National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE)

Home , Common eagle ray, Common skate, Sailfin roughshark

Project Code: MB5201

Authors: J. R. Ellis, V. A. Bendall, S. J. Hetherington, J. F. Silva and S. R. McCully Phillips.

Issue date: 15-Jan-2016

Cefas Document Control

Title: National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE)

Project Code: MB5201

Submitted to: Defra Date submitted: 15-Jan-2016 Project Manager: Jim Ellis Project Sponsor: Wendy Dawson

Report compiled by: Jim Ellis, Vicky Bendall, Stuart Hetherington, Joana Silva and Sophy McCully Phillips Quality control by: David Righton Approved by & date: Version: V1.4 Ellis, J. R., Bendall, V. A., Hetherington, S. J., Silva, J. F. and McCully Suggested citation Phillips, S. R. (2015). National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE). Project Report (Cefas), x + 105 pp.

Version Control History Author Date Comment Version Ellis et al. 25 Feb 2015 Initial draft V1.0 Ellis et al. 26 Feb 2015 Edits made by JE and SM V1.1 Ellis et al. 04 Mar 2015 QA by DR, further edits by JE/SM V1.2 Ellis et al. 24 Jul 2015 Following comments from PSG V1.3 Ellis et al. 15 Jan 2016 Final version after external review V1.4

National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page i

National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page ii

Project Code: MB5201

National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE)

Authors: J. R. Ellis, V. A. Bendall, S. Hetherington, J. F. Silva and S. R.

McCully Phillips

Issue date: 15-Jan-2016

Head office

Centre for Environment, Fisheries & Aquaculture Science Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK

Tel +44 (0) 1502 56 2244 Fax +44 (0) 1502 51 3865 www.cefas.defra.gov.uk

Cefas is an executive agency of Defra

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Table of contents

Informing policy ...... 1 1 Introduction ...... 3 1.1 Background ...... 3

1.2 Project background ...... 4

1.3 Format of the report ...... 5

2 Elasmobranchs of the British Isles and prioritisation of species of interest ...... 7 Summary ...... 7

2.1 Elasmobranchs of the British Isles ...... 8

2.2 Prioritising elasmobranchs and holocephalans of interest ...... 13

2.3 Productivity Susceptibility Analyses ...... 17

3 Elasmobranch bycatch in the Celtic Sea ...... 25 Summary ...... 25

3.1 Introduction ...... 26

3.2 Stakeholder engagement ...... 26

3.3 Approach and data collection ...... 27

3.4 Catches of spurdog, common skate and porbeagle ...... 31

3.5 Tagging studies and biological information ...... 40

3.6 At-vessel mortality ...... 42

3.7 Best practice in handling elasmobranchs and developing a ‘Code of conduct’ ...... 44

3.8 Lessons learnt: Advantages and limitations of fisher-collected data ...... 47

4 Biological investigations of elasmobranchs ...... 49 Summary ...... 49

4.1 Introduction ...... 50

4.2 Starry smooth-hound Mustelus asterias ...... 53

4.3 Spurdog Squalus acanthias ...... 61

4.4 Porbeagle Lamna nasus ...... 69

4.5 Other biological investigations ...... 73

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5 Concluding remarks ...... 77 6 Acknowledgments ...... 81 7 References ...... 82 8 Annexes ...... 87 8.1 List of acronyms ...... 87

8.2 Outputs from project and associated work ...... 88

8.3 Taxonomic list of chondrichthyans of the British Isles and adjacent waters ...... 91

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Figures

Figure 1. Diversity of the elasmobranch fauna of the British Isles, showing (a) spurdog, (b) angel shark, (c) porbeagle, (d) blue shark, (e) tope, (f) starry smooth-hound, (g) lesser-spotted dogfish, (h) greater-spotted dogfish, (i) common stingray and (j) electric ray ...... 9 Figure 2. Diversity of the elasmobranch fauna of the British Isles, showing (a) starry ray, (b) blue skate, (c) sandy ray, (d) shagreen ray, (e) cuckoo ray, (f) blonde ray, (g) thornback ray, (h) small-eyed ray, (i) spotted ray and (j) undulate ray...... 10 Figure 3: PSA plot indicating vulnerabilities of Celtic Sea elasmobranchs in the demersal gillnet fishery. Species codes given in Table 9...... 24 Figure 4: PSA plot indicating vulnerabilities of Celtic Sea elasmobranchs in the demersal otter trawl fishery. Species codes given in Table 9...... 24 Figure 5: Disentangling a common skate from fishing gear ...... 28 Figure 6. Main fishing grounds of Vessel A when setting gillnets...... 32 Figure 7. Main fishing grounds of Vessel A when setting tangle nets...... 33 Figure 8. Main fishing grounds of Vessel B when setting gillnets...... 34 Figure 9. Main fishing grounds of Vessel C when setting gillnets...... 36 Figure 10. Main fishing grounds of Vessel C when setting tangle nets...... 37 Figure 11. Spatial distribution of spurdog bycatch observed by ICES rectangle ...... 38 Figure 12. Spatial distribution of porbeagle bycatch observed by ICES rectangle ...... 39 Figure 13. Spatial distribution of common skate bycatch observed by ICES rectangle ...... 39 Figure 14. Length frequency of Dipturus spp. tagged and released, showing those identified as Dipturus batis (BSKT), Dipturus cf. intermedia (FSKT) and Dipturus batis-complex (SKT) ...... 41 Figure 15. Relationship between disc width and total length in Dipturus batis ...... 41 Figure 16. Length frequency of spurdog Squalus acanthias tagged and released ...... 42 Figure 17. Length frequency of undulate ray Raja undulata tagged and released ...... 42 Figure 18. Example ‘Code of Conduct’ ...... 46 Figure 19. Length frequency distribution of starry smooth-hound examined by sex ...... 54 Figure 20. Relationship between total weight and total length in starry smooth-hound by sex and maturity stage ...... 55 Figure 21. Relationship between gutted weight and total length in starry smooth-hound by sex ...... 55 Figure 22. Relationship between liver weight and total length by sex ...... 56 Figure 23. Relationship between gonad weight and total length by sex and maturity stage ...... 57

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Figure 24. Relationship between width of the shell (or nidamental) gland and total length in female starry smooth-hound by maturity stage ...... 58 Figure 25. Relationship between outer clasper length and total length in male starry smooth-hound by maturity stage ...... 58 Figure 26. Relationship between uterine fecundity (embryos and term pups) and maternal total length in starry smooth-hound ...... 59 Figure 27. Relationship between the average length (left) and average weight (right) of term pups in relation to maternal length for starry smooth-hound ...... 60 Figure 28. Length frequency of spurdog examined by sex (black = female, n=307; grey = male, n= 803) ...... 62 Figure 29. Relationships between total weight and total length by maturity stage for female (n = 301) and male (n = 792) spurdog ...... 64 Figure 30. Relationship between gutted weight and total length in female (n = 301) and male (n = 793) spurdog ...... 64 Figure 31. Relationship between gonad weight and total length by maturity stage for female (n = 298) and male (n = 793) spurdog ...... 65 Figure 32. Relationship between width of the nidamental gland and total length in female spurdog (n = 300) ...... 66 Figure 33. Relationship between inner and outer clasper length and total length in male spurdog by maturity stage ...... 67 Figure 34. Ovarian (mature follicles) and uterine fecundity (embryos and term pups) in relation to maternal total length (n = 151 and 85, respectively) in spurdog. Some of these fish may have aborted some pups during capture ...... 68 Figure 35. Average total length (left) and average weight (right) of term pups in relation to maternal total length (n = 49) in spurdog ...... 68 Figure 36. Relationships between inner clasper length (taken as the distance from the anterior margin of the cloaca to the tip of the clasper) for male porbeagle (n = 33) for developing (open circles) and mature (closed circles) fish. Total length refers to total length with the upper lobe of the caudal fin depressed, measured under the body ...... 71 Figure 37. Length-weight relationships for porbeagle (n = 53) for (a) total weight and (b) gutted weight. Total length refers to total length with the upper lobe of the caudal fin depressed, measured under the body ...... 72

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Tables

Table 1. Taxonomic list of elasmobranchs and holocephalans occurring around the British Isles and adjacent waters (See Annex 8.3 for more comprehensive details)...... 11 Table 2. Scores applied to elasmobranch and holocephalan fishes in relation to conservation interest ...... 14 Table 3. Scores applied to elasmobranch and holocephalan fishes in relation to commercial importance ...... 14 Table 4. Scores applied to elasmobranch and holocephalan fishes in relation to biological sensitivity ...... 15 Table 5. Scores applied to elasmobranch and holocephalan fishes in relation to the importance of UK waters to the species range ...... 15 Table 6. Highest scoring elasmobranch fishes ...... 17 Table 7: Productivity attributes used in the PSA. Those in normal font were as used in the NOAA PSA framework, parameters modified from NOAA are shown in bold, and additional parameters shown in bold italics...... 21 Table 8: Susceptibility attributes used in this study. Those in normal font are taken from the NOAA PSA framework, those in bold are modified parameters, and added parameters are denoted by bold italics...... 22 Table 9: Results of the PSA vulnerabilities and overall rankings for elasmobranchs that may be encountered in otter trawl and gillnet fisheries in the Celtic Sea. Productivity is species-specific and does not change between fisheries, whilst susceptibility scores are fishery-specific)...... 23 Table 10. Details of the three vessels participating in the “Shark, Skate and Ray Scientific bycatch fishery”...... 29 Table 11. Summary details of commercial trips for which data were collated. Note: trips marked [1] and [2] only provided information for porbeagle and common skate, respectively...... 30 Table 12. Reported catches by Vessel A of spurdog (estimated biomass) and porbeagle (number) caught in gillnets per trip and in relation to the reported retained catch of the main species (hake and pollack, ‘na = data not available). Data aggregated at a trip level. For those sets where spurdog were counted, the biomass was estimated based on an average weight of 3.5 kg per fish...... 32 Table 13. Reported catches by Vessel A of Dipturus spp. (estimated biomass for all species in the genus) caught in tangle nets per trip and in relation to the reported retained catch of the main

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species (anglerfish and turbot). Data aggregated at a trip level. For those sets where common skate were counted, the biomass was estimated based on an average weight of 10 kg per fish...... 33 Table 14. Reported quantities of spurdog caught by Vessel B in relation to the main target species (pollack and saithe) between November 2013 and March 2014. Data shown by set, as spurdog were either enumerated, or the catch was estimated based on the number of fish boxes...... 35 Table 15. Summary details of the quantities of spurdog caught in relation to the main target species (pollack, cod and saithe) by Vessel C between December 2013 and March 2014, and between during October and December 2014. Catch data aggregated across trips...... 37 Table 16. Summary details of the quantities of Dipturus spp. caught in tangle nets in relation to the main target species (turbot and anglerfish) by Vessel B during three trips in 2014. Catch data aggregated across trips...... 37 Table 17. Numbers of elasmobranchs tagged and released during the pilot programme ...... 40 Table 18. Preliminary estimates of at-vessel mortality of porbeagle as reported by fishers on commercial netters ...... 43 Table 19. Preliminary estimates of at-vessel mortality of common skate complex as reported by fishers retrieving tangle nets (Vessel A only) ...... 43 Table 20. Maturity scale for viviparous sharks. Adapted from ICES (2009) ...... 52

Table 21. Hepatosomatic index (IH) of starry smooth-hound by sex and maturity stage ...... 56

Table 22. Mean gonad weight and gonadosomatic index (IG) by sex and maturity stage of starry smooth-hound ...... 57 Table 23. Summary of numbers (by sex) and length range of spurdog retained during the project ... 62 Table 24. Numbers of samples collected for future studies (preliminary) ...... 63

Table 25. Mean gonad weight (g) and gonadosomatic index (IG) by sex and maturity stage ...... 65 Table 26. Relationships between alternative length measurements with total length in porbeagle (n = 53), where total length refers to the total length with the upper lobe of the caudal fin flexed down

(LT_under) and measured under the body. Relationships given as an equation and in proportional terms

(percentage of LT_under)...... 71

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Informing policy

 Approximately 80 species of chondrichthyan fish (sharks, skates, rays and rabbitfish) occur around the British Isles. Only one species (spurdog) currently has a benchmarked stock assessment. Indices of relative abundance are currently used to inform on the status of the more commonly occurring demersal species. There is a clear need to increase our understanding of data-limited species, and to ensure that appropriate data are available to undertake more quantitative stock assessments in the future.

 A prioritisation process, incorporating commercial importance, conservation interest and biological vulnerability, identified species which may be of greater relevance to the ‘Shark, Skate and Ray Conservation Plan’. High ranking species included those of conservation interest (e.g. flapper skate, angel shark and white skate), commercial importance (e.g. starry smooth-hound and cuckoo, spotted, blonde and thornback ray) and species that have been of recent commercial interest as well as conservation concern (e.g. blue skate, porbeagle, undulate ray and spurdog).

 Productivity-Susceptibility Analyses were used to provide a semi-quantitative approach to identifying vulnerable stocks for case-study fisheries. The species ranked as most vulnerable in the Celtic Sea (e.g. angel shark, spurdog and tope) already have some form of restrictive management in place at the present time. Species that are subject to commercial exploitation in the Celtic Sea and ranked as vulnerable, but for which ICES has unable to gauge stock status, included blonde ray, shagreen ray and starry smooth-hound.

 A pilot project was undertaken in collaboration with commercial fishers to collect data on common skate, spurdog and porbeagle in the Celtic Sea. Fishing opportunities for these species ceased over the period 2009–2011, through either prohibited status or a zero Total Allowable Catch. These three species can all be locally and/or seasonally common in the Celtic Sea and are often caught in commercial gears, including gillnet and tangle net fisheries.

 Spurdog were taken in high numbers as a bycatch in the Celtic Sea. In the most extreme cases, the estimated biomass of spurdog caught exceeded the retained biomass of the main target species. Catches of spurdog were variable, due to the aggregating nature of the species (which may be influenced by seasonal factors) and as to whether fishing operations coincided with the locations of any aggregation.

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 Porbeagle bycatch in the Celtic Sea was highly seasonal, with the largest catches reported from August to October. The majority of porbeagle caught in gillnets did not survive. At-vessel mortality of porbeagle in set nets ranged from 56–97% in two of the vessels studied, with the former based on a small sample size. Across all trips, at-vessel mortality was >90%.

 Catches of the common skate complex were comprised mostly of the smaller of the two species (Dipturus batis), and this species could be taken in high numbers in tangle net fisheries. Estimated at-vessel mortality was ca. 34–39%, which is higher in comparison to those gillnet fisheries with shorter soak times.

 Biological sampling has enabled recent life history data to be collected for spurdog, starry smooth-hound and porbeagle. Data collection focused on those parameters relating to the reproductive biology which are required for future stock assessments and can provide evidence to support biologically meaningful management measures. In total 1,112 spurdog (307 females; 805 males); 430 starry smooth-hound (231 females; 199 males) and 53 porbeagle were sampled. Biological sampling of porbeagle sharks provided length conversion factors and biological samples for future studies, including contaminant levels and growth studies. Biological samples (including vertebrae and fin clips) were collected for spurdog and starry smooth-hound. These samples will allow contemporary data on the age and growth of these species to be collected.

 The size at maturity of spurdog does not appear to have changed over time, but fecundity may have increased. Female spurdog matured across the length range of 79–86 cm, with 50% maturity at about 82 cm - similar to previously published estimates. The maximum fecundity reported was 19 pups - higher than values reported in the 1960s. This provides further credence to the hypothesis that the fecundity of spurdog has increased.

 Starry smooth-hound is of increasing interest to UK fisheries. The data collected will provide input data to future assessment models. Females usually matured across the 78–87 cm length range, and males across the 65–74 cm length range. Ovarian and uterine fecundity ranged from 1–28 and 4–20, respectively. The number of pups increased with maternal size. Larger females produced bigger pups.

 Starry smooth-hound is probably the only smooth-hound species to occur in British waters. Genetic tissue samples from over 300 starry smooth-hound contributed to a larger-scale collaborative study across the Northeast Atlantic. No common smooth-hound have been recorded in the study.

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1 Introduction

1.1 Background

Sharks, skates and rays (Elasmobranchs) are key predators in the marine ecosystem. They are important to commercial and recreational fisheries. Elasmobranch populations are often susceptible to over-exploitation and slow to recover, due to their longevity, late age at maturity, slow growth rate and low fecundity (Holden, 1974; Ellis et al., 2008). However, there are still important gaps in our knowledge of elasmobranchs which restricts our ability to assess and monitor various stocks, and manage their fisheries.

There has been increased interest in elasmobranch fisheries. In 1999 the Food and Agriculture Organisation (FAO1) published the voluntary International Plan of Action (IPOA) for the conservation and management of sharks2 (FAO, 1999), which encouraged nations to establish national plans of action. Following the subsequent European Community (EC) Plan of Action for Sharks (CEC, 2009), Defra developed a ‘Shark, Skate and Ray Conservation Plan’ (Defra, 2011) that aims to “manage elasmobranch stocks sustainably so that depleted stocks recover and that those faring better are fished sustainably”. Key to this plan is that “Knowledge on elasmobranch fisheries and species is improved through better data collection and scientific research” so that appropriate ecological information can be “used to more effectively manage elasmobranchs” (Defra, 2011).

The assessments for many of the elasmobranch stocks around the British Isles are undertaken under the auspices of the International Council for the Exploration of the Seas (ICES), and their Working Group on Elasmobranch Fishes (WGEF)3. Although the ICES first convened a Study Group on Elasmobranch Fisheries in 1989, the lack of data hampered attempts to assess the stocks, and it did not meet again until 1995, when the Study Group on Elasmobranch Fishes (SGEF) was initiated. The initial meetings of this group provided descriptions of the fisheries, and collated landings data and biological information. Given the need for the ICES to provide regular advice to the EC, the SGEF

1 A summary list of acronyms is given in Annex 8.1

2 In general, ‘shark’ action plans tend to consider all chondrichthyan fish, which includes both sharks, dogfish, skates and rays (Class Elasmobranchii), as well as the rabbitfish, or chimaeras (Class Holocephali).

3 The International Commission for the Conservation of Atlantic Tunas (ICCAT) is the body responsible for the assessments of the main pelagic species that occur over the wider Atlantic Ocean

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became the Working Group on Elasmobranch Fish (WGEF) in 2003 and has helped in the provision of ICES advice since 2004.

ICES currently have only bench-marked one assessment for an elasmobranch stock: spurdog in the Northeast Atlantic (De Oliveira et al., 2013; ICES, 2013). Whilst exploratory assessments have been undertaken for some other stocks, including deep-water sharks, the main source of data currently used to evaluate the status of demersal elasmobranchs, including skates (Rajidae), catsharks (Scyliorhinidae) and smooth-hounds (Triakidae), are scientific trawl surveys. These surveys are thought to be effective for smaller-bodied species that are widespread across the survey areas, but data are more limited for larger-species species and those with patchy distributions.

Given the limitations of existing data to understanding the nature and status of elasmobranchs stocks that are of national interest, a variety of Defra-funded projects have been undertaken by Cefas, including:  Bristol Channel ray survival (Catchpole et al., 2007)  Thames ray tagging and survival (Ellis et al., 2008)  Spurdog in the Irish Sea (Ellis et al., 2010)  Spurdog, porbeagle and common skate bycatch and discard reduction (Bendall et al., 2012)  Assessing the survivability of bycaught porbeagle and spurdog and furthering our understanding of their movement patterns in UK marine waters  Assessing discard mortality of commercially caught skates (Rajidae) – validation of experimental results (Ellis et al., 2012b)  Monitoring thornback ray movements and assessing stock levels (McCully et al., 2013)

1.2 Project background

The current project, entitled “National Evaluation of Populations of Threatened and Uncertain Elasmobranch stocks (NEPTUNE)” was designed to improve our knowledge of those elasmobranch fishes that are either considered ‘threatened’ or that are of uncertain status. The project aimed to support both Defra’s ‘Shark, Skate and Ray Conservation Plan’ and the assessment and advisory process conducted through the ICES, by providing relevant scientific information to the WGEF.

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The project had two main work packages, (i) a bycatch monitoring and mitigation programme for elasmobranch catches in the Celtic Sea; and (ii) a synthesis of our current knowledge of the status and biology of UK elasmobranchs, with a prioritisation of species and stocks for further study and associated data collection to provide relevant biological data for those stocks ranked as important.

Synthesis of current knowledge and identification of data gaps: To help identify the priorities for future study, the elasmobranchs occurring around the British Isles were prioritised in terms of their commercial and conservation importance, biological sensitivity and also the importance of the UK to the stock in question (Section 2). For the highest ranking species, data gaps and uncertainties that need to be addressed for appropriate assessments to be undertaken were identified, and studies to address some of these data gaps undertaken (Section 4).

Bycatch monitoring in the Celtic Sea: Development of pragmatic management measures for what are often regarded as some of the more ‘threatened’ elasmobranchs in British waters is currently hampered by limited data on their distribution and abundance, necessitating a precautionary approach. This part of the project involved collaboration with commercial fishermen in the south- west, to facilitate the collection of more detailed information on species that are of conservation interest and had also been of commercial interest prior to restrictive management, such as spurdog Squalus acanthias, common skate Dipturus batis-complex and porbeagle Lamna nasus.

This case study aimed to improve the availability of fishery-dependent information for assessing the fishery and status of the stocks, with participating fishermen trained to collect data on catch composition (Section 3). A proportion of dead bycatch was retained (under dispensation) by a small number of vessels for biological sampling (Section 4). Fishermen were also involved in the development of a “Code of conduct‟ for elasmobranch bycatch.

1.3 Format of the report

The initial work undertaken was to update the inventory of the elasmobranchs and holocephalans (chimaeras or rabbitfish) fishes occurring around the British Isles, prioritising species of interest and identifying data gaps. The work undertaken during this first phase of the project is summarised in Section 2. There has been an increased interest in Productivity Susceptibility Analyses (PSAs) as an approach to better understand data limited stocks taken in multi-species fisheries. Preliminary work

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on this topic had been undertaken during previous Defra-funded projects, and a specific case study to examine elasmobranchs in the wider Celtic Sea was also undertaken (Section 2).

Studies on the elasmobranch bycatch taken by gillnetters operating in the Celtic Sea (Section 3) were undertaken under a “Shark, Skate and Ray Scientific Bycatch Fishery”. This part of the project involved regular meetings with fishers and other stakeholders. Data on the seasonal bycatch of spurdog, porbeagle and common skate complex were collected in relation to the associated catches of commercial fish. A ‘code of conduct’ to promote the safe and effective release of live fish was developed. The “Shark, Skate and Ray Scientific Bycatch Fishery” associated with this study also enabled samples of dead bycatch to be landed for scientific study.

Updated biological data were collected for various elasmobranch species (Section 4). Samples of spurdog and porbeagle were available from the dead bycatch of the Celtic Sea case study. Biological data were also collected for starry smooth-hound Mustelus asterias, given that this species had been little studied, ranked high on the prioritisation exercise and has been subject to increased exploitation in recent years.

Some of the work undertaken during the project has been written up as working documents that were presented at annual meetings of the ICES WGEF. These and other outputs are summarised in Annex 8.2, with summary information provided in the main body of the report (Section 4.5).

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2 Elasmobranchs of the British Isles and prioritisation of species of interest

Summary

 An up-to-date inventory of sharks, skates, rays and rabbitfish occurring around the British Isles was compiled. Of the approximately 80 species, only one (spurdog) currently has a benchmarked stock assessment. The status of several others is evaluated regularly by ICES, but the status of several of the species that are of interest to national fisheries remains uncertain.

