Commercial catches and discards of a Mediterranean small-scale cuttlefish fishery: implications of the new EU discard policy

• Published in: Scientia marina 2018-12, Vol.82 (S1), p.155-164
• Main Authors: Gil, Maria Del Mar, Catanese, Gaetano, Palmer, Miquel, Hinz, Hilmar, Pastor, Elena, Mira, Antoni, Grau, Amalia, Koleva, Elka, Maria Grau, Antoni, Morales-Nin, Beatriz
• Format: Article
• Language: English
• Subjects: Bycatch; Captivity; Catch composition; Cephalopod fisheries; Coasts; Commercial fishing; Commercialization; cuttlefish; Discards; Dominant species; Ecosystem approach to fisheries; Fish; Fisheries; Fishers; fishers’ perception; Fishing; Fishing equipment; Landing; landing obligation; mallorca; Marine molluscs; Netting (materials/structures); Policies; Small-scale fisheries; small-scale fishery; Species composition; Surveys; Survival; trammel net; western mediterranean
• ISSN: 0214-8358; 1886-8134
• DOI: 10.3989/scimar.04735.03B

The cuttlefish (Sepia officinalis) trammel net fishery is one of the most important small-scale fisheries in the Mediterranean Sea. Here we describe the main catch, by-catch and discard patterns found in this fishery on Mallorca Island by onboard surveys of 1005 netting walls from 23 fishing trips. The number of items captured, their size and their subsequent use, i.e. kept for sale or discarded, were recorded. Furthermore, the immediate survival of the unwanted items (i.e. vitality state when the gear came on board) and the medium-term survival of a subsample were assessed. The cuttlefish was the dominant species in the commercial fraction of the catch, particularly during the fishing season peak (March). However, S. officinalis catches quickly decreased further into the season, with other high-value fish, such as Scorpaena scrofa, increasing in the commercial fraction of the catch. As species composition is continuously changing, it is often difficult to determine the main target species of this fishery. This strategy possibly complicates management but maximizes fishing revenue, which was an average of €175 per trip. With respect to discards, up to 104 different species were caught but not commercialized. The most abundant were Holothuria sp. and Torpedo marmorata. Their immediate survival was 100% and 20%, respectively. In both cases, the medium-term survival and the vitality status were high after seven days in monitored captivity. Therefore, in these cases, their immediate release to the sea should be promoted, given that they are exempt from the EU landing obligation. Interviews with fishers revealed that the perceived quantity of discards was lower than the amount recorded by the present study. Currently, just a small percentage (1.5%) of these discards will be affected by the landing obligation enforced by the new European discards ban.