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use of the most threatening fishing gear used in  bly, the majority of strandings along the Italian
               Mediterranean waters, where the fishery has  coasts between 1986-90, the cause of which
               dramatically impacted several cetacean popula-  could be related to fishing gear, were caused by
               tions.  Multifilament nylon nets for swordfish  driftnets  (Cagnolaro and Notarbartolo di Sciara
               have 36-52 cm mesh and are 2-40 km long, with   1992).  Sperm whale and striped dolphin popula-
               a typical length of 12-15 km.  Similar nets are  tions were reportedly the most impacted, but by-
               used for albacore, with a mesh size of 16-20 cm  catch also involved Cuvier’s beaked whales,
               and a total length of 9-15 km (IWC 1994).      long-finned pilot whales, Risso’s dolphins, com-
                  Mediterranean countries with driftnetting  mon bottlenose dolphins and short-beaked com-
               fleets reportedly included Algeria, Morocco,  mon dolphins (IWC   1994).  Although fin whales
               Spain, France, Italy, Malta, Greece, and Turkey  may at times be capable of breaking the nets after
               (Di Natale and Notarbartolo di Sciara  1994, Sil-  entanglement and find their way out (Di Natale
               vani et al.  1999).  The number  of vessels rapidly  1992), even Mediterranean mysticetes may die in
               increased to over 1,000 by 1990 (IWC  1994).   pelagic driftnets (Centro Studi Cetacei  1992,
               For instance, the Italian driftnet fleet – reported   IWC 1994).
               as being the largest in the Mediterranean  - had   When driftnet fisheries reached their peak, a
               increased by 57% between 1987-90, totalling 700  total annual bycatch of over 8,000 cetacean
               boats carrying nets up to 22.5 km long.  After  specimens (mostly striped dolphins, but including
               management measures taken in 1990, the Italian  at least 30 sperm whales) was estimated for the
               fleet was reduced to 120 units (Di Natale and No-  Italian Seas alone (Di Natale and Notarbartolo di
               tarbartolo di Sciara  1994).  Based on fishermen  Sciara  1994), and perhaps up to 10,000 cetacean
               interviews conducted in the southern Tyrrhenian  specimens died annually in the whole Mediterra-
               Sea, about 90% of the bycatch was composed of  nean (IWC  1994).  The current annual toll that
               “dolphins”, while sperm whales represented the   cetaceans have to pay to driftnets fisheries is un-
               remaining 10%; up to 15 dolphins were reported   known, but remains potentially unsustainable in
               to die in fishing gear deployed overnight by a  some areas (e.g., in the Tyrrhenian Sea,  Mi-
               single boat in the area (B. Mussi and A. Mi-   ragliuolo et al.  2002).  Between 1993-98, it has
               ragliuolo, pers. comm.)                        been reported that 15 of 24 sperm whale strand-
                  Due to recent regional legislation, the situa-  ings in the Balearic Islands where caused by by-
               tion is changing  in European Union countries,  catch in driftnets (Làzaro and Martìn 1999).
               where driftnets have been be banned starting
               from 1 January 2002; meanwhile, a decommis-    Entrapment in bottom gillnets. Bottom gillnets
               sioning process of the Italian driftnet fleet is in  have been known to cause incidental entrapment
               process.  However, the unregulated use of pelagic  and death of thousands of cetaceans worldwide
               driftnets by non EU countries (possibly including  (Jefferson  et al.  1992, IWC  1994, Read  1996,
               both Mediterranean and non-Mediterranean na-   Reeves et al., In press).  This fishing gear is used
               tions) represents a source of concern.  Moreover,  in coastal waters up to 200 m deep, and usually
               illegal driftnetting is still an issue in some EU  targets demersal and bentho-pelagic prey.
               countries (e.g., in Italy, Miragliuolo et al.  2002).    Bycatch in bottom gillnets largely affects
               Owing to lack of enforcement measures, in most  small coastal cetaceans such as harbour por-
               Mediterranean countries cetacean bycatch in  poises, bottlenose dolphins (Tursiops sp.), hump-
               driftnets and deliberate killing of cetaceans  backed dolphins (Sousa  sp.), common dolphins
               caught alive in these nets occur irrespective of  (Delphinus sp.), and virtually all riverine cetace-
               national regulations that prohibit the taking of  ans (IWC  1994, Reeves and Leatherwood  1994,
               marine mammals (Di Natale and Notarbartolo di  Read  1996).  Mortality in gillnets is considered
               Sciara 1994).                                  as the main threat to the survival of the vaquita,
                  It was estimated that in the ‘90s thousands of  Phocoena sinus  (Vidal  1995, D’Agrosa et al.
               Mediterranean cetaceans have died in pelagic   1995) and the Hector’s dolphin,  Cephalorhyn-
               driftnets every year, at rates deemed unsustain-  chus commersoni  (Dawson and Slooten  1993).
               able (Di Natale  1990, Notarbartolo di Sciara  Conversely, incidental takes of large cetaceans in
               1990, Cagnolaro and Notarbartolo di Sciara  bottom gillnets are a rare occurrence (Reeves and
               1992, Di Natale and Notarbartolo di Sciara 1994,  Leatherwood  1994).  Factors that may contribute
               IWC   1994, UNEP/IUCN     1994, Forcada and  to the entrapment of cetaceans in gillnets include
               Hammond   1998, Silvani  et al.  1999).  Remarka-  (Jefferson et al. 1992, Lien  1994, Tregenza et al.

                                    Cetaceans of the Mediterranean and Black Seas   –   9.5
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