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Genetic Analysis Of White Marlin (Tetrapturus Albidus) Stock Structure, John Graves, Jan Mcdowell
Genetic Analysis Of White Marlin (Tetrapturus Albidus) Stock Structure, John Graves, Jan Mcdowell
VIMS Articles
The genetic basis of stock structure of white marlin (Tetrapturus albidus Poey, 1860) was inferred from analyses of five tetranucleotide repeat microsatellite loci (n = 214) and the mitochondrial (mt)DNA control region (n = 99) of white marlin from four geographic regions in the Atlantic Ocean. Considerable genetic variation was present in all collections for all molecular markers. Analysis of replicate collections taken in different years from three regions revealed no significant differences in the distribution of allele frequencies among years within regions. The value of global F-statistics for both multilocus microsatellite data and mtDNA control region sequences approached significance …
Phylogeny Of Recent Billfishes (Xiphioidei), Bb Collette, Jan Mcdowell, John Graves
Phylogeny Of Recent Billfishes (Xiphioidei), Bb Collette, Jan Mcdowell, John Graves
VIMS Articles
Billfishes are genetically and morphologically distinct enough from scombroids to merit placement in a separate suborder, Xiphioidei. Two extant families are usually recognized: Xiphiidae (swordfish, Xiphias) and Istiophoridae, currently containing three genera, Istiophorus (sailfishes), Makaira (marlins), and Tetrapturus (spearfishes, white, and striped marlins). Phylogenetic analyses of molecular data from mitochondrial and nuclear gene sequences (mitochondrial control region, ND2, 12S, and nuclear MN 32 regions) show a different picture of relationships. Makaira is not monophyletic: blue marlin cluster with sailfish and placement of black marlin is unstable. Accepting the molecular phylogeny gives two possible classifications: (1) two genera: blue marlin + …
Genetic Heterogeneity Of Atlantic Bluefin Tuna Caught In The Eastern North Atlantic Ocean South Of Iceland, J Carlsson, Jr Mcdowell, Et Al
Genetic Heterogeneity Of Atlantic Bluefin Tuna Caught In The Eastern North Atlantic Ocean South Of Iceland, J Carlsson, Jr Mcdowell, Et Al
VIMS Articles
Atlantic bluefin tuna (Thunnus thynnus) are currently managed by the member nations of the International Commission for the Conservation of Atlantic Tunas (ICCAT) as distinct western and eastern stocks, separated by the 45 degrees W meridian. Previous studies of Atlantic bluefin tuna caught in the northeast Atlantic south of Nor-way suggested mixing of putative stocks in the region, based on abrupt shifts in the size and condition of fish during the fishing season. By contrast, more recent studies south of Iceland reported only small differences in size of tuna caught at different times of the season in that area. To …
Incentive-Based Approaches To Sustainable Fisheries, Rq Grafton, R Arnason, Et Al, Je Kirkley, Et Al
Incentive-Based Approaches To Sustainable Fisheries, Rq Grafton, R Arnason, Et Al, Je Kirkley, Et Al
VIMS Articles
The failures of traditional target-species management have led many to propose an ecosystem approach to fisheries to promote sustainability. The ecosystem approach is necessary, especially to account for fishery-ecosystem interactions, but by itself is not sufficient to address two important factors contributing to unsustainable fisheries: inappropriate incentives bearing on fishers and the ineffective governance that frequently exists in commercial, developed fisheries managed primarily by total-harvest limits and input controls. We contend that much greater emphasis must be placed on fisher motivation when managing fisheries. Using evidence from more than a dozen natural experiments in commercial fisheries, we argue that incentive-based …
Fish Assemblages Found In Tidal-Creek And Seagrass Habitats In The Suwannee River Estuary, Troy D. Tuckey, Mark Dehaven
Fish Assemblages Found In Tidal-Creek And Seagrass Habitats In The Suwannee River Estuary, Troy D. Tuckey, Mark Dehaven
VIMS Articles
Fish assemblages were investigated in tidal-creek and seagrass habitats in the Suwannee River estuary, Florida. A total of 91,571 fish representing 43 families were collected in monthly seine samples from January 1997 to December 1999. Tidal creeks supported greater densities of fish (3.89 fish/m(2); 83% of total) than did seagrass habitats (0.93 fish/m(2)). We identified three distinct fish assemblages in each habitat: winter-spring, summer, and fall. Pinfish (Lagodon rhomboides), pigfish (Orthopristis chrysoptera), and syngnathids characterized seagrass assemblages, whereas spot (Leiostomus xanthurus), bay anchovy (Anchoa mitchilli), silversides (Menidia spp.), mojarras (Eucinostomus spp.), and fundulids characterized tidal-creek habitats. Important recreational and commercial …
