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Commercial testing of a sorting grid to reduce catches of juvenile hake (Merluccius merluccius) in the western Mediterranean demersal trawl fishery

Published online by Cambridge University Press:  15 March 2005

Francesco Sardà ,
N. Bahamón ,
Francesc Sardà-Palomera  and
Balbina Molí
Francesco Sardà
Affiliation:
Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain
N. Bahamón
Affiliation:
Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain
Francesc Sardà-Palomera
Affiliation:
Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain
Balbina Molí
Affiliation:
Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain
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Abstract

Mediterranean demersal fisheries have experienced an ongoing decline in catches over the past 20 years as a result of excessive increases in effort caused both by growth in trawler engine power and by rapid technological advances in fish finding and fishing technology. This has led to an overexploitation of these resources. An increasing share of the catches consists of immature individuals. This study was undertaken to test a sorting grid with a bar spacing of 20 mm as a means of excluding juveniles in the commercial hake (Merluccius merluccius) fishery in the Catalan Sea, western Mediterranean. The grid was placed in the extension section of the gear 5 m in front of a cod-end. Divided cod-end design was used to collect the escapees and target species. The mean selection length (L50) of the ten hauls was 14.2 ± 0.7 cm SE, with a selection range of 7.3 cm ± 0.4 SE. The biomass of hake under L50 that escaped through the grid represented 50.1% ± 6.7 SE of the total hake biomass. These results are promising and indicate that a sorting grid can be used in excluding young hake. This was a first step toward implementation of sorting grids in commercial trawl gears as means of avoiding unwanted catches of small individuals in the hake fisheries in the Mediterranean Sea. Further trials are required to improve the sorting efficiency of the grid.

Keywords

TrawlingGridSelectivityHakeMerluccius merlucciusJuvenilesMediterranean Sea
Type
Research Article
Information
Aquatic Living Resources , Volume 18 , Issue 1 , January 2005 , pp. 87 - 91
Copyright
© EDP Sciences, IFREMER, IRD, 2005

