Sea Watch research projects and surveys
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Although regular surveys are needed throughout sea areas of the British Isles, some regions require special attention either because they have particularly diverse marine mammal faunas or because they hold important populations of certain species. The Shetland Isles, Hebrides, and waters west of Wales are identified as areas requiring special attention through dedicated surveys, whilst particular species that would benefit from conservation biology projects include bottlenose dolphins, common dolphins, harbour porpoises in the Irish Sea and Channel; and minke whales and white-beaked dolphins in Scotland. Finally, cetaceans face a number of potentially serious conservation threats (accidental capture in fishing gear, sound disturbance from industry, military and recreational activities, competition for food, and toxic chemical pollution). Scientific research is urgently required to better understand the nature of these respective threats and how best to counter them. The major projects in which Sea Watch is currently involved, and for which funding support is always need, are listed below:
- Shetland Cetacean Studies
- Whale and Dolphin Surveys in the Hebrides
- Biopsy sampling, photo-ID and radio-tracking of minke whales (and potentially other top marine mammal predators) in the Hebrides
- Bottlenose Dolphin and Harbour Porpoise Studies in West Wales and the Irish Sea
- Common Dolphin Studies in South-West Wales and the Celtic Deep
- Bottlenose Dolphins and Harbour Porpoises in the English Channel
- National Cetacean Photo-ID Catalogues
Shetland Cetacean Studies
The Shetland Islands are one of the most important areas for cetaceans in Europe, with 16 species recorded there in recent years. Since 1992, humpback whales have been seen almost annually close to the coast, and the Northern Isles are currently the most important region in the UK for killer whales. Land-based systematic observations and boat surveys were conducted between 1992-95, to investigate factors causing the decline of harbour porpoises in the region, and to determine distribution of other cetaceans around the Shetland Islands so that appropriate management strategies could be developed.
A Shetland Sea Mammal Group (SSMG) was established in 1993 and this needs funding support to enable cetacean monitoring to be conducted on an annual basis, particularly for harbour porpoise and killer whale. In 1999, Sea Watch obtained funding for a hydrophone POD to be purchased and deployed by Paul Fisher for monitoring the vocal activity of harbour porpoises. This has been deployed for short periods. It has great potential because theoretically it can operate remotely day and night and year-round. However, for routine long-term maintenance, data downloading and analysis, further funding will be needed, and it would be valuable for 1-2 more PODs (cost £1,269 per POD) to be deployed elsewhere in Shetland. Land-based systematic watches need to be undertaken on a regular basis, and arrangements are being made for SSMG to do this with a grant of £1,000 from Sea Watch via its BG funding for support of Scottish local groups.
Whale and Dolphin Surveys in the Hebrides
Local oil and gas developments, pollution from inputs to salmon farms, increased pressures from the fishing industry on potential food resources, Naval undersea trials, and a marked increase in recreational activities together impose potential conservation threats upon the internationally significant cetacean populations occupying Hebridean waters in summer.
Line-transect surveys and photo-identification studies in the region were started in 1992, and have highlighted the importance of the area to several species, notably harbour porpoise, minke whale, common dolphin, white-beaked dolphin, Risso’s dolphin, and killer whale. However, absolute abundance estimates have yet to be made for any species in the region, and further surveys are needed, along with more detailed studies, so as to identify the main factors determining the importance of some areas over others for cetaceans and why these may change from year to year.
Between 1992 and 1998, Sea Watch used an 80 ft gaff-rigged sailing vessel, the “Marguerite Explorer”, as the research platform, with facilities for public participation in cetacean studies. The results of those surveys have not yet been analysed in any detail, and resources are needed for the processing of remote sensing data and so that generalized additive modelling can be conducted in relation to various potentially important environmental parameters. There is also a need for further dedicated surveys. The “Marguerite Explorer” is no longer available, but either the “Silurian” (belonging to the Hebridean Whale & Dolphin Trust) or “Wild Free” (belonging to James Fairbairns of Sea Life Surveys) could be chartered.
Biopsy sampling, photo-ID and radio-tracking of minke whales (and potentially other top marine mammal predators) in the Hebrides
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The only species of cetacean in the North Atlantic that is the target for commercial whaling is the minke whale, with an annual take of nearly one thousand animals by the Norwegians in waters adjacent to the British Isles. At present, we have no idea whether the animals being killed by Norway are the same as occur in UK waters. Using recently developed biopsy techniques, it has been possible to take skin and blubber samples of known individuals (in conjunction with photo-ID) not only for DNA analysis but also for pollutant studies, and stable isotope work (for dietary studies). This technique promises to be the major way forward for biological studies of this nature upon free-living cetaceans, and the first licences for this work in the UK were granted to Rus Hoelzel (of University of Durham) and Peter Evans for application initially to minke whale, killer whale, and Risso’s dolphin. Attempts are also being made, under licence, to initiate the first study involving radio-tracking of a cetacean species in the UK.
