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Mediterranean and Black Sea Cetacean Red List Assessment Delphinus delphis Evaluator/s Reeves, R.R. & Taylor, B. (Cetacean Red List Authority) Justification At the outset, it is necessary to acknowledge that definitive quantitative data on absolute abundance and rate and extent of decline are not available for this subpopulation, and that it is unlikely that such data will become available in the near future. The Preamble of the 2001 IUCN Red List Categories, under Item 6, states that “the absence of high-quality data should not deter attempts at applying the criteria, as methods involving estimation, inference and projection are emphasized as being acceptable throughout - so long as these can reasonably be supported.” The abundant qualitative data and limited quantitative data that are available for the Mediterranean subpopulation of Common Dolphins are sufficient to infer a reduction in population size of more than 50% over a three-generation period (i.e., the past 30-45 years). [Note: Estimated age at sexual maturation varies with region, from three years (Black Sea) to 7-12 years (eastern Pacific) for males and from 2-4 years (Black Sea) to 6-7 years (eastern Pacific) for females (Perrin 2002). Variation between regions may be partly a result of density-dependent effects due to exploitation. Maximum estimated age is 22 years (Black Sea). These values support an estimate of generation time of 10-15 years.] The reduction or its causes may not have ceased, are not understood, and may not be reversible. These inferences are based on the expert judgment of researchers from the region who have observed declines in the number of animals (subcriterion a) and in the subpopulation’s extent of occurrence, as well as a deterioration in the quality of Common Dolphin habitat in large portions of the Mediterranean (subcriterion c). Although no formal index of abundance (subcriterion b) is available to demonstrate a numerical decline, there is reason to believe that such a decline has occurred, based on the species’ progressive disappearance from the Adriatic, Balearic, and Ligurian Seas and Provençal Basin, the significant decline in group encounter rates in the eastern Ionian Sea (see documentation under Range and Population), and the reasonable assumption that a decline in abundance has been commensurate with the large (albeit unquantified) decline in extent of occurrence. For additional detail, readers are referred to Bearzi et al. (2003). Consultation and peer review: This assessment and the supporting documentation was drafted by Giovanni Bearzi in consultation with Ana Cañadas, Alexandros Frantzis, Giuseppe Notarbartolo di Sciara, Elena Politi, Randall Reeves, and Barbara Taylor. It was reviewed by the CSG membership prior to submission to IUCN. Distribution Country Names Albania Algeria Bosnia and Herzegovina Croatia Cyprus Egypt France Gibraltar (UK) Greece Israel Italy Lebanon Libya Malta Monaco Morocco Palestinian Territory Serbia and Montenegro Annex 7: Delphinus delphis 131
Mediterranean and Black Sea Cetacean Red List Assessment Delphinus delphis Slovenia Spain Syria Tunisia Turkey Aquatic Regions Mediterranean and Black Sea Summary Documentation System Marine Major Habitat(s) 9.1 Sea - Open 9.2 Sea - Shallow Major Threat(s) 1.3.2.3 Habitat Loss/Degradation - Extraction - Fisheries - Large-scale/industrial (past) 4.1.1.2 Accidental mortality - Bycatch - Fisheries-related - Netting (past, present) 6.1.1 Pollution (affecting habitat and/or species) - Atmospheric pollution - Global warming/oceanic warming (present, future) 6.3 Pollution (affecting habitat and/or species) - Water pollution (ongoing) 8.3 Changes in native species dynamics - Prey/food base (past, present) Population Trend Conservation Action(s) 1.1.1 Policy-based actions - Management plans - Development (needed) 1.2.1.1 Policy-based actions - Legislation - Development - International level (in place) 1.2.1.2 Policy-based actions - Legislation - Development - National level (in place) 2.2 Communication and Education - Awareness (needed) 3.5 Research actions - Threats (needed) 3.9 Research actions - Trends/Monitoring (needed) 4.4.2 Habitat and site-based actions - Protected areas - Establishment (in place, needed) Detailed Documentation Range The Short-beaked Common Dolphin (hereafter the Common Dolphin) is a small cetacean species with a wide distribution. Like most other cetaceans, however, it is not panmictic and occurs as a series of geographically separate subpopulations (e.g., Jefferson and Van Waerebeek 2002). Once one of the commonest species in the Mediterranean Sea, the Common Dolphin has experienced a generalized and major decrease in this region during the last 30-40 years (Bearzi et al. 2003). Coastal groups in western Greece seem to exhibit relatively high levels of site fidelity (Politi 1998), but little is known about the movements and ranging patterns of animals living offshore. The case for regarding Mediterranean Common Dolphins as a distinct subpopulation is not perfect, and admittedly rests upon a somewhat complicated chain of inference. Genetic studies indicate a significant level of divergence between Mediterranean and Atlantic populations (Natoli et al. in press). Differences in contaminant levels between dolphins from the Alboràn Sea (northwestern Mediterranean) and Atlantic Annex 7: Delphinus delphis 132
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Published by: The World Conservatio
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Contents Preface ------------------
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Background and Introduction The con
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Results Of the 12 assessed units in
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Acknowledgements Workshop participa
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Annex 1 Workshop Agenda Mediterrane
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Blue World Institute of Marine Rese
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Fin whale (Balaenoptera physalus) M
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Mediterranean and Black Sea Cetacea
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Long-finned pilot whale (Globicepha
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Risso’s dolphin (Grampus griseus)
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Harbour porpoise (Phocoena phocoena
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Striped dolphin (Stenella coeruleoa
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Page 86 and 87: Mediterranean and Black Sea Cetacea
Page 96 and 97: Annex 4 Visitor Species Species Com
Page 114 and 115: Annex 5 Vagrant Species Species Com
Page 118 and 119: North Atlantic right whale (Eubalae
Page 120 and 121: Northern bottlenose whale (Hyperood
Page 128 and 129: Harbour porpoise (Phocoena phocoena
Page 130 and 131: Indo-Pacific humpback dolphin (Sous
Page 132 and 133: Annex 6 Introduced Species Species
Page 142: Annex 8 Species reported to have oc
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