نتایج جستجو برای: alosa braschnikowi

تعداد نتایج: 268  

2005
JOEL C. HOFFMAN JOHN E. OLNEY

—We estimated the variation in instantaneous rates of growth (G) and mortality (M) between intraannual cohorts of juvenile American shad Alosa sapidissima in the Pamunkey River, Virginia. The ages of juveniles captured by push net during the juvenile abundance index surveys in 1998 and 1999 were estimated by counting daily rings on the sagittal otoliths. Weight-at-age and abundance-at-age data ...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد گرمسار - دانشکده دامپزشکی 1390

در تحقیق حاضر در زمستان سال 1390 در منطقه ساحلی قائم شهر در سه ایستگاه چپک رود،لاریم و یزدانی صورت گرفته است.تعداد 30 قطعه ماهی زالون پس از صید از سواحل ساحلی دریای خزر بلافاصله با آب سرد شسته و بعد از بیومتری ماهیان کاملا شکم شده است.متوسط طول ماهیان در این بررسی در ایستگاه شماره یک 19 سانتی متر در ایستگاه شماره دو 20 سانتی متر و در ایستگاه شماره سه 17 سانتی متر بوده است.متوسط وزن ماهیان در ای...

2012
Sergiusz Czesny John Epifanio Pawel Michalak

Alewife Alosa pseudoharengus, a small clupeid fish native to Atlantic Ocean, has recently (∼150 years ago) invaded the North American Great Lakes and despite challenges of freshwater environment its populations exploded and disrupted local food web structures. This range expansion has been accompanied by dramatic changes at all levels of organization. Growth rates, size at maturation, or fecund...

Journal: :Aquatic Conservation-marine and Freshwater Ecosystems 2021

Artificial barriers on lowland rivers impede the spawning migrations of anadromous fishes, preventing access to historical areas. In cryptic European shads Alosa alosa and fallax (‘shad’ hereafter), this has resulted in population declines across their range. Conservation programmes aim facilitate passage migrators over these so require baseline information spatial temporal extent current migra...

Journal: :Evolution; international journal of organic evolution 2015
Jonathan P Velotta Stephen D McCormick Eric T Schultz

Adaptation to freshwater may be expected to reduce performance in seawater because these environments represent opposing selective regimes. We tested for such a trade-off in populations of the Alewife (Alosa pseudoharengus). Alewives are ancestrally anadromous, and multiple populations have been independently restricted to freshwater (landlocked). We conducted salinity challenge experiments, wh...

Journal: :Vision Research 2011
Gabriel E. Machovsky Capuska Leon Huynen David Lambert David Raubenheimer

Ultraviolet-sensitive vision (UVS), believed to have evolved from an ancestral state of violet-sensitive vision (VS), is widespread among terrestrial birds, where it is thought to play a role in orientation, foraging, and sexual selection. Less is known, however, about the distribution and significance of UVS in seabirds. To date UVS has been definitively demonstrated only in two families (Lari...

Journal: :Canadian Journal of Fisheries and Aquatic Sciences 1997

Journal: :Bulletin Français de la Pêche et de la Pisciculture 2001

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