 A prioritisation exercise was conducted to identify the species of greater relevance for the ‘Shark, Skate and Ray Conservation Plan’. Whilst several of these ranked highly in terms of their conservation interest (e.g. flapper skate, angel shark and white skate), some data-limited species of commercial interest also ranked highly (e.g. starry smooth-hound and blonde ray). Other species that ranked highly were those that were of recent commercial interest but are also of conservation concern (e.g. blue skate, porbeagle, undulate ray and spurdog).

 Productivity-Susceptibility Analyses were used to provide a semi-quantitative approach to identifying vulnerable stocks for specific fisheries. The species ranked as most vulnerable in the Celtic Sea already have some form of restrictive management in place at the present time. The species that are subject to commercial exploitation and ranked of intermediate vulnerability, but for which ICES has unable to gauge stock status, included blonde ray, shagreen ray and starry smooth-hound. The species that ranked least in their vulnerability (including thornback, spotted and cuckoo ray and lesser-spotted dogfish) are generally species for which ICES has been able to provide advice.

 Given the precautionary approach to fisheries management, it will become increasingly important to be able to evaluate the statuses of those species of intermediate vulnerability, so as to ensure that their exploitation is sustainable.

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2.1 Elasmobranchs of the British Isles

The British Isles has a relatively diverse elasmobranch fauna, including a variety of sharks (Figure 1) and skates (Figure 2). Whilst the majority of sharks occurring around the British Isles are deep-water species, there are several species that occur on the continental shelf that are of either conservation interest or commercial importance. The skates (Rajidae) form the most diverse family of elasmobranchs in the shelf seas of the British Isles.

Although there have been several earlier taxonomic lists of the elasmobranchs occurring around the British Isles (Wheeler, 1992; Edwards and Edwards, 1987; Wheeler et al., 2004; Fowler et al., 2004; George, 2009), changes in the taxonomy of certain taxa and reports of new species has necessitated an updated list. Wheeler (1992) originally listed 39 elasmobranchs and one rabbitfish (holocephalan) as occurring in the shelf seas around the British Isles, with deep-water species mostly excluded. Some deep-water species were included by Edwards and Davis (1987), with 49 elasmobranchs and one holocephalan listed. More recently, Fowler et al. (2004) listed 68 chondrichthyans from British and adjacent waters and Wheeler et al. (2004) reported 71 elasmobranchs and six holocephalans from around the British Isles.

This report provided an up-to-date inventory of the elasmobranchs of the British Isles, updates their taxonomic names where appropriate, and provides sources of information to better document the evidence for their occurrence in the waters around the British Isles (Annex 8.3). The higher taxonomic ordering of Eschemeyer (2012) is followed. This updated taxonomic list included 80 species of chondrichthyan fish that have been reported from around the British Isles (Table 1), with information for a further 13 species that are either based on questionable records, reported from adjacent waters or have been found washed ashore in neighbouring areas also given (Annex 8.3).

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(a) (b)

(e) (f)

(g)

(i) (j) (h)

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(a) (b)

(e) (f) (g)

(i) (j)

(h)

Figure 2. Diversity of the elasmobranch fauna of the British Isles, showing (a) starry ray, (b) blue skate, (c) sandy ray, (d) shagreen ray, (e) cuckoo ray, (f) blonde ray, (g) thornback ray, (h) small-eyed ray, (i) spotted ray and (j) undulate ray.

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Table 1. Taxonomic list of elasmobranchs and holocephalans occurring around the British Isles and adjacent waters (See Annex 8.3 for more comprehensive details).

Family Common name Scientific name and authority CLASS ELASMOBRANCHII ORDER HEXANCHIFORMES

1 Hexanchidae Bluntnose six-gill shark Hexanchus griseus (Bonnaterre, 1788)

2 Sharpnose seven-gill shark Heptranchias perlo (Bonnaterre, 1788) 3 Chlamydoselachiidae Frilled shark Chlamydoselachus anguineus Garman, 1884 ORDER LAMNIFORMES 4 Lamnidae Shortfin mako Isurus oxyrinchus Rafinesque, 1810 5 Porbeagle shark Lamna nasus (Bonnaterre, 1788) 6 Cetorhinidae Basking shark Cetorhinus maximus (Gunnerus, 1765) 7 Alopiidae Big-eye thresher shark Alopias superciliosus (Lowe, 1841) 8 Thresher shark Alopias vulpinus (Bonnaterre, 1788) ORDER CARCHARHINIFORMES 9 Scyliorhinidae White ghost catshark Apristurus aphyodes Nakaya & Stehmann, 1998 10 Iceland catshark Apristurus laurussonii (Saemundsson, 1922) 11 Ghost catshark Apristurus manis (Springer, 1979) 12 Black roughscale catshark Apristurus melanoasper 13 Smalleye catshark Apristurus microps (Gilchrist, 1922) 14 Black-mouth dogfish Galeus melastomus Rafinesque, 1810 15 Mouse catshark Galeus murinus (Collett, 1904) 16 Lesser-spotted dogfish Scyliorhinus canicula (Linnaeus, 1758) 17 Greater-spotted dogfish Scyliorhinus stellaris (Linnaeus, 1758) 18 Pseudotriakidae False catshark Pseudotriakis microdon Capello, 1867 19 Triakidae Starry smooth- hound Mustelus asterias Cloquet, 1821 20 Smooth-hound Mustelus mustelus (Linnaeus, 1758) 4 21 Tope shark Galeorhinus galeus (Linnaeus, 1758) 22 Carcharhinidae Blue shark Prionace glauca (Linnaeus, 1758) 23 Sphyrnidae Smooth hammerhead Sphyrna zygaena (Linnaeus, 1758) ORDER SQUALIFORMES 24 Dalatiidae Kitefin shark Dalatias licha (Bonnaterre, 1788) 25 Etmopteridae Black dogfish Centroscyllium fabricii (Reinhardt, 1825) 26 Great lantern shark Etmopterus princeps Collett, 1904 27 Velvet belly Etmopterus spinax (Linnaeus, 1758) 28 Somnosidae Portuguese dogfish Centroscymnus coelolepis Bocage & Capello, 1864

4 Whilst Mustelus mustelus was originally included in this list, recent examination of museum specimens would suggest that this species occurs off western Africa and in the Mediterranean Sea and may not occur in British seas (E. Farrell, S. McCully and J. Ellis, pers. obs.)

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Family Common name Scientific name and authority 29 Longnose velvet dogfish Centroselachus crepidater (Bocage & Capello, 1864) 30 Knifetooth dogfish Scymnodon ringens Bocage & Capello, 1864 31 Greenland shark Somniosus microcephalus (Bloch & Schneider, 1801) 32 Oxynotidae Angular roughshark Oxynotus centrina (Linnaeus, 1758) 33 Sailfin roughshark Oxynotus paradoxus Frade, 1929 34 Centrophoridae Leafscale gulper shark Centrophorus squamosus (Bonnaterre, 1788) 35 Birdbeak dogfish Deania calcea (Lowe, 1839) 36 Rough longnose dogfish Deania hystricosa (Garman, 1906) 37 Squalidae Spurdog Squalus acanthias Linnaeus, 1758 38 Little gulper shark Squalus uyato Rafinesque, 1810 39 Echinorhinidae Bramble shark Echinorhinus brucus (Bonnaterre, 1788) ORDER SQUATINIFORMES 40 Squatinidae Angel shark Squatina squatina (Linnaeus, 1758) ORDER TORPEDINIFORMES 41 Torpedinidae Common electric ray Torpedo (Tetronarce) nobiliana Bonaparte, 1835 42 Marbled electric ray Torpedo (Torpedo) marmorata Risso, 1810 ORDER RAJIFORMES 43 Arhynchobatidae Pale ray Bathyraja pallida (Forster, 1967) 44 Richardson's ray Bathyraja richardsoni (Garrick, 1961) 45 Spinytail ray Bathyraja spinicauda (Jensen, 1914) 46 Unknown deep-water ray Bathyraja sp. 47 Rajidae Arctic skate Amblyraja hyperborea (Collett, 1879) 48 Jensen’s skate Amblyraja jenseni (Bigelow & Schroeder, 1950) 49 Starry ray Amblyraja radiata (Donovan, 1808) 50 Blue skate Dipturus batis (Linnaeus, 1758) 51 Flapper skate Dipturus cf. intermedia (Parnell, 1837) 52 Norwegian skate Dipturus nidarosiensis (Storm, 1881) 53 Long-nose skate Dipturus oxyrinchus (Linnaeus, 1758) 54 Sandy ray Leucoraja circularis (Couch, 1838) 55 Shagreen ray Leucoraja fullonica (Linnaeus, 1758) 56 Cuckoo ray Leucoraja naevus (Müller & Henle, 1841) 57 Krefft's ray Malacoraja kreffti (Stehmann, 1977) 58 Soft (Prickled) skate Malacoraja spinacidermis (Barnard, 1923) 59 Blue pygmy skate Neoraja caerulea (Stehmann, 1976) 60 Blonde ray Raja brachyura Lafont, 1873 61 Thornback ray Raja clavata Linnaeus, 1758 62 Small-eyed ray Raja microocellata Montagu, 1818 63 Spotted ray Raja montagui Fowler, 1910 64 Undulate ray Raja undulata Lacepède, 1802 65 Deepwater ray Rajella bathyphila (Holt & Byrne, 1908)

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Family Common name Scientific name and authority 66 Bigelow's ray Rajella bigelowi (Stehmann, 1978) 67 Mid-Atlantic skate Rajella fyllae (Lütken, 1887) 68 Round skate Rajella kukujevi (Dolganov, 1985) 69 White skate Rostroraja alba (Lacepède, 1803) ORDER MYLIOBATIFORMES 70 Dasyatidae Common Stingray Dasyatis pastinaca (Linnaeus, 1758) 71 Pelagic stingray Pteroplatytrygon violacea (Bonaparte, 1832) 72 Myliobatidae Common eagle ray Myliobatis aquila (Linnaeus, 1758) CLASS HOLOCEPHALI ORDER CHIMAERIFORMES 73 Chimaeridae Rabbit fish Chimaera monstrosa Linnaeus, 1758 74 Opal chimaera Chimaera opalescens Luchetti, Iglésias & Sellos, 2011 75 Small-eyed rabbitfish Hydrolagus affinis (Capello, 1868) 76 Large-eyed rabbitfish Hydrolagus mirabilis (Collett, 1904) 77 Pale chimaera Hydrolagus pallidus Hardy & Stehmann, 1990 78 Rhinochimaeridae Smallspine spookfish Harriotta haeckeli Karrer, 1972 79 Longnose chimaera Harriotta raleighana Goode & Bean, 1895 80 Straightnose rabbitfish Rhinochimaera atlantica Holt & Byrne, 1909

2.2 Prioritising elasmobranchs and holocephalans of interest 5

There have been earlier studies that had included elasmobranchs in exercises to prioritise marine species for improved management (Hiscock et al., 2011, 2013). These exercises, however, were based on species being listed on some form of conservation instrument and a more holistic and standardised approach to considering all elasmobranchs had been lacking.

To prioritise the elasmobranch and holocephalan fishes of the British Isles, all species were scored under the following four categories: conservation interest, commercial importance, importance of UK waters to the species range and perceived biological sensitivity.

Conservation interest: This was ranked according to the regional International Union for the Conservation of Nature (IUCN) listings (Gibson et al. 2008), and also as to whether the species was listed for legal protection on the UK Wildlife and Countryside Act and/or listed on Appendix I or II of

5 This section is based on: Ellis, J. R. and McCully, S. R. (2013). An overview of the sharks, skates and rays (Elasmobranchii) and rabbit fish (Holocephali) of the British Isles, and prioritisation of species of interest. Working Document to the ICES Working Group on Elasmobranch Fishes, Lisbon, June 17–21 2013, 41 pp.

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CITES. The scores allocated for these criteria (Table 2) could range from 0–15, as the three parameters were summed.

Table 2. Scores applied to elasmobranch and holocephalan fishes in relation to conservation interest

IUCN Listing Score UK Wildlife and Countryside Act Score Critically Endangered 5 Listed + 5 Endangered 4 Not listed 0 Vulnerable6 3 Data Deficient 2 CITES7 Score8 Near Threatened 1 Listed + 5 Least Concern 0 Not listed 0 Not Evaluated9 1

Commercial importance: This was scored according to (i) ICES landings data (based on data provided for the 10 year period 2000–2009), and (ii) market value for the UK fishery in terms of the value of fish (value per kg), as reported in 2008. Data for market value were only derived from 2008 data, as data prior to this were not always reported to species level, and data after this year were limited for those species with restricted fishing opportunities (e.g. species allocated a zero Total Allowable Catch (TAC) or listed as ‘prohibited species’ status on TAC and quota regulations). The scores allocated for these two criteria (Table 3) ranged from 1–5 (magnitude of landings) and 1–3 (value of fish), with the two scores multiplied to give totals of 1–15.

Table 3. Scores applied to elasmobranch and holocephalan fishes in relation to commercial importance

Commercial (FAO) Score Value to UK £ per kg Score Landings (t) > 1500 5 High > 1.0 3 > 500 4 Medium 0.5 – 0.99 2 > 100 3 Low < 0.5 1 > 15 2 < 15 1

6 Where the term ‘Vulnerable’ is capitalised, it refers to IUCN listing criteria. The term ‘vulnerable’ (lower case) is used in the context of vulnerability studies (see Section 2.3) 7 Since this work was undertaken, porbeagle Lamna nasus was listed on Appendix II of CITES 8 Given that very few elasmobranchs from the British Isles are listed on CITES, no differentiation between Appendices I and II were made. If the current method were to be applied to other taxa, then there should be consideration of a higher score for species on Appendix I. 9 Given that the IUCN Shark Specialist Group has attempted to review all elasmobranch fish through various regional and taxonomic workshops, there were few ‘NE’ species. If the current method were to be applied to other taxa, then there should be consideration of increasing the score for ‘NE’ species

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Biological sensitivity: This was scored by maximum body length (scored from 1–5) and reproductive mode (scored as 1–3), as outlined in Table 4. Values were multiplied to create the overall score of biological sensitivity ranging from 1 (e.g. blue pygmy skate) to 15 (e.g. porbeagle).

Table 4. Scores applied to elasmobranch and holocephalan fishes in relation to biological sensitivity

Maximum length (cm) Score Reproductive mode Score 200+ 5 Viviparous (Fecundity <10) 3 150 – 199 4 Viviparous (fecundity >10) 2 100 – 149 3 Oviparous 1 50 – 99 2 <50 1

Importance of UK waters to the stock range: This was scored according to the importance of the eastern North Atlantic to the species and by their occurrence in waters around the British Isles (Table 5). For the former, species were identified as (a) cosmopolitan (i.e. occurring in the Atlantic and the Indian and/or Pacific basins); (b) occurring in the wider Atlantic (i.e. they also occurred in the western North Atlantic and/or South Atlantic) and (c) occurring in the eastern North Atlantic (which could include the Mediterranean and parts of north-western Africa).

Species were subsequently scored as either (a) absent from the British Isles (i.e. those species which occur in waters adjacent to the British Isles, but have not been reported from the area), (b) occasional vagrants have been reported, (c) regular visitor, (d) present around the British Isles, but this area was only the fringe of the distribution, (e) present and widely distributed around the British Isles and (f) present and (probably) breeds in British waters (the term ‘breeding’ used to highlight whether the species had mating, egg-laying/parturition or nursery grounds in the area), or with discrete stocks in the area. Values of these two parameters were multiplied to give scores between 0 and 15.

Table 5. Scores applied to elasmobranch and holocephalan fishes in relation to the importance of UK waters to the species range

Global distribution Score UK Distribution Score British waters has ecologically important breeding sites and/or NE Atlantic only 3 5 discrete stocks Wider Atlantic 2 Present around the British Isles 4 Cosmopolitan 1 Present in British seas, but only the fringe of the distribution 3 Regular visitor to British seas 2 Occasional vagrants reported 1 Absent, no authenticated records in British seas 0

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Overall ranking process: Conservation importance (0–15), biological sensitivity (1–15) and commercial importance (1–15) were summed, and this was then multiplied by the importance of this species to the UK (0–15). This approach prevented those species that have not been officially reported from around the British Isles from attaining a high score. This approach gave final scores (out of a maximum of 675) to allow species to be prioritised impartially.

The current status of management advice, in relation to advice given by either ICES or ICCAT, was also listed. Although this was not scored or used in the prioritisation process, it was included in the prioritisation table (see Ellis and McCully, 2013) to identify those species for which the ability to provide advice has been hampered by a lack of data. Where advice is not provided, this is a good indication of data deficiencies, a lack of presence in trawl surveys, limited catch/landings records, or that this stock is rare in wider European waters. Each species was listed as having (i) advice based on a quantitative stock assessment, (ii) advice based on survey trends (usually fishery-independent trawl surveys), (iii) qualitative assessment only, given limited signal from survey trends or other data sources; or (iv) no assessment has been possible.

Prioritised list of chondrichthyans occurring around the British Isles: The results of the prioritisation process identified 15 species that scored > 120 (Table 6) and these species were considered further in terms of data availability and data gaps. Of these 15 species, the main group were the skates (Dipturus cf. intermedia, Dipturus batis, Leucoraja naevus, Raja montagui, Raja brachyura, Leucoraja circularis, Raja clavata, Leucoraja fullonica, Raja undulata and Rostroraja alba), with the highest ranking sharks and dogfish including Squatina squatina, Mustelus asterias, Lamna nasus, Squalus acanthias and Cetorhinus maximus. Of these species, data were collected for three species (Dipturus batis, Lamna nasus and Squalus acanthias) under the south-west pilot programme. Another high ranking species was M. asterias (ranked fifth in Table 6). This species was also selected for further study, as existing trawl surveys generally only catch smaller individuals and the biology of this species is little known, despite it being subject to increasing exploitation.

The prioritisation approach described here included all chondrichthyan fish from around the British Isles. The inclusion of all species invariably necessitates a more qualitative approach, as some species are data-limited. However, more quantitative approaches can be developed for better defined assemblages and fisheries, as highlighted in Section 2.3.

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Table 6. Highest scoring elasmobranch fishes

675)

–

sensitivity Rank Scientific name 15) 15) 15) 15)

– – – –

(0 (1 (0 (0

trawl surveys trawl

Importance of UK of Importance

Final score (0 Final

ICES / ICCAT advice ICES / ICCAT

Sampled in existing existing in Sampled

Biological Biological

Commercial importance Commercial

Conservation importance importance Conservation 1 Dipturus cf. intermedia Survey data QA 5 5 12 15 330 limited 2 Dipturus batis Survey data QA 5 4 12 15 315 limited 3 Squatina squatina Isolated records (QA) 10 15 1 12 312 4 Leucoraja naevus Data for advice ST 0 2 15 15 255 5 Mustelus asterias Data for advice ST 0 6 10 15 240 6 Raja montagui Data for advice ST 0 2 12 15 210 7 Raja brachyura Survey data QA 1 3 9 15 195 limited 8 Leucoraja circularis Survey data QA 3 3 9 12 180 limited 9 Lamna nasus Isolated records SA 5 15 15 5 175 10 Raja clavata Data for advice ST 1 3 12 10 160 11 Leucoraja fullonica Survey data QA 1 3 6 15 150 limited 12 Raja undulata Survey data QA 4 3 3 15 150 limited 13 Rostroraja alba No (QA) 10 5 3 8 144 14 Squalus acanthias Data for advice SA 5 6 15 5 130 15 Cetorhinus maximus No QA 14 15 3 4 128

2.3 Productivity Susceptibility Analyses 10

Following the United Nations Code of Conduct for Responsible Fisheries (FAO, 1995), the “best scientific evidence available” should be used when evaluating the state of a fishery and to inform management decisions. In order to support this, various risk-based approaches, including Ecological Risk Assessments (ERAs) and Productivity Susceptibility Analyses (PSAs), have been developed for data-limited, multi-species scenarios. These approaches gauge the ‘vulnerability’ of a species (or stock) to over-exploitation based on its biological sensitivity (or ‘productivity’), and its ‘susceptibility’

10 This section is based on: McCully Phillips, S. R., Scott, F. and Ellis, J. R. (2015). Having confidence in Productivity Susceptibility Analyses: A method for underpinning scientific advice on skate stocks? Fisheries Research, 171, 87–100.

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to the fisheries being considered (Stobutzki et al., 2002; Fletcher, 2005; Griffiths et al., 2006; Hobday et al., 2011).

Semi-quantitative PSAs have been considered for elasmobranch species elsewhere in the world (reviewed by Gallagher et al., 2012), including elasmobranchs taken in pelagic (Simpfendorfer et al., 2008; Cortés et al., 2010; Arrizabalaga et al., 2011) and deepwater fisheries (Watling et al., 2011; Dransfeld et al., 2013).

To evaluate the elasmobranch fauna that may be encountered in Celtic Sea fisheries, an existing PSA framework was updated, using a semi-quantitative approach, based upon their characteristics of biological productivity and their susceptibility to fisheries. The NOAA toolbox11 PSA framework (Patrick et al., 2009) was used, albeit with some modifications to address better the biological characteristics of elasmobranchs. Twelve ‘productivity’ attributes were included in the PSA (Table 7) of which two (measured fecundity and breeding strategy) were modified from the default NOAA toolbox, and an additional two attributes (breeding cycle and genetic distinctness) also included. Thirteen ‘susceptibility’ attributes were included (Table 8), of which three (fishery importance, management applicable and monitoring (or assessment) of status) were added attributes (replacing the single ‘management strategy’ attribute in the NOAA toolbox), as these attributes were all considered discrete issues. One attribute (‘fishing rate relative to M’) was excluded, as this is unknown for the species in this case study, and another attribute (value of fishery) removed exact monetary definitions and made the scoring more qualitative in terms of desirability.

Score for each ‘productivity’ and ‘susceptibility’ attribute were between 0–3 (with bridging values of 1.5 and 2.5 permitted). Attributes were also ‘weighted’ (i.e. how much consideration was given to this attribute in the assessment). Following Patrick et al. (2009), the default score was two (where each attribute would be given equal importance), with a range of zero (i.e. excluded from the assessment) to four (of greatest importance). The weights assigned to each attribute remained constant across all species in the assessment, and for each fishery assessed. The attribute score multiplied by the weight gives the ‘weighted attribute score’.

The attributes for ‘productivity’ were scored based on published information, and these scores were also reviewed by an international colleague with considerable experience in elasmobranch biology. Four national experts from three European countries scored the ‘susceptibility’ attributes for the case-

11 Available at http://nft.nefsc.noaa.gov/index.html

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study species in two broad types of fishery (demersal otter trawl and gillnet fleets) operating in the Celtic Sea. They also provided a ‘data quality’ score to assign weightings (between zero and four, the higher the score, the more ‘weight’ that attribute carries within the assessment) that they believed appropriate to each attribute. Weightings were assigned to attributes using the modal values attained, and did not change between species within a gear, or between the two gears themselves. In addition to ‘data quality’, a ‘confidence score’ (low, medium, high, very high scored as 0.2, 0.5, 0.8 and 0.9, respectively) was also given to each attribute by each assessor to represent their degree of confidence of being correct. More detailed analyses of these are given in McCully Phillips et al. (2015).

The data quality score for biological productivity ranged from low (nine species, including angel shark) to high (one species, spurdog), with 11 species deemed of ‘medium’ data quality. For the ‘susceptibility’, all species in both fisheries achieved a data quality score of ‘medium’.

The relative vulnerabilities (final PSA score) of all species were ranked from high to low for both gillnet (Table 9, Figure 3) and otter trawl fisheries (Table 9, Figure 4). In the gillnet fishery, the most vulnerable species were tope Galeorhinus galeus (score of 2.00) followed by five other species that are either currently designated as prohibited species or have a zero TAC in the Celtic Seas ecoregion. Of the species that are not subject to restrictive management, the most vulnerable members of the commercially exploited ‘skate and ray’ assemblage were blonde ray Raja brachyura, long-nose skate Dipturus oxyrinchus and shagreen ray Leucoraja fullonica. The former species is a commercially important species for which ICES has been unable to ascertain the stock status, and the latter two species are deeper water skates that are infrequent on the continental shelf. Results for the otter trawl fishery were broadly similar, with angel shark Squatina squatina (which is now a protected species) ranking as the most vulnerable species (1.98), followed by tope and then three prohibited or zero TAC species (spurdog, white skate Rostroraja alba and flapper skate Dipturus cf. intermedia).

