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Commercial Shark Fishery Observer Program

Fin Weight

Fin Weight in Relation to Body Weight of Sharks
The Commercial Shark Fishery Program (CSFOP) is operated by the Florida Program for Shark Research at the Florida Museum of Natural History, University of Florida. Since 1994 the CSFOP has sent trained biological observers to sea aboard commercial shark fishing vessels operating in the Atlantic waters off the United States east coast from New Jersey to Texas. Observers gather species composition and catch/effort data, document fishing mortality and by-catch composition, obtain life history information, and record the weights of shark carcasses and fins landed by the fishers.

From the latter, ratios of fin weights to carcass weights can be calculated. [A "carcass," as used in this context, is the dressed animal - head, entrails, and fins removed]. Such ratios are integral to fishery management because the practice of "finning" - the removal and marketing of fins from sharks without retention of the remainder of the carcass - has developed in many areas of the world, leading to increased fishing mortality (much unrecorded) of sharks. Fishery management measures often are constructed using fin-carcass (or fin-whole body) weight ratios as a means of discouraging this wasteful practice and gaining better data on fishing mortality.

Fin-carcass weight ratios have been developed by the CSFOP. These data are based on more than 27,000 sharks taken in the U.S. Atlantic coastal fishery during the 1994-2002 period (data is unavailable for 1998 and 2000-1). A variety of species are taken in this fishery. The fishery largely targets the sandbar shark (Carcharhinus plumbeus), a large-finned species, and other requiem sharks (Carcharhinidae). The overall fin-carcass ratio during this time period was 4.90 % fins. This percentages actually is somewhat inflated because hammerhead sharks, which usually were not landed, and other species discarded or retained for use as bait often were finned. Thus use of 5.0% as a target figure in shark fishery management plans allows considerable flex for species-specific variation in fin-carcass weights and should not be exceeded.

George H. Burgess
Alexia Morgan
Commercial Shark Fishery Observer Program

Fin Weights




Species Composition