Contribution of fishery discards to the diet of the Black-browed albatross (Thalassarche melanophris) during the non-breeding season: an assessment through stable isotope analysis

Foraging Strategies of Laysan Albatross Inferred from Stable Isotopes: Implications for Association with Fisheries

“…In contrast, the higher mean δ 15 N and δ 13 C values of failed breeders may be indicative of foraging on or near the continental shelf where the Alaskan longline fisheries are concentrated, and/or on higher-trophic level prey in mid-oceanic waters, including fisheries-associated food such as tuna or swordfish. Stable isotope studies in the South Atlantic of ship-following seabirds have attributed enriched δ 15 N values of blood to the consumption of fisheries-associated food [ 77 – 78 ]. We did not separate the effect of foraging location from the effect of prey type on stable isotope values, so we can not conclude with certainty from this study alone that elevated δ 15 N or δ 13 C among fisheries-associated birds were the direct result of consuming fisheries-associated food.…”

“…Tracking studies are ideally suited for assessing geographic overlap of North Pacific albatrosses with regional fisheries [ 5 ], [ 88 ], as well as for measuring foraging association with remotely sensed oceanographic features, such as sea surface temperature, hydrographic fronts or wind [ 14 ], [ 21 ], [ 37 ], [ 78 ], [ 89 ]. However, tracking studies alone can not determine which prey are consumed when an individual travels to different parts of its foraging range.…”

“…The effect of foraging location can be measured by analyzing isotopic values of feathers of known seasonality collected from tagged individuals that have seasonally identifiable foraging ranges [ 59 ]. The effect of prey composition can be measured by first measuring stable isotope values for a range of location-specific prey (including fisheries-associated food), then develop location-specific stable isotope mixing models [ 77 – 78 ]. These stable isotope research efforts would facilitate modeling of the demographic consequences of both fisheries-associated mortality (e.g., [ 91 ]), and changing foraging dynamics due to climate change [ 78 ].…”

Pelagic seabirds as biomonitors of persistent organic pollutants in the Southwestern Atlantic

“…Previous studies dealing with different bird species have attributed the observed differences in pollutant loads to dietary habits and location of breeding areas (Rajaei et al, 2011;Behrooz et al, 2009;Jaspers et al, 2006). The diet of both studied species is mostly comprised of fish, cephalopods and crustaceans (Prince, 1980;Hodum and Hobson, 2000;Fijn et al, 2012;Mariano-Jelicich et al, 2014). Besides, both species feed on discards and offal while attending commercial fishing vessels in the study area during their non-breeding seasons (Seco Pon et al, 2015), and have relative similar nesting areas; i.e.…”

“…Pollutants load are suspected to vary in those species with differential diet and/or foraging areas or even with body-size differences between sexes. However, dietary analyses based on stable isotopes showed that during the non-breeding season both sexes of BBA and CAP forage at the same trophic level (Mariano-Jelicich et al, 2014;Mariano Jelicich et al, unpublished data). Otherwise, a certain degree of spatial segregation was observed between sexes in satellite-tracked BBA during the non-breeding period (Paz et al, unpublished data).…”