Comparison of diamond- and square-mesh codends in the hake (Merluccius merluccius L. 1758) trawl fishery of the Adriatic Sea (central Mediterranean)


  • Alessandro Lucchetti National Research Council (CNR), Institute of Marine Sciences (ISMAR)



discards, square mesh, Merluccius merluccius, Adriatic Sea, fishery management, selectivity, bottom trawl


A traditional codend (40 mm diamond mesh) and an experimental codend (40 mm square mesh) made of 2.6 mm diameter knotless PA netting were tested on a commercial trawl net on a sandy-muddy bottom (~70 m depth) of the Adriatic sea in order to assess the size selectivity of European hake (Merluccius merluccius) and the reduction of the discards in a demersal multi-species trawl fishery. The catch was sorted as target species and bycatch and the selectivity with respect to European hake was investigated using the covered codend method. The square-mesh codend allowed a reduction of about 37% of the fraction discarded at sea. The mean catch obtained with the experimental codend was lower than that obtained with the traditional codend (about 14 kg per haul) but the short-term economic losses were low (~12%). The square-mesh codend was also more selective than the traditional codend, giving the juveniles of European hake a good chance of escape: the mean selection length (L50) was 7.60 cm in DM and 12.98 cm in SM. Moreover, the mesh configuration did not affect the gear’s performance. Thus, the square-mesh codend could be an easy, inexpensive and useful solution for a more sustainable management of the resources in Adriatic multi-species fishery.


Download data is not yet available.


Akaike, H. – 1973. Information theory and an extension of the maximum likelihood principle. In: B.N. Petrov and F. Csaki, (eds.), Second International Symposium on Information Theory, pp. 267-281. Budapest, Akademia Kaido.

Arneri, E. and B. Morales-Nin. – 2000. Aspects of the early life history of European hake from the central Adriatic. J. Fish. Biol., 53: 1155-1168.

Bahamon, N., F. Sardà and P. Suuronen. – 2006. Improvement of trawl selectivity in the NW Mediterranean demersal fishery by using a 40 mm square mesh codend. Fish. Res., 81: 15-25. doi:10.1016/j.fishres.2006.05.020

Can't connect to PubMed

Broadhurst, M.K., R.B. Millar, M.E.L. Wooden and W.G. Macbeth. – 2006. Optimising codend configuration in a multi-species demersal trawl fishery. Fish. Manage. Ecol., 13: 81-92. doi:10.1111/j.1365-2400.2006.00479.x

Brodgar. – 2000. Software package for Multivariate Analysis and Multivariate Time Series Analysis.

Campos, A., P. Fonseca and K. Erzini. – 2003. Size selectivity of diamond and square mesh codends for four by-catch species captured in the crustacean fishery off the Portuguese south coast. Fish. Res., 60: 79-97. doi:10.1016/S0165-7836(02)00061-9

Coll, M., A. Santojanni, I. Palomera, S. Tudela and E. Arneri. – 2007. An ecological model of the Northern and Central Adriatic Sea: analysis of ecosystem structure and fishing impacts. J. Mar. Sci., 67: 119-154.

ConStat. – 1995. CC selectivity program. Gronspaettevej 10, DK- 9800 Hjorring, Denmark. EC-1967. – 2006. Council Regulation concerning management measures for the sustainable exploitation of fishery resources in the Mediterranean Sea. Off. J. of the European Union. L409, 75 pp.

Fonteyne, R. – 2005. Protocol for the Use of an Objective Mesh Gauge for Scientific Purposes. ICES Coop.Res Rep. 1-14.

Fryer, R.J. – 1991. A model of between-haul variation in selectivity. ICES J. Mar. Sci., 48: 281-290. doi:10.1093/icesjms/48.3.281

Fryer, R.J. and J.G. Shepherd. – 1996. Models of codend size selection. J. North. Atl. Fish. Sci., 19: 51-58.

Guijarro, B. and E. Massutí. – 2006. Selectivity of diamond- and square-mesh codends in the deepwater crustacean trawl fishery off the Balearic Islands (western Mediterranean). ICES J. Mar. Sci., 63: 52-67. doi:10.1016/j.icesjms.2005.08.011

Hendrickson, L. – 2005. Effectiveness of a square-mesh escape panel in reducing finfish bycatch in a small-mesh bottom trawl used in the longfin inshore squid (Loligo pealeii) fishery. U.S. Dep. Commer., Northeast Fish. Sci. Cent. Ref. Doc. 05-05.

