Vertebral Counts and the Problem of Races in the Atlantic Shad

Warfel, Herbert E.; Olsen, Yngve H.

doi:10.2307/1438846

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…In A . sapidissima, which also shows variation in certain morphological characters between different river systems (Hildebrand & Schroeder, 1928;Vladykov & Wallace, 1938;Warfel & Olsen, 1947;Fischler, 1959;Hill, 1959), there is a trend of increase in the proportion of repeat spawners in the spawning population with latitude from south to north (Leggett & Carscadden, 1978). If a similar trend exists for A .…”

Section: Discussionmentioning

confidence: 99%

The effect of the migration of Alosa fallax fallax (Laécpède) into fresh water, on branchial and gut parasites

Aprahamian

1985

Journal of Fish Biology

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The prevalence and relative density of branchial and gut parasites taken from Almafullax in the estuary of the River Severn, at the start of the freshwater phase of its spawning migration, were compared with those taken from their spawning grounds in fresh water. Mazocrues alosue showed no significant difference in prevalence between the two habitats, though their relative density did fall significantly. Because of the direct relationship between length and relative density, this difference may be explained by the estuary samples of A. fullux being of fish significantly larger than those from fresh water. Other possible causes are discussed. The prevalence and relative density of M. alosae showed a trend to increase with age of the host. Repeat spawning A. fallax had a significantly greater relative density and prevalence of M. alosue when compared to virgin fish. Analysis of the sampled population showed that Clavellisu emarginata declined significantly in both prevalence and relative density in fresh water, and this was confined to the younger and first time spawning A. fullux. Thynnuscuris aduncum showed significant reductions in prevalence and relative density of infection in fresh water when compared to the estuarine samples. The species Hemiurus uppendiculatus and Pomphorhynchus laevis showed no significant difference in prevalence and relative density of infection, and Pronoprymna ventrzcosa no significant difference in prevalence, between the two habitats.

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Section: Discussionmentioning

confidence: 99%

The effect of the migration of Alosa fallax fallax (Laécpède) into fresh water, on branchial and gut parasites

Aprahamian

1985

Journal of Fish Biology

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“…Early efforts focused on natural variability in meristic and morphometric characters among rivers (e.g., Warfel and Olsen 1947;Carscadden and Leggett 1975;Melvin et al 1992). Mitochondrial and microsatellite DNA polymorphisms showed subtle but significant variation among fish from groups of rivers throughout the range of the species (Epifanio et al 1995;Waters et al 2000;Nolan et al 2003), and mtDNA polymorphisms have been used to examine the stock structure of oceanic harvests of American shad (Brown et al 1999).…”

Section: Connmentioning

confidence: 99%

Continental-scale variation in otolith geochemistry of juvenile American shad (Alosa sapidissima)

Walther

Thorrold

2008

Can. J. Fish. Aquat. Sci.

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Abstract:We assembled a comprehensive atlas of geochemical signatures in juvenile American shad (Alosa sapidissima) to discriminate natal river origins on a large spatial scale and at a high spatial resolution. Otoliths and (or) water samples were collected from 20 major spawning rivers from Florida to Quebec and were analyzed for elemental (Mg:Ca, Mn:Ca, Sr:Ca, and Ba:Ca) and isotope ( 87 Sr: 86 Sr and d 18 O) ratios. We examined correlations between water chemistry and otolith composition for five rivers where both were sampled. While Sr:Ca, Ba:Ca, 87 Sr: 86 Sr, and d 18 O values in otoliths reflected those ratios in ambient waters, Mg:Ca and Mn:Ca ratios in otoliths varied independently of water chemistry. Geochemical signatures were highly distinct among rivers, with an average classification accuracy of 93% using only those variables where otolith values were accurately predicted from water chemistry data. The study represents the largest assembled database of otolith signatures from the entire native range of a species, encompassing approximately 2700 km of coastline and 19 degrees of latitude and including all major extant spawning populations. This database will allow reliable estimates of natal origins of migrating ocean-phase American shad from the 2004 annual cohort in the future.

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“…Early efforts focused on natural variability in meristic and morphometric characters among rivers (Warfel and Olsen 1947;Fischler 1959;Nichols 1960a;Carscadden and Leggett 1975b;Melvin et al 1992). Mitochondrial and microsatellite DNA polymorphisms showed subtle but significant variation among fish from groups of rivers throughout the range of the species (Bentzen et al 1989;Nolan et al 1991;Epifanio et al 1995;Waters et al 2000;Nolan et al 2003), and mtDNA polymorphisms have been used to examine the stock structure of oceanic harvests of American shad (Brown et al 1999).…”

Section: Discussionmentioning

confidence: 99%

Migratory patterns of American shad (Alosa sapidissima) revealed by natural geochemical tags in otoliths

Walther¹

2007

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Geochemical signatures in the otoliths of diadromous fishes may allow for retrospective analyses of natal origins. In an assessment of river-specific signatures in American shad (Alosa sapidissima), an anadromous clupeid native to the Atlantic coast of North America, stable isotope and elemental ratios in otoliths of juvenile American shad produced accurate natal tags from 12 rivers. Significant inter-annual variability in geochemical signatures from several rivers was detected, due largely to differences in δ 18 O values among years. The database was further expanded to include 20 rivers from Florida to Quebec, encompassing all major spawning populations. This task was accomplished by collecting juvenile otoliths along with water samples from rivers where juveniles were not sampled. Regressions between otolith and water chemistry for those rivers where both were collected showed significant relationships for Sr:Ca, Ba:Ca, δ 18 O, and 87 Sr: 86 Sr ratios but not for Mg:Ca or Mn:Ca. Despite reducing the combined signature to only four chemical ratios, cross-validated classification accuracies of knownorigin juveniles averaged 93%. Ground-truthed signatures were used to classify migrants of unknown origins. Adults returning to spawn in the York River were classified according to their otolith composition. Only 6% of spawners originated from rivers other than the York, supporting the hypothesis that most American shad spawn in their natal river. Of remaining spawners, 79% originated from the Mattaponi River and 21% from the Pamunkey River. The results suggested that while most American shad home to their natal river there is less fidelity to individual tributaries, allowing subsidies to subpopulations with persistent recruitment failure. Otolith signatures were also used in mixed-stock analyses of immature migrants along the coast of Maine in the spring and Minas Basin in the summer. Mixed-stock compositions showed remarkably low diversity and were dominated by fish from the Shubenacadie and Hudson rivers, with an increasing proportion of Potomac River fish over time. In contrast to results from adult tagging studies, southern stocks were virtually absent. These data suggest ontogenetic shifts in migratory behavior. The thesis concludes with a report that water contributed 83% of Sr and 98% of Ba in the otoliths of a marine fish.

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Vertebral Counts and the Problem of Races in the Atlantic Shad

Cited by 4 publications

References 6 publications

The effect of the migration of Alosa fallax fallax (Laécpède) into fresh water, on branchial and gut parasites

The effect of the migration of Alosa fallax fallax (Laécpède) into fresh water, on branchial and gut parasites

Continental-scale variation in otolith geochemistry of juvenile American shad (Alosa sapidissima)

Migratory patterns of American shad (Alosa sapidissima) revealed by natural geochemical tags in otoliths

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