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Overvie w                                      sources and fishery-related habitat loss represent
                                                              a source of concern in many Mediterranean areas.
                  Interactions between cetaceans and fisheries   While it is known that cetaceans have been
               in the Mediterranean Sea are probably as old as   facing serious problems owing to fisheries in the
               the first human attempts to catch fish with a net.   last half-century (Reeves and Leatherwood
               Countless reports and artefacts from the former  1994), there is no clear evidence that depredation
               Tethys Ocean tell the story of dolphins interact-  may have risen in recent times.  Therefore,  it is
               ing with fishermen.  The earliest reports describe  unclear why the issue appears to be increasingly
               idyllic relationships between dolphins and peo-  perceived by Mediterranean fishermen to be
               ple, but things changed as fisheries developed.  causing economic hardship, particularly as far as
               As early as in 1587 a Papal Decree was issued  small-scale, coastal fisheries are concerned.  One
               “anathematising the vermin” in response to con-  of the reasons may be that small-scale fisheries in
               cerns in France about the effect of dolphins on  many  parts of the Mediterranean have become
               fisheries (Smith  1995).  Eighteenth century re-  economically marginal, whether due to the deple-
               ports describe fishermen attempts to keep dol-  tion of fish stocks, over-capitalisation, market
               phins away from their nets, by means including  changes or socio-cultural factors (Reeves et al.
               loud noises, dynamite, weapons, modifications of  2001).  Therefore, even relatively small losses to
               fishing techniques and schedules, and large-mesh  dolphin depredation can now have a proportion-
               nets surrounding the fishing nets to protect them   ally large impact on a fisherman’s livelihood.
               from dolphin incursions. The animals were  The resulting economic distress may be prompt-
               claimed to be “consistently seeking a parasitic  ing fishermen to complain about the depredations
               life at the poor fishermen’s expenses” and re-  by dolphins and to perceive these animals as
               quests were repeatedly submitted by fishermen to  competitors.  Moreover, fishermen have learned
               governmental bodies to reduce dolphin numbers  of new opportunities to gain compensation and
               through culling (Barone 1895, Smith 1995).     have therefore become more vocal about the im-
                  In some Mediterranean areas, direct killings  portance of dolphin interactions in recent times
               and bounties for dolphins represented the first  (Reeves et al. 2001).
               human attempts to solve the problem of net dep-   Although approaches to marine mammal con-
               redation , a strategy that was supported by sev-  trol such as culling or harassment have become
               eral governments for at least one century (Smith  illegal in most Mediterranean countries, and are
               1995).  In the 1950s, retaliation measures were  no longer viewed as appropriate by most fishing
               still encouraged by State money rewards, result-  organisations, direct killings are occasionally en-
               ing in hundreds of dolphins being killed annually  acted by individual fishermen.  Nevertheless,
               in the Adriatic Sea (Holcer 1994).             many fishermen are becoming aware that blam-
                  Although bounties are no  longer issued, the  ing the dolphins for the ongoing changes within
               overall impact of world fisheries on cetaceans  the ecosystem does not represent sensible behav-
               remains extremely high (Reeves et al., In press).   iour.  If solutions to the problems of cetacean-
               Together with deliberate kills, incidental catches   fisheries interactions are to be found, these must
               of cetaceans in fishing gear also increased with   be based on the comprehension of ecosystem dy-
               the worldwide development of fisheries.  How-  namics.
               ever, it was only in the last few decades that by-
               catch became one of the major threats to the very   Impact of cetaceans on fisheries.  Interactions
               survival of several cetacean populations.  In the  between cetaceans and coastal fisheries may
               Mediterranean, where most data are sparse or dif-  negatively affect the fisheries through:
               ficult to evaluate, this impact has never been  •   damage to fishing gear in the form of holes
               comprehensively assessed.  Nevertheless, unsus-    torn in the nets as the dolphins attempt to
               tainable bycatch rates have been reported for sev-  remove fish, or other forms of gear damage
               eral fisheries, and the combined effect of inten-  caused by cetaceans;
               tional killings, bycatch, reduction of prey re-  •   reduction in the amount or value of the catch
                                                                  as the dolphins mutilate or remove caught
                                                                  fish from nets or longlines;
                                                                  •   reduction in the size or quality of the catch
               1  Referring to “predators taking, or attempting to take, prey that are   as the dolphins’ presence causes fish to flee
               confined in pens or that have been - or are about to be  - caught in
               fishing gear” (Reeves et al. In press).            from the vicinity of the nets;

                                    Cetaceans of the Mediterranean and Black Seas   –   9.2
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