Effect of a lateral square-mesh panel on the catch pattern and catch efficiency in a Mediterranean bottom trawl fishery

Published: Mar 31, 2020
Mediterranean bottom trawl square-mesh panels release efficiency exploitation pattern discard.

The current legal codends used in Mediterranean bottom trawl fisheries are at high risk of retaining undersized individuals of several commercial fish species. This entails that codends alone are unable to provide the desired exploitation pattern. A simple technological measure that potentially can provide higher release efficiency of undersized fish are Square-Mesh Panels (SMPs). SMPs are often applied in the upper section of the trawl belly, just ahead the codend. However, recent studies in the Mediterranean have demonstrated that SMPs mounted in this position provided limited release efficiency, because very few fish came into contact with their meshes. In attempt to improve SMPs efficiency in the Mediterranean bottom trawl fisheries, we applied them on the lateral sides of the last tapered section of the trawl belly, just ahead of the codend, and fitted two guiding panels in the trawl belly to enhance fish-SMP contact. We compared the catch performance of a standard commercial trawl with a 52 mm diamond-mesh codend and of a similar trawl fitted with lateral SMPs (70 mm mesh size) in the belly using a twin trawl. The study focused on red mullet (Mullus barbatus), a commercially important species, but data for gurnard (Chelidonichthys lucerna and Chelidonichthys cuculus)  were also obtained and analysed. In contrast to previous research on SMPs mounted in the top panel of the trawl, in this study SMPs induced a significant effect on catch performance for red mullet, demonstrating that their lateral position involved greater fish-SMP contact. However, since the test trawl lost a significant amount of legal-sized red mullet compared with the standard trawl, the effect was not wholly positive, possibly due to an excessively large mesh size. Therefore, future studies should be encouraged to test lateral SMPs with smaller mesh sizes.

