Seabirds attending bottom long‐line fishing off southeastern Brazil

Abstract

Flocks of seabirds attending commercial bottom long‐line fishing operations on the coastal shelf off southeastern Brazil show a greater species diversity during the summer than the winter (16 v 9 species), although the number of birds per flock tended to be greater during the cold season. During the summer, the Spectacled Petrel Procellaria aequinoctialis conspi‐cillata was the commonest species, followed by the Great Shearwater Puffinus gravis, Cory's Shearwater Calonectris diomedea, skuas Stercorarius spp. and the Yellow‐nosed AlbatrossDiomedea chlororhynchus. During the winter, the White‐chinned Petrel Procellaria aequin‐octialis, Yellow‐nosed Albatross and Black‐browed Albatross Diomedea melanophrys were jointly the commonest species. Marked differences in the relative abundance of species were observed between the different sampling periods, probably because of migratory movements but also because of seasonal shifts of the sea currents and the influence of cold fronts. Waters off southeastern Brazil are important feeding areas for some seabird populations nesting in the Tristan da Cunha and Gough group, especially for nonbreeding Spectacled Petrels and post‐breeding Yellow‐nosed Albatrosses.

Structure of the seabird assemblage associated with pelagic longline vessels in the southwestern Atlantic: implications for bycatch

“…6) allowed us to characterize 2 species groups: species with little or no association with discards that usually fly through the sampled area, and species of albatross and petrel that make direct use of the resources made available by the fishery. These latter species interact inter-and intraspecifically, as observed in other longline fisheries (Vaske 1991, Olmos 1997). Other studies have described interspecific interactions during feeding on discards and bait in longline fisheries, suggesting a relationship between dominance and body size (Brothers 1991, Vaske 1991, Olmos 1997.…”

“…These latter species interact inter-and intraspecifically, as observed in other longline fisheries (Vaske 1991, Olmos 1997). Other studies have described interspecific interactions during feeding on discards and bait in longline fisheries, suggesting a relationship between dominance and body size (Brothers 1991, Vaske 1991, Olmos 1997. We evaluated this hypothesis, confirming a strong negative correlation between hierarchical ranking and body mass, which indicates a higher probability of success in interspecific interactions as species' body mass increases.…”

“…> 38 species) is greater than that observed in any other longline or trawl fishery (i.e. a range of 12 to 23 species) operating in the southwest Atlantic (Vaske 1991, Olmos 1997, Yorio & Caille 1999, González-Zevallos & Yorio 2006, Sullivan et al 2006, Gandini & Seco Pon 2007, González-Zevallos et al 2007, Bugoni et al 2008, Favero et al 2011, Goetz et al 2011). This may be explained by the presence of the BMC, the dynamic of which (see next section) determines that the assemblage under study is tran-249 Fig.…”

Foraging range and habitat associations of non‑breeding Tristan albatrosses: overlap with fisheries and implications for conservation

“…The population is estimated to be decreasing by almost 3% yr −1 , with annual mortality from longline fishing estimated to be around 250 individuals (Wanless et al 2009). Tristan albatrosses have been killed by pelagic longline fisheries off Brazil (Olmos 1997, Cuthbert et al 2005) and southern Africa (Petersen et al 2009). A recent assessment conducted under the auspices of the International Commission for the Conservation of Atlantic Tunas (ICCAT) concluded that the Tristan albatross was one of the species most at risk from longline fishing within the ICCAT area of jurisdiction (Tuck et al 2011).…”

Serum biochemistry of an, atlantic Yellow-Nosed Albatross Thalassarche chlororhynchos (Gmelin, 1789)

“…Other ways of interaction are by incidental mortality and using fisheries waste as food. The fisheries waste that frequently causes the gathering of large numbers of seabirds would rarely or never be seen under natural conditions (Olmos, 1997). South American and South African fleets are responsible for just a small part of the total longline fishing effort in the South Atlantic, considering the most fishing effort is being undertaken by Japan and Taiwan.…”