Research Document - 2012/031

The extent and diversity of the harvest fishery bycatch in Canadian commercial fisheries and the possible rational utilization for aquaculture feed production

By E.M.P. Chadwick

Abstract

The potential to use bycatch and discards as a source of feed for the Canadian aquaculture industry was examined in two steps. The first step estimated the weight of bycatch and discards in the 2009-2010 fisheries by directed species, location, gear type and season using logbook data archived in DFO’s Zonal Interchange File Format database, from data sources on groundfish, shellfish and Pacific salmon in DFO Pacific Region and from published scientific analyses of observer data. There were many gaps in the literature, very few of the studies were completed during 2009-10 and there were very few analyses of bycatch and discards in gillnets, purse seines, longlines and pot fisheries. Despite these gaps, the major source of discards appeared to be the dredge fisheries for scallop and surfclam, shrimp trawls, groundfish trawls and large pelagic longlines. The lowest and most reliable estimate of discards was 38,000 t, which was about 4% of total landings. The high estimate of 96,000 t represented about 10% of total landings. The second step examined the potential for utilizing the discarded material, a mixture of groundfish, crustaceans, molluscs and echinoderms, as an ingredient in aquafeeds. Currently, aquafeed components are created almost entirely from small pelagic fish taken from global stocks that are generally fully exploited. Discards could be used as a future source of fishmeal and fish oil but first it would be necessary to develop methods to collect and store the material that is likely landed at many widely dispersed ports. In the meantime, fishmeal and fish oil could be obtained from the large amount of waste in seafood processing, which is about 400,000 t, tenfold the weight of discards from capture fisheries. 

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