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About SeaWatch SW

Science and conservation
Survey location
Survey methods
Project co-ordinator
Target species
Schedule of volunteers


The primary aim of SeaWatch SW is to collect data on the abundance, distribution and behaviour of migratory species in UK waters, in particular the Balearic Shearwater and the Basking Shark. A variety of migrant seabirds will also be recorded, as well as species such as Ocean Sunfish, Grey Seals and cetaceans. The results will 1) aid planning of UK conservation strategy for the main target species, 2) provide information on migration patterns and behaviour of seabirds and marine animals around our coasts, and 3) allow us to assess how changing environmental (e.g. tides, weather and long-term climate change) and biological (plankton and prey fish) factors affect marine animals at the top of the food chain.

The main survey phase of the project will involve continuous ‘dawn-to-dusk’ observations from Gwennap Head at the southwest tip of the UK mainland, to record animals passing around the peninsula. The survey will run from mid-July to mid-October, over a period of several years. Observational data will be collected in a standard format, ensuring results are scientifically valid and reproducable. Survey results will be compared to those from adjacent control sites to provide a regional perspective. In addition the project will act as a focal point for Balearic Shearwater recording in UK waters.

Basking Shark, Skye (image courtesy Colin Speedie)

SeaWatch SW is being run from the National Oceanography Centre, Southampton, and is supported by a number of major conservation and scientific organisations including RSPB, MCS and SAHFOS. It is hoped that the project will raise awareness of the impacts of environmental change on ‘high-profile’ marine species in UK waters, and will provide a mechanism for volunteers to engage in observation of spectacular species like Basking Shark, whales and dolphins.

Science and conservation

Global climate change is now a major issue in wildlife conservation, especially in the offshore realm. Sea surface temperatures around southwest UK have risen by 0.5oC in the last 15 years, and the impacts on our marine fauna are becoming increasingly evident. For example, it is widely accepted that plankton and fish populations are shifting northwards, and there is a growing body of evidence indicating that species higher up the food chain are also being affected, including some that are of conservation concern.

Above: Sea watching from Gwennap Head, April 2007

New studies (Wynn and Yesou, 2007; Wynn et al., 2007) have shown that globally significant numbers of the Balearic Shearwater Puffinus mauretanicus are now dispersing north into UK and Irish coastal waters during the summer and autumn. This Mediterranean-breeding species is listed as critically endangered on the IUCN Red List, and could be in danger of extinction this century. In the UK we therefore have a responsibility to ensure that the species is protected while it visits our waters, and that we have accurate data to form a solid base for conservation strategy and planning.

The SeaWatch SW Project aims to quantify Balearic Shearwater numbers visiting UK waters, and will generate invaluable data for other endangered species such as Basking Sharks. This will be achieved by continuous observation from Gwennap Head in Cornwall, the southwest tip of the UK mainland. This is an ideal location to study Balearic Shearwaters in the UK, with most birds moving west as they round the headland and penetrate into the Celtic and Irish Seas. Most birds are seen between July and October in Cornish waters, so the survey is running from mid-July to mid-October to cover most of this period. There is good evidence to suggest that land-based observations from Gwennap Head will capture the majority of birds moving around the southwest tip of the UK; the species prefers coastal waters close to land, it tends to roost communally overnight so most movements are presumably in daylight, and it is readily identifiable from shore with standard optical aids (binoculars and telescope). The survey is planned to run for a minimum of five years, allowing assessment of year-to-year variation and overall long-term changes. 

It is likely that other marine animals are either expanding their range northwards, or are changing their favoured feeding areas in response to climate-driven changes in prey distribution. The SeaWatch SW Project will aim to produce scientifically valid effort-based data for some of these marine animals, particularly Basking Sharks, Ocean Sunfish and cetaceans (which are regularly seen from Gwennap Head within the survey period). Quantifying abundance of these species is difficult, as they spend varying amounts of time underwater out of sight. However, the survey will at least provide an indication of numbers seen at the surface from a single point, and this can be related to the relative influences of sea temperature, tide and weather conditions, and maybe even prey distribution (e.g. jellyfish seen during aerial surveys or sampled zooplankton data) on year-to-year basis. If a link between surface sightings and these external forces can be established in a quantitative fashion, then the results will complement, and may help reduce bias, in non-effort-based public sightings datasets, e.g. the MCS Basking Shark Project.

