نتایج جستجو برای: fishing effort
تعداد نتایج: 129837 فیلتر نتایج به سال:
Abstract. The purpose of the paper is to design a fishing strategy in order to regulate an exploited fish population. To this end, we use a stagestructured model of a harvested fish population that has been derived in [5]. We give a formula for the fishing effort as a feedback control that allows to stabilize the system. travail réalisé avec la contribution financière du CNCPRST (Maroc) et du C...
This report presents the findings of a study of subsistence salmon fishing on the Togiak River, southwest Alaska, conducted in 1997 and jointly funded by the Division of Subsistence of the Alaska Department of Fish and Game and the Tog&k National Wildlife Refuge, U.S. Fish and Wildlife Service. The study had two primary goals. The first was to document subsistence salmon fishing patterns by Tog...
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...
We aimed to develop alternative fishing gear for catching the common octopus, to decrease the use of bait and operating costs in comparison to commercial net pots. A tubular-type pot was designed, and behavioral responses of the common octopus were experimentally monitored in tank and replicated 10 times to compare fishing performances between 300 experimental and 300 commercial net pots in the...
Industrial catch-per-effort (cpue) data are used as an indicator of population abundance and, contrary to strong cautions of potential biases, are often used without regard for spatial interactions as the only data source from which inferences are made. Recent controversy surrounding the status of large predatory pelagic communities has resulted from varying interpretations of the Japanese long...
Sharks and rays' abundance can decline considerably with fishing. Community changes, however, are more complex because of species interactions, and variable vulnerability and exposure to fishing. We evaluated long-term changes in the elasmobranch community of the Adriatic Sea, a heavily exploited Mediterranean basin where top-predators have been strongly depleted historically, and fishing devel...
Over the last decades, views on fisheries management have oscillated between alarm and trust in management progress. The predominant policy for remedying the world fishing crisis aims at maximum sustainable yield (MSY) by adjusting gear selectivity and fishing effort. Here we report a case study on how striving for higher yields from the Eastern Baltic cod stock by increasing selectivity has be...
Background: Oxbow lakes are abundant in indigenous fishes, but they are subject to unsustainable fishing practices, potential overexploitation, and indiscriminate use of fine-meshed fishing gear. To quantify the catch per unit effort (CPUE) and impact of fishing gears on fish abundance, a survey was carried out in an oxbow lake in eastern India. Methods: The gear-wise CPUE for fish caught in...
The population parameters of Malabar trevally (Carangoides malabaricus) were studied in the Persian Gulf and Oman Sea from December 2016 to November 2017. 1030 specimens were collected. The fork length ranged from 14 to 34 cm, with average 25.60±3.52 cm. The total weight ranged from 60.4 to 534.5 g, with average 329.03±113.46 g. The asymptotic length (L∞) and growth coefficient (K) were 37 cm a...
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