Comparison of Fish Waste in Pelagic Longline Fisheries (and more)

Transcription

1 Comparison of Fish Waste in Pelagic Longline Fisheries (and more) John Kaneko Paul Bartram PacMar Inc.

2 CATCH (targeted and non-targeted) REJECTS MARKETABLE YIELD PROCESSING WASTE CAPTURE BYCATCH (non-viable) RELEASE (viable) DISCARDS HIGH GRADES PROHIBITED SPP FISH SPECIES Based on definitions of Martin Hall (1996) PROHIBITED SPP

3 Pelagic Longline Methods Not Created Equal Pelagic longline fishing is not a single or static method of fishing. Diverse longline gear configurations and fishing tactics have different impacts on bycatch. Splitting rather than lumping is crucial for evaluating and comparing the impacts

4 Products of the Study Typology of selected pelagic longline fisheries Comparison of fisheries bycatch Develop an index (target catch to bycatch ratio after M. Hall) Place Hawaii longline fisheries on scale Compare with other longline fisheries

5 Derivation of BPUE, CPUE, B/C and C/B ratios Longline fishing grounds and flag of Fishery A Average catch of targeted fish species per 10,000 hooks. Footnotes give sources of data for this calculation. Number of fish discarded dead or dying x average species wt. (mt) per 10,000 hooks. Footnotes give sources of data for this calculation. 2 Column 3 calculation divided by Column 2 calculation. Results may differ for fisheries with similar column 3 incidental catch rates because of the sensitivity to column 2 target species catch rates. Column 2 calculation divided by Column 3 calculation. Results may differ for fisheries with similar column 3 incidental catch rates because of the sensitivity to column 2 target species catch rates.

6 Catch to Bycatch Ratios (C/B): Mean Harvest of Target Fish (mt) Associated with One Sea Turtle Take in Selected Pelagic Longline Fisheries 100 LOW Impacts MT Target Fish Per Sea Turtle Take HIGH Impacts 0.01 Samoa CSP Japan Hawaii Tuna Eastern Australia California Historic Hawaii Swordfish Taiwan China South Africa offshore SA CSP = Central South Pacific; = Central and Western Pacific; EP = Eastern Pacific; SA = South Atlantic Brazil offshore SA Costa Rica offshore EP Brazil near nesting b eaches SA Costa Rica near nesting beaches EP

7 Catch to Bycatch Ratios (C/B): Average Harvest of Target Fish (mt) to Produce one mt of Selected Shark Species Bycatch (waste) in Selected Pelagic Longline Fisheries 100,000 10,000 Blue Shark Silky Shark LOW Bycatch Impacts MT Target Fish Per MT Fish Waste 1, HIGH Bycatch Impacts 1 Hawaii Tuna Japan = Central and Western Pacific; EP = Eastern Pacific Costa Rica EP Taiwan China Historic Hawaii Swordfish

8 Catch to Bycatch Ratios (C/B): Average Harvest of Target Fish (mt) to Produce one mt of Selected Fish Bycatch (waste) in Selected Pelagic Longline Fisheries 100,000 MT Target Fish Per MT Fish Waste 10,000 1, Shortbill spearfish Longnose lancetfish LOW Bycatch Impacts 1 Japan = Central and Western Pacific Taiwan China Historic Hawaii Swordfish Hawaii Tuna HIGH Bycatch Impacts

9 Applications Avoid Unilateral Management Actions that Indirectly Transfer Bycatch Effects to Problem Areas. Allow Marketers and Consumers to Participate in Bycatch Reduction by Comparing Impacts of Alternative Product Sources.

10 Comparison of the number of sea turtle takes per 100 mt of fresh swordfish from Hawaii and imported swordfish that replaced Hawaii swordfish after the 2001 fishery closure Area and Longline fishery Eastern tropical Pacific offshore of nesting beaches (e.g. Costa Rica, Mexico) Eastern tropical Pacific offshore (e.g. Costa Rica, Panama) South Africa Historic Hawaii Shallow-set swordfishstyle Sea turtle takes / 100 mt fresh swordfish catch¹

11 Observations A false impression of high bycatch is created because of the confusing Magnuson-Stevens Act definition of bycatch. This definition combines finfish waste (i.e., non-target finfish released dead or dying) with non- target finfish released alive after incidental capture.

12 Observations Regulators need to be careful not to penalize low-bycatch fisheries and indirectly stimulate the expansion of high-bycatch fisheries through indirect effects of unilateral management.

13 Observations More thorough analysis should be performed of life status (live versus dead) of finfish discards by Hawaii longline fisheries. This information exists in the Hawaii longline observer database maintained by NOAA Pacific Islands Regional Office. Such analysis would help to differentiate the amount of finfish that is actually wasted (true bycatch) from the fish that are released with a good chance of survival.