Finally, there is still much to learn about the migration of commoner seabird species around our coasts. The SeaWatch SW dataset will allow us to examine some of the controls on seabird migration, including weather and sea temperature. By incorporating results from the project ‘sister sites’ at Berry, Trevose and Strumble Head, we should also be able to put survey data into a regional context.


Survey location

The project watchpoint is at Gwennap Head near Porthgwarra, on the Land’s End peninsula in Cornwall (grid reference SW366215). This prominent and picturesque headland is at the southwest tip of the UK mainland, and is therefore an ideal location from which to record Balearic Shearwaters and Basking Sharks as they migrate along the coast or feed offshore. Another advantage of the location is the presence of the prominent Runnelstone buoy about 1.5 km offshore. This distinctive marker facilitates tracking of animals as they pass the watchpoint, and also aids assessment of their distance offshore.


 Above: Map showing location of the Gwennap Head watchpoint.
Observers will be located on Gwennap Head itself, although the exact position may vary depending on weather conditions.
Distance to the Runnelstone buoy is indicated. Location of the free Seabird Observer accommodation (Ardensawah Farm B&B) is shown

Left: Aerial photo of the SeaWatch SW watchpoint and surrounding area. Solid white line is the road to Porthgwarra public car park, and dashed white lines show footpaths to the coastguard lookout above Gwennap Head. Image courtesy of Google Earth. Right: Photo of the SeaWatch SW watchpoint below the coastguard lookout, viewed from Hella Point.

The above images show the location of the SeaWatch SW watchpoint. From the coastguard lookout, walk about 100 m to the southeast along the cliff edge and walk down the path onto Gwennap Head. Halfway down the cliff path is a prominent blowhole. Walk carefully around this and continue down the east side of the headland until you reach a rocky outcrop with a narrow gully passing through it. Carefully pass through this gully and the watchpoint is a few metres beyond this point in a mixed area of short grass and rocks. The exact position of observers in this area will vary according to weather conditions. Please take care when travelling to/from the watchpoint.

Control sites
During the SeaWatch SW survey, special effort will be made to cover three well-watched control sites in order to assess regional movements of the target species. The first of these is Berry Head in Devon (see map below); previous observations have shown that in favourable conditions for autumn seabird migration (usually stiff southwest winds and rain) Balearic Shearwaters are likely to fly west along the coast, and will take about four hours to get from Berry Head to Porthgwarra in direct flight. The other control sites are Trevose Head in Cornwall and Strumble Head in Wales, providing information on Balearic Shearwater and other seabird movements down the west side of the UK.


By maintaining close contact with the three control sites, we hope to be able to track significant movements and even individual animals in some cases. In addition to the three control sites, we will also be incorporating data obtained from other key watchpoints around the UK coast. If you would like to contribute data from a regularly covered site, or if you would like to help out by making observations at either of the three control sites, then please contact the project co-ordinator.

Survey methods

The SeaWatch SW survey will run for five years from 2007-2011, with the possibility of extension beyond this. The watchpoint is Gwennap Head, Porthgwarra, Cornwall and observers will always be located within 500 m of this headland. The watchpoint will be manned continuously from 15 July to 15 October. Each day will be split into two watch sessions:

Session 1: 30-60 minutes after sunrise to 1200 hrs
Session 2: 1400 hrs to 30-60 minutes before sunset

As an example, in mid-August the watch periods would be roughly 0600-1200 hrs and 1400-2000 hrs (i.e. about 12 hours in total). The watchpoint will be manned entirely by volunteers. Full details of survey times and the current list of volunteer observers can be found here. Further details on how to get involved can be found here.

