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Let the Fish Have Children then Your Children Will Have Fish

Let the Fish Have Children then Your Children Will Have Fish. Let them spawn!. Most fish are caught before maturity Most fish you have eaten were juveniles.

gabriel-johnson
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Let the Fish Have Children then Your Children Will Have Fish

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  1. Let the Fish Have ChildrenthenYour Children Will Have Fish Let them spawn! • Most fish are caught before maturity • Most fish you have eaten were juveniles Fig. 1. Length-frequency data of Atlantic Cod (Gadus morhua) landings from 1994 to 2001 in the Western Channel area, where Lm indicates length at first maturity, Lopt indicates the length range where maximum yield could be obtained, and Lmax is the maximum size reached during that time. Let them grow! An Assessment of Status and Trends in Major Fisheries Using Three Simple Indicators Poster Nr. 623470661 Rainer Froese, IfM-GEOMAR, Kiel, Germany, rfroese@ifm-geomar.deBirane Samb, CRODT, Dakar, Senegal, bsambe@yahoo.fr Mariama Dalanda Barry, CRODT, Dakar, Senegal To make fisheries management more transparent and encourage involvement of all stakeholders including consumers we present three simple and easily understood sustainability indicators. The first indicator measures percentage of mature specimens in the catch with the goal of letting all fish (100%) spawn before they are caught. The second indicator measures percentage of specimens caught within a length range of +/- 10% of optimum length, i.e., the length where the maximum potential yield can be obtained from a year class, with 100% as best value. The third indicator is measured as percentage of specimens in the catch that are longer than optimum length + 10%, with 0% as best value, i.e., the goal is to protect large fish as preservers of good genes and insurers against recruitment failures. The ability of these simple indicators to correctly represent the status of stocks is tested with data from pelagic and demersal fisheries of Senegal and with a stock from the ICES area. • Most fish are caught below • optimum economic size Fig. 2. Time series of percentages of mature, optimum size and mega-spawner specimens in the Senegalese catch ofWhite grouper (Epinephelus aeneus). Note that percentages of mature and optimum-size specimens are relatively low compared to the target of 100%; all indicators are declining since 1991. Let the mega-spawners live! • Large fish are mega-spawners of • good genes • Large fish provide an insurance • against recruitment failures • Most large fish have been eradicated Fig. 3. Time series of percentages of mature, optimum size and mega-spawner specimens in the Senegalese catch of Round sardinella (Sardinella aurita). Note that mature and optimum size percentages are close to or approaching the target of 100%. However, percentage of mega-spawners is below 30-40% and declining since 1997, which suggest reclining resilience.

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