Guy T.J.,University of Washington |
Jennings S.L.,University of Washington |
Jennings S.L.,University of California at Davis |
Suryan R.M.,Oregon State University |
And 18 more authors.
Fisheries Research | Year: 2013
We used a combination of seabird data (both fishery-dependent and fishery-independent) and fishing-effort data to evaluate the relative fisheries risk of five west coast groundfish fisheries and one shrimp fishery to black-footed (Phoebastria nigripes), short-tailed (P. albatrus) and Laysan albatrosses (P. immutabilis). To assess risk, an overlap index was derived as the product of total fishing effort and at-sea survey density of black-footed albatross. This index was used as the primary tool to estimate overlap with the endangered, relatively rare short-tailed albatross, which show similar habitat utilization from satellite telemetry tracks. Telemetry data indicate Laysan albatross primarily occur offshore beyond observed fishing effort. Black-footed and short-tailed albatross-fishery overlap was highest at the shelf-break (201-1000. m) north of 36° N. Overlap and reported albatross mortality indicate that the sablefish (Anoplopoma fimbria) longline and Pacific hake (Merluccius productus) catcher-processor fisheries pose the greatest risk to these species; the near-shore rockfish (Seabastes spp.) longline, pink shrimp (Pandalus jordani) trawl, California halibut (Paralichthys californicus) trawl, and non-hake groundfish trawl fisheries pose relatively little risk. Implementing proven seabird bycatch-reduction measures will likely minimize albatross mortality in the highest-risk fishery, sablefish longline. © 2013 Elsevier B.V.
Donnelly-Greenan E.L.,Moss Landing Marine Laboratories |
Donnelly-Greenan E.L.,Marine Wildlife Veterinary Care and Research Center |
Harvey J.T.,Moss Landing Marine Laboratories |
Nevins H.M.,Marine Wildlife Veterinary Care and Research Center |
And 2 more authors.
Marine Pollution Bulletin | Year: 2014
Marine plastic pollution affects seabirds, including Pacific Northern Fulmars (Fulmarus glacialis rodgersii), that feed at the surface and mistake plastic for prey or incidentally ingest it. Direct and indirect health issues can result, including satiety and possibly leading to inefficient foraging. Our objective was to examine fulmar body condition, identify cephalopod diet to species, enumerate and weigh ingested plastic, and determine if prey number and size were correlated with ingested plastics in beach-cast fulmars wintering in Monterey Bay California (2003, n= 178: 2007, n= 185). Fulmars consumed mostly Gonatus pyros, G. onyx, and G. californiensis of similar size for both years. We found a significant negative correlation between pectoral muscle index and average size of cephalopod beaks per stomach; a significant increase in plastic categories between 2003 and 2007; and no significant correlation between number and mass of plastic compared with number and size of prey for either year. © 2014 Elsevier Ltd.
Carle R.D.,Moss Landing Marine Laboratories |
Beck J.N.,Oikonos Ecosystem Knowledge |
Calleri D.M.,Oikonos Ecosystem Knowledge |
Hester M.M.,Oikonos Ecosystem Knowledge
Journal of Marine Systems | Year: 2014
We used stable isotopes (δ15N and δ13C) and compared prey provided to chicks by each sex to evaluate seasonal and sex-specific diets in Rhinoceros Auklets (Cerorhinca monocerata) in the central California Current system during 2012-2013. Mixing models indicated northern anchovy (Engraulis mordax) were important prey for adults during fall/winter and juvenile rockfishes (Sebastes spp.) were important prey during incubation both years. Adult trophic level increased between incubation and chick-rearing periods in both years. During 2012, δ15N and δ13C of chick-rearing males and females differed significantly; mixing models indicated that females ate more Pacific saury (Cololabis saira) and less market squid (Doryteuthis opalescens) than males. Likewise, females delivered significantly more Pacific saury and less market squid to chicks than males during 2012. Chick growth (g d-1) and chick survival to fledging were significantly lower during 2012 than 2013, likely because chicks were fed lesser quality prey or fed less frequently in 2012. Lesser body mass of females during incubation in 2012 indicated sex-specific diet differences may have been related to female energetic constraints. The observed variability in Rhinoceros Auklet diet underscores the importance of managing multiple prey populations in this system so that generalist predators have sufficient resources through changing conditions. © 2014 Elsevier B.V.