This PSA was conducted primarily to assess the relative vulnerabilities of the various skates caught in mixed fisheries that are currently managed under the generic ‘skate and ray’ TAC, whilst the inclusion of other elasmobranchs allowed comparisons to be drawn for six different families of elasmobranch, thereby allowing slightly different life histories to be included. Earlier studies (McCully et al., 2012b) investigated whether ‘data rich’ teleosts with quantitative stock assessments could be used to ‘ground-truth’ the elasmobranch results, but the results were inconclusive, as elasmobranchs generally clustered together on the PSA plot as a result of their life history being so different to most teleosts. The results presented here allowed the elasmobranchs to be better differentiated.

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Whilst this type of assessment allows the highest priority species within the elasmobranch assemblage to be identified, it is important to consider how such assessments can inform management advice. In this case, given that the top ranking 5–6 species are already subject to some form of restrictive management (e.g. through a zero TAC or prohibited listing), the focus for future assessments and management could usefully be directed towards the next most vulnerable elasmobranchs for which stock status is uncertain. This would include various members of the commercial skate complex such as blonde ray and shagreen ray.

The approach clearly highlights where knowledge gathering and management action could be prioritised, it is more difficult to see how PSAs could inform on quota management and estimating maximum sustainable yield (MSY). However, elsewhere in the world, information from PSA approaches has helped to identify ‘acceptable biological catches’ (ABC) for data-limited species (Berkson et al., 2011; Carmichael and Fenske, 2011). Such PSA approaches may also be useful in the initial evaluation of potential management options, especially when more quantitative susceptibility attributes can be defined for more discrete fisheries. Within the framework of regional management, fishers from relevant sectors of the fleet could be involved in identifying pragmatic and effective management options through iterative applications of PSA tools.

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Table 7: Productivity attributes used in the PSA. Those in normal font were as used in the NOAA PSA framework, parameters modified from NOAA are shown in bold, and additional parameters shown in bold italics.

Productivity Attributes Low (1) Moderate (2) High (3)

Intrinsic rate of population <0.16 0.5–0.16 (mid-point 0.10) >0.5 growth (R) Maximum Age > 30 years 10–30 years (mid-point 20) <10 Years Maximum Size >150 cm 60–150 cm (mid-point 105) < 60 cm von Bertalanffy Growth < 0.15 0.15–0.25 (mid-point 0.20) > 0.25 Coefficient (k) Estimated Natural Mortality < 0.20 0.20–0.40 (mid-point 0.30) > 0.40 Measured Fecundity < 10 10–100 > 100 Breeding strategy Live bearer Demersal egg layer Broadcast spawner Annual cycle with Annual cycle with a protracted breeding Breeding cycle (female) Bi / Triennial seasonal peak season or with multiple broods per year moderately frequent highly frequent infrequent recruitment recruitment success recruitment success (> 75% Recruitment Pattern success (< 10% of year (between 10% and 75% of of year classes are classes are successful) year classes are successful) successful) Age at Maturity > 4 years 2–4 years (mid-point 3.0) < 2 years Mean Trophic Level >3.5 2.5–3.5 (mid-point 3) <2.5 In this region, this In this region, this species In this region, this species is Genetic distinctness species is the only one in is one of several in its the only one in its genus its family genus

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Table 8: Susceptibility attributes used in this study. Those in normal font are taken from the NOAA PSA framework, those in bold are modified parameters, and added parameters are denoted by bold italics.

Susceptibility Attributes Low (1) Moderate (2) High (3)

Important bycatch in Important target mixed fisheries and/or Non-commercial fisheries operate or Fishery targeted in species in this fishery have operated in recent seasonal/localised times (for this metier) fisheries Landings or catches Landings or catches No management strictly regulated for Management applicable partly regulated for the measures for the much of the stock stock area species/species-complex area Appropriate Limited data can inform Monitoring (or Insufficient data to monitoring to inform on trends in catches or assessment) of stocks evaluate status on stock status landings Between 25% and 50% of < 25% of stock occurs > 50% of stock occurs in Areal Overlap the stock occurs in the in the area fished the area fished area fished Continuous: stock is Restricted: stock is Fragmented: stock is distributed in > 50% of distributed in 25% to Geographic Distribution distributed in < 25% of the range of the 50% of the range of the the range of the fishery fishery fishery Between 25% and 50% of < 25% of stock occurs > 50% of stock occurs in Vertical Overlap the stock occurs in the in the depths fished the depths fished depths fished B is between 25% and B is > 40% of B0 (or B is < 25% of B0 (or 40% of B0 (or maximum Biomass of Spawners maximum observed maximum observed observed from time (SSB) or other proxies from time series of from time series of series of biomass biomass estimates) biomass estimates) estimates) Seasonal migrations do Seasonal migrations Seasonal migrations not substantially affect Seasonal Migrations decrease overlap with increase overlap with the overlap with the the fishery the fishery fishery Behavioural responses Behavioural responses increase the catchability Schooling/Aggregation Behavioural responses do not substantially of the gear [i.e., and Other Behavioural decrease the affect the catchability of hyperstability of CPUE Responses catchability of the gear the gear with schooling behaviour] Species shows low Species shows moderate Species shows high Morphology Affecting selectivity to the selectivity to the fishing selectivity to the fishing Capture fishing gear. gear. gear. Survival After Capture and Probability of survival 33% < probability of Probability of survival < Release > 67% survival < 67% 33% stock is not highly stock is moderately Desirability/Value of the stock is highly valued or valued or desired by valued or desired by the Fishery desired by the fishery the fishery fishery Adverse effects more Adverse effects more Fishery Impact to EFH or Adverse effects than minimal or than minimal or Habitat in General for absent, minimal or temporary but are temporary and are not Non-targets temporary mitigated mitigated

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Table 9: Results of the PSA vulnerabilities and overall rankings for elasmobranchs that may be encountered in otter trawl and gillnet fisheries in the Celtic Sea. Productivity is species-specific and does not change between fisheries, whilst susceptibility scores are fishery-specific).

Otter Trawl Gillnet Otter Trawl Gillnet Productivity Susceptibility Susceptibility Vulnerability Vulnerability

FAO Species

Score

Code Score Rank Score Rank

Weighted Weighted Weighted Weighted

Quality Score Quality Score Quality Score Quality

Weighted Data Data Weighted Data Weighted Data Weighted

Attribute Score Attribute Attribute Score Attribute

Tope GAG 1.33 2.88 2.07 2.85 2.11 2.80 1.98 2 2.00 1 Angel shark AGN 1.29 3.82 2.00 3.22 1.97 3.07 1.98 1 1.97 2 Spurdog DGS 1.39 1.97 2.06 2.00 2.12 1.94 1.93 3 1.96 3 White skate RJA 1.52 3.55 2.10 3.37 2.16 3.48 1.85 4 1.88 4 Flapper skate RJB1 1.50 2.79 2.06 2.98 2.12 2.98 1.83 5 1.87 5 Electric ray TTO 1.48 4.06 1.93 3.00 1.95 3.06 1.78 6 1.79 7 Common skate RJB2 1.65 2.94 2.13 2.77 2.18 2.72 1.76 7 1.79 6 Blonde ray RJH 1.76 3.03 2.22 2.61 2.24 2.63 1.74 8 1.75 8 Long-nosed skate RJO 1.71 4.00 2.16 3.32 2.14 3.31 1.73 9 1.72 10 Norwegian skate JAD 1.65 3.88 2.04 3.35 2.10 3.36 1.70 10 1.74 9 Starry smooth-hound SDS 1.70 2.91 2.10 2.42 2.12 2.45 1.70 11 1.72 11 Shagreen ray RJF 1.77 3.76 2.14 2.91 2.19 2.86 1.67 12 1.71 12 Sandy ray RJI 1.77 3.76 2.12 3.42 2.14 3.47 1.66 13 1.68 13 Small-eyed ray RJE 1.80 3.03 2.10 2.56 2.12 2.60 1.63 14 1.64 15 Marbled electric ray TTR 1.67 3.82 1.93 3.02 1.95 3.09 1.63 15 1.64 16 Undulate ray RJU 1.86 2.88 2.12 2.84 2.19 2.78 1.60 17 1.65 14 Thornback ray RJC 1.89 2.24 2.18 2.44 2.11 2.44 1.61 16 1.56 17 Spotted ray RJM 1.98 2.55 2.10 2.55 2.10 2.56 1.50 18 1.50 18 Cuckoo ray RJN 1.98 2.42 2.06 2.46 2.07 2.51 1.46 19 1.48 19 Greater-spotted dogfish SYT 1.98 3.88 1.92 2.80 1.90 2.79 1.37 20 1.35 20 Lesser-spotted dogfish SYC 2.09 2.67 1.91 2.03 1.82 2.02 1.29 21 1.22 21

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3.0

2.5

RJH

RJO RJA RJU RJF RJB2 DGS RJM RJE GAG RJC JAD RJB1 RJN RJI SDS 2.0 AGN

SYT TTR TTO

SYC Susceptibility

1.5

Data Quality High Data Quality Medium Data Quality Low

1.0 3 2.5 2 1.5 1 Productivity

Figure 3: PSA plot indicating vulnerabilities of Celtic Sea elasmobranchs in the demersal gillnet fishery. Species codes given in Table 9.

3.0

2.5

RJH RJO RJC RJF RJA RJB2 RJM DGS RJI SDS GAG RJN JAD RJB1 2.0 RJE AGN RJU SYC SYT

TTR TTO Susceptibility

1.5

Data Quality High Data Quality Medium Data Quality Low

1.0 3 2.5 2 1.5 1 Productivity

Figure 4: PSA plot indicating vulnerabilities of Celtic Sea elasmobranchs in the demersal otter trawl fishery. Species codes given in Table 9.

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3 Elasmobranch bycatch in the Celtic Sea

Summary

 A pilot project was undertaken in conjunction with selected netters operating in the south-west in order to collect data on spurdog, common skate and porbeagle. These three species are locally and/or seasonally common in the area and the current regulations that prevent landing these species, especially when brought on board dead, has been controversial with the fishing industry.

 Spurdog could be taken in high numbers as a bycatch species and, in the most extreme cases, the estimated biomass of spurdog caught could exceed the retained biomass of the main target species. Catches were highly variable, which may be related to the aggregating nature of the species and as to whether fishing operations coincided with the locations of any aggregation.

 Porbeagle bycatch was much more seasonal and this species was caught mostly from August to December, with the largest catches reported from August to October.

 Catches of the common skate complex was comprised mostly of the smaller of the two species (Dipturus batis), and this species could be taken in high numbers in tangle net fisheries.

 At-vessel mortality of porbeagle in set nets ranged from 56–97% in two of the vessels studied, with the former based on a small sample size. Across all trips, at-vessel mortality was >90%.

 At-vessel mortality of common skate in tangle nets averaged 33.6% across the sets examined. Aggregated across all trips, at-vessel mortality was 38.5%. This confirms that the survival of skates in offshore net fisheries is lower than observed in inshore tangle and gillnet fisheries, presumably related to the higher soak times on offshore fishing grounds.

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3.1 Introduction

The reformed Common Fisheries Policy (CFP) aims to have a more ecosystem approach to fisheries management and to conserve threatened species, whilst also minimising waste, especially in terms of reducing ‘dead discards’ (CEC, 2013). These sentiments can, however, be difficult to balance when a species that is perceived as threatened can be taken as bycatch and a proportion of the bycatch is dead. The restrictive management of certain elasmobranchs, notably spurdog, porbeagle and common skate, has been a controversial issue, especially for those fleets that operate where these species are locally and/or seasonally abundant, and/or are taken as an incidental (and sometimes dead) bycatch.

A pilot project was conducted to understand better the extent to which these three species are taken as incidental bycatch in the offshore gillnet fishery in the Celtic Sea. This work was developed through a “Shark, Skate and Ray Scientific Bycatch Fishery”, with the aim to:  Collect fishery-dependent data on the seasonal and spatial variability in spurdog, common skate and porbeagle bycatch in Celtic Sea fisheries (ICES Divisions VIIe–j),  Collate further data and anecdotal information on discard survival,  Retain a proportion of the dead bycatch for subsequent biological examination  Develop a ‘Code of Conduct’ that could help reduce fishing mortality.

3.2 Stakeholder engagement

Engaging with commercial fishers in collaborative research can help develop stronger links between the fishing industry and the science that underpins management and policy decisions. In October 2012, one year before the start of the NEPTUNE project, a meeting on shark, skate and ray bycatch and discard issues was held with stakeholders in the south-west of the UK. Some of the commercial fishers considered that the science, fisheries policy and restrictive management measures for porbeagle, spurdog and common skate were not in line with what they encountered at sea. They perceived that these species were locally and/or seasonally abundant, and more so than inferred from scientific studies. It was agreed at this meeting that fisher’s knowledge and information could help improve the evidence used in the assessment and management process. An action of this meeting was for Defra and Cefas to develop an industry-led scientific sampling programme for porbeagle, common skate and spurdog. Given that fishery-independent data for these species are, to varying degrees, limited, it was considered that fishery-dependent sources could provide important information to better understand these stocks (see Section 3.3).

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Cefas organised two further stakeholder meetings in Newlyn, Cornwall (November 2013 and February 2015), with both meetings attended by 30 or more participants, including commercial fishers, as well as representatives from the Cornish Fish Producers Organisation (CFPO), Cefas, Defra, Marine Management Organisation (MMO), Natural Resource Wales (NRW), Cornwall Inshore Fisheries and Conservation Authority (CIFCA) and the Shark Trust. These meetings gave the fishing industry an opportunity to discuss issues relating to elasmobranchs with both scientists and policy staff, and gave a forum for the exchange of knowledge and views from the attending parties.

3.3 Approach and data collection

Following an open tender process, which was held in the spring of 2013, suitable commercial fishing vessels that would provide appropriate coverage and sampling of the case study species were identified. These vessels would be expected to encounter the case study species as incidental and unavoidable bycatch during the course of their normal fishing practices. Following a tender evaluation process (July 2013), six vessels were selected to participate in the “Shark, Skate and Ray Scientific Bycatch Fishery”. Cefas staff visited Newlyn and Plymouth to meet with the owners and skippers of these fishing vessels in September 2013 and, following this, detailed survey plans were drawn up for the first three vessels (netters) and agreed with the skippers, including protocols for data collection and tagging. Dispensations for these vessels to land dead bycatch of two species (spurdog and porbeagle, both of which were zero TAC species) were granted by the MMO, and permissions to retain and land both species were sought via the Foreign and Commonwealth Office (FCO), as participating vessels may not have always exclusively operated in or transited through UK waters. Whilst it was originally hoped to include further vessels representative of other métiers (e.g. beam and otter trawl), it was decided during the course of the project that it would be preferable to focus efforts on netters, and that single vessels from other métiers may not be representative.

During this pilot project, three commercial fishing vessels were used12. The first trip was undertaken on Vessel A (8–13 October 2013), with two Cefas scientists training the crew in self-sampling techniques. This was followed by trips on Vessel B (November 2013) and Vessel C (December 2013), each with a Cefas scientist aboard to help train the crew. The crews were trained in elasmobranch species identification, sexing, measurement, sub-sampling and recording (Figure 5). For those elasmobranchs alive and in a fit condition for live release, the crews were trained to tag and release with mark-ID tags.

12 Participating vessels are named here as Vessels A, B and C

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These vessels subsequently collected data, usually for at least one trip each month. In addition to the initial training period, there was observer coverage on one additional trip on both Vessel A and Vessel C, during which the crew recorded independently from the scientists for comparative data quality purposes. Summary details of the three vessels are provided in Table 10, and details of those trips undertaken and for which data were provided are summarised in Table 11.

Figure 5: Disentangling a common skate from fishing gear

The data provided included the broader location of the grounds fished each trip (but not usually the exact positions for each gear deployment), dates fished, gear used and number of sets. Catch data provided by the vessels included the approximate weights of commercial catch (typically in terms of the numbers of fish boxes raised by the approximate weight per box) and also the quantity (numbers or estimated biomass) of the case study species. These data were supplied by ICES Statistical Rectangle. Whilst information on the lengths of nets used and approximate soak times were provided on some occasions, which could then be used to estimate the catch per unit effort, these data were not available for all sets. For the purposes of this report, catches of case study species are expressed as a number or biomass per quantity of target species retained.

For the case study species, selected specimens that were alive were tagged with rototags, with information on sex, length and ‘health state’ (lively or sluggish) and tag number recorded before release back to the sea. Sub-samples of dead porbeagle and spurdog bycatch were retained for subsequent biological examination ashore.

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Table 10. Details of the three vessels participating in the “Shark, Skate and Ray Scientific bycatch fishery”.

Vessel Main fishing practices

A This offshore netter (22.65 m LOA), based at Newlyn, fished mainly on open grounds using a combination of gillnets and tangle nets. Gillnets were of 120–150 mm mesh size

and deployed in ranging from 7.5–10.5 nm (ca. 14–20 km). Soak times typically ranged from 16–34 h, although longer soak times were reported very occasionally. The main species taken in gillnets were hake and pollack, as well as other gadoids (ling, haddock, saithe and cod). Spurdog was a frequent bycatch species, and porbeagle was a seasonal bycatch in late summer and early autumn.

Tangle nets were of 250–300 mm mesh size and deployed in ranging from 12–27 nm (ca. 22–50 km). Soak times ranged from 24–120 hours, but most sets were from 72–96 h. The main commercial species taken in tangle nets were anglerfish and turbot, with skates and rays (including common skate) a frequent bycatch. Spurdog and porbeagle were also an occasional bycatch in tangle nets

B This gillnetter (20.43 m LOA), based at Newlyn, fished mainly on open grounds for pollack, saithe and cod, with spurdog a frequent bycatch species. The mesh size used

was 135–140 mm, with fleets of gillnet set at lengths of 600–3,300 yards (ca. 550–3,000 m), with soak times ranging from 6–16 h.

C This netter (20.6 m LOA), based at Newlyn, fished mainly near wrecks with gillnets, targeting pollack, saithe, cod, ling, hake and anglerfish with gillnets, and also fished for

turbot, hake and anglerfish with tangle nets. Gillnets (mesh size = 155 mm) were 3,420 m long and set for soak times of approximately 12 h. Tangle nets (271 mm mesh) were set in fleets ranging from 3,200–25,600 m, with a 48–120 h soak time.

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Table 11. Summary details of commercial trips for which data were collated. Note: trips marked [1] and [2] only provided information for porbeagle and common skate, respectively.

Stations fished with Vessel Year Trip no. Dates of fishing Notes Gillnet Tangle Vessel A 2013 1 10–13 Oct 8 5 2 14–15 Oct 3 3 3 10–13 Nov 13 4 23–24 Nov 8 5 26–30 Nov 17 5 6 03–07 Dec 14 6 7 11–14 Dec 11 8 2014 1 09–11 Jan 18 2 19 Jan 3 3 8–14 Mar 4 11 4 17–18 Mar 7 3 5 24–29 Mar 12 1 6 06–13 Apr 15 15 7 19–22 Apr 12 8 8 25–28 Apr 3 3 9 4–10 May 25 15 10–12 2–4 Aug, 6–8 and 17–19 Aug [1] 13 26 Sep–4 Oct 20 8 14–15 Oct–Dec [2] Vessel B 2013 1 11–13 Nov 6 2 24–28 Nov 5 3 11–13 Dec 3 2014 1 9 Jan 1 2 10–11 Feb 2 3 20–24 Feb 5 4 8–11 Mar 3 Vessel C 2013 1 09–13 Dec 7 2014 1 10–12 Jan 6 2 20–22 Jan 3 3 23–27 Jan 5 4 17–22 Feb 6 5 23–26 Feb 4 6 07–10 Mar 5 7 04–09 Jun 6 8 21–26 Jun 6 9 5–9 Jul 5 10 29–31 Oct 5 11 13–17 Nov 8 12 31 Nov –3 Dec 4 13 15–16 Dec 3

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3.4 Catches of spurdog, common skate and porbeagle

3.4.1 Vessel A

Vessel A operated with the most gear, using both tangle nets and gillnets on most trips. Gillnet catches were dominated by various gadiform fish, notably hake and pollack, with ling, haddock, saithe and cod also taken. The main fishing grounds for their gillnet operations were 160 km west of the Scilly Isles (ICES Rectangle 29E1; Figure 6), with adjacent grounds (mainly 29E2) fished with tangle nets (Figure 7). Some tangle net fishing was also undertaken in the western English Channel (27E6), where catches mostly comprised various skates, anglerfish and brill.

Spurdog was a frequent bycatch species that was taken in all months for which data were available (14 trips from October to May; Table 12). It could also be an abundant bycatch species. For example, the estimated biomass of spurdog taken in one trip during October was higher than the retained quantity of the main target species (hake and pollack). Spurdog was also taken in large quantities in four other trips, with catches equating to ca. 300–580 kg of spurdog per tonne of hake and pollack. Smaller catches (<30 kg of spurdog per tonne of hake and pollack) were reported on six of the trips. There was no apparent seasonal pattern in these ratios for the period examined, and catches of spurdog could be high or low in any given month.

Although porbeagle (n = 83) could be reported in low numbers (1–2 fish per trip) over much of the year, there was a clear seasonal peak. Most records were between August and November, with the largest catches made during trips undertaken in August and September (34 and 39 in two of the trips undertaken), confirming the seasonality of this species (Table 12).

Tangle net catches were composed primarily of anglerfish and turbot, with common skate-complex (primarily Dipturus batis with some D. cf. intermedia) an important bycatch ( Table 13). As with spurdog, the estimated biomass of common skate caught could occasionally exceed the weight of the retained catch of the main target species (anglerfish and turbot). For the majority of trips, however, catches of common skate were estimated to be in the range of 340–880 kg per tonne of anglerfish and turbot. Spurdog were also caught in tangle nets, albeit in lower quantities than gillnet, and occasionally porbeagle (n = 10).

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Figure 6. Main fishing grounds of Vessel A when setting gillnets.

Table 12. Reported catches by Vessel A of spurdog (estimated biomass) and porbeagle (number) caught in gillnets per trip and in relation to the reported retained catch of the main species (hake and pollack, ‘na = data not available). Data aggregated at a trip level. For those sets where spurdog were counted, the biomass was estimated based on an average weight of 3.5 kg per fish.

Hake Pollack Spurdog Porbeagle Year Trip Month Kg Kg Kg Kg/t No. No/t 2013 1 Oct 8976 214.5 23.9 2 0.22 2 Oct 1056 429 1914 1288.9 1 0.67 3 Nov 11121 99 8.9 2 0.18 4 Nov 11022 3348 303.8 – – 5 Nov 6072 1848 396 50.0 – – 6 Dec 3201 198 1980 582.5 – – 7 Dec 165 1782 709.5 364.4 – – 2014 1 Jan 1188 4917 102.5 16.8 – – 4 Mar 858 1023 157.5 83.7 – – 5 Mar 6369 363 17.5 2.6 – – 6 Apr 1505 2730 0.0 – – 7 Apr 2240 805 1235 405.6 – – 8 Apr 3366 429 231 60.9 – – 9 May 2640 1287 33 8.4 2 0.51 10 Aug na Na 33 – 2 11 Aug na Na na – 1 12 Aug na Na na – 34 13 Sep/Oct na Na 33 – 39

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Figure 7. Main fishing grounds of Vessel A when setting tangle nets.

