Sea Watch Foundation Cetacean Survey; Summer 2007
In the summer of
2007 the Seamark Trust funded a continuation of the cetacean survey that was
begun by ORCA during the previous summer.
The full report on the 2007 survey is available from the Sea Watch Foundation web site.
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Bluefin of Hamble, the Trust's survey vessel, was used as the observation platform and is shown here off the coast of Galecia.
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Nigel Greenyer, Captain |
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Matt Raine, Crew and Cook |
The Sea Watch Foundation survey sampled areas at the western margin of the Cap Breton Canyon, between Santander and Bermeo. This extended towards the East the area sampled by the Seamark/ORCA survey of 2006.
Continuity of data collection methods was ensured by Professor Ian Boyd, a Seamark Trustee as well as by the participation of Phil Coles and Anne Schoeers, both of whom had been members of the 2006 observer team.
Emphasis was placed on assessing the distribution, relative abundance and habitat preferences of Cuvier's beaked whale.
Eight volunteer observers were aboard and were split over two periods: July 2 to 11 and July 11 to 21.
| Peter Evans |
Sea Watch Foundation |
| Pia Anderwald |
Sea Watch Foundation |
| Mick Baines |
Sea Watch Foundation |
| Maren Reichelt |
Sea Watch Foundation |
| Phil Coles |
ORCA |
| Dave Curtis |
Santander Ferry Service |
| Laura Mandleberg |
Hebridean Whale and Dolphin Trust |
| Anne Schroeer |
Seamark Trust |
With the vessel maintaining a constant speed of between 6 and 7 knots a visual survey was conducted using line-transect methodology and application of DISTANCE sampling.
| Watches were conducted from an elevated position on either side of the centre cockpit. This position could be maintained safely over a wider range of weather conditions. |
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The
southern Bay of Biscay offers a range of habitats from shallow coastal bays to
deep canyons. Within 20 nautical miles of
the north Spanish coast, depths exceeding 2,500 m can be found and this attracts a variety of cetaceans.
The emphasis of the present study was the Cuvier's beaked whale.
However, a variety of other species was observed along the transects. The summary details of these sightings, as published in the Sea Watch Foundation report, were as follows:
Species |
# of Sightings |
# of Individuals |
| Bottlenose dolphin |
19 |
312 |
| Common dolphin |
2 |
6 |
| Striped dolphin |
23 |
563 |
| Common or striped dolphin |
3 |
12 |
| Risso's dolphin |
1 |
1 |
| Long-finned pilot whale |
9 |
89 |
| Cuvier's beaked whale |
7 |
21 |
| Unidentified beaked whale |
6 |
8 |
| Unidentified small whale |
1 |
1 |
Total
There were also possible sightings of both Sowerby's beaked whale and northern bottlenose whale. Such sightings were brief and often of distant breaches so that the species could not be confirmed.
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71 |
1013 |
Mick Baines, Maren Reichelt, Pia Anderwald, Dave Curtis and Peter Evans took most of the stunning photographs in the report. Only some of them are shown here:
Conclusions
Striped dolphin was the most abundant species followed by bottlenose dolphin and long-finned pilot whale, with more than 90% of sightings of all species occurring at depths of 500 metre or more. Information gained from encounters with Cuvier's beaked whales also followed our previous knowledge of that species, with sightings concentrated in a band of sea over gradual contours at depths ranging from 1,000 to 2,500 metre. Such contours occur within 15-20 nautical miles of the coast. Thus they are within daily reach of a research vessel like a sailing yacht, whose economy outweighs the fact that she requires a good breeze to attain speeds above 7 knots.
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