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| Ercoli, R.; Garcia, J.C.; Aubone, A.; Salvini, L.; Bertelo, R.. |
| This work reports on the inter rod distance in a single sorting grid adapted for the escape of hake juveniles. A good performance of the device was reported due to the DEJUPA trials carried out in April 1997. In may 1998 a new survey with DEJUPA was carrie out with 30 mm, 33 mm, and 40 mm separation distance bars, in order to optimise the escape of the species at first length maturity (35 cm). Selectivity curves with maximum likelihood method were obtained for each inter rod distance being the length at 50. (L50) 29, 32 and 37 respectively. A weighd lineal regression (Feasible General Squares Model) between L50 and inter rod distance was fitted from each L50 estimated variance. An estimation of 37 mm inter rod distance for L50=35 cm total length was... |
| Tipo: Journal Contribution |
Palavras-chave: Gear selectivity; Bottom trawls; Juveniles; Juveniles; Http://aims.fao.org/aos/agrovoc/c_25393. |
| Ano: 2000 |
URL: http://hdl.handle.net/1834/2536 |
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| Restrepo, Victor R; Ortiz De Urbina, J; Fromentin, Jean-marc; Arrizabalaga, Haritz. |
| Knowledge of gear-specific selectivity patterns can be useful in age-structured analyses. In recent assessments of eastern Atlantic bluefin tuna, Thunnus thynnus, the SCRS has derived selectivity estimates from the results of virtual population analyses. This document proposes an alternative approach, based on equilibrium catch curves, that is simple to apply and that relies on a smaller set of assumptions. The study uses the catch-at-age data from the last assessment conducted in 2002, and estimates recent and historical selectivity patterns for the total stock as well as some of the major gears (trap, baitboat, purse seine and longline). The resulting estimates seem reasonable for the various gears, given prior knowledge. The document also presents... |
| Tipo: Text |
Palavras-chave: Gear selectivity; Stock assessment; Bluefin tuna. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00192/30326/28800.pdf |
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| Fromentin, Jean-marc; Bonhommeau, Sylvain. |
| This study aims at examining the selectivity patterns among gears and years of the fleets targeting bluefin tuna in the Northeast Atlantic and Mediterranean Sea between 1970 and 2009, using catch curve analyses. The main outputs may be summarized as follow: (i) the general pattern of selectivity has highly varied through time, moving from ages 1-3 to ages 10+ from the 1970s to the 2000s; (ii) this important temporal drift primarily resulted from changes in PS selectivity patterns; (iii) these drastic variations in selectivity among gears and years can affect simple indicators which do not incorporate such information; (iv) the catch-at-age (CAA) matrix seems to be impaired by several inconsistencies that affect primarily the partial CAA of the purse... |
| Tipo: Text |
Palavras-chave: Gear selectivity; Stock assessment; Bluefin tuna. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00192/30279/28747.pdf |
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| Ercoli, R.; Salvini, L.; Garcia, J.C.; Izzo, A.; Roth, R.R.; Bartozzetti, J.D.. |
| This Technical Manual has been developed to frame, assemble and apply the single grid sorting device (DEJUPA). It is addressed to professionals, technicians in fishing gears, skippers, owners and fishermen. The Manual presents three DEJUPA sizes in function of the main engine power: less than 300 HP, between 300 and 800 HP and more than 800 HP. |
| Tipo: Journal Contribution |
Palavras-chave: Trawl nets; Gear selectivity. |
| Ano: 2000 |
URL: http://hdl.handle.net/1834/2539 |
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