Shark Fin Trade Myths and Truths: Bycatch

Posted on January 27, 2012
Written by: Mary O’Malley, Hannah Medd, and Samantha Whitcraft

bycatch-Aviram_Avigal.pngMuch of conservation lies in communication, in sharing facts that bring light to complicated issues. Today, the Internet provides a wealth of information, news and opinions but knowing which are facts and which aren’t can sometimes be confusing. Additionally, social media can help increase the volume of both information and ‘mis-information’, especially about sharks, shark finning, the shark fin trade and conservation of shark species.

In an effort to help guide the public conversation about protecting sharks and the shark fin trade, Shark Savers is producing a new monthly series of fact sheets directly  addressing what is fact and what is not. For more information on any given subject, we’ll provide a list of references that support the facts.  

We hope these summaries and downloadable FACT SHEETS will be helpful to shark advocates, volunteers, students, and anyone interested in applying sound science and rational thought to shark conservation. 

This month, we start with the issue of ‘bycatch’ and the shark fin trade. Download: SHARK BYCATCH FACT SHEET

What is bycatch?  

“Bycatch” is marine life caught unintentionally in a fishery that is targeting other, specific fish. Worldwide commercial fisheries discard an estimated 38.5 million tonnes of marine life, comprising over 40% of the estimated total global marine catch[i].   

What does bycatch have to do with sharks?  

Most bycatch of sharks comes from open ocean fishing fleets that target valuable fishes such as tunas, using thousands of baited hooks on miles and miles of long-line; and these hooks often catch sharks. Until relatively recently, this shark 'bycatch' was considered a nuisance, and sharks that survived on the line were cut loose and allowed to swim away. However, as shark fins have become increasingly valuable, these fleets have little incentive to take measures to reduce shark bycatch. Often sharks that would have been released alive are now retained whole or “finned” with the bodies dumped at sea.   
An estimated 50 million sharks are caught unintentionally as bycatch in commercial fisheries every year. In addition to longlines, bottom-trawling and gillnetting also produce large numbers of shark bycatch[ii].  

Common myths about shark “bycatch” from opponents of shark fin trade restrictions.

Myth: “The shark fin trade is not the problem. Most sharks are caught as unwanted and unused bycatch. Sharks are not targeted for their fins.”   

Truth: There are means available to decrease bycatch of sharks, but the high value of shark fins is a strong economic incentive to NOT decrease this bycatch.

For example, simple gear changes, such as switching from steel to nylon leaders, have been demonstrated to reduce shark bycatch and improve catch of ‘target’ species[iii]. Additionally, new hook designs including "weak" hooks and "smart" hooks[iv], shark deterrents and other shark avoidance measures could greatly reduce shark bycatch while also resulting in potentially higher yields of ‘target’ species and time savings for fishing crews[v].  

Finally, most sharks, especially blue sharks, which are by far the most common bycatch species caught in high seas fisheries, have high survival rates when released[vi].   

Myth: “The shark fin trade is just making use of an unwanted byproduct that would have otherwise been discarded.”   

Truth: “Shark fins are now among the most expensive seafood items in the world, and depending on the species, may fetch retail prices of over US $400 per kg in the world’s largest fin market in Hong Kong”[vii] .

The value of shark fin is reported to be 20 to 250 times the value of meat by weight.[viii]Logically, it makes little sense that the most expensive part of the animal would be considered an unwanted by-product.  

Myth: “Retaining shark bycatch will provide valuable fisheries data that can be used to improve conservation measures.”   

Truth: Since a majority of sharks can be released alive (greater than 95% for the species most commonly caught as bycatch[ix]), requiring retention of bycatch would require that fishermen kill sharks that could have been released alive. Therefore, the incentive for retaining shark bycatch is the economic value of the fins.   
Commercial fishing fleets and fishermen will not retain and bring bycatch back to port unless they can sell the fins[x].  If retention is required for research purposes only, oversight and compliance will be almost impossible to enforce. Experience has shown that data collection using on-board observers is a much more reliable means of gathering data on fisheries and bycatch, in general.  



[i] Davies, R. W. D., Cripps, S. J., Nickson, A., and Porter G. 2009. Defining and estimating global marine fisheries bycatch. Marine Policy, 33(4): 661-672.  
[ii] Bonfil, R. 2000. The problem of incidental catches of sharks and rays, its likely consequences and some possible solutions. Sharks 2000 Conference, Hawaii, 21-24 February.  
[iii] Ward, P., Lawrence, E., Darbyshire, R., Hindmarsh, S. 2007. Large-scale experiment shows that banning wire leaders help pelagic sharks and longline fishers. Western and Central Pacific Fisheries Commission, Scientific Committee Third Regular Session, Honolulu, 13-24 August.  
[iv] Stroud, R. 2011. Effects of SMART™ circle hooks on shark feeding behavior and catch rate. Circle Hook Symposium, Florida, 4-6 May.  
[v] Gilman, E., Clarke, S., Brothers, N., Alfaro-Shigueto, J., Mandelman, J., Mangel, J., Peterson, S., Piovano, S., Thomson, N., Dalzell, P., Donoso, M., Goren, M., Wener, T. 2008. Shark interactions in pelagic longline fisheries. Marine Policy, 32(1): 1-18.  
[vi] Moyes, C. D., Fragoso, N., Musyl, M.K., and Brill, R.W. 2006. Predicting post-release survival in large pelagic fish. Transactions of the American Fisheries Society, 135: 1389-1397.  
[vii] Clarke, S. 2004. Understanding pressures on fishery resources through trade statistics: a pilot study of four products in the Chinese dried seafood market. Fish and Fisheries, 5(1): 53-74.   Stefania Vannuccini, FAO (Food and Agriculture Organization of the United Nations). FAO FISHERIES TECHNICAL PAPER 389. Rome, 1999, (Table 3)   ix Moyes et al. 2006   x Gilman et al. 2008    
[viii] Stefania Vannuccini, FAO (Food and Agriculture Organization of the United Nations). FAO FISHERIES
TECHNICAL PAPER 389. Rome, 1999, (Table 3)
[ix] Moyes et al. 2006
[x] Gilman et al. 2008