Pia Anderwald, Sea Watch’s Database Officer, is currently undertaking a PhD on the minke whales, including studies on population genetics, foraging behaviour and ecology, and habitat preferences. For the summers of 2004 and 2005, we have had a National Geographic Society grant to undertake radio tracking and focal follows of individual minke whales.
If the field techniques prove successful, the possibility exists to extend them to other species including bottlenose dolphin, white-beaked dolphin and Risso’s dolphin.
Bottlenose Dolphin and Harbour Porpoise Studies in West Wales and the Irish Sea
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With funding from the Countryside Council for Wales (and previously through the EU INTERREG Programme), we have undertaken line-transect surveys and photo-ID studies of bottlenose dolphins in and adjacent to the Cardigan Bay Special Area of Conservation (SAC). These have provided the first abundance estimates for this population, as well as starting to identify those areas of the SAC used most frequently by the population during the summer months, all important for management of one of the first two of the UK’s protected areas for cetaceans. The relationship between bottlenose dolphins and harbour porpoises also needs further investigation since there is now good evidence that on occasions the former will kill the latter. The circumstances surrounding such incidents remain unclear.
For some aspects of monitoring, passive acoustic click detectors (called PODs) are likely to be effective at determining long-term use by porpoises and dolphins of particular locations. With funding from CCW Sea Watch has undertaken an acoustic monitoring project to investigate the habitat use and partitioning of bottlenose dolphins and harbour porpoises in the SAC Currently there are 10 PODs deployed along the SAC coastline and the project is expected to continue at least for the next 6 months.
Three other important areas of investigation remain to be developed:
- surveys of the bottlenose dolphin population further offshore in the Irish Sea and north of the SAC in northern Cardigan Bay;
- winter surveys over the region to determine status and distribution of the population between the months of October and March; and
- studies of the feeding ecology of the species using echo sounder surveys of fish distribution, underwater filming, and small-scale trawl sampling (a major area of investigation that has yet to be started but is clearly crucial to understanding the ecological requirements of the local dolphin population).
Countryside Council for Wales has been funding the photo-ID and line transect surveys.
Common Dolphin Studies in South-West Wales and the Celtic Deep
With 3-year funding from the Countryside Council for Wales from summer 2004, we have started line-transect surveys to estimate absolute abundance estimates and determine seasonal distribution of common dolphins in the Celtic Deep and waters off South-west Wales. Other cetacean species such as harbour porpoises and minke whales will be surveyed at the same time. Surveys will, where possible, be conducted on a monthly basis between the months of May and October.
Bottlenose Dolphins and Harbour Porpoises in the English Channel
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Both bottlenose dolphins and harbour porpoises are comparatively scarce in the English Channel, although once both species were apparently much more common at one time. Photo-ID studies and monitoring of bottlenose dolphins have been conducted at several locations along the Channel coasts of Southern England and from the Channel Islands, with support from English Nature and Durlston Marine Project (Dorset). This complements the detailed studies carried out by OCEANOPOLIS on the Channel coast of France.
Following three annual workshops held to bring together researchers studying bottlenose dolphins on the south coasts of England, the Channel Islands, and Northern France, and the establishment and publication of a photo-ID catalogue, funds are needed towards regular production of updates of the catalogue, and to charter a boat for photo-ID studies along the south coast of England.
Since bottlenose dolphins and harbour porpoises are scarce along the south coast of England, and their arrival near shore cannot easily be predicted, a remote monitoring system such as the acoustic POD that detects and records sonar clicks, offers a cost-effective means for determining the local presence of animals at any time of day or night and year-round. Funding was obtained to deploy four PODs at strategic locations along the south coast of England. These have now been tested, with some success.
Further funding is needed to increase the number of PODs deployed for better coverage (since a POD only detects animals within half a kilometre). If the system can be perfected to operate at low cost with minimal maintenance (e.g. by use of solar panels, and radio links for remote downloading of data), there is scope for expansion to locations around all the coasts of the British Isles.
National Cetacean Photo-ID Catalogues
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Local observers and research groups in several regions of UK conduct photo-identification either on an opportunistic basis or through dedicated surveys. Photo-ID provides photo-documentation of individual cetaceans where they can be distinguished using unique markings. This is invaluable for determining ranges, habitat preferences, social organization, as well as population abundance and dynamics.
Several of the groups have access to boats, are regularly at sea, and already have received some training in photo-ID. Individuals of several cetacean species (for example bottlenose dolphin, common dolphin, white-beaked dolphin, Risso’s dolphin, killer whale and minke whale) can be recognised by unique markings on their fin, head or flanks. Once recognised, repeat sightings tell us a great deal about the areas over which they will range, and help identify individual habitat requirements. As part of the EU funded EUROPHLUKES Project (running from 2002-04), we have already established a large European-wide Photo-ID catalogue (>54,000 images from 20 species throughout Europe; c. 8,000 images from nine species in NW Europe). There are a few further catalogues to be input, and some new images recently acquired this summer.