Discards ban could impact seabirds populationMarch 8, 2013 in Biology / Ecology
Species of seabirds could successfully return to their natural foraging habits following changes to European fisheries policies, scientists have suggested.
The European Parliament recently voted to scrap the controversial discards policy, which has seen fishermen throwing thousands of edible fish and fish waste back into the sea because they have exceeded their quotas.
Scientists at Plymouth University believe this could have a negative impact on some seabirds, which have become used to following the fishing vessels and are increasingly reliant on their discards.
But they say others could return to using foraging as their sole source of food, as long as there are sufficient numbers of fish to meet their needs.
Dr Stephen Votier, Associate Professor in Marine Ecology at Plymouth University, led the study. He said: "Policy changes can have unforeseen consequences, and the recent decision on the EU discards policy will pose challenges for a number of species. Many seabirds have come to rely to some extent on fishing vessels for food and globally, commercial capture fisheries generate huge quantities of discards. However, we believe there is a level of resilience among seabirds which means they will be able to overcome these challenges."
The study focused on populations of northern gannets on Grassholm Island, in Wales, with tiny cameras and GPS trackers being attached to birds to monitor their foraging habits.
The cameras captured more than 20,000 images, allowing scientists for the first time to analyse where the birds had flown to source food, precisely what they had fed on, and other details such as their sex and reproductive status.
The findings showed 42% of birds regularly targeted fishing vessels, as well as searching for naturally occurring prey, while 81% of male gannets used fishing vessels to source food and 30% of female birds did so.
Dr Votier added: "We have used cutting-edge technology to reveal the private lives of seabirds at sea – in this instance how they interact with fisheries – and the findings suggest scavenging is more common in this species than previously thought. This suggests a discard ban may have a significant impact on gannet behaviour, particularly so for males, but a continued reliance on 'natural' foraging shows the ability to switch away from discards, but only if there is sufficient forage fish to meet their needs in the absence of a discard subsidy."
The research study, which also involved scientists from the Plymouth Marine Laboratory and the Centre d'Etudes Biologiques de Chize in France, was conducted under licence from the Countryside Council for Wales and the British Trust for Ornithology.
It received funding from the National Environment Research Council, and the full findings are published in the latest issue of the PLOS ONE scientific journal.
Provided by University of Plymouth
"Discards ban could impact seabirds population" March 8, 2013 https://phys.org/news/2013-03-discards-impact-seabirds-population.html