Marine habitat use of wintering spectacled petrels Procellaria conspicillata, and overlap with longline fishery

Satellite transmitters were used to determine the marine habitat utilization and fishery overlap of wintering spectacled petrels Procellaria conspicillata in the southwestern Atlantic Ocean in 2006 and 2007. Kernel density analysis of tracked birds demonstrated intense use of waters in the Brazilian Exclusive Economic Zone, from 26 to 31°S, mainly over the continental shelf break and offshore waters (mean depth in the < 20% kernel density areas = 1043 ± 794 m), over warm tropical and subtropical waters (mean SST = 22°C and 21°C in 2006 and 2007, respectively) and mesotrophic/ oligotrophic waters (chlorophyll a density = 0.301 and 0.281 mg m–3 in 2006 and 2007, respectively). These habitats used by spectacled petrels are remarkably different from those used by their sister species, the white-chinned petrel P. aequinoctialis, which occurs mainly over the continental shelf on sub-Antarctic and productive waters. A close association between spectacled petrels and the pelagic longline fishery was demonstrated through comparison of the main kernel areas used by spectacled petrels and the areas used by the pelagic longline fleet determined by fishing effort at resolution of 1 × 1° quadrants. Travel speeds and distances during night and daytime periods did not differ. The present study demonstrates the importance of high resolution fishing effort data to address relationships between bird marine habitat use and specific fishing fleets, and to determine marine habitats and investigate at sea segregation between closely related species.