Very little is known about the critical habitat requirements of marine mammals. The lack of knowledge about distribution, reproductive cycles, migratory habits, ecological roles and so on limits the ability to develop conservation strategies. This makes marine mammals vulnerable to increased disturbance and habitat degradation. In the Alboran Sea, marine mammals are under threat. The Spanish organisation Alnitak has initiated a programme of research that aims to provide vital information for the conservation of dolphins and turtles.
Dolphin Decline and the Alboran Sea
The common dolphin has featured in Mediterranean human life since the earliest civilisations. Dolphins appear in myths and legends, as creatures considered close to humans and as their gods. Today, several thousands of years of this affinity remains. It is not surprising, therefore, that the decline of the common dolphin in the Mediterranean Sea has become an increasingly critical issue for scientists and conservationists. Although it is generally accepted that decline is occurring, the problem is in assessing, and providing clear evidence of, the magnitude of decline. This is mostly a result of a lack of historical data. The common dolphin, as well as other cetaceans in the Mediterranean Sea, is a useful bio-indicator for an ecosystem facing several pressures, such as mechanical destruction of the coastline, over-exploitation of resources, debris pollution, toxic pollution, and noise pollution. The effect of these threats in the Mediterranean is greatly increased by the semi-enclosed nature of this sea. The only renewal of water for the Mediterranean comes from the Atlantic Ocean through the narrow Strait of Gibraltar.
The Alboran Sea is a transition zone between the Mediterranean Sea and the Atlantic Ocean. The region is of vital importance for the regeneration of a Mediterranean ecosystem that is currently suffering from human-induced pressures such as pollution and over-fishing. The Alboran Sea represents essential habitat for the largest population of bottlenose dolphins in the Western Mediterranean, the last stronghold for harbour porpoises, and the most important feeding grounds for loggerhead turtles in Europe.
The Alboran stands out as a region of unique oceanographic characteristics. The Mediterranean is a semi-enclosed sea, open to the Atlantic Ocean only at the Strait of Gibraltar. Here, the difference in conditions between the Atlantic and Mediterranean, influenced by wind and atmospheric pressure, creates an inflow of Atlantic surface waters. The Alboran Sea is the transition chamber where the Atlantic and Mediterranean waters clash. Although the Atlantic surface waters entering the Alboran are not especially rich in nutrients, their reduced temperature and salinity create an important clash when entering the warm and saline Mediterranean. This has led many to consider the Alboran to be the oceanographic ‘motor’ of the Western Mediterranean basin. The inflowing Atlantic current is diverted by the Coriolis force (the cyclical flow of water resulting from the magnetic poles – clockwise flow in the northern hemisphere, anti-clockwise in the southern hemisphere) and topography. This creates ‘gyres’ (whirlpools), which end along the North African coast. The gyres, in turn, create several important thermal fronts and regions of up-welling. Marine life thrives in these up-wellings and this creates an important feeding ground for certain cetacean species, such as dolphins.
The physiography of the region is also of great interest, as the distribution of many cetaceans appears to be mainly affected by the depth, slope or nature of the sea floor. The Alboran Sea offers unique characteristics for research, with different types of sea floor, from volcanic escarpments and canyons to gentle slopes of sediments, gravel, sand or shells. The continental shelf of the Alboran Sea is very narrow compared to that of other Mediterranean regions, at about 150 metres.
Due to the ecological importance of the Alboran Sea, it has been established as a Marine Protected Area (MPA). The creation of MPAs is considered one of the most useful conservation mechanisms for marine habitats and species. The Alboran Sea was recognised as an MPA thanks to the work of Ana Cañadas (University of Madrid) and Ricardo Sagarminaga van Buiten (Spanish Cetacean Society), who established the Alnitak research project.
Alnitak is a non-profit NGO founded in 1990, which aims to carry out marine environmental investigation and education programmes in the Mediterranean Sea. Although research activities are carried out with a global approach to the marine ecology, Alnitak has concentrated its efforts mainly on cetaceans and sea turtles of the Mediterranean Sea. In 1992, Alnitak initiated a long-term monitoring programme on the cetacean population in the south-west Mediterranean Sea in order to establish the magnitude and causes of the decline of certain species of dolphins. Establishing close co-operation with other research teams in Spain, Alnitak chose the Alboran Sea as the research site due to its extraordinary oceanographic characteristics.
Earthwatch was established at the 1972 United Nations Conference on the Human Environment in Stockholm. The Earthwatch mechanism is a broad initiative to coordinate, harmonise and catalyse environmental observation activities. Through Earthwatch, UN agencies exchange and share environmental data and information. The UN Environment Programme (UNEP) provides the Earthwatch secretariat.
As part of the UN Earthwatch programme, Alnitak’s research is a major contributor to the Spanish Cetacean Society, a body that works within the legal frameworks of the European Union’s Habitats Directive. Alnitak’s work is part of one of Europe’s most ambitious marine biodiversity conservation projects, financed by the European Commission as part of the LIFE Nature programme.
Launched in 1992, LIFE (The Financial Instrument for the Environment) is one of the spearheads of community environment policy. LIFE co-finances environmental initiatives in the European Union, as well as in certain external countries such as those bordering the Mediterranean and Baltic Sea, and central and east European countries that have decided to participate in LIFE.
One of the main objectives of Alnitak conservationist work is to apply and develop non-intrusive research methods during its research programmes. This means non-disturbance of the animals, and especially of marine mammals, which can be extremely sensitive to disturbance. On board the Toftevaag, researchers from different fields of science work together with a global approach to three main objectives:
- To identify the dolphin populations of the Alboran Sea;
- To analyse their conservation status;
- To identify important habits of migration, breeding and feeding.
