Genetic analysis of wandering albatrosses killed in longline fisheries off the east coast of New Zealand

Abstract

1.Fisheries bycatch is an important global conservation issue. Each year many species, including seabirds, are killed accidentally in longline fisheries. Highly vagile marine species such as the wandering albatross species complex (Diomedea spp.), populations of which have declined dramatically due to fisheries-related mortality, traverse large areas of open ocean and as a result are at high risk of negative fisheries interactions. 2.For most wandering albatrosses found dead at-sea the provenance is unknown unless they are ringed, as their poor condition make species identification very difficult. However, molecular markers can be used as genetic tags to identify the population of origin of bycatch birds. 3.Five microsatellite markers and mitochondrial restriction fragment length polymorphism were used to genotype 41 individuals belonging to the wandering albatross species complex killed in longline fisheries in two locations off the east coast of the North and South Islands of New Zealand, an area known to be visited by at least three members of the wandering albatross groups. 4.Assignment tests indicate that the majority (22/30 of assigned individuals) of bycatch birds were D. antipodensis antipodensis from Antipodes Island, the closest breeding site. More than half of the North Island birds were assigned to D. a. antipodensis (8/14); the remaining samples were assigned to both the D. a. gibsoni from The Auckland Islands (n=3) and D. exulans from the South Atlantic/Indian Ocean (n=3). The South Island samples were almost exclusively assigned to D. a. antipodensis (14/16) of which 13 were males. In the North Island samples there were 14 males and 8 females. 5.This study has shown that molecular markers are a powerful tool to determine the species identity, population of origin and sex of bycatch birds to better understand the impact of fisheries-related mortality and conservation priorities for individual populations. Copyright © 2008 John Wiley & Sons, Ltd.