An overview of dolphin depredation in Italian artisanal fisheries

Abstract

Conflict between dolphins and fisheries is an important management issue in many parts of the world. In 2002, we examined the extent of depredation in the Italian small scale fishery by means of in situ interviews. Overall, 245 landing sites were investigated, representing 11.09% of the whole Italian artisanal fleet. The association between the commonly used artisanal fishing gear and the interacting fauna was investigated by means of correspondence analysis. Set gillnet and trammel nets were the types of the fishing gear most vulnerable to dolphin depredation; the interaction with these gear amounted to 66.4% while fish damage was reported in 72.2% of the cases. A regional ranking of the interactions in terms of both fishing gear alteration and fish damage, shows that the problem is most pressing in the Friuli, Campania, Sardinia and Apulia regions. This study is the first attempt to monitor dolphin -fisheries interactions and assess depredation rates in Italy, providing information on the areas where future investigation should be concentrated.

Interactions between fisheries and cetaceans in the Thracian sea (Greece) and management proposals

“…For the Thracian Sea, the north part of the Aegean Sea (Figure ), the cause of death was determined, where possible, for stranded cetaceans recorded and analysed by Milani, Vella, Vidoris, Christidis, Koutrakis, Frantzis, et al. (2017).…”

Odontocete bycatch and depredation in longline fisheries: A review of available literature and of potential solutions

“…Longline gear poses a significant injury and drowning risk to depredating odontocetes, which affect the welfare of individuals and the conservation of populations (Ashford et al 1996, Northridge and Hofman 1999, Visser 2000, South Pacific Regional Environment Program 2002, Secchi et al 2005, Gilman et al 2006, Forney and Kobayashi 2007, Hamer 2009 a , Lauriano et al 2009, Reeves et al 2009). Some individuals may accidentally ingest a hook when they depredate catch from longline hooks, which may become lodged in their mouth, throat, or stomach (Secchi et al 2005, Fig.…”

“…Although concerns about the welfare and conservation of depredating odontocetes have become more common in recent times, concerns about the economic impact of depredation on affected longline fisheries have persisted since the 1960s (Dahlheim 1988, Yano and Dahlheim 1995, South Pacific Regional Environment Program 2002, Australian Fisheries Management Authority 2005, Indian Ocean Tuna Commission 2007). Depredation can reduce the overall size and condition of the landed catch, because target fish may be deterred from taking baited hooks, or caught fish may be damaged or removed completely (Yano and Dahlheim 1995, Northridge and Hofman 1999, Gilman et al 2006, Hamer 2009 b , Lauriano et al 2009). When depredation occurs, affected fisheries are likely to experience sporadic, seasonal, or ongoing reductions in profit, which may lead to economic decline, especially if the problem persists.…”

Interaction between bottlenose dolphin (Tursiops truncatus) and trammel nets in the Archipelago de La Maddalena, Italy

“…The lack of information on the frequency and amount of depredation, or on its economic effects, makes any effort to solve or manage the conflict very difficult (Lauriano et al, 2009). …”