858 Teleostei Long-snout boarfish Pentaceropsis recurvirostris 000000 Sand flathead Platycephalus bassensis 000000 Total Teleostei 572 (324) 0 106 (106) 0 71 (71) 18

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Appendix 3. Catch rate of bycatch species caught in the different surveys (continued)

Eastern Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch

1973–76 Fishing effort (km-hour) 33 29 31 29 21 Number of stations 23 20 20 19 14 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 000000 Spikey spurdog Squalus megalops 853 (594) 338 (302) 144 (144) 0 0 114 Draughtboard shark Cephaloscyllium laticeps 480 (272) 569 (210) 2173 (868) 2706 (784) 705 (175) 219 Port Jackson shark Heterodontus portusjacksoni 0 216 (145) 524 (151) 917 (426) 387 (155) 63 Total Chondrichthyes 4359 (1276) 3973 (1247) 8565 (2021) 6359 (1537) 1839 (335) 962 Teleostei Long-snout boarfish Pentaceropsis recurvirostris 0 0 289 (147) 94 (94) 0 11 Sand flathead Platycephalus bassensis 1023 (579) 171 (137) 601 (601) 82 (57) 0 151 Total Teleostei 2473 (669) 550 (178) 1469 (1195) 208 (108) 63 (63) 529

1998–2001 Fishing effort (km-hour) 0 0 1017 0 0 Number of stations 0 0 29 0 0 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus —— 0 ——0 Spikey spurdog Squalus megalops —— 0 ——0 Draughtboard shark Cephaloscyllium laticeps —— 86 (49) ——98 Port Jackson shark Heterodontus portusjacksoni —— 137 (48) ——105 Total Chondrichthyes —— 2818 (315) ——2647 Teleostei Long-snout boarfish Pentaceropsis recurvirostris —— 12 (5) ——12 Sand flathead Platycephalus bassensis —— 0 ——0 Total Teleostei —— 80 (40) ——85

2007–08 Fishing effort (km-hour) 64 61 65 62 61 Number of stations 16 16 16 16 16 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 0 0 104 (38) 264 (81) 167 (61) 33 Spikey spurdog Squalus megalops 749 (463) 202 (169) 42 (30) 0 0 63 Draughtboard shark Cephaloscyllium laticeps 258 (83) 1163 (319) 3107 (435) 4041 (560) 1631 (389) 628 Port Jackson shark Heterodontus portusjacksoni 20 (20) 99 (43) 192 (100) 296 (103) 291 (87) 54 Total Chondrichthyes 20489 (6059) 19522 (4206) 9791 (1362) 6880 (670) 2992 (596) 3704 Teleostei Long-snout boarfish Pentaceropsis recurvirostris 0 43 (31) 16 (16) 38 (26) 29 (29) 7 Sand flathead Platycephalus bassensis 000000 Total Teleostei 733 (185) 131 (62) 203 (125) 60 (47) 49 (34) 68

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Appendix 3. Catch rate of bycatch species caught in the different surveys (continued)

Zones Bass Strait Common name or effort Scientifc name Mean (s.e.) No. of individuals caught per 1000 km-lift hours n 4-inch 5-inch 6-inch 7-inch 8-inch

1973–76 Fishing effort (km-hour) 41 37 38 36 25 Number of stations 29 26 25 24 17 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 0 0 0 50 (50) 49 (49) 3 Spikey spurdog Squalus megalops 1263 (600) 599 (273) 176 (121) 0 218 (218) 384 Draughtboard shark Cephaloscyllium laticeps 381 (218) 695 (211) 1761 (711) 2186 (653) 630 (154) 229 Port Jackson shark Heterodontus portusjacksoni 0 568 (348) 701 (180) 1256 (526) 616 (306) 119 Total Chondrichthyes 6516 (1623) 6268 (1463) 10311 (2065) 8509 (2200) 2863 (1033) 1729 Teleostei Long-snout boarfish Pentaceropsis recurvirostris 0 0 269 (122) 151 (104) 0 14 Sand flathead Platycephalus bassensis 1588 (700) 373 (166) 481 (481) 65 (45) 0 267 Total Teleostei 2914 (762) 724 (173) 1213 (957) 240 (110) 52 (52) 722

1998–2001 Fishing effort (km-hour) 0 0 1597 0 0 Number of stations 0 0 41 0 0 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus —— 5 (2) ——9 Spikey spurdog Squalus megalops —— 139 (54) ——228 Draughtboard shark Cephaloscyllium laticeps —— 180 (54) ——307 Port Jackson shark Heterodontus portusjacksoni —— 169 (40) ——226 Total Chondrichthyes —— 2723 (246) ——3892 Teleostei Long-snout boarfish Pentaceropsis recurvirostris —— 16 (5) ——25 Sand flathead Platycephalus bassensis —— 1 (1) ——2 Total Teleostei —— 115 (36) ——180

2007–08 Fishing effort (km-hour) 92 90 92 83 81 Number of stations 22 22 22 22 22 Chondrichthyes Broadnose sevengill shark Notorynchus cepedianus 0 54 (34) 143 (39) 239 (62) 205 (68) 56 Spikey spurdog Squalus megalops 700 (359) 751 (544) 30 (22) 0 0 125 Draughtboard shark Cephaloscyllium laticeps 188 (65) 846 (256) 2586 (475) 3424 (646) 1392 (331) 676 Port Jackson shark Heterodontus portusjacksoni 15 (15) 158 (75) 204 (75) 338 (128) 249 (68) 81 Total Chondrichthyes 15671 (4703) 16318 (3271) 9556 (1023) 7593 (603) 3432 (514) 4562 Teleostei Long-snout boarfish Pentaceropsis recurvirostris 0 31 (23) 12 (12) 27 (19) 21 (21) 7 Sand flathead Platycephalus bassensis 000000 Total Teleostei 689 (158) 95 (46) 176 (94) 44 (34) 55 (31) 86

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