Jennings, S. and M.J. Kaiser. – 1998. The effects of fishing on marine ecosystems, Advances in Marine Biology, 34: 201-351. doi:10.1016/S0065-2881(08)60212-6

Jukic, S. and E. Arneri. – 1984. Distribution of hake (Merluccius merluccius, L.) striped mullet (Mullus barbatus, L.) and pandora (Pagellus erythrinus, L.) in the Adriatic Sea. FAO Fish. Rep., 290: 85-91.

Kaiser, M.J. and B.E. Spencer. – 1994. Fish scavenging behaviour in recently trawled areas. Mar. Ecol. Prog. Ser., 112: 41-49. doi:10.3354/meps112041

Kelleher, K. – 2005. Discards in the world’s marine fisheries. An update. FAO Fish. Tech. Pap. No. 470. Rome, FAO.

Main, J. and G.I. Sangster. – 1991. A different approach to covered codend selection experiments. Scot. Fish. Work. Paper No 4/91.

Millar, R.B. – 1994. Sampling from trawl gears used in size selectivity experiments. ICES J. Mar. Sci., 51: 293-298. doi:10.1006/jmsc.1994.1030

Ordines, F., E. Massutí, B. Guijarro and R. Mas. – 2006. Diamond vs. square mesh codend in a multi-species trawl fishery of the western Mediterranean: effects on catch composition, yield, size selectivity and discards. Aquat. Living Resour., 19: 329-338. doi:10.1051/alr:2007003

Petrakis, G. and K. Stergiou. – 1997. Size selectivity of diamond and square mesh codends for four commercial Mediterranean fish species. ICES J. Mar. Sci., 54: 13-23. doi:10.1006/jmsc.1996.0172

Pranovi, F., S. Raicevich, G. Franceschini, M.G. Farrace and O. Giovanardi. – 2000. Rapido trawling in the northern Adriatic Sea: effects on benthic communities in an experimental area. ICES J. Mar. Sci., 57: 517-524. doi:10.1006/jmsc.2000.0708

Ramsay, K., M.J. Kaiser and R.N. Hughes. – 1998. Responses of benthic scavengers to fishing disturbance by towed gears in different habitats. J. Exp. Mar. Biol. Ecol., 224: 73-89. doi:10.1016/S0022-0981(97)00170-6

Sánchez, P., P. Sartor, L. Recasens, A. Ligas, J. Martin, S. De Ranieri and M. Demestre. – 2007. Trawl catch composition during different fishing intensity periods in two Mediterranean demersal fishing grounds. Sci. Mar., 71(4): 765-773.

Sardà, F., N. Bahamon, B. Molí and F. Sardà-Palomera. – 2006. The use of a square mesh codend and sorting grids to reduce catches of young fish and improve sustainability in a multi-species bottom trawl fishery in the Mediterranean. Sci. Mar., 70(3): 347-353.

Stergiou, K.I., C.Y. Politou, E.D. Christou and G. Petrakis. – 1997. Selectivity experiments in the NE Mediterranean: the effect of trawl codend mesh size on species diversity and discards. ICES J. Mar. Sci., 54: 774-786. doi:10.1006/jmsc.1997.0231

Tokaç, A., A. Lök, Z. Tosunoˇglu, C. Metin and R.S.T. Ferro. – 1998. Cod-end selectivities of a modified bottom trawl for three fish species in the Aegean Sea. Fish. Res., 39: 17-31. doi:10.1016/S0165-7836(98)00172-6

Wileman, D.A, R.S.T. Ferro, R. Fonteyne and R.B. Millar. – 1996. Manual of methods of measuring the selectivity of towed fishing gears. ICES Coop. Res. Rep. 215, Copenhagen, 1-126.




How to Cite

Lucchetti A. Comparison of diamond- and square-mesh codends in the hake (Merluccius merluccius L. 1758) trawl fishery of the Adriatic Sea (central Mediterranean). scimar [Internet]. 2008Sep.30 [cited 2020Nov.25];72(3):451-60. Available from:




Similar Articles

You may also start an advanced similarity search for this article.