Reducing unwanted catches of trammel nets: experimental results of the “guarding net” in the caramote prawn, Penaeus kerathurus, small-scale fishery of the Ligurian Sea (western Mediterranean)




experimental fishing, discards, trammel net, caramote prawn, small-scale fisheries, Mediterranean Sea


This study aimed to test the effectiveness of a “guarding net”, a device placed at the bottom of a trammel net, for reducing unwanted catches in the caramote prawn trammel net fishery of the Ligurian Sea. This specialized and profitable fishery is affected by unwanted catches that generate high discard rates and damage to the nets, with environmental impacts and costs for fishermen. The experimental study consisted in comparing the catches of a standard trammel net (STN) with those of two “experimental” trammel nets, e.g. STNs provided with a guarding net of 19 cm (TGN20) and 24 cm height (TGN25), respectively. The guarding net, a strip of gillnet placed at the bottom of the net, can be considered a by-catch reducer device (BRD). Some fishermen of the investigated fishery have been using this device for several years. The results of the 15 experimental fishing trials performed from June to July 2016 indicate that the guarding nets significantly reduce discards (e.g. crabs and other invertebrates); the biomass of the unwanted species caught was 75% lower than that produced by the STN. The catch rates of the target species obtained with TGN20 and TGN25 were also significantly lower than those of the STN, though of a lesser amount. Nonetheless, this economic loss can be compensated by the decrease in sorting time and material and labour costs that can be achieved using the guarding net.


Download data is not yet available.


Akaike H. 1987. Factor analysis and AIC. Psychometrika 52: 317-332.

Alverson D.L., Freeberg M.H., Murawski S.A., et al. 1994. A global assessment of fisheries bycatch and discards. FAO Fish. Tech. Pap. 339, 233 pp. Alves D.M., Cristo M., Sendão J., et al. 2006. Diet of the cuttlefish Sepia officinalis (Cephalopoda: Sepiidae) off the south coast of Portugal (eastern Algarve). J. Mar. Biol. Ass. U.K. 86: 429-436.

Aydin I., Gokce G., Metin C. 2013. Using guarding net to reduce regularly discarded invertebrates in trammel net fisheries operating on seagrass meadows (Posidonia oceanica) in _zmir Bay (Eastern Aegean Sea). Med. Mar. Sci. 14: 282-291.

Batista M.I., Teixeira C.M., Cabral H.N. 2009. Catches of target species and bycatches of an artisanal fishery: The case study of a trammel net fishery in the Portuguese coast. Fish. Res. 100: 167-177.

Bellido J.M., Santos M.B., Pennino M.G., et al. 2011. Fishery discards and bycatch: Solutions for an ecosystem approach to fisheries management? Hydrobiologia 670: 317-333.

Bellido J.M., Carbonell A., Garcia M., et al. 2014. The obligation to land all catches: Consequences for the Mediterranean. European Parliament, Directorate General for Internal Policies Policy Department B: Structural and Cohesion Policies, 52. Bolognini L. 2017. Penaeus kerathurus. In: Sartor P., Mannini A., Carlucci R., et al. (eds). Synthesis of the knowledge on biology, ecology and fishery of the halieuthic resources of the Italian Seas. Biol. Mar. Mediterr. 24 (suppl. 1): 54-62.

Crespi V., Prado J. (eds). 2002. Fishing Technology Equipments. Bycatch Reduction Devices (BRDs). In: Technology Fact Sheets, FAO Fisheries and Aquaculture Department,

Erzini K., Monteiro C.C., Ribeiro J., et al. 1997. An experimental study of gill net and trammel net ghost fishing off the Algarve (southern Portugal). Mar. Ecol. Progr. Ser. 158: 257-265.

European Commission (EC). 2007. Communication from the Commission to the Council and the European Parliament. A policy to reduce unwanted by-catches and eliminate discards in European fisheries. COM (2007) 136 final, 8 pp.

European Union (EU). 2013. Regulation (EU) No 1380/2013 of 11 December 2013 on the Common Fisheries Policy, amending Council Regulations (EC) No 1954/2003 and (EC) No 1224/2009 and repealing Council Regulations (EC) No 2371/2002 and (EC) No 639/2004 and Council Decision 2004/585/EC. Official Journal of the European Union L 354/22.

FAO. 2016. The State of Mediterranean and Black Sea Fisheries. General Fisheries Commission for the Mediterranean. Rome, Italy, 135 pp.

Fabi G., Manoukian S., Spagnolo A. 2006. Feeding behavior of three common fishes at an artificial reef in the northern Adriatic Sea. Bull. Mar. Sci. 78: 39-56.

Garcia S.M., Zerbi A., Aliaume C., et al. 2003. The ecosystem approach to fisheries. Issues, terminology, principles, institutional foundations, implementation and outlook. FAO Fish. Tech. Pap. 443: 71 pp.

Gökçe G., Bozao_lu A.S., Erya_ar A.R., et al. 2016. Discard reduction of trammel nets in the Northeastern Mediterranean prawn fishery. J. Appl. Ichthyol. 32: 427-431.

Grati F., Bolognini L., Domenichetti F., et al. 2015. The effect of monofilament thickness on the catches of gillnets for common sole in the Mediterranean small scale fishery. Fish. Res. 164: 170-177.

Guyader O., Berthou P., Koutsikopoulos C., et al. 2013. Small-scale fisheries in Europe: A comparative analysis based on a selection of case studies. Fish. Res. 140: 1-13.