It is intended that a minimum of two observers will cover each session: a Seabird Observer and a Marine Wildlife Observer. If possible, the observers should always be located within 10-20 m of sea level to ensure optimum coverage of both the near and far-fields. This is essential, as many Balearic Shearwaters pass relatively close inshore at this location and are easily missed when scanning from the traditional cliff-top viewpoint at Hella Point. In addition, the offshore Runnelstone buoy must always be within sight of the observer, preferably roughly in the centre of the field of view. The process of counting birds as they move along the coast is then facilitated as they cross the imaginary 'line' between the observer and this marker. However, the exact location of the observer may vary according to weather conditions.

Further details on survey methods will be provided to core observers in the coming months. However, if you have any questions in the meantime, please contact the project co-ordinator.

Project co-ordinator, Dr Russell Wynn

SeaWatch SW co-ordinator Russell Wynn:
he's a man who loves a Cornish pasty...

Seawatch SW is co-ordinated by Dr Russell Wynn, a Senior Research Scientist at the National Oceanography Centre, Southampton. Russell has a background in various aspects of marine science. As part of his job he undertakes research cruises to rarely-visited parts of the ocean, giving him the opportunity to observe and photograph a wide variety of seabirds and other marine fauna. Recent expeditions have visited the deep ocean around the volcanic Canary and Madeira archipelagos, the cold gateway between the Faroe and Shetland Islands, and the upwelling waters off the Sahara Desert (for more information on marine wildlife seen during NOC research cruises click here). Some of these trips have yielded valuable scientific data, and Russell's recent ornithological papers are listed at the bottom of the page. Russell is currently Honorary Advisor to the Royal Naval Bird-watching Society and has Associate Researcher status at SAHFOS.

Outside work, Russell has been heavily involved in seabird observation for about 15 years, and has spent many hundreds of hours ‘sea-watching’ from the south coast of England. He was co-editor of the Hampshire Bird Report in 2001-2002 and is a keen field ornithologist, with particular interest in finding and identifying rare birds (click here for an account of his recent expeditions to Foula, Shetland).

Russell's interest in Balearic Shearwaters was initiated in 2001, when he observed an unprecedented influx into Hampshire waters. Whilst observing large movements of Balearic Shearwaters off Gwennap Head in July and September 2006, he decided to try and establish a designated watchpoint at the site to monitor Balearic Shearwaters, Basking Sharks and other marine animals. He also wanted to set up a website that would act as a focal point for Balearic Shearwater recording in UK waters; the data collected would then be used to inform conservation strategy.

Recent ornithological papers

Wynn, R.B. (2003) Further developments in ‘Black Brant’ identification, including the effects of body moult on the wintering grounds. British Birds, v.96, 297-301.
Wynn, R.B. and Knefelkamp, B. (2004) Seabird distribution and oceanic upwelling off northwest Africa. British Birds, v.97, 323-335.
Wynn, R.B. (2006) Leach’s Storm-petrels Oceanodroma leucorhoa landing on a research vessel at night. Atlantic Seabirds, v.7, 41-42.
Wynn, R.B., Josey, S.A., Martin, A.P., Johns, D.J. and Yésou, P. (2007) Climate-driven range expansion of a critically endangered top predator in northeast Atlantic waters, Biology Letters, v.3, 529-532, doi: 10.1098/rsbl.2007.0162.
Wynn, R.B., Josey, S.A., Martin, A.P., Johns, D.G. and Yésou, P. (2008) Reply to comment: Is climate change the most likely driver of range expansion of a critically endangered top predator in northeast Atlantic waters? Biology Letters, doi: 10.1098/rsbl.2007.0624.
Wynn, R.B. and Yésou, P. (2007) Changing status of the Balearic Shearwater Puffinus mauretanicus in northwest European waters. British Birds, v.100, 392-406.
Yésou, P., Barzic, A., Wynn, R.B. and Le Mao, P. (2007) La France est responsable de la conservation du Puffin des Baléares Puffinus mauretanicus. Alauda, v.75, 287-289.

Click on the links below for more information on:

Target species
Schedule of volunteers

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