Commercial trawl pelagic fisheries in Argentina: seabird attendance and interactions with the vessels

PAZ J.; COPELLO S.; SECO PON J.P.; FAVERO M.

Conferencia; Second World Seabird Conference; 2015

Commercial fishing has been identified as one of themain threats affecting the survival of most seabird species around the globe. Althoughseabird mortality in Argentinean longline and demersal trawl fisheries hasalready been characterized and quantified, the interactions with pelagic trawlfisheries targeting anchovy (Engraulisanchoita) remains unknown. Thegoal of this study was to characterize the composition of seabird assemblages attendingpelagic trawl vessels and to analyze their interactions with fishing activities.Data on seabird interaction and abundance were obtained by on-board observersduring 2011-2013. From a total of 333 observations, there were over 45,000 seabirdsidentified (23 species). Procellariform followed by Charadriforms birds, werethe more frequent and abundant groups. The Black-browed albatross (Thalassarchemelanophris, mean ± SD = 46.7 ± 103.1 per haul; occurrence= 94%), the White-chinnedpetrel (Procellaria aequinoctialis, 14.4 ± 38.8; 71%), shearwaters (Puffinus spp. and Ardenna spp, 37.7 ± 62.5; 86%) and the Kelp gull (Larus dominicanus, 22.4 ± 60.8; 64%)were the most frequent and abundant species in the flocks. Seabird-fisheryinteractions occurred in ca. 70% of the hauls (n= 267). The bulk of these (93%)included light contacts (with no apparent resulting injuries), while the remainingwere heavy contacts with potential or confirmed harm. A total of 121 birds werebycaught, chiefly unidentified shearwaters (n= 58), Great shearwater (A. gravis, 43) and Magellanic Penguin (Spheniscusmagellanicus, 12). Lowerlevels of mortality were recorded in Black-browed albatross and White-chinnedpetrel. The average mortality rate was 0.70 birds per haul, a value greater thanthe one estimated for demersal trawlers operating in the same area. This study is relevant to the implementation of the ArgentineNational Plan of Action-Seabirds, as well as for the ongoing fisherycertification process.