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Commercial Shark Fishery Observer Program

Final Report Abstracts

2000-2002 (Winter Season) Final Report Abstract
George Burgess and Alexia Morgan
University of Florida

The southeastern United States commercial shark fishery has been monitored through a fishery observer program since 1994. Data gathered during the 1 January 2000 to 1 April 2002 period was compiled and entered into the Commercial Shark Fishery Observer Program database and analyzed for fishery and biological life history trends. Species composition was characterized regionally and by sub-regions. The large coastal catch, which comprised 64.8% of the total catch, consisted mostly (41.1%) of sandbar sharks (Carcharhinus plumbeus), with tiger (Galeocerdo cuvier) and blacktip (Carcharhinus limbatus) sharks less often taken. Small coastal sharks comprised 32.4% of the total shark catch. The Atlantic sharpnose shark (Rhizoprionodon terraenovae), a small coastal species, was the most frequently captured shark (31.7% of total catch). Sandbar sharks formed the bulk of catches in the Carolinas and Florida Gulf regions. Small coastal sharks were taken more frequently than large coastals in the Florida East Coast region, with the Atlantic sharpnose shark the dominant species. Dusky (Carcharhinus obscurus) sharks represented less than 1% of the total shark catch. Small coastal sharks were targeted (largely to be used as bait) in at least some sets on all Florida East Coast trips. Total on-vessel fishing mortality of sharks was 87.6%, including a cryptic mortality of 39.0% largely incurred by small coastal sharks used for bait. Carolina region fishers set more hooks and fished longer than Florida Gulf Coast and Florida East Coast region fishers. The Florida Gulf Coast region had the highest catch-per-unit-effort (CPUE) for large sharks in each season. Sandbar sharks dominated the catch in the Carolinas and Florida Gulf Coast regions. Sandbar shark CPUE's were generally highest in the winter in all regions. Captured sandbar sharks were mostly sexually mature in both Florida regions year round and in the summer in North Carolina; winter catches in North Carolina were primarily of immature individuals. Blacktip CPUE's were highest in the summer in both Florida regions. Blacktip shark catch data is difficult to interpret because this species is not normally targeted and because catches are opportunistic. Data is presented on species specific survivability as related to the stresses of longline capture. Of the major species caught, nurse (Ginglymostoma cirratum), sandtiger (Carcharias taurus), lemon (Negaprion brevirostris) and tiger (Galeocerdo cuvier) are considered extremely hardy; bull (Carcharhinus leucas), sandbar, blacknose (Carcharhinus acronotus) and sharpnose sharks are considered moderately hardy; while spinner (Carcharhinus brevipinna), blacktip, night (Carcharhinus signatus), dusky, and all hammerhead (Sphyrna lewini, S. mokarran, S. tiburo) sharks largely are dead when brought to the vessel. Measures to protect any of the latter group of sharks by prohibiting the landing of the species will have only a limited positive affect because of high fishing mortality. Bycatch, mostly groupers, batoids, and amberjacks, was generally low and was highest in Gulf Florida where fishing often occurs near reefs and hard bottom. Four sea turtles were captured and three released alive.

Reprinted from: FINAL REPORT- National Marine Fisheries Award- NA06FM0194- "Support for an observer program monitoring the directed commercial shark fishery in the Eastern Gulf of Mexico and Atlantic Ocean," July 1, 2002.