DURHAM, N.C. Tens of thousands of albatrosses and other far-ranging seabirds are killed each year after they become caught in longline fishing gear. Innovative new models developed by a Duke University-led research team may help reduce these casualties by more precisely projecting where and when birds and boats are likely to cross paths.
The models use remotely sensed physical and biological data to predict changing conditions such as sea surface temperatures or the availability of phytoplankton that make different parts of the ocean suitable habitats for foraging, nesting and other seabird behaviors at different times of the year, or from year to year.
Conservationists and fisheries managers can overlay maps of predicted habitat suitability onto maps of longline fishing activity and telemetry-tracked bird migrations to better avoid bird bycatch.
Old bycatch models don't account for these dynamic factors; they rely almost exclusively on static overlays based on historic fishery and bird-tracking data.
The Duke-led team tested the new models in case studies of two species of pelagic seabirds, the Laysan albatross and the black-footed albatross, whose long-distance migrations intersect areas of heavy swordfish and tuna fishing activity in Hawaiian fisheries. The studies used historic bycatch and tracking data from 1997 to 2000. Results were published March 23 online in the British peer-reviewed journal Proceedings of the Royal Society B.
The models' predictions corresponded closely to actual historic bycatch observations, says lead researcher Ramunas Zydelis, a postdoctoral research associate at Duke's Center for Marine Conservation. Black-footed albatrosses were more frequently caught in 1997-2000 despite being 10 times less abundant than Laysan albatrosses, probably because their habitat overlapped more with fisheries, according to the model's predictions.
Zydelis says the findings demonstrate
|Contact: Tim Lucas|