An insight into the status of the striped dolphins, Stenella coeruleoalba, of the southern Tyrrhenian Sea

Abstract

Drift-nets are known to result in high incidental catches of some cetacean species. Despite a UN moratorium on their use in the high seas and a ban in the Mediterranean by all European Union countries, including Italy (EC Reg. 1239/98), some fisheries continue to operate illegally. In 2002 and 2003 three line-transect surveys were conducted in the southern Tyrrhenian Sea around the Aeolian archipelago. These transects were designed to assess the presence, distribution and population size of cetacean species likely to be affected by accidental captures in this area. Data were only sufficient to estimate abundance for the striped dolphin. The best estimate (and first such estimate for this area) was 4030 individuals (CV=0.30, 95% CI=2239–7253) for May 2003. A rough estimate of striped dolphin by-catch, based on floating carcases, was calculated as 36 by-caught animals over a period of 12 days (CV=0.58, 95% CI=11–113). These results, although approximate, are a cause for concern. Conservation and management implications of the results are discussed.