Built in 1910 for fishing herring in the North Atlantic, Toftevaag is a 20-metre gaff rigged ketch of great historic value. Toftevaag was rescued, together with hundreds of classic working ships, from ending her days as firewood and was restored to her original state.
Toftevaag is built entirely from Norwegian pine apart from the keel stem and sternposts, which are made from oak and protected by steel plates. The masts are made from Norway spruce and have undergone a long drying and impregnation process. The deck is pine treated with linseed oils. The well-preserved original planking of the ship shows signs of her traditional construction.
After nearly a century of sailing the fierce North Atlantic waters, Toftevaag has come to the Mediterranean as a survivor of the great age of sailing ships.
Toftevaag has proved over the last years to be perfectly adapted for her new role in the Mediterranean as an environmental protection ship. Her crow’s nest has become an ideal lookout post for sighting cetaceans, sea birds and turtles. She is stocked with up-to-date technology, which enables the research team to track and analyse the marine mammals. Toftevaag sails the Mediterranean offering the research teams an ideal working platform for their investigations, which will lead to better understanding and the conservation of the Mediterranean marine environment.
Every twenty minutes, the Toftevaag stops at a sampling station, where volunteers on board the vessel take part in recording surface water salinity and temperature, listening for cetacean sounds on the towed array hydrophone, and analysing the depth and slope of the sea floor and presence of fish shoals. Cetacean groups encountered are tracked visually, without creating disturbance, in order to be able to study their habitat use. Photo-identification is used along with skin sampling to identify populations. Underwater digital video is used with acoustic recording to study their behaviour. Some of the data is processed on board the Toftevaag during days of bad weather.
In the Alboran Sea region commonly sighted species include: striped dolphin (Stenella coeruleoalba -33.7% of the sightings), common dolphin (Delphinus delphis – 25%), long-finned pilot whale (Globicephala melas- 11.7%), bottlenose dolphin (Tursiops truncates -8.8%) and Risso’s dolphin (Grampus griseus – 4.1%). Other species are more rarely seen, such as the sperm whale (Physeter macrocephalus- 0.8%) or the Cuvier’s beaked whale (Ziphius cavirostris- 0.4%). On some occasions, it is even possible to see very rare species such as the false killer whale (Pseudorca crassidens – 0.1%) or the orca (Orcinus orca – actually a very large type of dolphin). In 1996, two bottlenosed whales (Hyperoodon – 0.1%) were also seen. The fin whale (Balaenoptera physalus)can also be observed on some occasions migrating through the region (1.9%).
In order to properly analyse the distribution and dynamics of cetaceans it is vital to take into consideration the ecosystem in which they evolve. For this reason, in parallel to the work carried out on cetaceans, several meteorological and oceanographic parameters are recorded at regular intervals during research sailings.
Application of Results
While not aboard the Toftevaag, Alnitak conducts general public awareness events and educational activities in coastal community schools. The project aims to identify all possible stakeholders of the marine protected areas in order to involve them in the management schemes. Most of these efforts concentrate on the fisherman whose future depends on the sustainable use of marine resources.
In the community
During the initial phases of Alnitak’s work, contacts with the local community and mass media had been opportunistic and low profile, to prevent the uncontrolled development of a whale-watching type of industry. However, once the MPA process was in place, raising public awareness became a fundamental part of Alnitak’s conservation goals. Together with the Spanish Cetacean Society, Alnitak involves the different interest groups, and especially fishermen, in the design, management and monitoring of MPAs. The published public awareness materials have become part of Alnitak’s global awareness campaign.
In public policy
Alnitak’s research has a direct application to the conservation of cetaceans and Mediterranean ecosystems in general. The co-operation between Alnitak, scientists and policy-makers is useful for MPA and other conservation work. The project results have helped update the Spanish National Endangered Species Act. The science resulting from the project will form the basis for the location and size of future MPAs.
The audio-visual results provide useful data for making educational material. Alnitak is one of the main groups running the LIFE Nature project, ‘Conservation of Cetaceans and Sea Turtles in Andalucía and Murcia’, which involves authorities and educates interest groups in the establishment of MPAs. Fishermen, divers’ clubs, maritime authorities, merchant mariners, and othe users of the marine ecosystem are involved in the management of MPAs. The challenge is to make them feel a part of the MPAs so that they appreciate the benefits of biodiversity and the sustainable management of resources.
Where Does it all Lead?
The results collected aboard the Toftevaag between 2002 and 2005 will be essential for monitoring cetacean populations and analysing trends in their conservation status to ensure that the Marine Protected Areas are effective. Long-term monitoring is the only way to verify trends in dolphin life, as well the conservation objectives of MPAs. Alnitak is contributing to long-term data collection, as well as finding new, improved and more cost-effective ways of monitoring cetacean populations.
Cañadas, A. and Sagarminaga van Buiten, R. Spanish Dolphins: Expedition Briefing. Alnitak.
Sea Mammal Research Unit – University of St Andrews www.smru.st-andrews.ac.uk
Donor and Supporting Organisations
Department for International Development (DFID) www.dfid.gov.uk
World Bank www.worldbank.org
European Cetacean Society www.europeancetaceansociety.eu
ITDG Technical Briefs answers.practicalaction.org
Other Relevant Hands On Case Studies
Dolphin Rescue – Pakistan
Shore Thing – Comoros