نتایج جستجو برای: alosa saposchnikowii
تعداد نتایج: 268 فیلتر نتایج به سال:
—We developed and applied a stable isotope turnover model to estimate how long age-0 American shad Alosa sapidissima reside within tidal freshwater and brackish-water habitats in the York River estuary, Virginia. The residence time was estimated by modeling the changing stable isotope ratio (either the carbon [dC] or sulfur [dS] stable isotope ratio) of an age-0 American shad as it migrates sea...
—The physiological responses of juvenile American shad Alosa sapidissima were evaluated during the period of downstream migration in freshwater (FW) and after seawater (SW) acclimation associated with postmigration. Fish were subjected to a standardized, acute handling and confinement stress (3 h). Changes in plasma cortisol, plasma chloride, and hematocrit were monitored for 24 h. Basal levels...
Larval and juvenile American shad (Alosa sapidissima) raised from eggs in the laboratory were subjected to biweekly 24-h seawater (35 ppt) challenges. There was no survival in seawater before 36 days post-hatch, and most mortalities occurred within 2 h of transfer. Twenty-four hour survival reached 89% in seawater at 45 days post-hatch (when larvaljuvenile metamorphosis occurred), 96% at 58 da...
به منظور شناسایی و تعیین پراکنش شگ ماهیان در حوضه جنوب غربی دریای خزر در سالهای 87 و 88 همزمان با شروع فصل صید ماهیان استخوانی، نمونه برداری از تعاونیهای صیادی پره در نوار ساحلی استان گیلان از منطقه چابکسر تا منطقه آستارا انجام گرفت. در مجموع 132 قطعه شگ ماهی صید و مورد بررسی قرار گرفتند. جهت شناسایی گونه ها از دو شاخص اندازه گیری های ریخت سنجی(مورفو متریک) و خصوصیات شمارشی(مریستیک)...
Otsego Lake (42o 41’N-70o’W) is the headwaters of the glacially-created Susquehanna River valley within the northern Appalachian Plateau. Historically considered oligo-mesotrophic, (Harman et al., 1997) the unauthorized introduction of alewives (Alosa pseudoharengus) in 1986 (Foster 1989) affected the lake, creating changes similar to those of eutrophy (Harman et al. 2002). Efficient planktivor...
Anadromous blueback herring Alosa aestivalis are declining throughout much of their range, and fishery closures in some systems have failed to produce population recovery. A potential contributing factor is increased predation pressure from sympatric striped bass Morone saxatilis. We integrated data on the predator–prey interaction between striped bass and blueback herring during vernal migrati...
Several nature-like fishway designs have been constructed in the northeastern US, but none of these fishways have been quantitatively evaluated for passage of northeastern diadromous species. This report summarizes data on passage performance from two studies of nature-like fishway designs for passage of river herring in the field (Town Brook, Plymouth, Massachusetts, and East River, Guilford, ...
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