I & I NSW Wild Fisheries research Program Silver Sweep ( lineolatus)

Exploitation Status Fully Fished

A long lived which may be susceptible to localised depletion. Fully fished in localised areas such as Wollongong but maybe moderately fished state-wide.

Scientific name Standard name comment

Scorpis lineolatus silver sweep

Scorpis lineolatus Image © Bernard Yau

Background Silver sweep (Scorpis lineolatus) are most In NSW, more than 80% of commercial landings abundant in NSW waters but also occur in of silver sweep are by fish traps in the Ocean southern , Victoria and . Trap and Line Fishery, with the remaining catch Adults and juveniles are associated with coastal taken by purse seine nets in the Ocean Hauling and estuarine reefs. Silver sweep mature at Fishery. Trap landings are highest during spring approximately 17 cm fork length at an age of and summer months, whereas purse seine 2 to 3 years and during winter in NSW. landings tend to be higher during autumn. Growth slows substantially following sexual Silver sweep are caught in significant numbers maturity and silver sweep exhibit significant by recreational fishers angling from rock longevity, with a maximum estimated age of 54 platforms and boats in coastal waters. years. A recent study estimated that more than 50% of silver sweep landed in NSW were greater than 15 years old. The longevity and slow growth of this species may make it particularly vulnerable to over-harvesting.

status of fisheries resources in nsw, 2008/09 Silver sweep | p 287 wild fisheries research program

Additional Notes Landings by Commercial Fishery of Silver Sweep

• Silver sweep is a long-lived inshore rocky reef Ocean Trap and Line (Key Secondary Species)

species taken commercially by purse-seine Ocean Hauling (Target Species) and trap fishers, and is a common recreational catch. 150 • Research (Stewart and Hughes, 2005) found silver sweep can live for more than 50 years;

however they mature at a small size and early 100 age (17 cm FL and 2-3 years). Landings (t)

• The age structure of samples obtained in 50 2003 and 2005/06 was indicative of a stock under relatively low fishing pressure, however

silver sweep may be susceptible to localised 0 depletion. 97/98 99/00 01/02 03/04 05/06 07/08 Financial Year • Catch rates of the purse seine fishery (centred Reported landings of silver sweep by NSW commercial on the Wollongong area) have declined over fisheries from 1997/98. Fisheries which contribute less the past decade; catch rates for fish trapping, than 2.5% of the landings are excluded for clarity and after a decline in the late 1990’s, have recently privacy. returned to previous levels.

Catch Catch Per Unit Effort Information of Silver Sweep Harvested by Fish Trapping in NSW Recreational catch of Silver Sweep The annual recreational harvest of silver sweep 1.0 in NSW is likely to lie between 30 and 60 t. This estimate is based upon the results of the offsite 0.8 National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) and onsite 0.6 surveys undertaken by I & I NSW. 0.4 Relative Catch Rate

Historical Landings of Silver Sweep 0.2 0.0 150 93/94 98/99 03/04 08/09 Financial Year Catch rates of silver sweep harvested using fish trapping

100 for NSW. Two indicators are provided: (1) median catch rate (lower solid line); and (2) 90th percentile of the catch rate (upper dashed line). Note that catch rates are not a

Landings (t) robust indicator of abundance in many cases. Caution

50 should be applied when interpreting these results. 0

90/91 92/93 94/95 96/97 98/99 00/01 02/03 04/05 06/07 08/09 Financial Year

Commercial landings (including available historical records) of silver sweep for NSW from 1990/91 to 2008/09 for all fishing methods.

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Growth Curve of Silver Sweep Further Reading Sweep Curley, B.G., M.J. Kingsford and B.M. Gillanders (2002).

30 Spatial and habitat related patterns of temperate reef fish assemblages: implications for the design of Marine Protected Areas. Marine and Freshwater

25 Research 53: 1197-1210. Dedual, M. and N.W. Pankhurst (1992). Plasma

20 steroid hormone concentrations in relation to the reproductive cycle of the sweep Scorpis lineolatus FL (cm) (Kyphosidae) caught from the wild. Australian

15 Journal of Marine and Freshwater Research 43 (4): 753-763.

10 Henry, G.W. and J.M. Lyle (2003). The National Recreational and Indigenous Fishing Survey. Final Report to the Fisheries Research & Development 5 Corporation and the Fisheries Action Program 0 10 20 30 40 50 Project FRDC 1999/158. NSW Fisheries Final Report Age (years) Series No. 48. 188 pp. Cronulla, NSW Fisheries. Age-length data with fitted growth curve of silver sweep Stewart, J. and J.M. Hughes (2005). Longevity, growth, (Stewart and Hughes, 2005). Lengths are presented as fork length (FL). reproduction and a description of the fishery for silver sweep Scorpis lineolatus off , Australia, New Zealand Journal of Marine and Freshwater Research: 827-838. Length Frequency of Silver Sweep Stewart, J. and J. M. Hughes (2008). Determining appropriate sizes at harvest for species shared 1998/99−2005/06 by the commercial trap and recreational fisheries n = 4872 in New South Wales. FRDC Project No. 2004/035. 0.15 Fisheries Final Report Series No.97 Cronulla, NSW Department of Primary Industries: 282pp. 0.10

Proportion Please visit the CSIRO website, 0.05 http://www.marine.csiro.au/caab/ and search for the species code (CAAB) 37 361009, common name or scientific name to find further information. 0.00

10 15 20 25 30 35 40 FL (cm)

The length distribution of commercial landings of silver sweep comprised mainly of fish between 20 and 30 cm fork length (FL). There is no minimum legal length for sweep in NSW.

© State of New South Wales through Industry and Investment NSW 2010. You may copy, distribute and otherwise freely deal with this publication for any purpose, provided that you attribute Industry and Investment NSW as the owner.

Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (April 2010). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of Industry and Investment NSW or the user’s independent adviser.

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