Hall S.J. 1999. The effects of fishing on marine ecosystem and communities. Blackwell Science, London. 274 pp.

Hastie T.J., Tibshirani R.J. 1990. Generalized additive models. Vol. 43. CRC Press. Kelleher K. 2005. Discards in the world's marine fisheries. An update. FAO Fish. Tech. Pap. 470: 131 pp. Lleonart J., Demestre M., Martín P., et al. 2014. The co-management of the sand eel fishery of Catalonia (NW Mediterranean): The story of a process. Sci. Mar. 78S1: 87-93.

Machias A., Vassilopoulou V., Vatsos D., et al. 2001. Bottom trawl discards in the northeastern Mediterranean Sea. Fish. Res. 53: 181-195.

Maynou F., Recasens L., Lombarte A. 2011. Fishing tactics dynamics of a Mediterranean small-scale coastal fishery. Aquat. Liv. Resour. 24: 149-159.

Metin C., Gökçe G., Aydın _., et al. 2009. Bycatch reduction in trammel net fishery for prawn (Melicertus kerathurus) by using guarding net in Izmir Bay on Aegean Coast of Turkey. Turk. J. Fish. Aquat. Sci. 9: 133-136.

Pranovi F., Colla S., Valeri P., et al. 2016. Present and future status of artisanal fisheries in the Adriatic Sea (western Mediterranean Sea). Ocean Coast. Manag. 122: 49-56.

Prchalová M., Mrkvi_ka T., Peterka J., et al. 2011. A model of gillnet catch in relation to the catchable biomass, saturation, soak time and sampling period. Fish. Res. 107: 201-209.

R Core Team. 2016. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria.

Razali. N.M., Wah Y.B. 2011. Power comparisons of Shapiro-Wilk Kolmogorov-Smirnov, Lilliefors and Anderson-Darling tests. J. Stat. Model. Analyt. 2: 21-33.

Relini G., Relini M., Torchia G., et al. 2002. Trophic relationships between fishes and an artificial reef. ICES J. Mar. Sci. 59: 536-542.

Rossetti I., Vannucci A., Sartini M., et al. 2006. Pesca di mazzancolla Penaeus kerathurus (Forsskal, 1775) con reti da posta presso la marineria artigianale di Viareggio (Mar Ligure sudorientale). Biol. Mar. Mediterr. 3: 284-285 (in Italian).

Sánchez P., Demestre M., Martin P. 2004. Characterisation of the discards generated by bottom trawling in the northwestern Mediterranean. Fish. Res. 67: 71-80.

Sartor P., De Ranieri S., Serena F., et al. 2006. Studio sperimentale per l'individuazione di accorgimenti tecnici mirati alla riduzione della cattura 'indesiderata' di invertebrati bentonici con reti da posta. Tuscany Region Reg. UE 1263/99, FIFG, Final Report (in Italian).

Sartor P., Silvestri R., Sbrana M., et al. 2007. Experimentation of technical devices for the discard reduction in the set net fishery along the Livorno coast. Biol. Mar. Mediterr. 14: 360-361.

Shapiro S.S., Wilk. M.B. 1965. An analysis of variance test for normality (complete samples). Biometrika 52: 591-611.

Silvestri R., Baino R., Voliani A. 2003. Caratteristiche delle catture di Sepia officinalis con reti da posta. Biol. Mar. Mediterr. 10: 927-930 (in Italian).

Scientific, Technical and Economic Committee for Fisheries (STECF). 2016. The 2016 Annual Economic Report on the EU Fishing Fleet (STECF 16-11); Publications Office of the European Union, Luxembourg; ISBN 978-92-79-64633-1.

Stratoudakis Y., Fryer R.J., Cook R.M. 1998. Discarding practices for commercial gadoids in the North Sea. Can. J. Fish. Aquat. Sci. 55: 1632-1644.

Tsagarakis K., Machias A., Giannoulaki M., et al. 2008. Seasonal and temporal trends in metrics of fish community for otter-trawl discards in a Mediterranean ecosystem. ICES J. Mar. Sci. 65: 539-550.

Tzanatos E., Somarakis S., Tserpes G., et al. 2006. Identifying and classifying small-scale fisheries métiers in the Mediterranean: A case study in the Patraikos Gulf, Greece. Fish. Res. 81: 158-168.

Tzanatos E., Somarakis S., Tserpes G., et al. 2007. Discarding practices in a Mediterranean small-scale fishing fleet (Patraikos Gulf, Greece). Fish. Manag. Ecol. 14: 277-285.

Villasante S., Pazos Guimeráns C., Rodrigues J., et al. 2015. Smallscale fisheries and the zero-discard rate. European Parliament Study, Directorate-General for Internal Policies Directorate B- Structural and Cohesion Policy. Brussels.

Vassilopoulou V., Rochet M.-J., Helmond A.T.M. van, et al. 2012. Bycatch and discards: Management indicators, trends and location (BADMINTON). Final report, 50 pp.

Wood S.N. 2006. mgcv 1.3. R package.



How to Cite

Sartor P, Li Veli D, De Carlo F, Ligas A, Massaro A, Musumeci C, Sartini M, Rossetti I, Sbrana M, Viva C. Reducing unwanted catches of trammel nets: experimental results of the “guarding net” in the caramote prawn, Penaeus kerathurus, small-scale fishery of the Ligurian Sea (western Mediterranean). Sci. mar. [Internet]. 2018Dec.30 [cited 2024Apr.20];82(S1):131-40. Available from:




Most read articles by the same author(s)

<< < 1 2