Scientia Marina, Vol 82, No S1 (2018)

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)

Paolo Sartor
CIBM, Consorzio per il Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci”, Italy

Daniel Li Veli
University of Pisa, Department of Biology, Italy

Francesco De Carlo
Aplysia Soc. Coop. r.l., Italy

Alessandro Ligas
CIBM, Consorzio per il Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci”, Italy

Andrea Massaro
Aplysia Soc. Coop. r.l., Italy

Claudia Musumeci
CIBM, Consorzio per il Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci”, Italy

Marina Sartini
Aplysia Soc. Coop. r.l., Italy

Ilaria Rossetti
Aplysia Soc. Coop. r.l., Italy

Mario Sbrana
CIBM, Consorzio per il Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci”, Italy

Claudio Viva
CIBM, Consorzio per il Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci”, Italy


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.


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

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