Table 13. Reported catches by Vessel A of Dipturus spp. (estimated biomass for all species in the genus) caught in tangle nets per trip and in relation to the reported retained catch of the main species (anglerfish and turbot). Data aggregated at a trip level. For those sets where common skate were counted, the biomass was estimated based on an average weight of 10 kg per fish.

Anglerfish Turbot Dipturus spp. Year Trip Month Kg Kg Kg Kg/t target species 2013 1 Oct na na 2602.5 na 2 Oct na na 790 na 5 Nov 1089 37.5 858 761.7 6 Dec 726 25 535 712.4 7 Dec 1023 50 363 338.3 2014 2 Jan 66 25 80 879.1 3 Mar 4320 100 23.1 4 Mar 240 25 270 1018.9 5 Mar – 25 66 2640.013 6 Apr 1085 625 – – 7 Apr 240 125 806 2208.2 8 Apr 840 400 470 379.0 9 May – 2050 – – 13 Sep/Oct na na 620 na

13 Catch data for this gear limited on this trip and so the ratio is not representative

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3.4.2 Vessel B

Vessel B targeted pollack and saithe primarily, with spurdog the most frequent case study species taken as bycatch. This vessel operated over a variety of grounds, in the Celtic Sea, with the largest catches made in ICES Rectangle 29E0 (Figure 8). Few common skate were reported, and only a single porbeagle. Spurdog catches were generally reported as the numbers of fish, but in those sets where they were caught in greater numbers they were quantified in terms of numbers of fish boxes. Spurdog was encountered mostly in low numbers (<15 fish per set, typically at a rate of 3.6 spurdog per tonne of Pollachius spp.), but there were some instances where up to three fish boxes (estimated at 40 kg per box) of spurdog could be caught, equating to ca. 23–53 kg of spurdog per tonne of Pollachius spp. (Table 14). This vessel left the fishing industry during the course of the project, and data were only available from November 2013 to March 2014.

Figure 8. Main fishing grounds of Vessel B when setting gillnets.

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Table 14. Reported quantities of spurdog caught by Vessel B in relation to the main target species (pollack and saithe) between November 2013 and March 2014. Data shown by set, as spurdog were either enumerated, or the catch was estimated based on the number of fish boxes.

Pollack Saithe Spurdog Spurdog Year Trip Set kg/t target No/t target Kg Kg Kg No. species species 2013 1 (Nov) 1 1260 924 – 2 – 0.92 2 630 378 – 2 – 1.98 3 210 840 – 4 – 3.81 4 210 798 – 10 – 9.92 5 378 924 – 8 – 6.14 6 210 336 – 4 – 7.33 2 (Nov) 1 966 630 – 1 – 0.63 2 1554 588 0 0 0.00 0.00 3 1092 756 0 0 0.00 0.00 4 1302 588 0 0 0.00 0.00 5 462 504 0 0 0.00 0.00 3 (Dec) 1 714 546 40 na 31.75 2 756 756 – 12 – 7.94 3 420 546 0 0 0.00 0.00 2014 1 (Jan) 1 52.5 na 2 (Feb) 1 2100 84 80 na 36.63 2 2226 42 120 na 52.91 3 (Feb) 1 420 42 42 na 23.26 2 756 – – 9 – 11.90 3 1218 42 – 1 – 0.79 4 840 336 – 2 – 1.70 5 798 – – 6 – 7.52 4 (Mar) 1 1344 – 42 na 31.25 – 2 na na 6 – na 3 na na 1 – na

3.4.3 Vessel C

Vessel C fished mainly near wrecks for pollack, saithe, cod, ling, hake and anglerfish with gillnets (the main gear used over the period for which data were collected), and turbot, and anglerfish were targeted with tangle nets. This vessel operated over a broad range of grounds, in the Celtic Sea and western Channel, with the main area fished with gillnet corresponding to ICES Rectangles 28E4 and 26E3 (Figure 9) and tangle nets used on the grounds covering 28E2, 29E2 and 28E1 (Figure 10). Catches of spurdog were generally small (up to 24 spurdog per set) and were always enumerated (the smaller catches of spurdog possibly related to the shorter lengths of gillnet deployed in the vicinity of

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wrecks). They occurred in 29 of the 53 sets (54.7%) for which data were collected. The highest bycatch rates in individual sets were about 21 spurdog per tonne of gadoid (for this vessel defined as the aggregated landed weight of pollack, saithe and cod), but the average was only 3.6 spurdog per tonne of gadoid landed. Once again, spurdog catches were quite sporadic, with high and low catches taken in any given month (Table 15).

A total of 42 porbeagle sharks were reported, of which four were reported to have either dropped out of the net on retrieval or to have been returned alive and five were noted as dead. The single largest catch was of 15 porbeagle in one set (October 2014), with most porbeagle recorded in the period October to December.

Common and flapper skates were recorded in tangle net catches (Table 16), with only a single porbeagle recorded in this gear. This gear was used seasonally, with data available for June and July, and Dipturus spp. were caught at rates of about 5.1–16.9 fish per tonne of anglerfish and turbot.

Figure 9. Main fishing grounds of Vessel C when setting gillnets.

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Figure 10. Main fishing grounds of Vessel C when setting tangle nets.

Table 15. Summary details of the quantities of spurdog caught in relation to the main target species (pollack, cod and saithe) by Vessel C between December 2013 and March 2014, and between during October and December 2014. Catch data aggregated across trips.

Cod Pollack Saithe Spurdog Year Trip Month Kg Kg Kg No No/t target species 2013 1 Dec 3680 2562 2256 2 0.24 2014 1 Jan 5754 240 4 0.67 2 Jan 6048 20 30 4.94 3 Jan 13052 48 50 3.82 4 Feb 4788 4 24 5.01 5 Feb 6426 20 5 0.78 6 Mar 12402 432 58 4.52 10 Oct 1912 1116 3344 11 Nov 4576 1804 2860 4 0.43 12 Dec 1870 1496 2354 13 Dec 528 704 1232 26 10.55

Table 16. Summary details of the quantities of Dipturus spp. caught in tangle nets in relation to the main target species (turbot and anglerfish) by Vessel B during three trips in 2014. Catch data aggregated across trips.

Anglerfish Turbot Dipturus spp. Trip Month No/t target Kg Kg No species 7 Jun 337.5 2747 52 16.9 8 Jun 200 1523 9 5.2 9 Jul 218 2132 12 5.1

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3.4.4 Summary

Catches of spurdog in gillnets were a common occurrence, and this species was often taken in large numbers. Catches also occurred over a wide area (Figure 11) and successive trips could have high and low catches, even when a short time apart. Such a pattern is consistent with the known aggregating behaviour of this species, highlighting the problems in identifying times and locations where any aggregation may occur.

Although catches of porbeagle were also made over a relatively large area (Figure 12), the catches described above showed a clear seasonality, which could be related to the migratory behaviours of this species. Most catches occurred between August and December, and peaked in September and October.

Catches of common skate in tangle nets were mostly reported from a more restricted number of rectangles (Figure 13), and large catches could be reported during all the months for which data were available, confirming the view that this species has more restricted movements.

Figure 11. Spatial distribution of spurdog bycatch observed by ICES rectangle

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Figure 12. Spatial distribution of porbeagle bycatch observed by ICES rectangle

Figure 13. Spatial distribution of common skate bycatch observed by ICES rectangle

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3.5 Tagging studies and biological information

Overall, 759 elasmobranchs were tagged and released (Table 17), and relevant details supplied. These data have been archived on Cefas’ Tagged Fish Database. Whilst there have only been limited numbers of recaptures to date, this is in part related to the current ‘prohibited status’ of one of the species (common skate) and that the time at liberty has been limited.

Table 17. Numbers of elasmobranchs tagged and released during the pilot programme

Species No. tagged Length range (cm) Lamna nasus 5 127–196 Squalus acanthias 279 40–122 Galeorhinus galeus 1 130–130 Dipturus batis 412 53–176 Dipturus cf. intermedia 24 88–204 Dipturus batis complex 5 48–184 Raja undulata 33 68–104

The most frequently tagged species was common skate Dipturus batis, with small numbers of flapper skate also reported. The majority of fish were in the 110–135 cm length range (Figure 14). The largest common skate recorded were much larger than that observed by Iglésias et al. (2010), suggesting that some of these fish may have been misidentified flapper skate. Information on the relationship between total length (LT) and disc width (D) was also recorded, and the linear relationship (Figure 15)

2 was described as D = 0.6727. LT+ 4.9083 (n = 151, r = 0.967). Most of the common skate complex were reported as Dipturus batis, with smaller numbers of Dipturus cf. intermedia, which is in keeping with earlier studies (Griffiths et al., 2010; Bendall et al., 2014).

Most of the spurdog tagged were either in the 65–90 cm length range, where males were the predominant sex, or from 101–113 cm (Table 16). The latter cohort would be expected to comprise mature females, although the records did include some males in this length range. These nominal records are greater than the maximum length that would be expected for males, indicating that the sex (or species) was not recorded correctly.

One vessel, which operated occasionally in the western English Channel, tagged and released a sample of undulate ray (Figure 17), with most of the larger (>90 cm LT) individuals female.

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As part of the “Shark, Skate and Ray Scientific Bycatch Fishery” a proportion of dead spurdog and porbeagle bycatch was retained and landed, under dispensation, for biological study. Samples of spurdog (1,112 specimens) were kept in frozen storage in the south-west, and transported to Lowestoft in September 2014, where detailed biological sampling was undertaken (Section 4.3). The sample of dead porbeagle (n = 53), which was also kept frozen, was brought to Lowestoft in January 2015 for examination (Section 4.4).

25 BSKT FSKT SKT 20

10 Frequency

95 50 55 60 65 70 75 80 85 90

100 105 110 115 120 125 130 135

>190

140-144 165-169 Total length (cm)

Figure 14. Length frequency of Dipturus spp. tagged and released, showing those identified as Dipturus batis (BSKT), Dipturus cf. intermedia (FSKT) and Dipturus batis-complex (SKT)

110 y = 0.6727x + 4.9083 100 R² = 0.9668 90 80 70 60

Disc Disc width(cm) 50 40 30 20 40 60 80 100 120 140 160 Total length (cm)

Figure 15. Relationship between disc width and total length in Dipturus batis

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18 16 14 12 10

8 Frequency 6 4 2 0 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 Total length (cm)

Figure 16. Length frequency of spurdog Squalus acanthias tagged and released

2 Frequency

0 40 45 50 55 60 65 70 75 80 85 90 95 100 105 Total length (cm)

Figure 17. Length frequency of undulate ray Raja undulata tagged and released

3.6 At-vessel mortality

Data on the vitality and fate of porbeagle were provided by all three vessels, but most specimens caught by Vessel A. During the course of the project, porbeagle were recorded in four categories: (a) tagged and released, (b) released in ‘sluggish condition’ or dropped out of the net alive, (c) dead, or (d) fate unknown or dropped out of the net in unspecified condition. Three estimates of at-vessel mortality were calculated, depending as to whether specimens of ‘unknown fate’ were excluded case), assumed alive (best case scenario) or assumed dead (worst case scenario). Across all trips and vessels, the at-vessel mortality was >90% (

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Table 18), unless specimens of ‘unknown fate’ were assumed alive, which would indicate at-vessel mortality of 77.5%. One of the vessels (Vessel C) encountered only small numbers of porbeagle, and estimates of at-vessel mortality were lower (ca. 56%) for this vessel than with Vessel A (> 97%).

Data on the vitality and fate of common skate complex were provided by one vessel, with these data collected in most detail across ten trips and 14 sets. In total, at-vessel mortality was 38.5% (data aggregated across trips) with the mean at-vessel mortality (averaged across all sets) 33.6% (Table 19). This confirms that the survival of skates in offshore net fisheries is lower than observed in inshore tangle and gillnet fisheries (Ellis et al., 2012b), presumably relating to the higher soak times on offshore fishing grounds.

Table 18. Preliminary estimates of at-vessel mortality of porbeagle as reported by fishers on commercial netters

Alive Dead Fate unknown At-vessel mortality (%) Tagged Sluggish or (including and dropped out dropped out) Base Worst Best Vessel released alive Total case case case Vessel A 1 1 80 14 96 97.6% 97.9% 83.3% Vessel B 1 1 2 50.0% 50.0% 50.0% Vessel C 3 1 5 4 13 55.6% 69.2% 38.5% Total 5 2 86 18 111 92.5% 93.7% 77.5%

Table 19. Preliminary estimates of at-vessel mortality of common skate complex as reported by fishers retrieving tangle nets (Vessel A only)

Vitality Lively Sluggish Alive Dead Total At-vessel (unspecified) mortality 18 6 3 27 11.1% 39 1 75 115 65.2% 2 0 9 11 81.8% 25 2 1 28 3.6% 21 18 39 46.2% 17 2 11 3 33 9.1% 17 4 4 25 16.0%

Sets 15 4 0 19 0.0% 5 0 16 21 76.2% 2 2 4 50.0% 9 14 23 60.9% 8 0 8 0.0% 28 11 39 28.2% 20 4 24 16.7% Total 205 19 32 160 416 38.5% Average 33.6%

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3.7 Best practice in handling elasmobranchs and developing a ‘Code of conduct’

There have been increasing numbers of studies on elasmobranch discard survival (see Ellis et al., 2014 for a review). An important consideration that is rarely addressed is that the care and short handling times afforded to fish by scientists and observers can be more benign than could be experienced under normal commercial fishing conditions. Hence, there has been an increased impetus to consider ways of promoting best practice in the handling and release of fish (e.g. Jones and Francis, 2012; Poisson et al., 2012; Australian Fisheries Management Authority, 2014).

Whilst such approaches are relatively well established in some recreational fisheries (Pelletier et al., 2007; Arlinghaus et al., 2010), there have been fewer studies addressing welfare and handling in commercial fisheries (Campbell and Cornwell, 2008; Metcalfe, 2009). Similarly, the progress that has been made to encourage bycatch mitigation for seabirds, sea turtles and marine mammals is less developed for elasmobranchs, and studies to help develop safe and effective handling and release protocols for commercial fishers encountering elasmobranchs has received limited consideration (Poisson et al., 2014).

Bycatch mitigation can take several forms, ranging from modifying fishing gears and fishing practices to reduce the likelihood of catching vulnerable bycatch species, through to more simply using ‘best practise’ in terms of handling catches and releasing unwanted catch. For such approaches to be validated and supported by the fishing industry requires that there is minimal economic impact (i.e. catch value should be maintained, whether in terms of quantity and/or quality; consideration of costs that may be incurred for fishing gears and operations) as well as modifications being both practical and safe. Some measures, such as communication with other vessels in the fleet in order to inform other fishers where vulnerable species may occur in large numbers, can be implemented easily.

The survivability of the species of concern is also a key factor. If a species to be released is hardy and typically resilient to capture, then changes to fishing gears and patterns may not actually be required, as appropriate handling can ensure any bycatch can be released alive. However, if there is a higher rate of mortality of the bycatch species, and at a level that could result in population level affects, then there is a stronger rationale to examine how changes to gears and/or fishing patterns may either reduce the likelihood of capture and/or minimise the mortality of those captures.

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Various measures can help maximise the prospects of discarded elasmobranchs surviving capture and release, such as:

 Reducing tow duration / soak time on grounds where vulnerable species may occur

 When hauling nets and lines, trying to return lively fish to the sea as soon as practical and before they go through the net hauler or bait stripper

 When processing trawl catches, returning unwanted fish that are alive as soon as possible, and avoid leaving unwanted fish on deck, and not in direct sunlight

 Not using a gaff to bring unwanted fish on board or to move them about

 Supporting the fish when lifting them (e.g. using one hand to support the underside and the other to support the tail) and not lifting or dragging them by their tail, gills or eye sockets

 Not standing on the fish

 Removing any gear remains (e.g. lines) from the caught specimen or cutting the trace as short/close to the body as possible.

 When releasing fish into the sea, try not to throw them, but place them in the sea (small boats) or gently slide them head first from as low a height as safely possible.

To promote good handling, it is important to work with the fishing industry and to develop and dissemination of user-friendly posters (e.g. Figure 18) to convey important messages to the skippers and crews of fishing vessels.

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Figure 18. Example ‘Code of Conduct’

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3.8 Lessons learnt: Advantages and limitations of fisher-collected data

There has been increased interest in incorporating fisher knowledge into the assessment and advisory process. Furthermore, with resources for observers to conduct scientific monitoring often limited, there is increasing consideration of how fishers could assist in data collection, such as with self- sampling.

The pilot project undertaken has highlighted several advantages and limitations of dedicated data collection by fishermen during their normal commercial fishing practices.

Advantages include:

 Commercial fishers involved in data collection, so it is an avenue whereby their knowledge and information can be passed onto scientists (which may in turn result in greater ‘buy-in’ to future management)  Data collected for species that are not sampled effectively in scientific surveys and/or only seen occasionally during discard observer trips;  Facilitates data collection for bycatch species throughout the year, allowing improved knowledge of seasonality;  Effective supply of biological material that would not typically be available from other sources, thereby allowing the collection of relevant life history data to inform assessments and management advice  Fishers proactively involved in tagging programmes (including tagging and release fish, and reporting of tags), which can provide evidence of longer-term survival of discards;  Data on the estimated numbers and/or biomass of selected species can be collected in relation to the reported catches of the target species, so allowing alternative ways of estimating catch.

There are, however, several limitations, including:

 Reliable effort data for nets set under commercial conditions (in terms of total lengths, soak times and whether any gear damage has affected fishing efficiency) are difficult to record consistently;  Possibilities that assessment scientists will not accept fisher data without independent verification;  Resolution of data can be limited (e.g. numbers of fish boxes multiplied by typical weight; fishers may be reluctant to supply exact coordinates where large catches are made);

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 Units can be variable (e.g. smaller catches often counted, larger catches have estimates of biomass);  More species were often recorded in final set, presumably due to part-filled fish boxes for more infrequent commercial species only being quantified at the end of the trip;  Potential issues of incorrect species identification, sex or length being recorded.

Other factors that need to be considered include:

 Degree and rigour of sampling can be related to workload. For example, larger catches may be associated with lower quality data as the crew are busier. Similarly, catches of occasional fish to be discarded may be reported as ‘live’ or ‘dead’, which is not always practicable for larger catches;  Recorded observations were sometimes semi-quantitative or anecdotal, so it is difficult to collate all information in an unbiased and representative way;  Biological sampling of samples retained frozen can be problematic for some parameters. For example, the ‘candle’ stage (where uteri are filled with segmented yolky matter, without visible embryos, see Section 4) of spurdog breaks down, so preventing fecundity determination for this maturity stage. Similarly, the numbers of pups that may have been aborted is unknown.

Finally, as well as issues relating to ‘data’ there are several other important factors to be considered in programmes where fishers contribute knowledge and data: stakeholder ‘fatigue’, managing expectations and trust (Hetherington et al., in prep.). Regular dialogue with fishers (e.g. through stakeholder meetings and observer trips) and the inclusion of fishery organisations on the PSG were found to be very beneficial to those programmes collating data and knowledge from fishers.

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4 Biological investigations of elasmobranchs

Summary

 An appropriate biological and ecological knowledge is needed to underpin the assessment and advisory processes that inform management of elasmobranchs. Whilst existing surveys have allowed some of these data to be collected for some species, many data gaps remain. The data collection presented here focused on those parameters relating to the reproductive biology which are required for future stock assessments and can provide information to inform biologically meaningful management measures. Material for future age and growth studies were collected.

 During the present study, recent life history data were collected for spurdog, complementing the extensive data collected for this species by Lowestoft scientists in the 1960s. In total, 1,112 specimens (805 males and 307 females) were examined. Females matured across the 79–86 cm length range. The length at 50% maturity was about 82 cm, which is similar to previously published estimates. The maximum fecundity reported was 19 pups, which was higher than values reported in the 1960s, providing further credence to the hypothesis that spurdog fecundity has increased.

 Starry smooth-hound is of increasing interest to UK fishermen, yet the biology and status of this species had been little studied. In total, 430 specimens (199 males and 231 females) were sampled. The length at maturity of females was typically between 78 and 87 cm, although one female matured at 69 cm. Males matured across the 65–74 cm length range. Ovarian and uterine fecundity ranged from 1–28 and 4–20, and the number of pups increased with maternal size. Larger females also produced longer and heavier pups. The data collected during the project will facilitate the development of future demographic assessments, as already developed for spurdog.

 Genetic tissue samples from over 300 starry smooth-hound specimens were contributed to a larger-scale collaborative study across the Northeast Atlantic. Preliminary results of this study indicate that Mustelus asterias is probably the only Mustelus species to occur in British waters.

 Biological sampling of porbeagle sharks (n=53) that were taken as dead bycatch from the south- west have provided length conversion factors and biological samples for future studies, including contaminant levels and growth studies.

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4.1 Introduction

An improved biological and ecological knowledge of elasmobranchs is considered essential for developing pragmatic management plans for elasmobranchs. Furthermore, there will be increasing options for the types of assessment that can be developed as such biological data (as well as commercial catch data) improve. For example, recent estimates of spurdog fecundity collected by Cefas scientists (Ellis and Keable, 2008), which suggested that spurdog produce more pups nowadays than they did in the 1960s (possibly due to a density-dependent increase in fecundity), were used in the subsequent benchmark assessment (De Oliveira et al., 2013). This was one of the factors that resulted in the estimated decline in spurdog not being as high as previous exploratory assessments.

Existing trawl surveys undertaken by Cefas have provided extensive data on demersal elasmobranchs, and such data have been used to further our understanding of distribution, stock structure and habitats (Pawson and Ellis, 2005; Ellis et al., 2005a; Chevolot et al., 2006), size at maturity (McCully et al., 2012a), movements (Burt et al., 2013) as well as analyses of time series data (Ellis et al., 2005b, ICES, 2013).

Although Cefas have maximised the use of existing surveys to collect additional data for elasmobranchs, including the collection of biological material for genetic studies, existing trawl surveys have clear limitations in terms of what samples and data can be collected. To augment the data collected during these surveys, the NEPTUNE project has facilitated more detailed and dedicated investigations to be undertaken for spurdog and starry smooth-hound. Samples of the former were collected from the “Shark, Skate and Ray Scientific Bycatch Fishery”. (Section 3), whilst the latter were sourced from commercial fishermen and from existing trawl surveys. Additional biological data were also collected for porbeagle retained under the “Shark, Skate and Ray Scientific Bycatch Fishery”.

The main life history data reported here relate to the reproductive biology of the species. The size at which fish mature, fecundity and reproductive periodicity are all important factors to determine in fisheries management, as they are key parameters for various assessment methods (e.g. demographic models). Furthermore, if fisheries managers are to consider size restrictions as possible management measures, these are often related to the size at maturity. With regards to elasmobranchs, it is also important to consider measures to ‘protect’ the larger or reproductively active part of the stock, as there is generally assumed to be a closer relationship between recruitment and spawning stock in elasmobranchs than in teleosts. Measures to protect large females are often questioned by fishers, and data to show how fecundity and pup size relate to the size of females provides the evidence to

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inform such discussions. Understanding the reproductive cycle and the timings of key events (e.g. parturition or egg-laying) are also important if seasonal management is to be considered.

Recent studies on the length at maturity of skates (McCully et al., 2012) have indicated that some previously purported decreases in the size at maturity, which are often viewed as an effect of overfishing, have been based on the use of different maturity scales and interpretation of ‘mature’ fish. In order to ensure that robust maturity data are collected, it is important to use standardised maturity keys (Table 20) and also, where possible, to collect data that quantitatively support the assignment of maturity, rather than a more simple visual assessment, which can be somewhat arbitrary and not necessary equate with any future studies.

Age and growth are also very important parameters to be understood, and whilst not undertaken during the present project, samples of vertebrae (and spines of spurdog) have been collected to enable such studies to be undertaken in the near future.

