Bycatch, the accidental capture of a non-target species in fisheries, is both a common and universal phenomenon. Between a quarter and a fifth of all fish caught across the world is simply thrown overboard- that is the equivalent of 20 million tonnes of marine life discarded every year. Trawls, seines, hooks and lines, gillnets and driftnets and even lines of pots and creels take their toll on all sorts of animals - marine mammals, sea birds, turtles and sharks. Worst affected are long-lived, slow breeding species like whales, seals, turtles and albatrosses. Indeed, 19 of 22 species of albatross are threatened with extinction, and the primary threat they face comes from longline fisheries.

Moreover, it is not just the species that suffer; entire marine ecosystems are damaged as they lose an important element of their structure. In the face of this serious threat, CMS has taken a lead and it’s Parties have endorsed resolutions and recommendations at the last four Conferences (Cape Town 1999, Bonn 2002, Nairobi 2005 and Rome, 2008) calling for immediate action by the international community to address the problem and improve fishing practices to reduce the unnecessary death of so many non- target species. In addition, there are several CMS-related Agreements and Memoranda of Understanding dedicated to species for which bycatch is a major issue.

It is only recently that the extent of the problem of bycatch has become apparent. Our knowledge is improving as more data are collected and analysed and coverage by observers of fishing fleets increases. But the data obtained paints a gloomy picture as the conservation status of key species such as the Wandering Albatross (Diomedea exullans) and Amsterdam Albatross (Diomedea amsterdamensis) remains alarming - the latter is near extinction. 

Another cause for concern is the fate of marine turtles. Across their entire migratory range bycatch is a problem but at least global action is now being taken. It is estimated that since 2000, each year thousands of Harbour Porpoises (Phocoena phocoena) have died as a result of bycatch in North Sea fisheries alone. Losses of this magnitude are unsustainable and populations will only recover when bycatch levels fall drastically.

Further species face similar threats but have yet to attract the same level of attention to their plight. The total annual bycatch of marine mammal bycatch is thought to be in excess of 300,000 individuals. For some species, like the Vaquita (Phocoena sinus) which is only found in the Gulf of California, extinction looms; for others, like the Irrawaddy Dolphin (Orcaella brevirostris), the extent of bycatch has yet  to be ascertained and no remedial actions are being taken.

The Food and Agriculture Organisation (FAO) has been instrumental in negotiating International Plans of Action aiming to reduce bycatch levels of sharks and sea birds. Innovative fishing techniques are subject of trials in the Southern Hemisphere to reduce albatross and petrel losses. In several fisheries in the Indian Ocean and South Pacific, it is now required to fit turtle excluder devices. A start is being made to addressing bycatch with stricter regulations being enforced in many regions, but still, more needs to be done. The CMS Resolution 9.18 adopted in 2008 calls on Parties to compile information to assess the impact of bycatch on migratory species and take action regarding fishing activities within their control.

Links to CMS and FAO documents:

UNEP/CMS/Resolution 9.18 on Bycatch

FAO 2009. FAO Technical Guidelines For Responsible Fisheries No 1, Supplement 2.  Best practices to reduce incidental catch of seabirds in capture fisheries. http://www.fao.org/docrep/012/i1145e/i1145e00.pdf

FAO Fisheries Department. Guidelines to reduce sea turtle mortality in fishing operations. Rome, FAO. 2009. 128p. http://www.fao.org/docrep/012/i0725e/i0725e00.htm

CMS Agreements and MoUs addressing Bycatch:

Barry Baker, CMS Appointed Scientific Councillor on Bycatch (Deutsche Welle Interview)

Other Related Links:

Last updated on 16 October 2014