Методика определения запаса, промысловой и естественной смертностей шпрота восточной Балтики.
By the results of trawling surveys carried out in May 1977 - 1981 a relative sprat stock by subdivisions was determined. Simultaneously, in spring 1977 an absolute sprat eggs amount was found for Subdivision 26, and proceeded from its abundance, sprat fecundity, males and females ratio and the share of spawning females, an absolute sprat stock was calculated. By the ratio of relative and absolute stock values in Subdivision 26 in 1977 a transitional coefficient was determined for the recalculation of relative stock values found by the trawling survey method into absolute ones. The obtained stock values for Subdivisions 26 and 28 in 1977 - 1981 are comparable with those defined by VPA on the ICES Working Groups. It was determined that in present VPA method overestimates the Baltic sprat stock abundance to a great extent that in its turn leads to an overestimated value of TAC predicted. The trawling survey method gives a more precise estimate of a stock value. Main reasons conditioning the errors in VPA application for the determination of Baltic sprat absolute stocks are revealed, and concrete ways of investigations which allow increasing the VPA method precision concerning the Baltic sprat are offered.
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| Format: | Journal Contribution biblioteca |
| Language: | Russian |
| Published: |
1983
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| Subjects: | Trawling surveys, Absolute stock, Relative stock, Baltic sprat stock, ASFA_2015::F::Fish stocks, ASFA_2015::N::Natural mortality, ASFA_2015::F::Fishing mortality, |
| Online Access: | http://hdl.handle.net/1834/15795 |
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