The need to have important biological and ecological data for elasmobranchs has already been noted in the ‘Shark, Skate and Ray Conservation Plan’, which highlights that ecological information can be “used to more effectively manage elasmobranchs” (Defra, 2011) and in ICES advice. For example, the 2014 ICES advice for skates and rays stated that “Biological knowledge (age, growth, fecundity) of many skate species is limited; therefore some life-history assessment models cannot be developed at the present time” (ICES, 2014a) and for spurdog, it was noted that “Future assessments require updated and validated growth parameters (particularly for larger individuals)” (ICES, 2014b).

In addition to the biological information shown in greater detail here for starry smooth-hound (Section 4.2), spurdog (Section 4.3) and porbeagle (Section 4.4), various other biological studies have been undertaken and written up in the form of working documents to the ICES WGEF (summarised in Section 4.5).

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Table 20. Maturity scale for viviparous sharks. Adapted from ICES (2009)

Stage Male Female

A Immature: Claspers Immature: Ovaries small, gelatinous undeveloped, shorter than extreme tips of posterior margin or granulated, but no differentiated of pelvic fin. oocytes visible. Oviducts small and thread-shaped, width of shell gland

not much greater than the width of Testes small and thread-shaped, the oviduct. sperm ducts straight B Developing: Claspers longer than posterior margin of pelvic Developing: Ovaries enlarged and fin, their tips more structured, with more transparent walls. but the claspers are soft and Oocytes differentiated in various flexible and the cartilaginous small sizes (usually <5mm) and pale elements are not hardened. in colour. Oviducts small and thread- shaped, width of the shell gland

greater than the width of the Testes enlarged, sperm ducts oviduct, but not hardened. beginning to meander. C Mature: Claspers longer than posterior margin of pelvic fin, Mature: Ovaries large with very cartilaginous elements large, yolk-filled oocytes, (> 5mm hardened and claspers stiff. and often 10–30 mm in diameter). Shell gland fully formed and hard.

Uteri fully developed but without Testes enlarged, sperm ducts yolky matter (Stage D) or embryos meandering and tightly filled (Stages E-F) and not dilated (Stage G) with sperm. D Early gravid (or candle stage): Uteri Active: Clasper reddish and filled with yolky matter, which may swollen, sperm present in appear unsegmented, or if clasper groove, or flows if segmented, without visible pressure exerted on cloaca. embryos. E Mid-term gravid: Uteri filled with yolk sacs and small developing embryos that can be counted. F Late gravid: Uteri filled with well- developed term pups, and the yolk

sac has been absorbed (or is very small). G Post partum: Similar to stage C, but with a greater number of

degenerating follicles and uteri dilated and flaccid.

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4.2 Starry smooth-hound Mustelus asterias 14

Seasonal catches of starry smooth-hound Mustelus asterias have been commonplace around the UK coast for many years. These were historically discarded due to their low commercial value; however national landings statistics have indicated a steady increase in reported smooth-hound landings over the period 2000–2012. Following a prioritisation exercise of the chondrichthyans of the British Isles (see Section 2), this species was deemed to be a high priority for study, given its life history, importance of UK waters to the stock and the emerging commercial interest. Furthermore, many aspects of the biology of this species are poorly known. A biological sampling programme was initiated to collect data on those life history parameters necessary for any future stock assessment.

The reproductive biology of Mustelus spp. in the Northeast Atlantic has been relatively little studied to date (Capapé, 1983; Farrell et al., 2010a), despite it having a broad geographical distribution and being increasingly exploited. The main published study on the reproductive biology from Atlantic waters is from Farrell et al. (2010a), who reported on ovarian and embryonic fecundities, and alluded to a possible two year reproductive cycle (12 month gestation and possible resting period) for starry smooth-hound in the Irish Sea. Further work by Farrell et al. (2010b) investigated the age and growth of this species, with longevity estimated at 13 and 18.3 years for males and females respectively.

Whilst triakid sharks are often considered relatively productive, relative to some other elasmobranch groups, the longevity, large size, late age at maturity, low fecundity, protracted gestation periods and aggregating nature of this species means that exploitation may need to be managed if overfishing, such as occurred with S. acanthias, is to be avoided. Given their comparable biology, and the fact that currently there is limited management for smooth-hounds, increasing our knowledge of their life history at this stage will facilitate more robust assessments and management in the future.

Samples of larger specimens were sourced from commercial fisheries operating in the southern North Sea and eastern English Channel across an 18-month period. Smaller specimens were collected from the dead bycatch in surveys of the Celtic Sea and western English Channel undertaken by RV Cefas Endeavour. In addition to data on length and weight, those parameters needed to understand the

14 Preliminary findings from this work were given in: McCully, S. R. and Ellis, J. R. 2014. Biological studies to inform management of smooth-hounds (Mustelus spp.) in the North-east Atlantic. Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 16 pp. Final publication resulting from this work: McCully Phillips, S. R. and Ellis, J. R. 2015. Reproductive characteristics and other life history parameters starry smooth-hound Mustelus asterias in British waters. Journal of Fish Biology, 87: 1411–1433.

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reproductive biology were recorded, including maturity stage, gonad weight, clasper length (males) and, for females, width of the shell gland, the number of mature ovarian follicles, maximum follicle diameter, and uterine and ovarian fecundity. The diet was also quantified, with data on the stomach contents collected using the fullness/points method and numerical abundance of prey taxa. Furthermore, biological samples were collected for collaborative studies and future work. Fin clips were collected from mature adults (n = 305) and their pups (n = 121) for genetic studies. Vertebrae were dissected out of the body cavity for future studies on age and growth.

In total, 430 specimens (199 males, 27–99 cm LT and 231 females, 28–124 cm LT) were examined (Figure 19), with information also collected for 238 uterine pups. The relationships between total weight and length (Figure 20), and gutted weight and length (Figure 21) highlight the increased variability in total weight in larger specimens, as the weights of the reproductive organs and the liver will be influenced by maturity stage. Of note is the 119 cm ‘outlier’, which related to a post-partum female with a very low body mass.

Figure 19. Length frequency distribution of starry smooth-hound examined by sex

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Figure 20. Relationship between total weight and total length in starry smooth-hound by sex and maturity stage

Figure 21. Relationship between gutted weight and total length in starry smooth-hound by sex

Given that the reproductive cycle of starry smooth-hound is uncertain, information on the weight of the liver and the hepatosomatic index (IH, the weight of the liver as a percentage of total weight) were also collected. This is because the liver is the main site of energy storage and supports the high maternal investment to pup production over the reproductive cycle. The relationship between liver weight and total length (Figure 22) is highly variable, especially for larger fish, as it is strongly influenced by sex and maturity stage. The lowest IH values were seen in gravid females with term pups

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(stage F), and the highest values observed in females at stage C, which includes fish at the stage preceding gestation (Table 21).

Table 21. Hepatosomatic index (IH) of starry smooth-hound by sex and maturity stage

Maturity Mean IH of n Mean IH of males n Stage females A 5.12 72 4.45 58 B 8.58 64 7.10 20 C 9.91 44 5.32 117 D 8.05 9 7.24 2 E 6.96 4 F 3.30 17 G 4.68 3

Figure 22. Relationship between liver weight and total length by sex

The relationship between gonad weight and total length was also examined (Figure 23), with gonad weight clearly increasing with length but also showing an increased variability between maturity stages of adult fish, with pregnant and post-partum females having smaller gonads than mature females not carrying young. Gonad weight was also examined by gonadosomatic index (IG), and the average IG by sex and maturity stage is given in Table 22. As expected, IG was low in immature and developing fish (stages A and B) and increased in mature fish (stage C). During the course of gestation,

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IG decreased during (stages D and E) and then appeared to increase in the latter stages, when the fish was either carrying term pups or had recently given birth (stages F and G)

Table 22. Mean gonad weight and gonadosomatic index (IG) by sex and maturity stage of starry smooth-hound

Sex Female Male Maturity Mean gonad Mean IG (%) n Mean gonad Mean IG (%) n Stage weight (g) weight (g) A 2.93 0.36 72 1.44 0.24 58 B 5.37 0.32 64 6.15 0.53 20 C 24.53 0.84 44 24.93 1.22 117 D 17.85 0.52 9 21.55 1.27 2 E 11.95 0.32 4 F 23.6 0.43 17 G 19.23 0.44 3

Figure 23. Relationship between gonad weight and total length by sex and maturity stage

The smallest mature and largest immature females recorded in the present study were 69 and 87 cm, respectively. The smallest mature female that Farrell et al. (2010a) reported was 83 cm – considerably larger than the smallest mature female recorded in the present study, although this was an exceptional specimen, and the next smallest female recorded was 78 cm LT. This is also interesting, as Farrell et al. (2010a) considered females to be mature when follicles were yellow and >3 mm in diameter, whereas the maturity keys used here (Table 20), which are comparable to those keys developed within ICES, assign a female as mature when the follicles are larger (>5 mm). The smallest mature and largest immature males in the present study were 65 and 74 cm, respectively. In order to

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help quantify the maturity stage, the width of the shell gland of females (Figure 24) and length of the claspers of males (Figure 25) were also recorded.

Figure 24. Relationship between width of the shell (or nidamental) gland and total length in female starry smooth-hound by maturity stage

Figure 25. Relationship between outer clasper length and total length in male starry smooth-hound by maturity stage

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The number of mature ovarian follicles ranged from 1–28 in mature females. These will not all necessarily develop into embryos, however, and estimates of ovarian fecundity generally exceed estimates of uterine fecundity. The diameters of the mature follicles of females (all mature stages) ranged from 4.1 mm (mid-term gravid female) to 20.7 mm (mature female). Uterine fecundity ranged from 4–20, which exceeds the maximum uterine fecundity (18) reported by Farrell et al. (2010a), however they stated that their values may be underestimated due to females aborting pups on capture. The highest fecundity (20 pups) was a female carrying full-term pups. Uterine fecundity increased with length (Figure 26). Furthermore there were also positive linear relationships identified between maternal length and average pup length and weight (Figure 27).

Farrell et al. (2010a) alluded to a possible two year reproductive cycle (12 month gestation and possible resting period) for starry smooth-hound in the Irish Sea. However, within our mature female fish, 16 late gravid females with term pups (uterine fecundity 4–20) were also found to have numerous mature follicles (n = 6–22, length range 6–10 mm). This could indicate a possible annual reproductive cycle, but more in depth analysis is required to confirm or reject this hypothesis.

Figure 26. Relationship between uterine fecundity (embryos and term pups) and maternal total length in starry smooth- hound

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Figure 27. Relationship between the average length (left) and average weight (right) of term pups in relation to maternal length for starry smooth-hound

The main prey items of starry smooth-hound were dominated by crustaceans, including the mantis shrimp Rissoides desmaresti, amphipods (in smaller individuals), natantid shrimps (Alpheus glaber, Processa spp., pandalids, Crangon allmanni and Crangon crangon), thalassinoid shrimps (Callianassa tyrrhena and Upogebia spp.), hermit crabs (Anapagurus laevis and Pagurus bernhardus), squat lobsters (Galathea spp. and Mundia rugosa), brachyuran crabs (Hyas coarctatus, Macropodia spp., Atelecyclus rotundatus, Cancer pagurus, Corystes cassivelaunus, Liocarcinus depurator, Liocarcinus holsatus, Liocarcinus pusillus and Necora puber). A few specimens had contained squid (the bait from longline fisheries), with the mussel Mytilus edulis, the brittlestar Ophiura albida and hydroids found in occasional specimens. In some samples, either Necora puber or Cancer pagurus could be important prey items, indicating that starry smooth-hound could be an important predator of these commercially valuable shellfish.

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4.3 Spurdog Squalus acanthias

Spurdog was formerly an important commercial species that was targeted in longline and gillnet fisheries around the British Isles. These fisheries were unmanaged for several decades, and management measures may have only been restrictive since 2007. Intensive biological sampling of spurdog was undertaken in the North-east Atlantic in the 1960s, when the fishery was at its peak, but life-history parameters for recent times are more limited. It is known, however, that many life history parameters can change in relation to exploitation. The latest stock assessment incorporated both historic and recent fecundity data, as several studies have suggested that spurdog may have become more fecund in recent times. Given the low numbers of spurdog taken in Cefas’ current scientific trawl surveys and restrictions on commercial landings, the specimens collected during the “Shark, Skate and Ray Scientific Bycatch Fishery” provided a unique opportunity to collect contemporary biological data to complement data collected by scientists at Lowestoft in the 1960s. The results of these biological investigations are presented here.

Data collected included total length (cm), total and gutted weight (g), sex, maturity stage, gonad weight (0.1 g), weight of the stomach contents (0.1 g) and stomach “fullness” (a qualitative score of 0–10) and a description of the stomach contents. Additional data collected for females were shell gland width (0.1 mm), number of mature ovarian follicles (ovarian fecundity), maximum follicle diameter (0.1 mm), uterine fecundity (by uterus), and the number of any atretic/undeveloped eggs. Data were also collected for pups including sex, total length (mm), total weight of the embryo and yolk sac, and weights of the embryo and yolk sac only (0.1 g). Additional data collected for males were the inner and outer lengths of the clasper (0.1 mm).

A total of 1,112 specimens were examined (Figure 28), including 805 males (53–92 cm LT) and 307 females (47–122 cm LT), as well as associated pups (n = 935, 98–296 mm LT). The number of spurdog sampled by vessel, date, sex and length range are summarised in Table 23. Biological samples that were taken for all specimens where possible included fin clips for genetic analysis, and the spine from the second dorsal fin and vertebrae (taken from the body cavity corresponding to that part of the body just anterior to and below the first dorsal fin) for age determination. Samples of stomach contents and muscle were also retained as frozen material for future studies Table 24.

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Figure 28. Length frequency of spurdog examined by sex (black = female, n=307; grey = male, n= 803)

Table 23. Summary of numbers (by sex) and length range of spurdog retained during the project

Males Females Vessel Trip date N Length range (cm) N Length range (cm) 8–12 Oct 2013 64 * 53–92 49*** 47–116 14 Oct 2013 22 73–89 6 72–109 14 Nov 2013 46 58–90 6 98–109 27 Nov 2013 103 60–89 34 60–117 1 Dec 2013 159 57–89 5 61–109 A 2–8 Dec 2013 86 67–92 8 102–116 10–12 Dec 2013 64 65–91 5 99–107 12 Jan 2014 44 72–87 1 102 16– 19 Mar 2014 21 71–87 8 * 76–109 24 Apr 2014 118 * 55–86 56 56–111 30 Apr 2014 19 **** 58–81 20 * 58–107 Unknown trip 1 5 67–74 6 68–103 Unknown trip 2 17 75–85 2 75–108 11–16 Dec 2013 9 76–87 10 97–109 8–10 Jan 2014 – – 13 83–111 B 9–14 Feb 2014 24 $ 61–87 43 58–113 7–13 Mar 2014 – – 18 * 87–115 7–15 Nov 2014 4 74–86 17 79–122 TOTAL 805 53–92 307 47–122 Footnotes: * included one specimen that had been scavenged internally, so data unavailable for some parameters (*** = three specimens scavenged; **** = four specimens scavenged); $ length data not collected for two specimens

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Table 24. Numbers of samples collected for future studies (preliminary)

Samples Males Females Total Spine 750 279 1029 $ Vertebrae 803 302 1105 Fin clip 803 303 1106 Muscle 161 87 248 Stomach 160 76 236 $ Spines that were broken or badly damaged were not collected

The relationships between total length and total weight are shown by sex and maturity stage (Figure 29) and gutted weight by sex only (Figure 30). The outlier on these figures was due to an abnormal female specimen that was emaciated, presumed to be a mature fish given the state of the nidamental gland, although no mature ovarian follicles were present and the uteri were not flaccid as would be observed in a post-partum specimen (stage G). In addition, a hook was present in its liver.

The smallest mature and largest immature fish were 79 and 86 cm, respectively (female) and 59 and 79 cm (male). All specimens were mature (100% maturity) when >87 cm (female) and >80 cm (male). The length at 50% maturity was approximately 82 cm (female) and 66–67 cm (male). The length at maturity of females seems unchanged from the earlier estimates of Holden and Meadows (1962), indicating that this life history parameter may not change in relation to overexploitation.

The relationship between gonad weight and total length sex and maturity stage is shown in Figure 31 and summary data on the gonadosomatic index (gonad weight as a percentage of total weight) given in Table 25.

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Figure 29. Relationships between total weight and total length by maturity stage for female (n = 301) and male (n = 792) spurdog

Figure 30. Relationship between gutted weight and total length in female (n = 301) and male (n = 793) spurdog

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Figure 31. Relationship between gonad weight and total length by maturity stage for female (n = 298) and male (n = 793) spurdog

Table 25. Mean gonad weight (g) and gonadosomatic index (IG) by sex and maturity stage

Mean gonad Gonadosomatic index (IG) Sex Maturity stage N weight (g) Mean SD Min Max A 2.98 0.27 0.09 0.12 0.58 66 B 8.97 0.49 0.15 0.18 0.80 22 C 73.71 2.99 2.24 1.09 12.48 27

D 48.15 1.16 0.42 0.48 2.27 59 E 180.80 3.88 1.29 0.45 7.79 45

Female F 532.94 10.47 1.90 6.06 13.99 56 G 455.84 9.75 3.93 1.35 16.44 22 X (Abnormal) 28.40 0.91 - - - 1 A 1.08 0.19 0.06 0.13 0.26 6 B 6.66 0.79 0.47 0.12 3.04 48

Male C 24.75 1.76 0.69 0.68 7.17 128 D 34.51 2.02 0.42 0.97 4.96 609

The qualitative assignment of maturity stage was based on the visual inspection of reproductive organs (uterus, shell gland and ovaries for females; claspers, testes and degree of coiling in the epididymus in males). Given that there have been several studies purporting changes in length at maturity in elasmobranchs that may not have had standardised approaches to assigning maturity stage, quantitative data were also collected, as this helps validate the assignment of maturity stages. For females, the width of the shell gland in relation to total length (Figure 32) ranged from ca. 1.5 mm in an undeveloped uterus to 28 mm in mature fish. The length of the claspers of male fish are often

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used a standardised approach to quantifying maturity, as shown here for here for outer and inner clasper length (Figure 33).

For females, the number of mature ovarian follicles ranged from two (a specimen at stage D) to 22 (a specimen at stage F), and the maximum follicle diameter for mature follicles for fish at stages C–F ranged from 10.3–55.3 mm. Post-partum females (stage G) had a minimum of five degenerating follicles, and a maximum of 21 mature follicles, with the follicle diameters ranging from 27–59.2 mm.

Figure 32. Relationship between width of the nidamental gland and total length in female spurdog (n = 300)

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Figure 33. Relationship between inner and outer clasper length and total length in male spurdog by maturity stage

To minimise the potential impact of aborted specimens on fecundity estimations, specimens where the difference in the number of pups between uteri was ≥4 (similar to Ellis and Keable, 2008) or with no pups in one of the two uteri were excluded from further analysis (n = 17). For the remaining specimens (n = 85), uterine fecundity ranged from 2–19 (Figure 34), although these values might still underestimate fecundity, as some females may have aborted pups from the uteri. In addition to possible abortion on capture, occasional aborted pups were found in the sample boxes and the maternal origin could not always be determined. Uterine fecundity for females at stage D (the candle stage) could not be estimated in most cases, as the membranes separating the yolks broke down during the freezing process. The total numbers of term pups increased with maternal length (Figure 34), and larger females also produced larger pups, as evident from the relationships between the average length and average weight of term pups in relation to the maternal length (Figure 35).

The fecundity reported here is higher than reported in earlier studies (e.g. Ford, 1921; Holden and Meadows, 1964; Gauld, 1979), and provides further support to the hypothesis that there has been a density-dependent increase in fecundity (see Ellis and Keable, 2008 and references therein).

Stomach contents analysis gave limited data, as a high proportion of fish had stomachs that were either empty or only with a small quantity of fully digested remains. The maximum weight of stomach contents was 528 g and an average weight of ca. 36 g. The main prey species that were recorded included a variety of pelagic fish (mackerel, herring and other clupeids, garfish and horse mackerel), demersal fish (hake, haddock, poor cod, lesser weaver and common dragonet), and cephalopods (Loligo spp., Todaropsis eblanae and Eledone cirrhosa).

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Figure 34. Ovarian (mature follicles) and uterine fecundity (embryos and term pups) in relation to maternal total length (n = 151 and 85, respectively) in spurdog. Some of these fish may have aborted some pups during capture

Figure 35. Average total length (left) and average weight (right) of term pups in relation to maternal total length (n = 49) in spurdog

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4.4 Porbeagle Lamna nasus

There have been several biological investigations on porbeagle shark in the North-east Atlantic (Aasen, 1961; Gauld, 1989; Ellis and Shackley, 1995), yet several important parameters have been lacking, and there has often been a lack of recent life-history information. Recent studies to better understand the movements and behaviour of porbeagle (Bendall et al., 2013 and references therein) have been undertaken. Here, the dead bycatch of porbeagle taken in gillnet fisheries has allowed recent biological samples and new data to be collected. A total of 53 dead specimens (females = 20; males = 33) were retained by participating vessels, and these were examined in February 2015. The following data were collected:

 Total length (tail extended, measured both over and under the body)  Total length (tail in a natural position, measured both over and under the body)  Fork length (measured both over and under the body)  Standard length (measured both over and under the body, measured from the tip of the snout to the origin of the pre-caudal pit)  Sex and maturity  Pre-dorsal length  Girth (anterior to the pectoral fins, and posterior to the first dorsal fin)  Height and length of the first dorsal fin  Pre-oral length  Outer and inner clasper length (males only)  Width of the shell gland (females only)  Total body weight and gutted weight (kg)  Weight of the first dorsal, caudal and pectoral fins (g)  Liver and gonad weight (g)

In addition to these measurements, the following samples were also collected for future analyses

 Samples of muscle and liver to examine contaminant levels (Cefas)  Vertebrae for age determination (Cefas)  Stomach contents for analyses of diets (Cefas and University of East Anglia)  Heads and jaws (provided to the Natural History Museum, London)  Eyes, dorsal muscle and vertebrae for stable isotope research (Southampton University)  Fin clips for genetic studies (samples collected for Aberdeen University and samples also retained by Cefas)  Spiral valves for potential microplastic research (as pelagic predators, it is possible they accumulate microplastics from their prey)  Fins (Cefas and the Shark Trust)  Internal health status bacteriology (Zoological Society London)

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There are various approaches for measuring the sizes of large sharks, and lamnid sharks can be measured as either total length (for which the upper lobe of the caudal fin may be in a natural position, or flexed down to be in line with the main axis of the body), fork length or standard length. Whilst most fisheries sampling use measuring boards for which a straight measure can be recorded, larger fish are sometimes easier to measure with a tape measure over the body, although this then can add the curvature of the body and so exaggerate true length. For the present sample of porbeagle, four length measurements were recorded both under and over the body. The relationships between these different measures showed significant linear relationships, and the parameter for these relationships summarised in Table 26. The measurement of total length with the tail flexed down and measured under the body (LT_under) has been used as the standard unit for analyses here, as recommended by Francis (2006).

All females (119–221 cm) were immature. Males were immature (staged as ‘developing’) over the length range 113–194 cm (n = 21), with larger males (178–218 cm, n = 12) considered mature. The relationship between clasper length (shown here as the inner clasper length, measured from the anterior margin of the cloaca to the posterior tip of the clasper) is shown in Figure 36. The relationships between total and gutted weight with total length are illustrated in Figure 37.

Given the recent prohibited listing for porbeagle, for which MMO cannot give dispensation for dead bycatch to be landed, these samples have provided a unique source of contemporary data. Muscle and liver samples for a sub-sample of the fish are currently being used to examine concentrations of metals, to complement work undertaken in an earlier study (Bendall et al., 2014).

