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• time, money, or gear loss by fishermen due trawl fisheries / bottlenose dolphin interactions
to cetaceans interacting with fishing opera- off the Israeli coast (Goffman et al. 1995, 2001).
tions, or getting caught in nets; In addition to these areas, some information
• a real or perceived ecological competition exists on conflicts between cetaceans and fisher-
with cetaceans, based on the conviction that ies in several Mediterranean areas, including the
depredation – particularly by dolphins - re- Thracian Sea (Mitra et al., In press), the Am-
duces the amount of fish available to fisher- vrakikos Gulf, Greece (I. Siori and E. Hatzidimit-
ies (Reeves et al. 2001). riou, pers. comm.), the Ionian Sea (Tringali et al.,
Beneficial effects may also occur. These may In press), the sea area off Tunisia (Lofti 2000),
involve dolphins “co-operating” in fishing opera- the Tyrrhenian Sea (Consiglio et al. 1992, Mussi
tions, or otherwise increasing the chances of suc- et al. 1998), and the Gibraltar Strait (De Stepha-
cess of a fishery (e.g., Pryor et al. 1990). Indirect nis et al. 2000, Pèrez Gimeno et al., In press). In
beneficial effects may include cetaceans making the past, there have also been recorded interac-
an area more attractive to tourists, thus providing tions between false killer whales, Pseudorca
economic advantages (e.g., increased request for crassidens, and tuna fisheries in the Messina
seafood) that may positively impact local fisher- Strait, Italy (Scordìa 1939).
ies. More importantly, marine mammals are es- Overall, most information on the economic ef-
sential components of healthy ecosystems, and fects of dolphin interactions with Mediterranean
their ecological importance (e.g., Estes et al. fisheries is qualitative and inadequately docu-
1998) is an issue that has been given little con- mented. Although it is certain that in some areas
sideration until the present day. fishermen suffer from either gear damage, re-
The main types of fishing gear used in coastal duced catch, or time/money loss, no attempt has
Mediterranean waters where conflict with dol- ever been made to evaluate trends, nor to quan-
phins has been reported are bottom-set trammel tify the costs of such interactions (Reeves et al.
nets and gillnets. Dolphins also interact with 2001).
trawl nets, and occasionally with small purse Most interactions having a negative impact on
seines targeting pelagic schooling fish (Reeves et Mediterranean fisheries have involved the com-
al. 2001). Although perceived conflict is being mon bottlenose dolphin and the short-beaked
reported from a number of Mediterranean areas, common dolphin, which are the most abundant
there have been few studies aimed at defining the coastal cetaceans in the Mediterranean (Notarbar-
extent of the conflict, and estimating the actual tolo di Sciara and Demma 1994). However, it
costs to fisheries. must be considered that Mediterranean common
Studies specifically focusing on fishery- bottlenose and short-beaked common dolphin
dolphin interactions have been initiated in a few populations, which are thought to be geographi-
Mediterranean areas. In Italy’s Asinara Island cally isolated from those in the Atlantic Ocean
National Park, north-western Sardinia, an attempt (A. Natoli and R. Hoelzel, pers. comm.), have
has been made to quantify the impact of dolphin now declined considerably and their numbers are
depredation in the trammel net fishery for red certainly not as high as they used to be only 50
mullet (Mullus surmuletus) (Cannas et al. 1994, years ago.
Lauriano et al., In press). In two areas of Sicily Today, the common bottlenose dolphin – that
(Catania and Favignana) a European Commis- in the basin is typically found on the continental
sion-sponsored study (project ADEPTs) has been shelf - remains the species involved in most cases
initiated to test the feasibility and efficacy of us- of interactions with coastal fisheries, although its
ing pingers to reduce dolphin depredation in populations appear to be increasingly scattered
trammel and gill net fisheries (Quero et al. 2000). and fragmented into small units.
Studies conducted by the University of Barcelona Interactions with Mediterranean fisheries have
in the Balearic Islands from 1992-95 indicated also involved the short-beaked common dolphin,
that about 30 bottlenose dolphins were dying an- but the current extent of such interactions is lim-
nually as a result of entanglement or direct killing ited by the fact that the species has faced a dra-
by fishermen, in retaliation for depredation on matic decline in numbers over the past few dec-
trammel nets and shore-anchored gill nets set for ades. The forthcoming revised IUCN/SSC action
red mullet and cuttlefish (Sepia officinalis) (Sil- plan recognises that short-beaked common dol-
vani et al. 1992, Gazo et al., In press). Finally, phins in the central and eastern Mediterranean
research is underway to evaluate the dynamics of have declined precipitously and that conservation

Cetaceans of the Mediterranean and Black Seas – 9.3