نتایج جستجو برای: fishing mortality proxy
تعداد نتایج: 325174 فیلتر نتایج به سال:
Penguins are the most threatened group of seabirds after albatrosses. Although penguins are regularly captured in fishing gear, the threat to penguins as a group has not yet been assessed. We reviewed both published and grey literature to identify the fishing gear types that penguins are most frequently recorded in, the most impacted species and, for these susceptible species, the relative impo...
Title of Document: HISTORICAL EFFECTS OF FISHING ON AGE STRUCTURE AND STOCK MIXING IN NORTHWEST ATLANTIC BLUEFIN TUNA Matthew Ryan Siskey, Master of Science, 2015 Directed By: Professor David H. Secor Marine Estuarine Environmental Sciences Bluefin tuna support important fisheries in the Northwest Atlantic Ocean, which have declined in yield from intense, size-selective exploitation. Age struct...
Size-selective fishing, environmental changes and reproductive strategies are expected to affect life-history traits such as the individual growth rate. The relative contribution of these factors is not clear, particularly whether size-selective fishing can have a substantial impact on the genetics and hence on the evolution of individual growth rates in wild populations. We analysed a 25-year ...
Size-selective fishing may induce rapid evolutionary changes in life-history traits such as size at maturation. A major concern is that these changes will reduce population biomass and detrimentally affect yield and recruitment. Although marine reserves have been proposed as a tool for fisheries management, their evolutionary implications have as yet attracted little scrutiny. A simple model is...
Acoupa weakfish, Cynoscion acoupa, in Lake Maracaibo is subject to intense commercial fishing by an artisanal fleet, and a recent decrease in fish size observed from landings is of concern. This fishery has not yet been modeled, and its assessment and the establishment of management practices to overcome the current overfished condition are urgently needed. To address this, we used recent and p...
Fisheries bycatch mortality poses a primary threat to the majority of world’s 22 albatross species, 15 which are at risk extinction. Although quantitative estimates often unavailable due relative or total absence monitoring, spatial overlap between fisheries and albatrosses is used estimate extent interaction, proxy for exposure bycatch, inform avoidance mitigation actions. Using comprehensive ...
Frequent application of the term “proxy war” indicates its prominent place in academic researches on international relations. Separate implementation of soft power and hard power proved to be unsuccessful in recent years. Accordingly, great failures in classic wars increased tendencies towards proxy wars. By the outbreak of Arab Springs in the early 2011, Syria was devastated by different oppo...
I examined how the fitness (r) associated with early- and late-maturing genotypes varies with fishing mortality (F) and age-/size-specific probability of capture. Life-history data on Newfoundland's northern Atlantic cod (Gadus morhua) allowed for the estimation of r for individuals maturing at 4 and 7 year in the absence of fishing. Catch selectivity data associated with four types of fishing ...
Biodiversity loss and fishing-induced changes in the size distributions of fishes can impact ecosystem function on coral reefs. These changes have led to an urgent need for studies on the particular roles of species to underpin effective coral reef management. The present study focuses on the feeding ecology of 6 size classes (from 2.5 to 30 cm total length) of Scarus rivulatus (family Labridae...
The size structure of fish-communities is an emergent high-level property of marine food webs responsive to changes in structure and function. To measure this food web property using data arising from routine fisheries surveys, a simple metric known as Typical Length has been proposed as more suitable than the Large Fish Indicator, which has been highly engineered to be responsive to fishing pr...
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