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Table 26. Relationships between alternative length measurements with total length in porbeagle (n = 53), where total length refers to the total length with the upper lobe of the caudal fin flexed down (LT_under) and measured under the body. Relationships given as an equation and in proportional terms (percentage of LT_under).

Measurement Equation r2

Total length (flexed), measured over body (LT_over) LT_over = 1.0279.LT_under – 0.3109 0.99

Total length (natural), measured under body (LN_under) LN_under = 0.9906.LT_under – 3.9749 0.99

Total length (natural), measured over body (LN_over) LN_over = 0.9979.LT_under – 1.0713 0.99

Fork length, measured under body (LF_under) LF_under = 0.877.LT_under – 3.6981 0.99

Fork length, measured over body (LF_over) LF_over = 0.8919.LT_under – 1.4538 0.99

Standard length, measured under body (LS_under) LS_under = 0.7688.LT_under – 2.1165 0.99

Standard length, measured over body (LS_over) LS_over = 0.7849.LT_under – 0.2599 0.99

Measurement % of LT_under (mean ± SD and range)

Total length (flexed), measured over body (LT_over) 102.6 ± 1.31 (100.0–106.7)

Total length (natural), measured under body (LN_under) 96.7 ± 1.72 (91.9–101.9)

Total length (natural), measured over body (LN_over) 99.1 ± 1.82 (95.3–102.6)

Fork length, measured under body (LF_under) 85.5 ± 0.99 (83.3–88.9)

Fork length, measured over body (LF_over) 88.3 ± 1.34 (85.2–92.5) Standard length, measured under body (LS_under) 75.6 ± 1.07 (74.1–79.1) Standard length, measured over body (LS_over) 78.3 ± 1.34 (75.6–82.2)

400

350

300

250

200

150

100 Inner clasper length(mm)

0 50 70 90 110 130 150 170 190 210 230 Total length (cm)

Figure 36. Relationships between inner clasper length (taken as the distance from the anterior margin of the cloaca to the tip of the clasper) for male porbeagle (n = 33) for developing (open circles) and mature (closed circles) fish. Total length refers to total length with the upper lobe of the caudal fin depressed, measured under the body

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(a) 100 y = 1E-05x2.908 80 R² = 0.9634

Total weight (kg) 20

0 50 100 150 200 250 Total length (cm)

(b) 80 y = 7E-06x3.0079 R² = 0.9715 60

20 Guttedweight (kg)

0 50 100 150 200 250 Total length (cm)

Figure 37. Length-weight relationships for porbeagle (n = 53) for (a) total weight and (b) gutted weight. Total length refers to total length with the upper lobe of the caudal fin depressed, measured under the body

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4.5 Other biological investigations

This section provides the abstracts of four other working documents presented to the ICES WGEF providing biological information on elasmobranch fish.

4.5.1 Summary results from opportunistic tagging programmes for smooth-hound Mustelus spp., greater-spotted dogfish Scyliorhinus stellaris and tope Galeorhinus galeus around the British Isles

Since 2000, research vessel groundfish surveys and other field programmes have been used as platforms to opportunistically tag and release various elasmobranch species, including smooth- hounds Mustelus spp. (n = 717), greater-spotted dogfish Scyliorhinus stellaris (n = 567) and tope Galeorhinus galeus (n = 159). Additional opportunities during Fishery Science Partnership (FSP) and Defra-funded research projects that targeted other elasmobranch species have also been used to tag these species. Overall, 74% of the releases were from groundfish surveys. Most specimens were tagged and released with Petersen disc and were tagged around much of the British Isles, although the greatest tagging activity occurred in the Irish Sea, Celtic Sea and, to a lesser extent, the western English Channel and southern North Sea. The overall return rate was relatively low (1.6%), and to date a total of 24 fish were returned (eight greater-spotted dogfish, four tope and 12 smooth-hounds). Nevertheless, the recaptured fish were at liberty for a total 9568 days. Although the number of returns was limited, useful information was obtained about their biology and behaviour that would not have been realised if it was not for the programme. In general, greater-spotted dogfish were recaptured close to their release positions, and there was no indication of mixing between the western English Channel and Irish Sea. In contrast, tope and smooth-hounds travelled further and there was mixing between the North Sea and Celtic Seas ecoregions. The greatest time at liberty for an individual fish was for a 2403 days for a tope, and the furthest that a fish had travelled was 408 km, which was for a smooth-hound that had travelled from the western English Channel to the southern North Sea in 73 days, recording the highest average daily speed of 5.6 km/day.15

15 Burt, G. J., Silva, J. F., McCully, S. R., Bendall, V.A. and Ellis, J. R. 2013. Summary results from opportunistic tagging programmes for smooth-hound Mustelus spp., greater-spotted dogfish Scyliorhinus stellaris and tope Galeorhinus galeus around the British Isles. Working Document to the ICES Working Group on Elasmobranch Fishes, Lisbon, June 17–21 2013; 12 pp.

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4.5.2 A global review of elasmobranch discard survival studies and implications in relation to the EU ‘discard ban’

There is a need to better understand the survivorship of discarded fish, both for commercial stocks and species of management concern. The landing obligations that are currently being phased in as part of the European Union’s reformed Common Fisheries Policy means that an increasing number of fish stocks, with certain exceptions, should not be discarded unless it can be demonstrated that there is a high probability of survival. This working document reviews various approaches which can be used to examine the discard survival of elasmobranchs (in terms of at-vessel mortality and post-release mortality), with relevant findings summarised by the main fishing gears used. Discard survival varies with biological attributes (e.g. species, size, sex and mode of gill ventilation) as well as variety of factors associated with capture (e.g. gear type, soak time, catch weight and composition, handing practices and temperature). In general, demersal species with buccal-pump ventilation have a higher survival than obligate ram ventilators; some studies indicate that females may have a higher survival than males; and it is apparent that some taxa (e.g. hammerhead sharks Sphyrna spp. and thresher sharks Alopias spp.) are prone to high rates of mortality when caught.16

4.5.3 Bycatch and discarding patterns of dogfish, sharks and catsharks taken in commercial fisheries around the British Isles

The discard and retention patterns of dogfish, sharks and catsharks taken as a bycatch in UK commercial fisheries were examined. Data were collected primarily on English vessels fishing on the continental shelf of the North Sea ecoregion (ICES Divisions IV a–c, VIId) and Celtic Seas ecoregion (ICES Divisions VIa, VIIa–c,e–k). Vessels examined represented four main gear types (otter, beam and Nephrops trawls, and gillnet), with only limited data available for longline and mid-water trawl. Beam trawlers generally captured proportionally more small (juvenile) dogfish and catsharks than otter trawlers. Gillnets were the most size selective gear. Data on the elasmobranch catches from Nephrops trawlers were frequently too limited to draw an accurate discard/retention pattern, which may reflect a low catchability of sharks by this gear and/or that elasmobranchs are not abundant on these muddy fishing grounds. In general, juvenile sharks (Triakidae and Squalidae) were usually discarded, and

16 Ellis, J. R., McCully, S. R. and Poisson, F. 2014. A global review of elasmobranch discard survival studies and implications in relation to the EU ‘discard ban’. Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 48 pp.

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larger fish retained, whilst catsharks (Scyliorhinidae) were generally discarded. Discarding patterns are discussed in relation to recent changes in management regulations.17

4.5.4 Demersal elasmobranchs in the western English Channel (ICES Division VIIe)

In 2006 a new Cefas beam trawl survey was initiated in the western English Channel to provide information on sole Solea solea and plaice Pleuronectes platessa, as well as providing information on other demersal fish and ecosystem components. The western English Channel is an important area for a number of demersal elasmobranchs, with species of interest including undulate ray Raja undulata, which is locally abundant and, prior to their prohibited status, was an important commercial species in some inshore areas. This study presents preliminary results on the spatial distribution and size frequency for all dogfish, catsharks, skates and rays encountered during 2006–2014. Results indicated that species including common skate Dipturus batis-complex, cuckoo ray Leucoraja naevus, thornback ray Raja clavata and undulate ray showed persistent association with specific sites, with lesser- spotted dogfish Scyliorhinus canicula and smooth-hounds Mustelus spp. distributed over much of the survey grid. Juvenile skates were routinely caught, as beam trawls are more selective for smaller fish. Mature specimens of the smaller bodied skate species, such as cuckoo ray, were also represented in the catch, while fewer mature specimens of the larger bodied skate species (e.g. undulate, blonde and thornback ray) were observed.18

17 Silva, J. F., Ellis, J. R., Catchpole, T. L. and Righton, D. 2013. Bycatch and discarding patterns of dogfish and sharks taken in commercial fisheries around the British Isles. Working Document to the ICES Working Group on Elasmobranch Fishes, Lisbon, June 17–21 2013; 31 pp.

18 Silva, J. F., McCully, S. R., Ellis, J. R. and Kupschus, S. 2014. Demersal elasmobranchs in the western English Channel (ICES Division VIIe). Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 28 pp.

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5 Concluding remarks

The reformed Common Fisheries Policy has clear objectives with regards the status of our marine resources. It states that “the exploitation of marine biological resources restores and maintains populations of harvested stocks above levels that can produce the maximum sustainable yield … by 2015 (and) ... no later than 2020”, that “An ecosystem-based approach to fisheries management needs to be implemented” and that management of our fisheries should be coherent with European biodiversity targets. In terms of fisheries management, it also highlights that “Technical measures may include… Requirements for fishing vessels to cease operating in a defined area for a defined minimum period in order to protect temporary aggregations of endangered species, spawning fish, fish below minimum conservation reference size, and other vulnerable marine resources”.

Elasmobranchs feature among our more vulnerable fish species, and so there is increasing interest in this group of fish from conservation bodies and the public. Whilst fisheries scientists have highlighted the need for improved management of these stocks for several decades, management at a European level has evolved slowly. For example, although a TAC for skates in the North Sea was first established in 1999, catch limits for skates were only established for other areas in 2009. Similarly the TAC and associated management of spurdog, initiated from 2000, may only have become restrictive since 2007 (De Oliveira et al., 2013).

Given a history of over-exploitation and lack of management actions, some of the elasmobranchs of northern Europe have shown signs indicative of near-extirpation (e.g. angel shark and white skate) whilst others have shown marked declines in either geographic distribution (e.g. common skate complex) or population size, as seen in spurdog (Brander, 1981; Rogers and Ellis, 2000; Ellis et al., 2010). In contrast, however, it is important to also note that several stocks of demersal elasmobranchs have shown recent increases in relative abundance.

There are many limitations to the data that are available for elasmobranchs. Much of the historical landings data were not species-specific, some data confound multiple species, and species- misidentifications are a common occurrence in both landings and observer data. Whilst data quality appears to be improving, much of the data are of too restrictive a time series to inform the types of assessment that are undertaken routinely for many of our teleost stocks. Against this background,

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there are two important sources of information that have been used to inform management advice; fishery-independent survey data and biological information.

Trawl surveys, primarily those coordinated under the auspices of the ICES Working Group on Beam Trawl Surveys (WGBEAM) and the International Bottom Trawl Survey Working Group (IBTSWG), have provided data to support the advice on stock status for several of the smaller-bodied and more frequently encountered demersal elasmobranchs. Data from existing trawl surveys could usefully be further investigated to better understand the temporal dynamics of the demersal elasmobranch assemblage, especially to inform how environmental parameters and multispecies interactions may influence the interpretation of the ‘traditional’ single-species assessments and advice provided by ICES. However, more targeted surveys, including work with the fishing industry and studies to improve our biological knowledge, are needed to underpin any advice for those species not sampled effectively in surveys, as shown recently for undulate ray Raja undulata (Ellis et al., 2012a; STECF, 2015).

The current project has supported a proportion of our ongoing and continuing work on elasmobranch fish, and will provide data for use in future meetings of the ICES WGEF, further peer-reviewed publications and other studies, thereby supporting the development of biologically-meaningful assessments and management.

The current project has compiled an up-to-date inventory of the elasmobranch and holocephalan fishes of the British Isles and adjacent areas. Whilst some earlier studies have identified data gaps, these works have only considered a subset of species (e.g. those species listed on conservation instruments). A more holistic prioritisation exercise to consider all species in a consistent approach, as also undertaken by the IUCN’s Shark Specialist Group, has enabled species to be ranked incorporating their commercial importance, conservation interest, biological characteristics and the relative importance of British waters to the species. This approach clearly ranked many of the known threatened species highly (e.g. angel shark and flapper skate), but commercial species of less conservation interest would also rank quite highly. Whilst the status of some of these species may be gauged by existing surveys, some species that ranked quite highly, such as starry smooth-hound and blonde ray, are not sampled effectively in existing surveys and the status of such species is somewhat uncertain.

Whilst such approaches have the benefits of including all species, it does means that they are invariably more qualitative, as many data-limited stocks are included. Such approaches can be

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developed further using Productivity-Susceptibility Analyses and, as PSAs are best applied for specified fisheries, a more defined suite of fish can be included and the approaches start to become more quantitative.

PSAs were undertaken for the elasmobranch fish taken in ‘otter trawl’ and ‘gillnet’ fisheries in the Celtic Sea, and this enabled novel approaches, such as the inclusion of expert opinion and modelling confidence scoring, to be trialled and applied. The outputs of the PSA, as could be expected, ranked many of the species currently under very conservative management as the most vulnerable. Similarly, those species for which the stock status is thought to be no cause for concern ranked as least vulnerable. Several of the intermediate species, which are relatively vulnerable, are often data limited stocks. It will become increasingly important to evaluate the status of such species in the future.

Fisheries in the Celtic Sea are known to encounter several of the species of conservation interest, particularly some of the larger netters that deploy both gillnets (in which spurdog and porbeagle can be an important bycatch) and tangle nets, which are highly effective at catching batoids, including common skate.

A pilot project to allow fishers to help collect data on these vessels was initiated, as coverage of observer programmes is often limited and so risks missing some of the potential seasonality. The type and quality of data that fishers can collect at sea is variable. Vessels deploying smaller amounts of nets catch fewer fish, and so more quantitative data can be collected. In contrast, vessels encountering large quantities of fish invariably risk having more variability in the quality of additional data that are recorded. Another issue related to vessels operating with net is estimating ‘fishing effort’, as the numbers of nets and soak times may not always be recorded accurately, and it is not generally known where gear damage (which would then affect overall catches) has occurred. For the present study, the catches of species of concern have been related as a function of the reported weight of the main target species. The pilot project was only based on three vessels operating over 5–10 months, and so these data have not been raised to reported landings of the target species by the gears in question.

Data collected by commercial fishers in this study (see Section 3.6), and from previous Defra-funded projects (e.g. Ellis et al., 2008, 2012b), have indicated that at-vessel mortality can be relatively low for some elasmobranchs and there are also some data regarding their short-term survival (Catchpole et al., 2007). Whilst there are an increasing number of studies from around the world on the longer-term

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post-release mortality of elasmobranchs (see Section 4.5.2), further studies may be required if derogations from the landings obligation are to be sought.

The pilot project also allowed vessels to retain and land (for scientific study only) specimens of spurdog and porbeagle. Catches of spurdog in trawl surveys are sporadic, and so biologically meaningful sample sizes cannot be collected over a short time. Whilst there have been several studies on the biology of spurdog over the last century (see Ellis and Keable, 2008, and references therein), recent studies have been more limited. Contemporary biological data were collected for over 1 000 specimens. The data presented here focused on reproductive parameters, but spines and vertebrae were also collected, and future studies could usefully reappraise age and growth parameters. Cefas also have a large collection of spines collected from the 1960s (which could be used to examine temporal changes in growth parameters) and have also collected spines from dead spurdog caught in ground fish surveys, including smaller fish.

Starry smooth-hound ranked quite highly in the prioritisation exercise and was one of the more vulnerable species in the PSA. Despite increased exploitation of this species, there is currently no management for this species. The increased landings of starry smooth-hound has allowed cost- effective data collection for this species, with a full range of biological parameters to be collected for the stock. These data (length at maturity, fecundity at length) will be important input parameters for future stock assessments undertaken in the ICES community.

Previous work undertaken by members of the project team have indicated that several published studies purporting a decreased length at maturity for elasmobranchs (which are claimed to relate to the impacts of fishing) may simply be artefacts due to inconsistent use of maturity keys and misinterpretation of maturity data. It is increasingly important that biological studies provide more robust estimates of life history parameters using better defined keys and improved quantification of reproductive stages.

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6 Acknowledgments

We gratefully acknowledge the continued support of the Department for Environment, Food and Rural Affairs towards elasmobranch research. We thank the Project Steering Group for their support and input, including Carole Kelly, Kirsty McGregor and Jamie Rendell (Defra), Paul Trebilcock (CFPO), Clare Bowers (MMO), Ali Hood (Shark Trust) and Matthew Gollock (Zoological Society of London). The project benefitted greatly from the assistance of the owners, skippers and crews of the vessels that assisted with the project and provided data and specimens. The following Cefas staff assisted with biological sampling: Dave Brown, Gary Burt, Scott Davis, Matt Eade, Rebecca Faulkner, Denise Goldsmith, Charlotte Jennings, Thomas Maes, Peter Randall, Ainsley Riley, Joanne Smith, Camilla Sguotti and Nicola Travell. Additional thanks to our national and international colleagues, including Oliver Crimmen (Natural History Museums, London), Guzman Diez (AZTI), Edward Farrell (University College Dublin), Graham Johnston (Marine Institute), and Bernard Séret (Muséum national d'Histoire naturelle, Paris), for their assistance. David Righton (Cefas) and the anonymous reviewer provided valuable comments on the report.

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7 References

Aasen, O. 1961. Some observations on the biology of the porbeagle shark (Lamna nasus). ICES CM Near Northern Seas Committee, No. 109: 7pp. Arlinghaus, R., Cooke, S. J. and Cowx, I. G. 2010. Providing context to the global code of practice for recreational fisheries. Fisheries Management and Ecology, 17: 146–156. Arrizabalaga, H., De Bruyn, P., Diaz, G.A., Murua, H., Chavance, P., De Molina, A. D., Gaertner, D., Ariz, J., Ruiz, J. and Kell, L. T. 2011. Productivity and susceptibility analysis for species caught in Atlantic tuna fisheries. Aquatic Living Resources, 24: 1–12. Bendall, V. A., Hetherington, S. J., Ellis, J. R., Smith, S. F., Ives, M. J., Gregson, J. and Riley, A. A. 2012. Spurdog, porbeagle and common skate bycatch and discard reduction. Fisheries Science Partnership 2011–2012, Final Report. 88 pp. Bendall, V., Ellis, J. R., Hetherington, S. J., McCully, S. R., Righton, D. and Silva, J. F. 2013. Preliminary observations on the biology and movements of porbeagle Lamna nasus around the British Isles. Collective Volume of Scientific Papers ICCAT, 69: 1702–1722. Bendall, V.A., Barber, J. L., Papachlimitzou, A., Bolam, T., Warford, L., Hetherington, S. J., Silva, J. F., McCully, S. R., Losada, S., Maes, T., Ellis, J. R. and Law, R. J. 2014 Organohalogen contaminants and trace metals in North-East Atlantic porbeagle shark (Lamna nasus). Marine Pollution Bulletin, 85: 280–286. Berkson, J., Barbieri, L., Cadrin, S., Cass-Calay, S. L., Crone, P., Dorn, M., Friess, C., Kobayashi, D., Miller, T. J., Patrick, W. S., Pautzke, S., Ralston, S. and Trianni, M. 2011. Calculating Acceptable Biological Catch for stocks that have reliable catch data only (Only Reliable Catch Stocks – ORCS). NOAA Technical Memorandum NMFS-SEFSC-616, 56 pp. Burt, G. J., Silva, J. F., McCully, S. R., Bendall, V. A. and Ellis, J. R. 2013. Summary results from opportunistic tagging programmes for smooth-hound Mustelus spp., greater-spotted dogfish Scyliorhinus stellaris and tope Galeorhinus galeus around the British Isles. Working Document to the ICES Working Group on Elasmobranch Fishes, Lisbon, June 17–21 2013; 12 pp. Campbell, L. M. and Cornwell, M. L. 2008. Human dimensions of bycatch reduction technology: current assumptions and directions for future research. Endangered Species Research, 5: 325–334. Capapé, C. 1983. Nouvelles données sur la biologie de la reproduction de Mustelus asterias Cloquet, 1821 (Pisces, Pleurotremata, Triakidae) des côtes Tunisiennes. Vie et Milieu, 33: 143–152. Carmichael, J. and Fenske, K. (Eds.). 2011. Third National Meeting of the Regional Fisheries Management Councils’ Scientific and Statistical Committees. Report of a National SSC Workshop on ABC Control Rule Implementation and Peer Review Procedures. South Atlantic Fishery Management Council, Charleston, October 19–21, 2010. Catchpole, T. L., Enever, R. and Doran, S. 2007. Bristol Channel ray survival. Cefas Fisheries Science Partnership 2007/2008, Programme 21, Final Report, 15 pp. CEC. 2009. On a European Community Action Plan for the Conservation and Management of Sharks. Brussels, 5.2.2009, COM(2009) 40 final, 15 pp. (Available from: http://eur-lex.europa.eu/legal- content/EN/TXT/PDF/?uri=CELEX:52009DC0040&from=EN) CEC. 2013. Regulation (EU) No 1380/2013 of the European Parliament and of the Council of 11 December 2013 on the Common Fisheries Policy, amending Council Regulations (EC) No 1954/2003 and (EC) No 1224/2009 and repealing Council Regulations (EC) No 2371/2002 and (EC) No 639/2004 and Council Decision 2004/585/EC. Official Journal of the European Union, L 354: 22–61. Chevolot, M., Ellis J. R., Hoarau, G., Rijnsdorp, A. D., Stam W. T. and Olsen J. L. 2006. Population structure of the thornback ray (Raja clavata) in British waters. Journal of Sea Research, 56: 305– 316. Cortés, E., Arocha, F., Beerkircher, L., Carvalho, F., Domingo, A., Heupel, M., Holtzhausen, H., Santos, M. N., Ribera, M. and Simpfendorfer, C. 2010. Ecological risk assessment of pelagic sharks caught in Atlantic pelagic longline fisheries. Aquatic Living Resources, 23: 25–34.