Standard And Routine Metabolic Rates Of Juvenile Sandbar Sharks (Carcharhinus Plumbeus), Including The Effects Of Body Mass And Acute Temperature Change, W Wesley Dowd, Richard Brill, Peter Bushnell, John A. Musick
Standard And Routine Metabolic Rates Of Juvenile Sandbar Sharks (Carcharhinus Plumbeus), Including The Effects Of Body Mass And Acute Temperature Change, W Wesley Dowd, Richard Brill, Peter Bushnell, John A. Musick
VIMS Articles
Standard and routine metabolic rates (SMRs and RMRs, respectively) of juvenile sandbar sharks (Carcharhinus plumbeus) were measured over a range of body sizes (n=34) and temperatures normally associated with western Atlantic coastal nursery areas. The mean SMR Q(10) (increase in metabolic rate with temperature) was 2.9 +/- 0.2. Heart rate decreased with increasing body mass but increased with temperature at a Q(10) of 1.8-2.2. Self-paired measures of SMR and RMR were obtained for 15 individuals. Routine metabolic rate averaged 1.8 +/- 0.1 times the SMR and was not correlated with body mass. Assuming the maximum metabolic rate of sandbar sharks …
Survival Of White Marlin (Tetrapturus Albidus) Released From Commercial Pelagic Longline Gear In The Western North Atlantic, David Kerstetter, John E. Graves
Survival Of White Marlin (Tetrapturus Albidus) Released From Commercial Pelagic Longline Gear In The Western North Atlantic, David Kerstetter, John E. Graves
VIMS Articles
To estimate postrelease survival of white marlin (Tetrapturus albidus) caught incidentally in regular commercial pelagic longline fishing operations targeting swordfish and tunas, short-duration popup satellite archival tags (PSATs) were deployed on captured animals for periods of 5-43 days. Twenty (71.4%) of 28 tags transmitted data at the preprogrammed time, including one tag that separated from the fish shortly after release and was omitted from subsequent analyses. Transmitted data from 17 of 19 tags were consistent with survival of those animals for the duration of the tag deployment. Postrelease survival estimates ranged from 63.0% (assuming all nontransmitting tags were evidence of …
Growth And Maturity Of Salmon Sharks (Lamna Ditropis) In The Eastern And Western North Pacific, And Comments On Back-Calculation Methods, Kenneth J. Goldman, John A. Musick
Growth And Maturity Of Salmon Sharks (Lamna Ditropis) In The Eastern And Western North Pacific, And Comments On Back-Calculation Methods, Kenneth J. Goldman, John A. Musick
VIMS Articles
Age and growth estimates for salmon sharks (Lamna ditropis) in the eastern North Pacific were derived from 182 vertebral centra collected from sharks ranging in length from 62.2 to 213.4 cm precaudal length (PCL) and compared to previously published age and growth data for salmon sharks in the western North Pacific. Eastern North Pacific female and male salmon sharks were aged up to 20 and 17 years, respectively. Relative marginal increment (RMI) analysis showed that postnatal rings form annually between January and March. Von Bertalanffy growth parameters derived from vertebral length-at-age data are L-proportional to=207.4 cm PCL, k=0.17/yr, and t(0)=-2.3 …
Estimating Consumption Rates Of Juvenile Sandbar Sharks (Carcharhinus Plumbeus) In Chesapeake Bay, Virginia, Using A Bioenergetics Model, W Wesley Dowd, Richard Brill, Peter Bushnell, John A. Musick
Estimating Consumption Rates Of Juvenile Sandbar Sharks (Carcharhinus Plumbeus) In Chesapeake Bay, Virginia, Using A Bioenergetics Model, W Wesley Dowd, Richard Brill, Peter Bushnell, John A. Musick
VIMS Articles
Using a bioenergetics model, we estimated daily ration and seasonal prey consumption rates for six age classes of juvenile sandbar sharks (Carcharhinus plumbeus) in the lower Chesapeake Bay summer nursery area. The model, incorporating habitat and species-specific data on growth rates, metabolic rate, diet composition, water temperature (range 16.8-27.9 degrees C), and population structure, predicted mean daily rations between 2.17 +/- 0.03 (age-0) and 1.30 +/- 0.02 (age-5) % body mass/day. These daily rations are higher than earlier predictions for sandbar sharks but are comparable to those for ecologically similar shark species. The total nursery population of sandbar sharks was …