SCHOOL SHARK – DRESSED (sCH DRE)

Executive Summary

1. MFish recommends that consideration be given to increasing the conversion factor (CF) for school shark in the dressed state (SCH DRE) from 1.95 to 2.00.
2. This recommendation is based on sampling by Scientific Observers over the years 2003 - 2005,with sampling appropriately distributed amongst vessel nationalities,mostly New Zealand vessels. Virtually every CF recently reported by Scientific Observers is higher than the current Gazette value. The data has been weighted to reflect the split between landings by inshore and deepwater vessels, with most landed in domestic target fisheries, particularly rig and school shark.

Background

3. This paper reviews the CF from greenweight to the ‘dressed’ (DRE) state for school shark (SCH) (Galeorhinus galeus). The current CF for this state is 1.95.
4. The “dressed” state is defined in the Fisheries (Conversion Factors) Notice 2005 for all species of sharks and ghost sharks (including elephant fish) as the body of a fish from which the head, guts, and fins have been removed with:
   1. The anterior cut being a continuous straight line passing immediately behind the posterior insertions of both pectoral fins;
   2. The forward angle of the anterior cut not less than 90 degrees in relation to the longitudinal axis of the fish;
   3. No part of the tail cut forward of the posterior base of the anal fin, or in ghost sharks, elephant fish,and those species without an anal fin, forward of the posterior base of the second dorsal fin; and
   4. The belly flap maybe removed by a cut, no part of which is dorsal to the cartilaginous backbone.
      
5. The CF for ‘trunked or dressed’ SCH was first introduced on 1 October 1986, and was set at 2.00. The state was renamed ‘dressed’ and revised down to 1.95 on 1 October 1993 based on sampling completed on the New Zealand domestic longline fleet. The CF has remained, without review, since that date.
6. The Scientific Observer Programme sampled 1.23tonnes greenweight of this state in the 2002 calendar year, 0.25tonnes in 2003, 0.13 tonnes in 2004, and 1.35 tonnes in 2005.

Rationale for Management Option

7. The DRE state accounts for almost all of the total landings of school shark. These levels have remained relatively constant over the years 2003–2005.
8. SCH DRE was landed almost exclusively by New Zealand registered vessels in 2003 - 2005,with only a few percent attributed to vessels registered in other nations. The sampling is appropriately distributed amongst vessel nationalities, with most of the sampling taking place on New Zealand vessels.
9. Samples of this state have been collected in every year since the state was renamed and revised in 1993. The annual unweighted CFs are very variable between samples and years,ranging from 2.05 to 3.48 (rounded) with an overall CF of 2.54. This is most likely to be a vessel effect, due to the small sample size. There is no indication of a trend in the CF between years.
10. This first review of the CF for SCH DRE since 1993 concentrates on observer data from the deepwater fleet. It is based on 54 samples collected between 2002 and 2005, and a greenweight catch of 3 tonnes. Sampling was well spread over the geographical range where school shark is commonly taken, but unequally spread among months and between years. The month weighted CF for SCH DRE of 2.57 is based on 5 months of data, due to sample size constraints. However, this was similar to the mean CF of 2.54 estimated by observers from 1990 to 2005.
11. Virtually every CF recently reported by Scientific Observers is higher than the current value (1.95). The current value was based on processing in the domestic target longline fishery. The wide variation between these (2.57) and the current CF (1.95) suggests a difference in processing school shark in the domestic target longline and trawl fisheries (not currently sampled by Scientific Observers), and by deepwater vessels processing SCH as bycatch.
12. From the relative weightings of SCH landed between the inshore and deepwater fisheries, most is landed in the domestic SCH target fishery, with smaller proportions landed in such target fisheries as häpuku/bass and tarakihi. The recommended CF weighted by landings of the deepwater and inshore fishery for the years 2003 - 05 is 1.98 (2.00).

Preliminary Recommendation

13. MFish recommends that the CF for the ‘dressed’ state of school shark be increased from 1.95 to 2.00.