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De Oliveira, J. A. A., Ellis, J. R. and Dobby, H. 2013. A stock assessment model for Northeast Atlantic spurdog, incorporating fecundity data to estimate the extent of density dependence in pup production. ICES Journal of Marine Science, 70: 1341–1353. Defra. 2011. Shark, Skate and Ray Conservation Plan. Defra, 14 pp. (Available from: http://archive.defra.gov.uk/environment/marine/documents/interim2/shark-conservation-plan.pdf) Dransfeld, L., Gerritsen, H. D., Hareide, N. R. and Lorance, P. 2013. Assessing the risk of vulnerable species exposure to deepwater trawl fisheries: the case of orange roughy Hoplostethus atlanticus to the west of Ireland and Britain. Aquatic Living Resources, 26: 307–318. Edwards, A. J. and Davis, P. S. 1987. Pisces. In: Directory of the British Marine Fauna and Flora (C.M. Howson, ed.), pp. 321–343. Marine Conservation Society, Ross-on-Wye. 471 pp. Ellis, J. R. and Keable, J. 2008. The fecundity of Northeast Atlantic spurdog (Squalus acanthias L., 1758). ICES Journal of Marine Science, 65: 979–981. Ellis, J. R. and Shackley, S. E. 1995. Notes on porbeagle sharks, Lamna nasus, from the Bristol Channel. Journal of Fish Biology, 46: 368–370. Ellis, J. R., Burt, G. J. and Cox, L. P. N. 2008. Thames ray tagging and survival. Cefas Fisheries Science Partnership 2007/2008, Programme 19, Final Report, 54 pp. Ellis, J. R., Clarke, M. W., Cortés, E., Heessen, H. J. L., Apostolaki, P., Carlson, J. K. and Kulka, D. W. 2008. Management of elasmobranch fisheries in the North Atlantic. In: Advances in Fisheries Science. 50 years on from Beverton and Holt (A.I.L. Payne, A.J. Cotter and E.C.E. Potter, eds.), pp. 184–228. Blackwell Publishing, Oxford. xxi + 547 pp. Ellis, J. R., Cruz-Martinez, A., Rackham, B. D. and Rogers, S. I. 2005a. The distribution of chondrichthyan fishes around the British Isles and implications for conservation. Journal of Northwest Atlantic Fishery Science, 35: 195–213. Ellis, J. R., Doran, S., Dunlin, G., Hetherington, S., Keable, J. and Skea, N. 2010. Spurdog in the Irish Sea. Cefas Fisheries Science Partnership 2008/2009, Programme 9, Final Report, 28 pp. Ellis, J. R., Dulvy, N. K., Jennings, S., Parker-Humphreys, M. and Rogers, S. I. 2005b. Assessing the status of demersal elasmobranchs in UK waters: A review. Journal of the Marine Biological Association of the United Kingdom, 85: 1025–1047. Ellis, J. R., McCully, S. R. and Poisson, F. 2014. A global review of elasmobranch discard survival studies and implications in relation to the EU ‘discard ban’. Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 48 pp. Ellis, J.R., McCully, S. R. and Brown, M.J. 2012a. An overview of the biology and status of undulate ray Raja undulata. Journal of Fish Biology, 80: 1057–1074. Ellis, J. R., McCully, S. R., Silva, J. F., Catchpole, T. L., Goldsmith, D., Bendall, V. and Burt G. 2012b. Assessing discard mortality of commercially caught skates (Rajidae) – validation of experimental results. Report to Defra, 142 pp. Ellis, J. R., Silva, J. F., McCully, S. R., Evans, M. and Catchpole, T. 2010. UK fisheries for skates (Rajidae): History and development of the fishery, recent management actions and survivorship of discards. ICES CM 2010/E:10, 38 pp. FAO. 1995. Code of Conduct for Responsible Fisheries. FAO, Rome. FAO. 1999. International Plan of Action for reducing incidental catch of seabirds in longline fisheries. International Plan of Action for the conservation and management of sharks. International Plan of Action for the management of fishing capacity. FAO, Rome, 26 pp. Farrell, E. D., Mariani, S. and Clarke, M. W. 2010a. Reproductive biology of the starry smooth-hound shark Mustelus asterias: Geographic variation and implications for sustainable exploitation. Journal of Fish Biology, 77: 1505–1525. Farrell, E. D., Mariani, S. and Clarke, M. W. 2010b. Age and growth estimates for the starry smoothhound (Mustelus asterias) in the northeast Atlantic Ocean. ICES Journal of Marine Science, 67: 931–939. Fletcher, W. J. 2005. The application of qualitative risk assessment methodology to prioritise issues for fisheries management. ICES Journal of Marine Science, 62: 1576–1587.

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Ford, E. 1921. A contribution to our knowledge of the life-histories of the dogfishes landed at Plymouth. Journal of the Marine Biological Association of the UK, 12: 468–505. Fowler, S., Mogensen, C. B. and Blasdale, T. 2004. Plan of Action for the conservation and management of sharks in UK waters. JNCC Report, No. 360, 66 pp. (Available from: http://jncc.defra.gov.uk/pdf/jncc360.pdf) Francis, M. P. 2006. Morphometric minefields - towards a measurement standard for chondrichthyan fishes. Environmental Biology of Fishes, 77: 407–421. Gallagher, A.J., Kyne, P.M. and Hammerschlag, N. 2012. Ecological risk assessment and its application to elasmobranch conservation and management. Journal of Fish Biology, 80: 1727–1748. Gauld, J. A. 1979. Reproduction and fecundity of the Scottish Norwegian stock of spurdogs, Squalus acanthias (L.). ICES Document CM 1979/H: 54. 15 pp. Gauld, J. A. 1989. Records of porbeagles landed in Scotland, with observations on the biology, distribution and exploitation of the species. Scottish Fisheries Research Report, 45: 15 pp. George, M. R. 2009. An annotated checklist of North Sea cartilaginous fish species. Journal of Applied Ichthyology, 25: 33–39. Gibson, C., Valenti, S. V., Fordham, S. V. and Fowler, S. L. 2008. The conservation of Northeast Atlantic Chondrichthyans. Report of the IUCN Shark Specialist Group Northeast Atlantic Red List Workshop; viii + 76 pp. Griffiths, A.M., Sims, D.W., Cotterell, S.P., El Nagar, A., Ellis, J.R., Lynghammar, A., McHugh, M., Neat, F.C., Pade, N.G., Queiroz, N., Serra-Pereira, B., Rapp, T., Wearmouth V.J., and Genner, M.J. 2010. Molecular markers reveal spatially segregated cryptic species in a critically endangered fish, the common skate (Dipturus batis). Proceedings of the Royal Society B. 277: 1497–1503. Griffiths, S., Brewer, D., Heales, D., Milton, D. and Stobutzki, I., 2006. Validating ecological risk assessments for fisheries: assessing the impacts of turtle excluder devices on elasmobranch bycatch populations in an Australian trawl fishery. Marine and Freshwater Research, 57: 395–401. Hetherington, S.J., Bendall, V. A. and Forster, R. In Prep. Science and fishery collaboration to understand incidental bycatch of elasmobranchs. Hiscock, K., Bayley, D., Pade, N., Cox, E. and Lacey, C. 2011. A recovery / conservation programme for marine species of conservation importance. Natural England Commissioned Reports, Number 065, xi + 229 pp. (Available from http://publications.naturalengland.org.uk/publication/188085) Hiscock, K., Bayley, D., Pade, N., Lacey, C., Cox, E., and Enever, R. 2013. Prioritizing action for recovery and conservation of marine species: a case study based on species of conservation importance around England. Aquatic Conservation: Marine and Freshwater Ecosystems, 23: 88–110. Hobday, A. J., Smith, A. D. M., Stobutzki, I. C., Bulman, C., Daley, R., Dambacher, J. M., Deng, R. A., Dowdney, J., Fuller, M., Furlani, D., Griffiths, S. P., Johnson, D., Kenyon, R., Knuckey, I. A., Ling, S. D., Pitcher, R., Sainsbury, K. J., Sporcic, M., Smith, T., Turnbull, C., Walker, T. I., Wayte, S. E., Webb, H., Williams, A., Wise, B. S. and Zhou, S. 2011. Ecological risk assessment for the effects of fishing. Fisheries Research, 108: 372–384. Holden, M. J. 1974. Problems in the rational exploitation of elasmobranch populations and some suggested solutions. In: Sea Fisheries Research (F. R. Harden-Jones, ed.). Paul Elek (Scientific Books) Ltd, London, pp. 117–137. Holden, M. J., and Meadows, P. S. 1964. The fecundity of the spurdog (Squalus acanthias L.). Journal du Conseil Permanent International pour l’Exploration de la Mer, 28: 418–424. ICES. 2013. Report of the Working Group on Elasmobranch Fishes (WGEF), 17–21 June 2013, Lisbon, Portugal. ICES CM 2013/ACOM:19; 649 pp. ICES. 2014a. Skates and rays in Subareas VI and VII (Celtic Sea and west of Scotland). ICES Advice 2014, Book 5, Section 5.3.29; 26 pp. ICES. 2014b Spurdog (Squalus acanthias) in the Northeast Atlantic. ICES Advice 2014, Book 9, Section 9.3.26; 9 pp.

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Iglésias, S. P., Toulhoat, L. and Sellos, D. Y. 2010. Taxonomic confusion and market mislabelling of threatened skates: important consequences for their conservation status. Aquatic Conservation: Marine and Freshwater Ecosystems, 20: 319–333. Jones, E. and Francis, M. 2012. Protected rays – occurrence and development of mitigation methods in the New Zealand tuna purse seine fishery. National Institute of Water and Atmospheric Research Ltd (NIWA); Client report prepared for the Department of Conservation, Contract Number 4352, ii + 37 pp. McCully Phillips, S. R., Scott, F. and Ellis, J. R. 2015. Having Confidence in Productivity Susceptibility Analyses: A method for Underpinning Scientific Advice on Skate Stocks? Fisheries Research, 171, 87-100. McCully, S. R., Burt, G. J., Silva, J. F. and Ellis, J. R. 2013. Monitoring thornback ray movements and assessing stock levels. Centre for Environment, Fisheries and Aquaculture Science (Lowestoft), Fishery Science Partnership, Programme 35, 33 pp. McCully, S. R., Scott F. and Ellis J. R. 2012a. Length at maturity and conversion factors for skates (Rajidae) around the British Isles, with a critique of earlier studies. ICES Journal of Marine Science, 69: 1812–1822. McCully, S. R., Scott, F., Ellis, J. R., Pilling, G. M., 2012b. Productivity and Susceptibility Analysis: application and suitability for data poor assessment of elasmobranchs in northern European Seas. Collective Volume of Scientific Papers ICCAT 69, 1679–1698. Metcalfe, J. D. 2009. Welfare in wild-capture marine fisheries. Journal of Fish Biology, 75: 2855–2861. Patrick, W. S., Spencer, P., Ormseth, O., Cope, J., Field, J., Kobayashi, D., Gedamke, T., Cortés, E., Bigelow, K., Overholtz, W., Link, J. and Lawson, P. 2009. Use of productivity and susceptibility indices to determine stock vulnerability, with example applications to six U.S. fisheries. US Department of Commerce, NOAA Tech. Memo. NMFS-F/SPO-101, 90 pp. Pawson, M. G. and Ellis, J. R. 2005. Stock identity of elasmobranchs in the North-east Atlantic in relation to assessment and management. Journal of Northwest Atlantic Fishery Science, 35: 173– 193. Pelletier, C., Hanson, K. C. and Cooke, S. J. 2007. Do catch-and-release guidelines from state and provincial fisheries agencies in North America conform to scientifically based best practices? Environmental Management, 39: 760–773. Poisson, F., Séret, B., Vernet, A. L., Goujon, M. and Dagorn, L. 2014. Collaborative research: Development of a manual on elasmobranch handling and release best practices in tropical tuna purse-seine fisheries. Marine Policy, 44: 312–320. Rogers, S. I. and Ellis, J. R. 2000. Changes in the demersal fish assemblages of British coastal waters during the 20th century. ICES Journal of Marine Science, 57: 866–881. Simpfendorfer, C., Cortés, E., Heupel, M., Brooks, E., Babcock, E., Baum, J., McAuley, R., Dudley, S., Stevens, J. D., Fordham, S. and Soldo, A. 2008. An integrated approach to determining the risk of over-exploitation for data-poor pelagic Atlantic sharks. Expert Working Group Report, ICCAT. STECF. 2015. Possible by-catch provisions for undulate ray in ICES areas VIIde, VIIIab and IX (STECF-15- 03). Publications Office of the European Union, Luxembourg, JRC, 61 pp. Stobutzki, I. C., Miller, M. J., Heales, D. S. and Brewer, D. T. 2002. Sustainability of elasmobranchs caught as by-catch in a tropical prawn (shrimp) trawl fishery. Fishery Bulletin, 100: 800–821. Watling, L., Haedrich, R. L., Devine, J., Drazen, J., Dunn, M. R., Gianni, M., Baker, K., Cailliet, G., Figueiredo, I., Kyne, P.M., Menezes, G., Neat, F., Orlov, A., Duran, P., Perez, J. A., Ardron, J. A., Bezaury, J., Revenga, C. and Nouvian, C. 2011. Can ecosystem-based deep-sea fishing be sustained? Report of a workshop held 31 August-3 September 2010. Walpole, ME: University of Maine, Darling Marine Center. Darling Marine Center Special Publication 11-1. 84 pp. (http://digitalcommons.library.umaine.edu/sms_facpub/145/). Wheeler, A. 1992. A list of the common and scientific names of fishes of the British Isles. Journal of Fish Biology, 41 (Supplement A): 1–37

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Wheeler, A. C., Merrett, N. R. and Quigley, D. T. G. 2004. Additional records and notes for Wheeler’s (1992) list of the common and scientific names of fishes of the British Isles. Journal of Fish Biology, 65 (Supplement B) iii + 40 pp.

Electronic references:

Australian Fisheries Management Authority 2014. Shark and ray handling practices: A guide for commercial fishers in Southern Australia. Australian Fisheries Management Authority, Commonwealth of Australia, Canberra, p. 28. Available at http://www.afma.gov.au/shark-handling- guide/

Eschmeyer, W.N. (ed). Catalog of Fishes. California Academy of Sciences (http://research.calacademy.org/research/ichthyology/catalog/fishcatmain.asp). Electronic version accessed 01/08/2012.

Poisson, F., Vernet, A. L., Séret, B. and Dagorn, L. 2012. Good practices to reduce the mortality of sharks and rays caught incidentally by the tropical tuna purse seiners. Available at https://www.wcpfc.int/node/3282

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8 Annexes

8.1 List of acronyms

BTS Beam Trawl Survey CITES Convention on International Trade in Endangered Species of Wild Fauna and Flora CFP Common Fishery Policy CFPO Cornish Fish Producers Organisation CPOA Community Plan of Action CPUE Catch per unit effort Defra Department for Environment, Food and Rural Affairs EC / EU European Commission / European Union ERA Ecological Risk Assessment FAO Food and Agriculture Organisation FV Fishing Vessel GOV Grande Ouverture Verticale (trawl) IBTS International Bottom Trawl Survey ICES International Council for the Exploration of the Seas IFCA Inshore Fisheries and Conservation Authority IPOA International Plan of Action IUCN International Union for Conservation of Nature LOA Length Overall MLL Maximum landing length MLS Minimum landing size MMO Marine Management Organisation MPA Marine Protected Area MSY Maximum Sustainable Yield NOAA National Oceanic and Atmospheric Administration NWWAC North Western Waters Advisory Council PSA Productivity Susceptibility Analysis RV Research Vessel SFC Sea Fishery Committee STECF Scientific, Technical and Economic Committee for Fisheries TAC Total Allowable Catch WGEF Working Group on Elasmobranch Fishes

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8.2 Outputs from project and associated work

During the period 2013–2015, Cefas scientists contributed to the following outputs in relation to elasmobranch fish. These outputs have been supported by Defra-funding through various projects, including MA funding and the NEPTUNE project (MB5201). Members of the project team also contributed to several of the species accounts drafted during the European elasmobranch Red List Workshop (Plymouth, 12–15 May 2014; see Nieto et al., 2015). Members of the project team also contributed to all chapters related to chondrichthyan fish in the ‘Fish atlas of the Celtic Sea, North Sea, and Baltic Sea’ (Heessen et al., 2015)

(a) Peer-reviewed publications

De Oliveira, J. A. A., Ellis, J. R. and Dobby, H. 2013. A stock assessment model for Northeast Atlantic spurdog, incorporating fecundity data to estimate the extent of density dependence in pup production. ICES Journal of Marine Science, 70: 1341–1353. Available from: http://icesjms.oxfordjournals.org/content/70/7/1341.full

Gubili, C., Sims, D. W., Veríssimo, A., Domenici, P., Ellis, J., Grigoriou, P., Johnson, A. F., McHugh, M., Neat, F., Satta, A., Scarcella, G., Serra-Pereira, B., Soldo, A., Genner, M. J. and Griffiths, A. M. 2014. A tale of two seas: Contrasting patterns of population structure in the small-spotted catshark across Europe. Royal Society Open Science, 1: 140175; 18 pp. Available from: http://rsos.royalsocietypublishing.org/content/1/3/140175

McCully Phillips, S. R., Scott, F. and Ellis, J. R. 2015. Having confidence in Productivity Susceptibility Analyses: A method for underpinning scientific advice on skate stocks? Fisheries Research, 171: 87– 100. Available from: http://www.sciencedirect.com/science/article/pii/S016578361500017X

McCully Phillips, S. R. and Ellis, J. R. 2015. Reproductive characteristics and other life history parameters starry smooth-hound Mustelus asterias in British waters. Journal of Fish Biology, 87: 1411– 1433. Available from: http://onlinelibrary.wiley.com/doi/10.1111/jfb.12826/full

(b) Other publications

Bendall, V., Ellis, J. R., Hetherington, S. J., McCully, S. R., Righton, D. and Silva, J. F. (2013). Preliminary observations on the biology and movements of porbeagle Lamna nasus around the British Isles. Collective Volume of Scientific Papers ICCAT, 69: 1702–1722. Available from: http://www.iccat.int/Documents/CVSP/CV069_2013/n_4/CV069041702.pdf

Heessen, H. J. L., Daan, N. and Ellis, J. R. (Eds.) (2015). Fish atlas of the Celtic Sea, North Sea, and Baltic Sea. Wageningen Academic Publishers / KNNV Publishing, 572 pp.

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McCully, S. R., Scott, F., Ellis, J. R., Pilling, G. M. 2013 Productivity and Susceptibility Analysis: Application and suitability for data poor assessment of elasmobranchs in Northern European seas. Collective Volume of Scientific Papers ICCAT, 69: 1679–1698. Available from: http://www.iccat.org/Documents/CVSP/CV069_2013/n_4/CV069041679.pdf

Nieto, A., Ralph, G. M., Comeros-Raynal, M. T., Kemp, J., García Criado, M., Allen, D. J., Dulvy, N. K., Walls, R. H. L., Russell, B., Pollard, D., García, S., Craig, M., Collette, B. B., Pollom, R., Biscoito, M., Labbish Chao, N., Abella, A., Afonso, P., Álvarez, H., Carpenter, K. E., Clò, S., Cook, R., Costa, M. J., Delgado, J., Dureuil, M., Ellis, J. R., Farrell, E. D., Fernandes, P., Florin, A-B., Fordham, S., Fowler, S., Gil de Sola, L., Gil Herrera, J., Goodpaster, A., Harvey, M., Heessen, H., Herler, J., Jung, A., Karmovskaya, E., Keskin, C., Knudsen, S. W., Kobyliansky, S., Kovačić, M., Lawson, J. M., Lorance, P., McCully Phillips, S., Munroe, T., Nedreaas, K., Nielsen, J., Papaconstantinou, C., Polidoro, B., Pollock, C. M., Rijnsdorp, A. D., Sayer, C., Scott, J., Serena, F., Smith-Vaniz, W. F., Soldo, A., Stump, E. and Williams, J. T. 2015. European Red List of marine fishes. Luxembourg: Publications Office of the European Union, iv + 81 pp. Available from: http://ec.europa.eu/environment/nature/conservation/species/redlist/downloads/European_marin e_fishes.pdf

Bendall, V., Hetherington, S., O’Brien, C., Righton, D., Riley, A. and Cragg, A. 2014. Proposal for a UK pilot project to develop a real-time spurdog by-catch avoidance programme to mitigate the potential for spurdog to become a choke species and so minimize fishing induced mortality. Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 12 pp.

Burt, G. J., Silva, J. F., McCully, S. R., Bendall, V.A. and Ellis, J. R. 2013. Summary results from opportunistic tagging programmes for smooth-hound Mustelus spp., greater-spotted dogfish Scyliorhinus stellaris and tope Galeorhinus galeus around the British Isles. Working Document to the ICES Working Group on Elasmobranch Fishes, Lisbon, June 17–21 2013; 12 pp.

Ellis, J. R. and McCully, S. R. 2013. An overview of the sharks, skates and rays (Elasmobranchii) and rabbit fish (Holocephali) of the British Isles, and prioritisation of species of interest. Working Document to the ICES Working Group on Elasmobranch Fishes, Lisbon, June 17–21 2013; 41 pp.

Ellis, J. R., McCully, S. R. and Poisson, F. 2014. A global review of elasmobranch discard survival studies and implications in relation to the EU ‘discard ban’. Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 48 pp.

McCully, S. R. and Ellis, J. R. 2014. Biological studies to inform management of smooth-hounds (Mustelus spp.) in the North-east Atlantic. Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 16 pp.

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Silva, J. F., Ellis, J. R., Catchpole, T. L. and Righton, D. 2013. Bycatch and discarding patterns of dogfish and sharks taken in commercial fisheries around the British Isles. Working Document to the ICES Working Group on Elasmobranch Fishes, Lisbon, June 17–21 2013; 31 pp.

Silva, J. F., McCully, S. R., Ellis, J. R. and Kupschus, S. 2014. Demersal elasmobranchs in the western English Channel (ICES Division VIIe). Working Document to the ICES Working Group on Elasmobranch Fishes (WGEF), 17–26 June 2014; 28 pp.

(d) Presentations

Bendall, V. A., Hetherington, S. J., Duggan, K., Corton, J. and Randall, P. 2013. Shark ByWatch UK – Regional bycatch awareness of sharks and rays in the southern North Sea. 17th European Elasmobranch Association Annual Scientific Conference, Plymouth.

Bendall, V., Law, R., Barber, J., Papachlimitzou, A., Bolam, T., Hetherington, S., Silva, J., McCully, S., Righton, D., Ellis, J. and Maes, T. 2013. Bioaccumulation of trace metals and organochlorines in North- East Atlantic porbeagle sharks Lamna nasus. 17th European Elasmobranch Association Annual Scientific Conference, Plymouth.

Ellis, J. R., McCully, S. R. and Silva, J. F. 2013. The skate complex of the British Isles: current status, discard survival and management options. 17th European Elasmobranch Association Annual Scientific Conference, Plymouth.

Heessen, H. J. L., Daan, N. and Ellis, J. R. 2014. Elasmobranchs of the North-East Atlantic Shelf. 18th European Elasmobranch Association Annual Scientific Conference, Leeuwarden.

Hetherington, S. J. and Bendall, V. A. 2013. “Science & Fishery Collaboration”: A new collaborative approach to scientists and fishermen actively working together to provide evidence and inform policy needs. 17th European Elasmobranch Association Annual Scientific Conference, Plymouth.

McCully, S. R. and Ellis, J. R. 2013. Biological studies to inform management of smooth-hounds Mustelus spp. in the Northeast Atlantic. 17th European Elasmobranch Association Annual Scientific Conference, Plymouth.

McCully, S. R. and Ellis, J. R. 2013. Chondrichthyan fish of the British Isles: Prioritising species for further study and the utility of Ecological Risk Assessments for informing management. 17th European Elasmobranch Association Annual Scientific Conference, Plymouth.

Silva, J. F., Ellis, J. R., Catchpole, T. L. and Righton, D. 2013. Bycatch and discarding patterns of dogfish and sharks taken in commercial fisheries around the British Isles. 17th European Elasmobranch Association Annual Scientific Conference, Plymouth.

Silva, J. F., McCully Phillips, S. R., Ellis, J. R. and Kupschus, S. 2014. Demersal elasmobranchs in the western English Channel. 18th European Elasmobranch Association Annual Scientific Conference, Leeuwarden.

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8.3 Taxonomic list of chondrichthyans of the British Isles and adjacent waters

This annotated list of the chondrichthyan fishes of the British Isles and adjacent waters gives sources of information in relation to their occurrence and distribution in the region. Rank refers to the taxonomic ordering.

