ABSTRACT
Regular monitoring of the status of cetacean populations is essential for conservation, policy and management. Changes in spatial and/or temporal distribution and abundance of cetaceans over time have implications for identifying, assessing and mitigating the effects of human activities upon them and for the development of suitable conservation and management strategies, as well as for our understanding of their ecology. By using a passenger ferry as a scientific research platform, this study provides information on seasonal, annual and longer-term changes in the occurrence of cetacean species along a Fixed Line Transect lying between Italian coast (Livorno) and Corsica (Bastia). From October 2009 to September 2010 data on cetacean occurrence were collected during regular surveys conducted by experienced observer boarded on Corsica & Sardinia Ferris passenger ferries, along the usual route from Livorno to Bastia. This is one of the five routes used as Fixed Line Transect forming the ISPRA managed monitoring network in Tyrrhenian and Ligurian Sea. Observations were undertaken in fine weather condition (Beaufort ≤ 3) and each transect was considered as an independent statistical unit.
Data collected during surveys have been analysed to investigate the distribution, encounter rate, and habitat characteristics of the principals cetacean species living in this area. In the Livorno-Bastia transect two species are certainly present: Stenella coeruleoalba and Tursiops truncatus, while Physeter macrocephalus have been seen just once. Otherwise Balaenoptera sp., considered a frequently seen specie in prior studies, has never been seen in 2009/2010.
In the last few years marine environment have been hugely interested by anthropic impacts and has become an overriding topic of national and international policy. So many conventions, treaties and agreements at national and international level explicitly refer to cetacean monitoring, protection and conservation as environmental status indicators. Frequently there is no integration between different policies there is a need of turning overlaps into sinergy. The June 2008 European Marine Strategy Directive intend to make a significant contribution to the preservation, protection and restoration of marine ecosystems, including pollution reduction and minimization, and represents the environmental pillar of the Integrated Maritime Policy. The Directive aims to achieve a good environmental status of the EU marine waters based on the evaluation of different criteria. Criteria also include the
evaluation of cetacean status in terms of “description of the population dynamics, natural and actual range and status of species of marine mammals”.
The aim of this paper is to analyse different policies in terms of targets, tools and standards required for cetacean monitoring and show how Fixed Line Transect method can be used to provide suitable information on changes in cetacean population status for research and conservation policy. In fact the method allow to study species range and pattern distribution, population abundance in terms of relative abundance and habitat use.
Moreover, this discussion is dedicated to highlight that a correct management of the marine environment and the protection of cetaceans species, needs a strong cohesion between biological and legal knowledge. A specific professional could summarize these characteristics: a trained and experienced observer boarded on vessels to prevent ship-cetaceans collisions, bycatch and to collect representative data both useful to research and in agree with conservation policy.
