Evaluating the dependence of opportunistic Yellowlegged Gulls (Larus michahellis) on marine habitat and fishing discards /
Nere Zorrozua, Igor Granado, Jose A. Fernandes-Salvador, Maite Louzao, Mikel Basterretxea, Juan Arizaga.
-- [S.l.] : British Ornithologists' Union. 2023.
Several bird species benefit from anthropogenic food subsidies, such as landfills and fishing discards, that are being reduced owing to introduced legislation. For instance, since 2019, Europe has passed legislation to reduce dramatically the amount of fisheries discards through the Landing Obligation (LO), which states that all fish species under Total Allowable Catch (TAC) should not be discarded at sea. This European discard ban is
expected to impact some gulls, as several gull populations have been observed to be heavily reliant on this resource. In this work, GPS tracking data from adult Yellowlegged Gulls Larus michahellis and Vessel Monitoring System (VMS) data (i.e. detailed data of the spatial distribution of fishing vessels) are used to determine the utilization of the marine habitat and the level of interaction of gulls with fishing activity offshore and
discards in the south-eastern part of the Bay of Biscay. We found that these gulls had a low use of the marine habitat (ca. 15%) compared with terrestrial habitats, in contrast to the ca. 40% of the diet of this population which comprises marine prey. Furthermore, we detected that most of the gull tracking positions at sea did not interact with the fishing vessels (an overlap of 21.5% between gulls and VMS data). Conversely, other gull
populations of the Iberian Peninsula were found to depend much more strongly on fishing activity. Therefore, the Yellow-legged Gull population of the SE Bay of Biscay did not obtain most of its fish prey from interactions with offshore fishing activity but most
possibly by taking fish remains in harbours and by feeding themselves. Consequently, we expect a minimal effect of the European policies oriented to ban fishing discards offshore
on this population, which would be more affected by policies directed towards the reduction of food availability in landfills or fish landing management in harbours.
Zorrozua, N., Granado, I., Fernandes-Salvador, J.A., Louzao, M., Basterretxea, M., Arizaga, J., 2023. Evaluating the dependence of opportunistic Yellowlegged Gulls (Larus michahellis) on marine habitat and fishing discards. Ibis 166 (I). https://doi.org/10.1111/ibi.13227
EU policies
fishing vessels
foraging activity
GPS
habitat use
VMS
Articulo científico
Several bird species benefit from anthropogenic food subsidies, such as landfills and fishing discards, that are being reduced owing to introduced legislation. For instance, since 2019, Europe has passed legislation to reduce dramatically the amount of fisheries discards through the Landing Obligation (LO), which states that all fish species under Total Allowable Catch (TAC) should not be discarded at sea. This European discard ban is
expected to impact some gulls, as several gull populations have been observed to be heavily reliant on this resource. In this work, GPS tracking data from adult Yellowlegged Gulls Larus michahellis and Vessel Monitoring System (VMS) data (i.e. detailed data of the spatial distribution of fishing vessels) are used to determine the utilization of the marine habitat and the level of interaction of gulls with fishing activity offshore and
discards in the south-eastern part of the Bay of Biscay. We found that these gulls had a low use of the marine habitat (ca. 15%) compared with terrestrial habitats, in contrast to the ca. 40% of the diet of this population which comprises marine prey. Furthermore, we detected that most of the gull tracking positions at sea did not interact with the fishing vessels (an overlap of 21.5% between gulls and VMS data). Conversely, other gull
populations of the Iberian Peninsula were found to depend much more strongly on fishing activity. Therefore, the Yellow-legged Gull population of the SE Bay of Biscay did not obtain most of its fish prey from interactions with offshore fishing activity but most
possibly by taking fish remains in harbours and by feeding themselves. Consequently, we expect a minimal effect of the European policies oriented to ban fishing discards offshore
on this population, which would be more affected by policies directed towards the reduction of food availability in landfills or fish landing management in harbours.
Zorrozua, N., Granado, I., Fernandes-Salvador, J.A., Louzao, M., Basterretxea, M., Arizaga, J., 2023. Evaluating the dependence of opportunistic Yellowlegged Gulls (Larus michahellis) on marine habitat and fishing discards. Ibis 166 (I). https://doi.org/10.1111/ibi.13227
EU policies
fishing vessels
foraging activity
GPS
habitat use
VMS
Articulo científico