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Alzorriz, N., Arregi, L., Herrmann, B., Sistiaga, M., Casey, J. et al., 2016. Questioning the effectiveness of technical measures implemented by the Basque bottom otter trawl fleet: implications under the EU landing obligation. Fisheries Research, 175, 116-126.
Anderson, D., Burnham, K., 2004. Model selection and multi-model inference. Second Edition. Springer-Verlag, New York, 488 pp.
Bolognini, L., Domenichetti, F., Grati, F., Polidori, P., Scarcella, G. et al., 2013. Weight-length relationships for 20 fish species in the Adriatic Sea. Turkish Journal of Fisheries and Aquatic Sciences, 13 (3), 555-560.
Brčić, J., Herrmann, B., De Carlo, F., Sala, A., 2015. Selective characteristics of a shark-excluding grid device in a Mediterranean trawl. Fisheries Research, 172, 352-360.
Brčić, J., Herrmann, B., Sala, A., 2016. Can a square-mesh panel inserted in front of the codend improve the exploitation pattern in Mediterranean bottom trawl fisheries? Fisheries Research, 183, 13-18.
Brčić, J., Herrmann, B., Sala, A., 2018. Can a square-mesh panel inserted in front of the cod end improve size and species selectivity in Mediterranean trawl fisheries? Canadian Journal of Fisheries and Aquatic Sciences, 75 (5), 704-713.
Catchpole T., Revill A., 2008. Gear technology in Nephrops trawl fisheries. Reviews in Fish Biology and Fisheries, 18 (1), 17-31.
Feekings, J., Bartolino, V., Madsen, N., Catchpole T., 2012. Fishery discards: factors affecting their variability within a demersal trawl fishery. PLoS ONE, 7 (4), e36409.
Efron, B., 1982. The jackknife, the bootstrap, and other resampling plans. Vol. 38. Siam, Philadelphia, 100 pp. EU, 2006. Council Regulation (EC) No. 1967/2006 of 21 December 2006, concerning management measures for the sustainable exploitation of fishery resources in the Mediterranean Sea, amending Regulation (EC) No. 2847/93 and repealing Regulation (EC) No. 1626/94. Official Journal of the European Union L. 409.
Glass, C.W., 2000. Conservation of fish stocks through bycatch reduction: a review. Northeastern Naturalist, 7 (4), 395-411.
Johnsen, J.P, Eliasen, S., 2011. Solving complex fisheries man agement problems: what the EU can learn from the Nordic experiences of reduction of discards. Marine Policy, 35 (2), 130-139.
Herrmann, B., Sistiaga, M., Nielsen, K.N., Larsen, R.B., 2012. Understanding the size selectivity of redfish (Sebastes spp.) in North Atlantic trawl codends. Journal of Northwest Atlantic Fishery Science, 44, 1-13.
Herrmann, B., Sistiaga, M., Rindahl, L., Tatone, I., 2017. Estimation of the effect of gear design changes on catch efficiency: methodology and a case study for a Spanish longline fishery targeting Hake (Merluccius merluccius). Fisheries Research, 185, 153-160.
Kaykac, H., 2010. Size selectivity of commercial (300 MC) and larger square mesh top panel (LSMTPC) trawl codends for blue whiting (Micromesistius poutassou Risso, 1826) in the Aegean Sea. African Journal of Biotechnology, 9 (53), 9037-9041.
Krag, L.A., Herrmann, B., Karlsen, J.D., 2014. Inferring fish escape behaviour in trawls based on catch comparison data: model development and evaluation based on data from Skagerrak, Denmark. PLoS One, 9 (2), e88819.
Metin, C., Özbilgin, H., Tosunoğlu, Z., Gökçe, G., Aydin et al., (2005). Effect of square mesh escape window on codend selectivity for three fish species in the Aegean Sea. Turkish Journal of Veterinary and Animal Sciences, 29 (2), 461-468.
Özbilgin, H., Tosunoğlu, Z., Aydin, C., Kaykaç, H. and Tokaç, A., 2005. Selectivity of standard, narrow and square mesh panel trawl codends for hake (Merluccius merluccius) and poor cod (Trisopterus minutus capelanus). Turkish Journal of Veterinary and Animal Sciences, 29 (4), 967-973.
Özbilgin, H., Tosunoğlu, Z., Tokaç, A., Metin, G., 2011. Seasonal variation in the trawl codend selectivity of red mullet (Mullus barbatus). Turkish Journal of Fisheries and Aquatic Sciences, 11 (2), 191-1.
Sala, A., Lucchetti, A., 2011. Effect of mesh size and codend circumference on selectivity in the Mediterranean demersal trawl fisheries. Fisheries Research, 110, 252-258.98.
Sala, A., Priour, D., Herrmann, B., 2006. Experimental and theoretical study of red mullet (Mullus barbatus) selectivity in codends of Mediterranean bottom trawls. Aquatic Living Resources, 19 (4), 317-327.
Sala, A., Lucchetti, A., Piccinetti, C., Ferretti, M., 2008. Size selection by diamond- and square-mesh codends in multi-species Mediterranean demersal trawl fisheries. Fisheries Research, 93, 8-21.
Sala, A., Lucchetti, A., Perdichizzi, A., Herrmann, B., Rinelli, P., 2015. Is square-mesh better selective than larger mesh? A perspective on the management for Mediterranean trawl fisheries. Fisheries Research, 161, 182-190.
Sala, A., Herrmann, B., De Carlo, F., Lucchetti, A., Brčić, J., 2016. Effect of codend circumference on the size selection of square-mesh codends in trawl fisheries. PLoS ONE, 11 (7), e0160354.
Santos, J., Herrmann, B., Otero, P., Fernandez, J., Pérez, N., 2016. Square mesh panels in demersal trawls: does lateral positioning enhance fish contact probability? Aquatic Living Resources, 29 (3), 1-10.
Soma, K., Nielsen, J.R., Papadopoulou, N., Polet, H., Zengin, M. et al., 2018. Stakeholder perceptions in fisheries management - Sectors with benthic impacts. Marine Policy, 92, 73-85.
Suuronen P., Sardá F., 2007. By-catch Reduction Techniques in European Fisheries: Traditional Methods and Potential Innovations. p. 37-74. In: By-catch Reduction in the World’s Fisheries. Reviews: Methods and Technologies in Fish Biology and Fisheries. Kennelly, S.J., (Eds).
Springer, Dordrecht. Tokaç, A., Ozbilgin, H., Kaykac, H., 2010. Selectivity of conventional and alternative codend design for five fish species in the Aegean Sea. Journal of Applied Ichthyology, 26 (3), 403-409.
Tokaç, A., Herrmann, B., Gökçe, G., Krag, L.A., Nezhad, D. et al., 2016. Understanding the size selectivity of red mullet (Mullus barbatus) in Mediterranean trawl codends: A study based on fish morphology. Fisheries Research, 174, 81-93.
Tsagarakis, K., Palialexis, A., Vassilopoulou, V., 2014. Mediterranean fishery discards: review of the existing knowledge. ICES Journal of Marine Science, 71 (5), 1219-1234.
Tsagarakis, K., Carbonell, A., Brčić, J., Bellido, J.M., Carbonara, P. et al., 2017. Old Info for a New Fisheries Policy: Discard Ratios and Lengths at Discarding in EU Mediterranean Bottom Trawl Fisheries. Frontiers in Marine Science, 4, 99.
Veiga-Malta, T., Feekings, J., Herrmann, B., Krag, L.A., 2019. Industry-led fishing gear development: Can it facilitate the process? Ocean & Coastal Management, 177, 148-155.
Vitale, S., Milisenda, G., Gristina, M., Baiata, P., Bonanomi, S. et al., 2018. Towards more selective Mediterranean trawl fisheries: are juveniles and trash excluder devices effective tools for reducing undersized catches? Scientia Marina, 82 (S1), 215-223.
Wileman, D., Ferro, R.S.T., Fonteyne, R., Millar, R.B., 1996. Manual of methods of measuring the selectivity of towed fishing gear. ICES Cooperative Research Report, 215, 132.
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