نتایج جستجو برای: acipenser nudiventris
تعداد نتایج: 1490 فیلتر نتایج به سال:
The present work reports behavioural responses by young-of-the-year (21-30 cm) Atlantic sturgeon Acipenser oxyrinchus oxyrinchus and shortnose sturgeon Acipenser brevirostrum to nine binary combinations of dissolved oxygen saturation (40, 70 and 100%), temperature (12, 20 and 28°C) and salinity (1, 8 and 15). Both species showed no acclimation effects and similar discrimination and avoidance re...
Histological examination of thymi from juvenile Acipenser ruthenus and Acipenser brevirostrum after haematoxylin and eosin staining revealed the presence of Hassall’s corpuscles, in a scattered distribution within the thymic medulla in two of seven, and one of nine examined specimens, respectively. Morphologically, the Hassall’s corpuscles were of the juvenile and premature type and no degenera...
Worldwide, sturgeons (Acipenseridae) are among the most endangered fishes due to habitat degradation, overfishing, and inherent life history characteristics (long life span, late maturation, and infrequent spawning). As most sturgeons are anadromous, a considerable portion of their life history occurs in estuarine and marine environments where they may encounter unique threats (e.g., intercepti...
the aim of this study was to investigate on obtained caviar quantity status of sturgeon at fishing grounds of the southwestern caspian sea. data of catches by means of fixed gill nets in sturgeon fish fishing grounds and beach seine were used during 5 years survey (2005-2009). a total of 1361 female sturgeon was caught including: 788 acipenser persicus, 410 a. stellatus, 60 a. guldenstaedti, 70...
This study was carried out to investigate the supplemental effects of dietary garlic extract (GE) on growth performance of juvenile sterlet sturgeon (Acipenser ruthenus). The first experiment was designed to determine the optimum levels of garlic extract as growth promoter during 10 weeks. Three groups (two replicates/group) of 240 fish with mean body weight of 85 g were fed with diets containi...
During teleost ontogeny the larval and embryonic stages are key stages, since failure during this period of tissue differentiation may cause malformations, developmental delays, poor growth, and massive mortalities. Despite the rapid advances in sequencing technologies, the molecular backgrounds of the development of economically important but endangered fish species like the Atlantic sturgeon ...
Russian ( Acipenser gueldenstaedtii), Persian ( A. persicus) and Siberian ( A. baerii) sturgeons are closely related 'Ponto-Caspian' species. Investigation of their population structure is an important problem, the solution of which determines measures for conservation of these species. According to previous studies, 'baerii-like' mitotypes were found in the Caspian Sea among 35% of Russian stu...
Immersing Siberian sturgeon fry of an average body mass of 40 ± 4 g in epin solution (0.1 mg l -1 ) resulted in an increase of ceruloplasmin level over the entire experimental period (P < 0.001). The differences between the treated and control groups gradually increased reaching the maximum in the fourth and fifth weeks of the study when average levels of ceruloplasmin in the epin-treated group...
The lake sturgeon, Acipenser fulvescens, belongs to one of the few extant nonteleost ray-finned fishes and diverged from the main vertebrate lineage about 250 million years ago. The aim of this study was to use this species to explore the peripheral neural coding strategies for sound direction and compare these results to modern bony fishes (teleosts). Extracellular recordings were made from af...
–Growth rates of juvenile lake sturgeon (initial weight 8 to 9 g, temperature 17.5° C), fed twice a day on brown worms for 56 days increased from -1.5% BW/d (% body wet weight/day) at zero ration to 2.6% BW/d at a ration of 13.2% BW/d. Maintenance ration was 1.6% BW/d. Fish fed larger rations had higher energy densities and lower water content. Appetite (average volitional daily food consumptio...
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