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Ontogenetic Dietary Information Of The California Sea Lion (Zalophus Californianus) Assessed Using Stable Isotope Analysis, Anthony J. Orr, Seth D. Newsome, Jeffrey L. Laake, Glenn R. Vanblaricom, Robert L. Delong
Ontogenetic Dietary Information Of The California Sea Lion (Zalophus Californianus) Assessed Using Stable Isotope Analysis, Anthony J. Orr, Seth D. Newsome, Jeffrey L. Laake, Glenn R. Vanblaricom, Robert L. Delong
United States Department of Commerce: Staff Publications
We used stable carbon (δ13C) and nitrogen (δ15N) isotopes to examine ontogenetic dietary changes in 289 California sea lions (Zalophus californianus) at San Miguel Island, California during 2004–2007. Tissues analyzed included fur, red blood cells, plasma, and serum. For all tissues, pups had higher δ15N values and lower δ13C values compared to adults, which indicated that pups were feeding higher trophically than older conspecifics and on a lipid-rich milk diet prior to weaning. Yearling δ15N values were slightly lower than pup or nearly indistinguishable from adult values depending …
The Response Of Fish Larvae To Decadal Changes In Environmental Forcing Factors Off The Oregon Coast, Toby D. Auth, Richard D. Brodeur, Heather L. Soulen, Lorenzo Ciannelli, William T. Peterson
The Response Of Fish Larvae To Decadal Changes In Environmental Forcing Factors Off The Oregon Coast, Toby D. Auth, Richard D. Brodeur, Heather L. Soulen, Lorenzo Ciannelli, William T. Peterson
United States Department of Commerce: Staff Publications
We conducted a statistical analysis to characterize the influence of large-scale and local environmental factors on presence-absence, concentration, and assemblage structure of larval fish within the northern California Current (NCC) ecosystem, based on samples collected at two nearshore stations along the Newport Hydrographic line off the central Oregon coast. Data from 1996 to 2005 were compared with historical data from the 1970s and 1980s to evaluate pseudo-decadal, annual, and seasonal variability. Our results indicate that the most abundant taxa from 1996 to 2005 differ from those of earlier decades. Concentrations of the dominant taxa and total larvae were generally greater …
Migration And Behavior Of Juvenile North Pacific Albacore (Thunnus Alalunga), John Childers, Stephanie Snyder, Suzanne Kohin
Migration And Behavior Of Juvenile North Pacific Albacore (Thunnus Alalunga), John Childers, Stephanie Snyder, Suzanne Kohin
United States Department of Commerce: Staff Publications
Archival tags were used to study the seasonal movements, migration patterns and vertical distribution of juvenile North Pacific albacore (Thunnus alalunga). Between 2001 and 2006, archival tags were deployed in North Pacific albacore in two regions of the Northeast Pacific: (i) off Northern Baja California, Mexico and Southern California, and (ii) off Washington and Oregon. Twenty archival tagged fish were recovered with times at liberty ranging from 63 to 697 days. Tagged albacore exhibited five distinct, seasonal migratory patterns. Depth and temperature data also showed a broad range of vertical behaviors. In certain regions such as off Baja …
Life History Of The Indo-Pacific Humpback Dolphin In The Pearl River Estuary, Southern China, Thomas A. Jefferson, Samuel K. Hung, Kelly M. Robertson, Frederick I. Archer
Life History Of The Indo-Pacific Humpback Dolphin In The Pearl River Estuary, Southern China, Thomas A. Jefferson, Samuel K. Hung, Kelly M. Robertson, Frederick I. Archer
United States Department of Commerce: Staff Publications
We studied life history characteristics of the Hong Kong/Pearl River Estuary population of Indo-Pacific humpback dolphins (Sousa chinensis), based on data from 120 specimens stranded between 1995 and 2009, 40 individuals biopsied at sea, and a long-term (14+ yr) photo-identification study. Ages were determined for 112 specimens by thin-sectioning teeth and counting growth layer groups. Estimated length at birth was 101 cm. Longevity was at least 38 yr, and there was little difference in growth patterns of males and females. Growth was described by a Bayesian two-phase Gompertz model; asymptotic length was reached at 249 cm. The tooth …