Bottlenose dolphin Tursiops truncatus health status as an assesment of environmental degradation?

Abstract

The Canary Islands represent an area of primary interest in terms of marine mammal biology and health because of the presence thoughout the year of 27 celacean'sp"ci"s along with a-greatconcentration of diverse human activities' The growing concem aboi marine mammal conservation ìed to ttre development of a local strandings network' allowing an exhaustive study ofthe pathologies causing their death. The coastal resident character of bottlenose dolphin Tursiops truncattus i'n th"." ,nut"., pãint" to thiã species as a suitable marker to estimate the parameters affecting the bio-cons"*"t¡on of this partiãular marine environment. To achieve the objective of assessing the population health of the local bottlenose dolphin population, a systematic post-mortem analysis of carcasses is routinely carried out at our veterinary schoãl faciliiies. we present here the pathological findings of rursiops stranded in the Canary Islands during the period, 1996-2000 (n:l l)' The diagnostics showed several processes leading to the death ofthe dolphins' Most of the animals (n:5) presented a multiorgarric failure accompanied by septicaemiå'and immunodeficiency. Fisheries interactions (n:2) appeared to be the second on the list. Interestingly, we found a case of interspecific interaction, together with thoracic ffauma resulting in a cardiovur*tu. faiíoíé. Finally, another individuàl showed an advanced parasitic lepto-meningoencephalitis caused by a trematode of the Nositremq sp' The diversity of the pathological processes affecting Tursiops t*n"!t^ in fhe canaries suggests that this species may not be the recipient ofã cleår predominant hr.inan acúvity-related pathology. Nevertheless, this preliminary conclusion and the ,"tatirely smaíl sample size indicate the necessity for a long-term monitoring of those p"rft"ngi""f processes in order to define the ìmpact of environmental degradation on this species'