نتایج جستجو برای: Sturgeon
تعداد نتایج: 1559 فیلتر نتایج به سال:
In the Bay of Fundy, Atlantic sturgeon from endangered and threatened populations in the USA and Canada migrate through Minas Passage to enter and leave Minas Basin. A total of 132 sub-adult and adult Atlantic sturgeon were tagged in Minas Basin during the summers of 2010-2014 using pressure measuring, uniquely coded, acoustic transmitters with a four or eight year life span. The aim of this st...
INTRODUCTION The sturgeons of the Caspian Sea are considered highly valuable species. The Caspian Sea has traditionally been regarded as the sea of sturgeon since it produces more than 90 percent of the world’s caviar. Despite a remarkable decline of sturgeon numbers over recent years, the Caspian Sea still continues to be of considerable importance in sturgeon fisheries. In 1997, the global la...
—Pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus are recognized morphologically as separate species. A previous genetic study with allozymes was unable to distinguish between the two species or demonstrate their reproductive isolation in regions of sympatry. Our main objective was to measure the genetic variability within and among populations of pallid and shovelno...
EXECUTIVE SUMMARY: All living organisms shed DNA into the environment. Recent studies have demonstrated that environmental water samples can be effectively assayed for the DNA of target organisms. The DNA contained in these samples is commonly referred to as environmental DNA or eDNA. Because DNA assays can be sensitive to very small amounts of genetic material, eDNA surveys have the potential ...
EXECUTIVE SUMMARY: All living organisms shed DNA into the environment. Recent studies have demonstrated that environmental water samples can be effectively assayed for the DNA of target organisms. The DNA contained in these samples is commonly referred to as environmental DNA or eDNA. Because DNA assays can be sensitive to very small amounts of genetic material, eDNA surveys have the potential ...
To determine the genetic origin of individual sturgeon that are morphologically intermediate to pallid (Scaphirhynchus albus) and shovelnose (Scaphirhynchus platorhynchus) sturgeon, we combined previously published mitochondrial DNA (mtDNA) and microsatellite data with additional microsatellite data. Two sympatric populations of pallid and shovelnose sturgeon from the upper Missouri River and a...
Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae) populations are currently at severely depleted levels due to historic overfishing, habitat loss, and pollution. The importance of biologically correct stock structure for effective conservation and management efforts is well known. Recent improvements in our understanding of Atlantic sturgeon migrations, movement, and the occurr...
The green sturgeon (Acipenser medirostris) is a highly migratory, oceanic, anadromous species with a complex life history that makes it vulnerable to species-wide threats in both freshwater and at sea. Green sturgeon population declines have preceded legal protection and curtailment of activities in marine environments deemed to increase its extinction risk. Yet, its marine habitat is poorly un...
Little is known of the swimming capacities of larval sturgeons, despite global population declines in many species due in part to fragmentation of their spawning and rearing habitats by man-made water-diversion structures. Larval green (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) inhabit the highly altered Sacramento-San Joaquin watershed, making them logical species to ...
Channelization for navigation and flood control has altered the hydrology and bathymetry of many large rivers with unknown consequences for fish species that undergo riverine migrations. In this study, we investigated whether altered flow distributions and bathymetry associated with channelization attracted migrating Lake Sturgeon (Acipenser fulvescens) into commercial navigation channels, pote...
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