نتایج جستجو برای: spawning biomass per recruit
تعداد نتایج: 511440 فیلتر نتایج به سال:
This paper uses GIS and spatiotemporal analysis of a historically and culturally modified marine ecosystem to evaluate Pacific herring abundance, declines, vulnerabilities, and future prospects, about which a Native Tribe and state fisheries managers disagree. In 2008, the Sitka Tribe of Alaska (STA) requested that an area within its traditional waters be closed to commercial sac roe fishing to...
It is generally assumed that fish populations are regulated primarily in the juvenile (pre-recruit) phase of the life cycle, although density dependence in growth and reproductive parameters within the recruited phase has been widely reported. Here we present evidence to suggest that density-dependent growth in the recruited phase is a key process in the regulation of many fish populations. We ...
Scientific interest in the dynamics of fish recruitment dates back to beginning 20th century. Since then, several studies have shown that environment may a stronger effect on (R) compared spawning stock biomass (SSB). By combining suite methods designed detect nonlinear, nonstationary and interactive relationships, we re-evaluated potential drivers their interactions responsible for multiannual...
Catch quotas for walleye pollock Gadus chalcogrammus, the dominant species in the groundfish fishery off Alaska, are set by applying harvest control rules to annual estimates of spawning stock biomass (SSB) from age-structured stock assessments. Adult walleye pollock abundance and maturity status have been monitored in early spring in Shelikof Strait in the Gulf of Alaska for almost three decad...
Synchronous variations in the abundance of geographically distinct marine fish populations are known to occur across spatial scales on the order of 1,000 km and greater. The prevailing assumption is that this large-scale coherent variability is a response to coupled atmosphere-ocean dynamics, commonly represented by climate indexes, such as the Atlantic Multidecadal Oscillation and North Atlant...
White-streaked grouper (Epinephelus ongus) is an important fisheries target and forms spawning aggregations at particular spawning grounds. The aims of the present study were to investigate the ecological characteristics of annual spawning aggregations such as (1) spatial variations in the density of E. ongus at the spawning ground, (2) the relationship between fish density and environmental va...
Several years of research on the gametic development and spawning of different species of holothurians have produced results that find applications in aquaculture and fisheries management programs. The first set of data shows that sea cucumbers secrete a biologically active chemical which allows gamete synthesis synchrony among conspecifics. Laboratory experiments have revealed that the gametic...
The growth pattern and reproductive biology of Acanthopagrus latus were studied to derive information required for their management in the south part of Iran, Persian Gulf. Samples collected monthly from October 2014 to September 2015. Parameter values of the Von Bertalanffy growth function fit to length frequency data (males and females combined) were estimated as k = 0.23 per year, L∞ =50.4 c...
Sand perch Diplectrum formosum were collected in the Atlantic Ocean waters off the south-eastern U.S. for life history analyses between April 2001 and July 2004 and ranged in size from 63 to 236 mm standard length (L(S)) and 0-8 years of age. Diplectrum formosum are simultaneous hermaphrodites that reach 50% sexual maturity at 12.2 months and 122.8 mm L(S) for testicular tissue and 13.6 months ...
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