Scientists Point out Possible Solutions to Address Impact of Marine Fisheries on Seabirds

Bonn, 11 November 2015 - How do marine fisheries impact on migratory seabirds in sub-Saharan Africa? A Review presented at the 6th Meeting of the Parties to the African-Eurasian Waterbird Agreement (AEWA) considers 54 seabirds covered by AEWA, an international treaty administered by the United Nations Environment Programme.

Longline and trawl fisheries have significant and widespread impacts on many seabird species with lethal effects for Cape Gannets. Cormorants are killed as bycatch in gillnets or traps. Penguins, gannets, boobies, cormorants, gulls, frigatebirds, oystercatchers, terns and noddies are also affected. 

Overfishing might affect many species, if it reduces preferred prey and has an impact on the entire marine ecosystem. Changes in foraging behaviour arising from competition for food or changes to marine ecosystems and food webs are predicted to affect most seabirds. The African Penguin and gannet, cormorant, gull and tern species are vulnerable to reduced prey availability, since tuna, which force seabird prey fish to the surface when foraging, are being overfished. As a result, the birds might desert their habitual feeding grounds.

Fishery discards have an impact on the largest number of species. Gull, tern, gannet and skua populations that scavenge around fishing vessels, particularly trawlers, may increase due to food in the form of fishery discards. However, the consequences for them and the ecosystem as a whole are difficult to predict and result in an ecological trap. In the case of the Cape Gannet, the low nutrition value of discards compared to natural prey can be detrimental to the survival of chicks.

Recommendations

The Review advises on three key issues affecting all countries in the region: collaboration, gillnet fishing and overfishing. Compliance, monitoring and surveillance need to be strengthened at national level. Further to managing fish stocks on the high seas, Regional Fisheries Management Organizations (RFMOs) and regional seas conventions are also bound to reduce bycatch including seabirds.  AEWA member states with large numbers of foreign vessels in their territorial waters could authorize RFMOs to represent them at negotiations of fishery agreements with fishing fleets. This would prevent overfishing of transboundary species.

Research should be undertaken with support from artisanal fishermen on the effects of gillnets on seabirds. In case of a direct link, educating local fishermen would help mitigate detrimental effects especially in high risk areas (Important Bird Areas). Studying the diets of breeding gulls and terns in Western Africa would help ascertain overlaps with fishery catches as risk factors.

As many African countries have concluded agreements with Asian and European States, stronger governmental controls need to ensure that agreed catches are observed. AEWA Parties operating fishing fleets in Africa should contribute with enhancing compliance and monitoring. Reinforcing RFMOs could strengthen interests of African countries over foreign fishing nations towards managing transboundary marine species. Introducing mandatory observer programmes for all foreign vessels fishing in African territorial waters, with transparency in data collection, submission and reporting could counteract overfishing.

Spatial quotas will be introduced to the South African sardine fishery in the coming years, to mitigate the effects of fishing on seabirds such as the African Penguin. Depending on the results, this management practice might be applicable in other AEWA member states.

The Review was prepared by BirdLife South Africa and based on a first draft by the University of Cape Town.

Last updated on 11 November 2015

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News item
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Birds