Science Advisory Report  2012/022

Guidance related to bycatch and discards in Canadian commercial fisheries

Summary

• Canada is committed domesticallyand internationally to implementing conservation and management measures to address bycatch and discards.
• This scientific advice refers to bycatch species for which information on their biology, distribution, or status is limited, and/or there is a lack of formal abundance estimates. 
• Compared to targeted species there will usually be less complete data on bycatch and less knowledge of the population dynamics and demographic rates of bycatch species.  Nonetheless, there are actions and analyses that can be undertaken where potential impacts have been identified, as long as those actions and analyses are ecologically appropriate and based on reliable information.
• A variety of strategies and measures are available to managers to ensure the risks associated with bycatch are managed effectively; examples of such strategies and measures are provided in this report. 
• Direct estimates of bycatch obtained from complete monitoring programs that reliably reflect the conditions in the fishery are highly desirable.  However, complete monitoring may not be possible and the allocation of monitoring resources in these situations should fully consider the risks of fisheries causing serious harm to the bycatch species.
• Benchmarks for bycatch species are used to evaluate whether or not bycatch rates and magnitudes are low enough to be sustainable and avoid serious harm.  There is no single best method and using a diversity of approaches is encouraged.
• Natural mortality (M) is a key parameter in developing benchmarks for management of bycatch and there are many ways to approximate it with limited information.  Approaches to calculate M and how to use it in evaluations of bycatch sustainability are provided in this report.
• Under appropriate circumstances, discards and processing waste have the potential to be rationally utilised as a source of raw material in the production of fishmeal and fish oil for aquaculture or other value-added products.  To make rational use of Canadian fisheries discards, feed component material must be fresh (i.e. processed close to where it is landed) and of suitable nutrient composition.  Given these constraints, the potential opportunities for discard utilisation appear to be limited and should be evaluated on a case-by-case basis.

This Science Advisory Report is from the Fisheries and Oceans Canada, Canadian Science Advisory Secretariat (CSAS) national science advisory meeting of March 5-7, 2012 to develop guidance related to bycatch and discards in Canadian commercial fisheries.  Additional publications from this process will be posted as they become available on the DFO CSAS website.

Complete document (PDF, 214 KB)

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