نتایج جستجو برای: spawning biomass per recruit
تعداد نتایج: 511440 فیلتر نتایج به سال:
Here we analyzed the relation between recruitment dynamic (recruitment or recruitment success) and temperature of 57 commercial fish stocks of the North Atlantic. We showed that, although the effect of temperature was generally significant, spawning biomass is the main factor governing recruitment dynamic. A significant effect of spawning biomass was evident for 67% of all stocks analyzed in th...
Parentage analysis, employing five hypervariable microsatellite markers, was used to follow spawning patterns of red drum Sciaenops ocellatus broodfish in two spawning tanks through most of a calendar year in a marine fish hatchery dedicated to stock enhancement. Five of six dams and all four sires spawned at least once during the year. Variation in dam and sire spawning incidence and in number...
population dynamic parameters of red mullet, mullus barbatus (n=592) caught by trawlers operating in arzew gulf (algeria) in the western mediterranean were studied. samples were collected between february 2013 and january 2014. females ranged from 10.9-23.2 cm in total length and 12-149.2 g in weight whereas males length was comprised between 12.6 and 19.7 cm and weight between 21.3 and 99.9 g....
Data from pelagic trawl surveys by TINRO-center from 1987 to 1996 in the Okhotsk Sea indicate that coho abundance is underestimated by coastal observations. The approximate Asian coho spawning biomass is 7,300-16,000 tons for the 1990s. Ways of improving Asian coho salmon resource management are discussed. Collection of precise fishery and escapement statistics must be expanded in areas previou...
Length and age at maturity are important life history parameters for estimating spawning stock biomass and reproductive potential of fish stocks. Bias in estimates of size and age at maturity can arise when disparate distributions of mature and immature fish within a population are not accounted for in the analysis. Here we investigate the spatial and temporal variability in observed size and a...
Sexual reproduction of the reef-building coral Montastrea cavernosa was studied in the Santa Marta area, Caribbean coast of Colombia, from October 1990 to October 1991. The area is subjected to a seasonal upwelling–outwelling regime. From microscopical analysis of tissue sections sampled each lunar month around the full moon, it was confirmed that this is a gonochoric, broadcasting species, wit...
This paper presents the results of study on age, growth, mortality rates and yield-per-recruit of Beluga (Huso huso) living in Caspian Sea. The mean length of successive years, mortality rates and yield-per-recruit studies indicated that at present the resource is under heavy fishing pressure. For the female Beluga growth was regarded as comprising of three stages, and the von Bertalanffy param...
The growth and mortality coefficient of Rutilus frisii kutum, were estimated using length frequency data collected in southern waters of the Caspian Sea during October 2008 to April 2009. The following population parameters were evaluated: length-weight relationship, W = 0.004L 3.258, (r= 0.976) Von Bertalanffy growth constants, W∞ (g) = 4192.3, L∞ (cm) = 70.45, K = 0.2, per year t0 = −0.75 tot...
Factors contributing to population growth through strong year-class formation have driven a century of directed research in fisheries science. A central discovery of Hjort's paradigm was that multiple generations overlap and longevity is matched with frequency of strong recruitments. Here, I elaborate on this tenet by examining how intra-population modalities in spawning and early habitat use f...
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