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References

Anonymous, 1996, Report of the Study Group on grid (grate) sorting systems in trawls, beam trawls and seine nets. ICES CM 1996/B:1, 1-87.
Bas C., Maynou F., Sardà F., Lleonart J., 2003, Variacions demogràfiques a les poblacions d'espècies demersals explotades els darrers quaranta anys a Blanes i Barcelona. Institut d'Estudis Catalans, Secció de Ciències Biològiques, Barcelona.
Bozzano A., Maynou F., Sardà F., Ríos J. in press. Vertical distribution in feeding patterns of the juveniles European hake, Merluccius merluccius, in the northwestern Mediterranean. Fish. Res., in press.
Broadhurst, M.K., Kennelly, S.J., O'Doherty, G., 1996, Effects of square-mesh panels in cod-ends and of haulback delay on by-catch reduction in the oceanic prawn trawl fishery off New South Wales, Australia. Fish. Bull. 94, 412-422.
Broadhurst M.K., Barker D.T., Kennelly S.J., 1999, Scale-loss and survival of juvenile yellowfin bream, Acanthopagrus australis, after simulated escape from a NordmØre-grid guiding panel and release from capture by hook and line. Bull. Mar. Sci. 64, 255-268.
Campos, A., Fonseca, P., Erzini, K., 2003, Size selectivity of diamond and square mesh cod ends for four by-catch species in the crustacean fishery off the Portuguese south coast. Fish. Res. 60, 79-97. CrossRef
Cheret Y., Farrugio H., Jadaud A., Lespagnol P., Mellon C., Gaza M., Massutí E., Pomar G., Pereda P., Lleonart J., 2002, Stock assessment of the French-Spanish shared stock of hake (Merluccius merluccius) in the Gulf of Lions. Working Document No. 6 to the GFCM SAC Working Group on the Assessment of Demersal Stocks, Rome.
Ercoli R., García J., Salvini L., Izzo A., Bartozzetti. J., 1997, Manual del dispositivo de selectividad de langostino con doble grilla Disela II. INIDEP, Inf. Téc. Int., pp 1-7.
Ercoli, R., Salvini, L., García, J., Izzo, A., Roth, R., Bartozzetti. J., 2000, Manual técnico del dispositivo para el escape de juveniles de peces en las redes de arrastre (DEJUPA) aplicado a la merluza (Merluccius hubbsi). INDEP, Inf. Téc. 39, 16.
Fryer, R.J., 1991, A model of between-haul variation in selectivity. ICES J. Mar. Sci. 48, 281-290. CrossRef
Graham, N., 2003, By-catch reduction in the brown shrimp (Crangon crangon) fisheries using a rigid sorting Nordmore grid (grate). Fish. Res. 59, 393-407. CrossRef
Graham, N., Kynoch, R.J., Fryer, R.J., 2003, Square mesh panels in demersal trawls: further data relating haddock and whiting selectivity to panel position. Fish. Res. 62, 361-375. CrossRef
Graham, N., O'Neill, F.G., Fryer, R.J., Galbraith, R.D., Myklebust, A., 2004, Selectivity of a 120 mm diamond cod-end and the effect of inserting a rigid grid or a square mesh panel. Fish. Res. 67, 151-161. CrossRef
Halliday, R.G., Cooper, C.G., 2000, Size selection of silver hake (Merluccius bilinearis) by otter trawls with square and diamond mesh cod-ends of 55-60 mm mesh size. Fish. Res. 49, 77-84. CrossRef
Irazola M., Lucchetti A., Lleonart J., Ocaña A., Tapia J.M., Tudela S., 1996, La pesca en el siglo XXI. Propuestas para una gestión pesquera racional en Catalunya. Ed. Federación del Transporte, Barcelona.
Isaksen, B., Valdemarsen, J.W., Larsen, R.B., Karlsen, L., 1992, Reduction of fish by-cath in shrimp trawl using a rigid sorting grid in the aft belly. Fish. Res. 13, 335-352. CrossRef
Kvalsik, K., Misud, O.A., Engas, A., Gamst, K., Holst, R., Galbraith, D., Vederhus, H., 2002, Size selection of large catches using sorting grid in pelagic mackerel trawl. Fish. Res. 59, 129-148. CrossRef
Larsen, R.B., Isaksen, B., 1993, Size selectivity of rigid dorting grid in bottom trawls for Atlantic cod (Gadus morhua) and haddock (Melanogrammus eaglefinus). ICES Mar. Sci. Symp. 196, 178-182.
Maynou, F., Lleonart, J., Cartes, J., 2003, Seasonal and spatial variability of hake (Merluccius merluccius L.) recruitment in the NW Mediterranean. Fish. Res. 60, 65-78. CrossRef
Millar, B.R., Broadhurst, M.K., Macbeth, W.G., 2004, Modelling between-haul variability in the size selectivity of trawls. Fish. Res. 67, 171-181. CrossRef
Oliver P., 1991, Dinámica de la población de merluza (Merluccius merluccius L.) de Mallorca (Reclutamiento, Crecimiento y Mortalidad). Tesis doctoral. Universidad Islas Baleares.
Olivar, M., Quílez, G., Emelianov, M., 2003, Spatial and temporal distribution and abundance of European hake, Merluccius merluccius, eggs and larvae in the Catalan coast (NW Mediterranean). Fish. Res. 60, 321-331. CrossRef
Polet, H., 2002, Selectivity experiments with sorting grids in the North Sea brown shrimp (Crangon crangon) fishery. Fish. Res. 54, 217-233. CrossRef
Recasens L., 1992, Dinàmica poblacional i pesqueria del lluç (Merluccius merluccius) al golf de Lleó i la mar Catalana. Tesis doctoral. Universitat de Barcelona.
Sardà, F., Molí, B., Palomera, I., 2004, Preservation of juvenile hake (Merluccius merluccius, L.) in the western Mediterranean multispecies demersal trawl fishery by using sorting grids. Scient. Mar. 68, 435-444. CrossRef
Suuronen, P., Pérez-Comas, J.A., Lehtonen, E., Tsechernij, V., 1996, Size-related mortality of herring (Clupea harengus) escaping through a rigid and trawl cod-end meshes. ICES J. Mar. Sci. 53, 691-700. CrossRef
Tokai, T., 1997, Maximum likelihood parameter estimates of a mesh selectivity logistic model through SOLVER on MS-Excel. Bull. Jpn. Fish. Oceanogr. 61, 288-298.
Valdermarsen J.W., Suuronen P., 2003, Modifying fishing gear to achieve ecosystem objectives. In: Sinclair M., Valdimarsson G. (Eds.). Responsible Fisheries in the Marine Ecosystem. FAO, Rome, pp. 321-341.
Villaseñor, R., 1997, Dispositivos excluidores de tortugas marinas. FAO Doc. Téc. Pesca 372, 1-116.