Project to support the conservation of Caretta caretta and Tursiops truncatus in the Canary Islands

PROJECT DESCRIPTION

BACKGROUND

The Canary Islands straddle the loggerhead turtle's (Caretta caretta) migration route across the Atlantic and important feeding and resting areas for the animals are found on the leeward side of Tenerife and Gran Canaria, sheltered from the trade winds and the Canaries current. These turtles can swim peacefully there for most of the year without being dragged away by currents and waves. This circumstance, which also applies to Madeira, is of vital importance for the turtles' ecology in the Eastern Atlantic. Yet the species, which is considered priority under the Habitats directive, is threatened, even here, as a result of various kinds of human activities: through accidental entanglement in fishing nets, by swallowing plastic debris, because of injuries inflicted by boats.

These turtle havens are also particularly favourable habitats for another species protected by the Habitats Directive, the bottle-nosed dolphin (Tursiops truncatus) as well as for other whales. These mammals are a tourist attraction for whale-watchers and cetacean enthusiasts, who cris-cross the sea by boat to spot them, causing an insufficiently known impact over their populations. Besides, the intense shipping traffic around the Las Palmas de Gran Canaria harbour challenges the welfare of a important sedentary population of dolphins.

OBJECTIVES

The main aim of the project was to define management plans for three marine Canarian SCIs frequented by the cetaceans and turtles, and to ease their implementation. A previous inventory and review of the natural resources and of the main threats caused by human activities was planned, in order to better define the relevant measures. Among the main features to evaluate, the impact of whale-watching and shipping on the cetaceans were particularly targeted.

Given the non-sedentary character of the target species, supplementary surveys of other marine stretches of the Canary archipelago were planned to check where they occur and their spatial patterns. The development of monitoring methods to get an improved knowledge of the species' ecology and behaviour features considered important for their conservation was also pursued.

Finally, the establishment of a rehabilitation centre for marine vertebrates and of a regional network for transporting and managing injured animals, and the execution of an awareness raising campaign, completed the set of activities proposed.

RESULTS

For the three target sites, the project generated a comprehensive background of scientific-technical information that will be key for undertaking a suitable management. The project was burdened by the lack of former experience in management planning of marine areas and final regulatory documents for the target sites were not produced. Nonetheless, the experience gained, with its successes and failures or gaps, and the contrast of techniques used in the project, can become a reference work for addressing the management of marine habitats and species in the Natura 2000 network in the marine environment.

As regards the bottle-nose dolphin (Tursiops truncatus), the main achievements that can be remarked in this project are the following:

Different fieldwork techniques were tested for estimating and monitoring populations of bottle-nose dolphin, delimiting their life ranges and modelling their use of the pSCI area. Baseline information was generated that improved much the knowledge about its biology, ecology and the status of the Canarian population of the species. Among the main findings relevant for the Natura 2000 network, the detection of a new colony and the finding that the Canarian dolphin population is the main one in Europe (1.000 ex.) are to be highlighted.

A proposal was made to enlarge the pSCI network, and a set of conservation measures to be included in the regulations of pSCIs was proposed after analysing the main threats for the species (i.e. fast-ferries, pollution and whale-watching).

An innovative study about the impacts of whale-watching activity over the ethological response of the individuals and groups of cetaceans was carried out. The study accounted for variables such as the boat’s movements and the environmental conditions, and had a straightforward application: the existing regional regulation for this activity was consequently modified by means of a new Decree adopted in September 2000.

For marine turtles (Caretta caretta), the following results can be highlighted:

a lot of valuable information about the species behaviour, habitat use and movements was obtained by means of a tagging and radio-tracking programme, through which 13 turtles were monitored for months. It complemented the work of another Life Mature project developed in Madeira (Portugal), which represents a pioneer experience in the systematic study of the pelagic stages of these turtles in the Eastern Atlantic area using satellite transmitters.

The results of the studies carried out showed a vast variation in the turtles’ behaviour, and the low relevance of limits for marine reserves for this species. Hence, it was concluded that specific conservation measures should be designed for it beyond the limits of Natura 2000, probably through enforcement of art. 10 of the Habitats Directive.

The need of international approaches to preserve the European turtles was also evidenced, as the project found out that our populations are cosmopolitan combinations of the different breeding populations of the World (America, Cabo Verde and Mediterranean basin). The very useful data obtained should be taken up in the medium term in order to propose direct management guidelines for this priority species.

The project also included a series of measures for the rehabilitation of turtles and other injured marine animals. A Recovery Centre was provided with infrastructure to allow for the simultaneous treatment of up to 28 turtles of the overall Canary Archipelago. In this regard, a regional network for the rescue and transport of injured animals to the centre was reinforced, and its awareness raising potential stimulated.

Two video spots and two booklets about the project and the target species deserve special attention as good dissemination products of this project. However, the aim of carrying out a sound awareness campaign among the stakeholders, the local people and the tourists was not sufficiently tackled, perhaps because the importance of this critical issue was disregarded: some of the usual activities carried out in the coastal fringe, and the whale watching itself, are major income sources for the Canaries as well as sources of impact for the marine environment; therefore, building strong consensus is required to make them conservation-friendly.

The roots for an improved networking were settled thanks to two technical international workshops. A Working group about C. caretta was created with the participation of teams from the Canaries, the Azores and Madeira archipelagos and from Andalucía, with the aim of carrying out joint projects for the future. For T. truncatus, the creation of a Working group with branches for the Mediterranean and the Atlantic populations was decided.