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Full-Text Articles in Physical Sciences and Mathematics
Alaska Marine Mammal Stock Assessments, 2008, R. P. Angliss, B. M. Allen
Alaska Marine Mammal Stock Assessments, 2008, R. P. Angliss, B. M. Allen
United States Department of Commerce: Staff Publications
This report provides information on the marine mammal stocks of Alaska under the jurisdiction of the National Marine Fisheries Service. Each stock assessment includes, when available, a description of the stock’s geographic range, a minimum population estimate, current population trends, current and maximum net productivity rates, optimum sustainable population levels and allowable removal levels, and estimates of annual human-caused mortality and serious injury through interactions with commercial fisheries and subsistence hunters. These data will be used to evaluate the progress of each fishery towards achieving the MMPA’s goal of zero fishery-related mortality and serious injury of marine mammals. The Stock …
Chronic Exposure To Polynuclear Aromatic Hydrocarbons In Natal Habitats Leads To Decreased Equilibrium Size, Growth, And Stability Of Pink Salmon Populations, Ron A. Heintz
United States Department of Commerce: Staff Publications
The immediate and delayed effects of embryonic exposure to low levels of polynuclear aromatic hydrocarbons (PAHs) have been shown to reduce survival to maturity by 50% in exposed pink salmon populations. This suggests that chronically exposed populations could be extirpated over relatively few generations, but the effect of density dependence on extirpation rate is unknown. This study examines the interaction of PAH effects and randomly varying density dependence on a simulated population. The simulation derives from 70 years of observations made on a single pink salmon population and toxicity studies involving a hatchery population in the same watershed. Results from …
First Estimates Of Vaquita Abundance, Jay Barlow, Tim Gerrodette, Greg Silber
First Estimates Of Vaquita Abundance, Jay Barlow, Tim Gerrodette, Greg Silber
United States Department of Commerce: Staff Publications
The abundance of the only population of vaquitas, Gulf of California harbor porpoise (Phocoena sinus), is estimated from four surveys conducted in Mexico between 1986 and 1993, using a variety of methods. A line-transect approach was applied, using some parameters estimated from a related species, the harbor porpoise (Phocoena phocoena). Vaquita abundance is estimated as 503 (CV = 0.63) from 1986-1988 boat surveys, 885 (CV = 0.50) from 1988-- 1989 aerial surveys, 572 (CV = 1.43) from a 1991 aerial survey, and 224 (CV = 0.39) from a 1993 ship survey. A weighted log-linear regression in …
Initial Colonization Of The Zebra Mussel (Dreissena Polymorpha) In Saginaw Bay, Lake Huron: Population Recruitment, Density, And Size Structure, Thomas F. Nalepa, James A. Wojcik, David L. Fanslow, Gregory A. Lang
Initial Colonization Of The Zebra Mussel (Dreissena Polymorpha) In Saginaw Bay, Lake Huron: Population Recruitment, Density, And Size Structure, Thomas F. Nalepa, James A. Wojcik, David L. Fanslow, Gregory A. Lang
United States Department of Commerce: Staff Publications
The various life stages of the zebra mussel (Dreissena polymorpha) were examined during the initial years (1991-93) of the mussel's invasion into Saginaw Bay, Lake Huron. Yearly trends in densities of larvae, newly-settled juveniles, and adults were poorly related. Larval densities were lowest in 1991 and increased each year, but the number of settled juveniles was highest in 1991. Adults increased between 1991 and 1992 and then declined in 1993. Mean adult densities at sites with hard substrates were 11,700,33,200, and 4,1001m2 in each of the 3 years, respectively. Year-to-year variation at individual sites was high and likely …