Family Rank Scientific name Common name Distribution around British Isles Source(s) CLASS ELASMOBRANCHII ORDER HEXANCHIFORMES Went (1979); Boeseman (1984a); Haedrich & Merrett Bluntnose six-gill Occurs on the outer continental shelf and in the deep-water to Hexanchidae 1 Hexanchus griseus (1988); Wheeler (1992); shark the west of the British Isles, including the Porcupine Seabight Gordon et al. (1996); Ellis et al. (2005) Although typically caught in deep waters south of the British Boeseman (1984a); Cappetta Sharpnose 2 Heptranchius perlo Isles, this species is caught occasionally on the continental shelf et al. (1985); Henderson & seven-gill shark and slope off the south-west British Isles Williams (2001) Chlamydoselachus Wheeler (1962, 1992); Chlamydoselachiidae 3 Frilled shark Deep water of the southern and western British Isles anguineus Boeseman (1984b) ORDER LAMNIFORMES Odontaspis ferox is reported from the Bay of Biscay. Recently a dead specimen (ca. 2.5 cm LT) of Odontaspis spp. was found Quéro (1984a); Fergusson et Odontaspidae – Odontaspis spp. Sand tiger washed ashore at Agon-Coutainville (French coast of the English al. (2008) Channel) (13/08/2012), but no records of live individuals in the area. No records from UK or Irish waters, although there have been Mitsukurinidae – Mitsukurina owstoni Goblin shark several records from the northern Bay of Biscay, at latitudes of Quéro (1984b) up to 46°N No records from UK or Irish waters, although there is an Carcharodon Quéro et al. (1978); Quéro Lamnidae – White shark authenticated record from the northern Bay of Biscay, at a carcharias (1984c). latitude of ca. 46°N (Quéro et al., 1978) Oceanic species, vagrants of which may occur to the west of the Wheeler (1992); Quéro 4 Isurus oxyrinchus Shortfin mako British Isles. May be confused with Lamna nasus and some (1984c).Henderson et al. records need to be treated with caution (1999) National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 91

Family Rank Scientific name Common name Distribution around British Isles Source(s) Widespread around the British Isles, with areas of high Quéro (1984c); Wheeler 5 Lamna nasus Porbeagle shark abundance known along south-western and western coasts, and (1992) North Sea Widespread around the British Isles, with areas of high Quéro (1984d); Wheeler Cetorhinidae 6 Cetorhinus maximus Basking shark abundance along south-western and western coasts (1992); Southall et al. (2005) Big-eye thresher Oceanic species. Typically occurs further south, but a large Alopiidae 7 Alopias superciliosus Quéro (1984e); Thorpe (1997) shark individual was captured to the west of the British Isles. Large pelagic species that may occur all around the British Isles, Quéro (1984e); Wheeler 8 Alopias vulpinus Thresher shark although caught relatively infrequently (1992); Ellis (2004) ORDER CARCHARHINIFORMES Overall distribution unclear, as the taxonomy of this genus is White ghost O'Hea et al. (2008), Neat et Scyliorhinidae 9 Apristurus aphyodes problematic. This species has been reported in the deep waters catshark al. (2008) west of the British Isles Overall distribution unclear, as the taxonomy of this genus is Quéro (1984f); O'Hea et al. 10 Apristurus laurussonii Iceland catshark problematic. This species has been reported in the deep waters (2008), Neat et al. (2008) west of the British Isles Although this nominal species was reported from the deep Madeiran – Apristurus maderensis waters west of the British Isles, it has more recently been treated Neat et al. (2008) catshark as a synonym of Apristurus laurussonii. Overall distribution unclear, as the taxonomy of this genus is O'Hea et al. (2008); Neat et 11 Apristurus manis Ghost catshark problematic. This species has been reported in the deep waters al. (2008) west of the British Isles Overall distribution unclear, as the taxonomy of this genus is Apristurus Black roughscale O'Hea et al. (2008); Neat et 12 problematic. This species has been reported in the deep waters melanoasper catshark al. (2008) west of the British Isles Overall distribution unclear, as the taxonomy of this genus is Smalleye 13 Apristurus microps problematic. This species has been reported in the deep waters Neat et al. (2008) catshark west of the British Isles No authenticated records from the UK or Ireland, but often Atlantic sawtail – Galeus atlanticus confused with Galeus melastomus, and now known to occur in Banon et al. (2010) catshark the southern Bay of Biscay (Banon et al., 2010) Went (1979); Quéro (1984f); Occurs on the outer continental shelf (including the deeper Black-mouth Haedrich & Merrett (1988); 14 Galeus melastomus waters of the Irish Sea) and continental slope all around the dogfish Wheeler (1992); Gordon et al. British Isles (1996); Ellis et al. (2005) National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 92

Family Rank Scientific name Common name Distribution around British Isles Source(s) Quéro (1984f); Haedrich & Occurs in the deep-water to the west of the British Isles, Merrett (1988); Gordon et al. 15 Galeus murinus Mouse catshark including the Rockall Trough and Porcupine Seabight (1996); O'Hea et al. (2008); Neat et al. (2008) Lesser-spotted Occurs on the continental shelf and upper slope all around the Quéro (1984f); Wheeler 16 Scyliorhinus canicula dogfish British Isles (1992); Ellis et al. (2005) Greater-spotted May occur all around the British Isles, but most frequent along Quéro (1984f); Wheeler 17 Scyliorhinus stellaris dogfish southern and western coasts, usually in waters <100 m deep (1992); Ellis et al. (2005) Pseudotriakis Deepwater species that is occasionally reported from off the Forster (1964; 1968); Quéro Pseudotriakidae 18 False catshark microdon continental slope to the west of the British Isles (1984g); Clarke et al. (2005) Triakidae Starry smooth- Occurs on the continental shelf all around the British Isles, but Branstetter (1984b); Wheeler 19 Mustelus asterias (subfamily Triakinae) hound more abundant in southern and western areas (1992); Ellis et al. (2005) Is reported to occur around the British Isles, although its distribution in UK waters is uncertain, due to widespread Branstetter (1984b); Wheeler 20 Mustelus mustelus19 Smooth-hound confusion between this and the more common Mustelus (1992) asterias. Triakidae Occurs on the continental shelf and upper slope all around the Branstetter (1984b); Wheeler 21 Galeorhinus galeus Tope shark (subfamily Galeorhininae) British Isles (1992); Ellis et al. (2005) A tropical and sub-tropical oceanic species. Although there are Carcharhinus Oceanic white- no records from the British Isles, a single specimen was washed Branstetter (1984a); George Carcharhinidae – longimanus tip shark ashore in Sweden (George, 2009), and this specimen would have (2009) had to have passed in or near to UK waters to reach Sweden A tropical and sub-tropical species. Although there are no Branstetter (1984a); Quéro et – Carcharhinus obscurus Dusky shark records from the British Isles, a specimen was recorded in the al. (2001). northern Bay of Biscay (47°N, 5°50’W) by Quéro et al. (2001). No authenticated records from the British Isles, although one Wheeler & Blacker (1972); – Galeocerdo cuvier Tiger shark unconfirmed sighting reported by Wheeler & Blacker (1972). A Jónsson (1983); Branstetter vagrant tiger shark was reported from Iceland (Jónsson, 1983). (1984a); Oceanic species that is a regular visitor to shelf seas along the Branstetter (1984a); Wheeler 22 Prionace glauca Blue shark southern and western coasts of the British Isles, and occasionally (1992); Vas (1990) in the North Sea.

19 Since undertaking this work, examination of more specimens from research vessel surveys, commercial landings and museum material indicate that this species may not occur in British waters, with authenticated specimens now only thought to have been reported from the Mediterranean Sea and the west coast of Africa. National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 93

Family Rank Scientific name Common name Distribution around British Isles Source(s) Smooth Very occasional vagrant that may occur in the south-west waters Quéro (1984h). Southall & Sphyrnidae 23 Sphyrna zygaena hammerhead of the British Isles Sims (2005) ORDER SQUALIFORMES McEachran & Branstetter Occurs in the deep-water to the west of the British Isles, (1984); Haedrich & Merrett Dalatiidae 24 Dalatias licha Kitefin shark including the Rockall Trough and Porcupine Seabight (1988); Wheeler (1992); Gordon et al. (1996); Occurs in the deep-water to the north and west of the British McEachran & Branstetter Etmopteridae 25 Centroscyllium fabricii Black dogfish Isles, including the Rockall Trough (1984); Haedrich & Merrett (1988); Gordon et al. (1996); McEachran & Branstetter Great lantern Occurs in the deep-water to the west of the British Isles, 26 Etmopterus princeps (1984); Haedrich & Merrett shark including the Rockall Trough and Porcupine Seabight (1988); Gordon et al. (1996); McEachran & Branstetter Occurs in the deep-water around the British Isles, including the (1984); Haedrich & Merrett Rockall Trough and Porcupine Seabight, and occasionally found 27 Etmopterus spinax Velvet belly (1988); Wheeler (1992); on the outer continetal shelf of the northern North Sea and Gordon et al. (1996); Ellis et Celtic Sea al. (2005) McEachran & Branstetter Centroscymnus Portuguese Occurs in the deep-water to the west of the British Isles, Somnosidae 28 (1984); Haedrich & Merrett coelolepis dogfish including the Rockall Trough and Porcupine Seabight (1988); Gordon et al. (1996); Reported (as Centroscymnus crepidater) Occurs in the deep- McEachran & Branstetter Centroselachus Longnose velvet 29 water to the west of the British Isles, including the Rockall (1984); Haedrich & Merrett crepidater dogfish Trough (1988); Gordon et al. (1996); Smallmouth – Scymnodon obscurus knifetooth Currently viewed as a junior synonym of Zameus squamulosus dogfish McEachran & Branstetter Knifetooth Occurs in the deep-water to the west of the British Isles, 30 Scymnodon ringens (1984); Haedrich & Merrett dogfish including the Rockall Trough and Porcupine Seabight (1988); Gordon et al. (1996); Large-bodied northerly shark species that has been captured Somniosus McEachran & Branstetter 31 Greenland shark occasionally along the northern and western coasts of the British microcephalus (1984); Wheeler (1992) Isles and in the North Sea. Lesser sleeper Although typically reported from further south (e.g. off the McEachran & Branstetter – Somniosus rostratus shark Iberian peninsula), it has been reported from deep-waters off (1984); Neat et al. (2008) National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 94

Family Rank Scientific name Common name Distribution around British Isles Source(s) Scotland (Neat et al., 2008). The taxonomy of this genus is problematic and until further records are confirmed, its occurrence around the British Isles is questionable A deep-water species. Although purported to occur around the British Isles, sometimes as Scymnodon obscurus, (Compagno, McEachran & Branstetter – Zameus squamulosus Velvet dogfish 1984; George, 2009) there does not appear to be published (1984); George (2009) accounts confirming its presence. Angular Occasionally reported from deep waters to the south-west of the Quéro (1984i); Wheeler et al. Oxynotidae 32 Oxynotus centrina roughshark British Isles, but generally occurs further south (2004) Quéro (1984i); Wheeler Sailfin Occasionally reported from deep waters to the west of the 33 Oxynotus paradoxus (1992); Quigley & Flannery roughshark British Isles (1994) Although recorded for the British Isles (Wheeler et al., 2004; Neat et al., 2008), the taxonomy of this genus is problematic, McEachran & Branstetter Centrophorus Centrophoridae – Gulper shark and many deep-sea studies have not reported this species. It is (1984); Wheeler et al. (2004); granulosus generally regarded to occur further south, up to the southern Neat et al (2008) Bay of Biscay McEachran & Branstetter Centrophorus Leafscale gulper Occurs in the deep-water to the west of the British Isles, 34 (1984); Haedrich & Merrett squamosus shark including the Rockall Trough and Porcupine Seabight (1988); Gordon et al. (1996); McEachran & Branstetter Occurs in the deep-water to the west of the British Isles, 35 Deania calcea Birdbeak dogfish (1984); Haedrich & Merrett including the Rockall Trough and Porcupine Seabight (1988); Gordon et al. (1996); Rough longnose Reported (as D. mauli) from a deep-water trawl survey off south- 36 Deania hystricosa Cappetta et al. (1985) dogfish west Ireland Wheeler (1992); Ellis et al. Squalidae20 37 Squalus acanthias Spurdog Widely distribution all around the British Isles (2005) This species is reported to occur in the Bay of Biscay, but there Longnose McEachran & Branstetter – Squalus blainvillei are no records from the British Isles and the northern limits of its spurdog (1984); geographic range in the NE Atlantic are unclear.

20 Blacker (1962) reported on an elasmobranch that “resembles the common spurdog (Squalus acanthias L.), but differs in the larger eye, deeper body and shorter distance between the second dorsal and caudal fins. It may perhaps be the southern species S. fernandinus Molina, but certain identification must await the capture and preservation of another specimen”. It is unclear as to whether this specimen would refer to S. blainvillei or S. uyato. National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 95

Family Rank Scientific name Common name Distribution around British Isles Source(s) The taxonomy of this species is problematic, and for many years was reported as Centrophorus uyato. Many deep-sea studies Little gulper McEachran & Branstetter 38 Squalus uyato have not reported this species. Although typically reported from shark (1984); Clarke (2000) further south (e.g. off the Iberian peninsula), it was reported from the Rockall trough (Clarke, 2000). Went (1978); McEachran & Unusual deep-water shark that has been reported sporadically to Echinorhinidae 39 Echinorhinus brucus Bramble shark Branstetter (1984); Wheeler the west of the British Isles (1992); ORDER SQUATINIFORMES Reported from many parts of the inner continental shelf of the Roux (1984); Wheeler (1992); Squatinidae 40 Squatina squatina Angel shark British Isles, although most records from southern and western Rogers & Ellis (2000) coasts ORDER TOPEDINIFORMES Stehmann & Bürkel (1984a); Torpedo (Tetronarce) Common electric Occurs on the continental shelf and upper slope, although most Torpedinidae 41 Wheeler (1992); Ellis et al. nobiliana ray frequently observed along south-western and western coasts (2005) Stehmann & Bürkel (1984a); Torpedo (Torpedo) Marbled electric Occurs in the English Channel, including occasionally in UK 42 Wheeler (1992); Ellis et al. marmorata ray waters (2005) ORDER RAJIFORMES Stehmann & Bürkel (1984b); Occasionally captured in deep water to the west of the British Arhynchobatidae 43 Bathyraja pallida Pale ray Clarke (2000); O'Hea et al. Isles (2008) Stehmann & Bürkel (1984b); Occurs in the deep-water to the west of the British Isles, Haedrich & Merrett (1988); 44 Bathyraja richardsoni Richardson's ray including the Rockall Trough and Porcupine Seabight Gordon et al. (1996); Clarke (2000) Deepwater species that may occur off the continental shelf of Stehmann & Bürkel (1984b); 45 Bathyraja spinicauda Spinytail ray the northern and western British Isles Wheeler et al. (2004) A specimen of what appears to be an undescribed member of 46 Bathyraja sp. the genus Bathyraja was caught west of Scotland in waters of ca. Quéro & Vayne (2001) 2000 m deep. The specimen was photographed but not retained Stehmann & Bürkel (1984b); This northerly species may occasionally occur in the deeper Rajidae 47 Amblyraja hyperborea Arctic skate Clarke (2000); Wheeler et al. waters around the northern parts of the British Isles (2004) National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 96

Family Rank Scientific name Common name Distribution around British Isles Source(s) Jensen’s skate Occasionally captured in deep water to the west and north of the Quéro et al. (2000); O'Hea et 48 Amblyraja jenseni (or short-tail ray) British Isles al. (2008) Stehmann & Bürkel (1984b); Widespread in the central and northern North Sea. Also occurs 49 Amblyraja radiata Starry ray Wheeler (1992); Ellis et al. off NW Scotland (2005) Stehmann & Bürkel (1984b); Dipturus batis (D. cf. Common skate Known from the Rockall Bank and Celtic Sea. Thought to have Ellis et al. (2005); Griffiths et 50 flossada) (or blue skate) been more widely distributed historically. al. (2010); Iglésias et al. (2010) Stehmann & Bürkel (1984b); Known from the northern North Sea, NW Scotland and Celtic Ellis et al. (2005); Griffiths et 51 Dipturus cf. intermedia Flapper skate Sea, although not as frequent as D. batis in the latter area. al. (2010) ; Iglésias et al. Thought to have been more widely distributed historically. (2010) Although no authenticated specimens from the British Isles, this northerly species occurs off the Faroes and in the north-eastern North Sea, and as such may occur in the deep waters off the – “Dipturus” linteus Sailray Stehmann & Bürkel (1984b) Shetland Isles. Currently accepted as being in the genus Dipturus, but some suggestions that it should be included within the genus Malacoraja Stehmann & Bürkel (1984b); Occurs in the deep-water to the west of the British Isles, 52 Dipturus nidarosiensis Norwegian skate Haedrich & Merrett (1988); including the Rockall Trough and Porcupine Seabight Gordon et al. (1996); Occurs on the outer continental shelf and continental slope all Stehmann & Bürkel (1984b); 53 Dipturus oxyrinchus Long-nose skate around the British Isles Wheeler (1992) Stehmann & Bürkel (1984b); Occurs on the outer continental shelf and continental slope all Haedrich & Merrett (1988); 54 Leucoraja circularis Sandy ray around the British Isles, typically in waters >100 m deep Wheeler (1992); Ellis et al. (2005) Occurs on the outer continental shelf and continental slope all Stehmann & Bürkel (1984b); 55 Leucoraja fullonica Shagreen ray around the British Isles, and occasionally in the deeper waters of Wheeler (1992); Ellis et al. the Irish Sea. (2002; 2005) Widespread on the continental shelf of the British Isles, although Stehmann & Bürkel (1984b); most frequent along western coasts and the northern North Sea, 56 Leucoraja naevus Cuckoo ray Wheeler (1992); Ellis et al. and only occasionally observed in the southern North Sea and (2005) eastern English Channel National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 97

Family Rank Scientific name Common name Distribution around British Isles Source(s) Deep-water species that has been reported from the Rockall Stehmann & Bürkel (1984b); 57 Malacoraja kreffti Krefft's ray Trough Stehmann (1993) Malacoraja Soft skate (or Deep-water species that has been reported on the Iceland-Faroe Stehmann & Bürkel (1984b); 58 spinacidermis prickled skate) Ridge and may occur to the north-west of the British Isles. Quéro et al. (2000) Stehmann & Bürkel (1984b); Blue pygmy Occurs in the deep-water to the west of the British Isles, 59 Neoraja caerulea Haedrich & Merrett (1988); skate including the Rockall Trough and Porcupine Seabight Gordon et al. (1996); Widespread but patchily distributed on the continental shelf of Stehmann & Bürkel (1984b); 60 Raja brachyura Blonde ray the British Isles, but most common along southern and western Wheeler (1992); Ellis et al. coasts in waters <150 m deep (2005) Widespread on the continental shelf of the British Isles, with Stehmann & Bürkel (1984b); 61 Raja clavata Thornback ray areas of high abundance on inshore grounds (e.g. Outer Thames Wheeler (1992); Ellis et al. Estuary, Bristol Channel, Irish Sea) (2005) Common and abundant in the Bristol Channel and parts of the Stehmann & Bürkel (1984b); 62 Raja microocellata Small-eyed ray English Channel. Occasional specimens reported from the Irish Wheeler (1992); Ellis et al. Sea, Firth of Clyde and southern North Sea. (2005) Stehmann & Bürkel (1984b); 63 Raja montagui Spotted ray Widespread on the continental shelf of the British Isles Wheeler (1992); Ellis et al. (2005) Locally common in parts of the English Channel, with very Stehmann & Bürkel (1984b); 64 Raja undulata Undulate ray occasional specimens from the Bristol Channel. Also occurs in Wheeler (1992); Ellis et al. some Irish bays. Typically in waters <100 m deep. (2012) Occurs in the deep-water to the west of the British Isles, Stehmann & Bürkel (1984b); 65 Rajella bathyphila Deepwater ray including the Rockall Trough Haedrich & Merrett (1988) Stehmann & Bürkel (1984b); Occurs in the deep-water to the west of the British Isles, 66 Rajella bigelowi Bigelow's ray Haedrich & Merrett (1988); including the Rockall Trough and Porcupine Seabight Gordon et al. (1996); Originally described from the North Atlantic Ridge, but Mid-Atlantic Clarke (2000); Rodríguez- 67 Rajella kukujevi subsequently reported from deep waters off NW Europe, skate Cabello et al. (2012) including in the Rockall Trough Stehmann & Bürkel (1984b); Occurs in the deep-water to the west of the British Isles, Haedrich & Merrett (1988); 68 Rajella fyllae Round skate including the Rockall Trough and Porcupine Seabight Wheeler (1992); Gordon et al. (1996);

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Family Rank Scientific name Common name Distribution around British Isles Source(s) On the southern wand western coasts of the British Isles. Stehmann & Bürkel (1984b); 69 Rostroraja alba White skate Reported to be one of the main commercial species in the Wheeler (1992); Ellis et al. English Channel during the 1800s, but now rarely caught. (2010) ORDER MYLIOBATIFORMES Occurs in the inshore waters of the English Channel, Bristol McEachran & Capapé (1984a); Common Dasyatidae 70 Dasyatis pastinaca Channel and southern North Sea, with occasional records from Wheeler (1992); Ellis et al. Stingray elsewhere in UK waters (2005) An oceanic species normally associated with tropical and sub- McEachran & Capapé (1984a); Pteroplatytrygon 71 Pelagic stingray tropical waters. Individuals have been reported from the North Henderson et al. (1999); Ellis violacea Sea and from west of Ireland, but these are considered vagrants (2007) Myliobatidae Common eagle Occasional vagrant to the southern and western parts of the McEachran & Capapé (1984b); 72 Myliobatis aquila (subfamily Myliobatinae) ray British Isles Wheeler (1992) O’Riordan (1968); One record of a stranded individual along the Irish coast from Myliobatidae McEachran & Capapé (1984c); – Mobula mobular Devil ray the ca. 1830 (O’Riordan, 1968) and has also been recorded from (subfamily Mobulinae) Wheeler (1992); the south coast of Brittany (Quéro et al., 1996). Quéro et al. (1996). CLASS HOLOCEPHALI; ORDER CHIMAERIFORMES Occurs in the deep-water around the British Isles, including the Stehmann & Bürkel (1984c); Rockall Trough and Porcupine Seabight, and occasionally found Haedrich & Merrett (1988); Chimaeridae 73 Chimaera monstrosa Rabbit fish on the outer continetal shelf of the northern North Sea and Wheeler (1992); Gordon et al. Celtic Sea (1996); Ellis et al. (2005) A recently described species which has been confused with Chimaera monstrosa. Has been described from specimens 74 Chimaera opalescens Opal chimaera collected from deep waters to the south of the British Isles, Luchetti et al., 2011 including the Porcupine Bank, Porcupine Seabight, Goban Spur, Great Sole Bank and Rockall Bank. Small-eyed Occurs in the deep-water to the west of the British Isles, Stehmann & Bürkel (1984c); 75 Hydrolagus affinis rabbitfish including the Rockall Trough and Porcupine Seabight Haedrich & Merrett (1988) Stehmann & Bürkel (1984c); Large-eyed Occurs in the deep-water to the west of the British Isles, 76 Hydrolagus mirabilis Haedrich & Merrett (1988); rabbitfish including the Rockall Trough and Porcupine Seabight Gordon et al. (1996); Occurs in the deep-water to the west of the British Isles, Hardy & Stehmann (1990); 77 Hydrolagus pallidus Pale chimaera including the Rockall Trough Gordon et al. (1996); Smallspine Some records of this species in the deep waters to the north- Rhinochimaeridae 78 Harriotta haeckeli Quéro et al. (2000) spookfish west of Ireland National Evaluation of Populations of Threatened and Uncertain Elasmobranchs (NEPTUNE) Page 99

Family Rank Scientific name Common name Distribution around British Isles Source(s) Stehmann & Bürkel (1984d); Longnose Occurs in the deep-water to the west of the British Isles, 79 Harriotta raleighana Haedrich & Merrett (1988); chimaera including the Rockall Trough and Porcupine Seabight Gordon et al. (1996); Stehmann & Bürkel (1984d); Rhinochimaera Straightnose Occurs in the deep-water to the west of the British Isles, 80 Haedrich & Merrett (1988); atlantica rabbitfish including the Rockall Trough and Porcupine Seabight Gordon et al. (1996);

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