|Impact of fisheries’ by-catch on seabird species
Seabirds are amongst the most threatened species of birds in the world, a recent study published by BirdLife International reveals that out of the 346 seabird species, 97 (28%) are globally threatened and a further 10% are close to being so. To give a broader idea, nearly half of all seabird species are known to be experiencing population declines and yet there have been limited attempts to reduce or eradicate their main source of mortality at sea: their accidental by-catch by fisheries.The interactions between fisheries and seabirds are pretty common, although not always negative, fishermen have had a long-standing relation with some species. As an example, it is widely known how Azorean fishermen follow Cory’s shearwater aggregations at sea to identify tuna schools; they will approach the birds and put their fishing canes to work, an artisanal art that has so far proved to be safe for the Cory’s shearwater.
Unfortunately this is a rare case, many seabird populations are currently threatened or on the brink of extinction. Albatrosses are probably the most known example; they have 17 of their 22 species currently threatened with extinction because of fisheries by-catch. In Europe, where Albatrosses do not occur, there was a general idea that fisheries by-catch was not as bad as a problem as in the Southern hemisphere. This assumption proved wrong, unfortunately.
BirdLife International estimates that every year at least 200,000 seabirds die as by-catch in fishing gears of EU fishing vessels – mainly longlines and gill-nets but to a lesser extent also trawls and purse seines –, with the Baltic and eastern North Sea probably accounting for at least half of this toll. This is even thought to be an underestimation.
The European Union has systematically delayed the publication of a specific Plan of Action on seabird by-catch. As it has recently happened with other animal groups, such as sharks, there is an urgent need for an immediate reaction from the EU and its Member States prioritising the issue and enforcing specific (and cost-effective) measures that could quickly minimize or even eliminate bycatch in our seas. This needs to be done not only in the European Union waters, but also by any EU vessel, wherever it fishes, that is, in any region of the world in which they may be operating.
In addition to the bycatch problem, previous reforms of the EU’s Common Fisheries Policy (CFP) have repeatedly underestimated the real threat that fisheries present to seabird populations. Many EU countries are well over their ideal fishing capacity, causing overfishing and quickly depleting fish stocks. Stock depletion is causing diet changes or even a decrease on the seabirds breeding success, which, added to adult mortality at sea by fisheries by-catch, represent a “lethal formula” to our most endangered species.
JOHN P. CROXALL, STUART H. M. BUTCHART, BEN LASCELLES, ALISON J. STATTERSFIELD, BEN SULLIVAN, ANDY SYMES and PHIL TAYLOR (2012): Seabird conservation status, threats and priority actions: a global assessment. Bird Conservation International, 22, pp 134
Ivan Ramirez, Ivan.Ramirez(at)birdlife.org