6 resultados para análise fecal

em Aquatic Commons


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This paper aims to analyse the results of a cruise aboard the vessel Cassiopeia, held from 7 to 15 May 1999. These results relate mainly to the Quissico area and have as an objective to verify different features: total fish catch, predominance of caught species, dimensions of captured fish and fishing effort.

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Marine mammal diet is typically characterized by identifying fish otoliths and cephalopod beaks retrieved from stomachs and fecal material (scats). The use and applicability of these techniques has been the matter of some debate given inherent biases associated with the method. Recent attempts to identify prey using skeletal remains in addition to beaks and otoliths are an improvement; however, difficulties incorporating these data into quantitative analyses have limited results for descriptive analyses such as frequency of occurrence. We attempted to characterize harbor seal (Phoca vitulina) diet in an area where seals co-occur with several salmon species, some endangered and all managed by state or federal agencies, or both. Although diet was extremely variable within sampling date, season, year, and between years, the frequency and number of individual prey were at least two times greater for most taxa when prey structures in addition to otoliths were identified. Estimating prey mass in addition to frequency and number resulted in an extremely different relative importance of prey in harbor seal diet. These data analyses are a necessary step in generating estimates of the size, total number, and annual biomass of a prey species eaten by pinnipeds for inclusion in fisheries management plans.

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The paper deals with the proper management of fishing resources of shrimps in shallow waters, those currently constitute the main source of foreign currency trade of the country. The analysis of the level of the productive sector is presented by the local Institute of Fisheries Research.

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Biological effects of management measures introduced in the shrimp fishery from 1985 to 1990 are analysed as well as the results from simulation of different closed seasons. Observed changes in recruitment, total catch, biomass and average individual weight during 1985 to 1990 for Penaeus indicus and Hetapenaeus Monoceros are also analysed. Further studies on a stock-recruitment relationship are important due to decline of recruitment levels in this period. A three-month closed season starting in January is recommended, without increases in the monthly fishing effort. The TAC shall be fixed according to the recruitment level each year.

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An estimation of the total industrial catch of the shallow water shrimp by-catch for the period 1986-1990 is presented. By-catch species compositions based on landings and onboard samples at ex-Emopesca/Beira (Marbeira) and Pescamar are also presented. The by-catch is essentially composed by 2nd and 3rd commercial fish categories, other crustaceans and cephalopods appearing in varying proportions in the catch. The total catch of shrimp by-catch estimated for the period is approximately 17 to 25 thousand tons per year.

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The main goal of this paper is to provide samples of fishing methods analyses applied to studies on shrimps stock assessment in the Sofala Bank. Especially the authors provide the administrators with the main limits of application of described methods.