Project Basking Shark & Clyde Cetacean Monitoring Programme

Progress Report for 2006

Summary for Project Basking Shark

In 2006, we focused on key aspects of the project:

1. raising awareness of Basking Shark conservation through the project and Save Our Seas Foundation
2. widening our observer network
3. working with Basking Sharks and their food resource

We would like to thank everyone in the Observer Network for their help and support. The sightings and photographs are a valuable part of the project.

1. Raising awareness

In 2006, we disseminated information through leaflets, website, newsletters, stickers and logging sheets to our observer network in 2006 and to new people who have joined as a result of hearing about the project. We contacted each person that provided sightings or showed interest in the project, and sent on any further information to them that they had not received. In asking how new contacts found out about the project, they had had a leaflet, googled our website, visited our display in the Robertson Museum at UMBSM, heard Dr Gore give a presentation or interview, or read about the project in a local newspaper article. We were heartened to know that the efforts to raise awareness have been successful. The new Scottish Marine Wildlife Watching Code provides good information on how to approach basking sharks, whales, dolphins and porpoises, summarised in the diagram in Fig. 1.

2. Observer network

We have over 200 contacts, which include many individuals, as well as fisher associations for static and mobile gear, Strathclyde Police Marine Unit, natural history and bird societies, conservation organisations, yacht clubs, harbour masters, and ferry staff. Their support is very important in adding to our knowledge of where and when Basking Sharks are sighted and under what conditions. Their reports help us to improve coverage of sightings and to respond to sightings for tagging Basking Sharks, and in 2006, we concentrated on searching for Basking Sharks largely through reported sightings.

3a. Basking Shark sightings

The first Basking Shark observed in 2006 was in March in the Clyde Sea Area and in April in the Inner Hebrides (West Scotland), although none was then seen again until June and May, respectively. The last one reported so far was on October 1st, 2006 (not included in analysis). We spent 96 hours at sea ourselves, covering 1290 km targeting 19 Basking Sharks.

The number of Basking Sharks sighted has differed significantly between the years 2004 to 2006 (χ²=245.2, df=2, P<<0.001). The number of Basking Sharks was higher in 2005 and 2006 than in 2004 (Table 1).

Table 1: Number of Basking sharks seen per year in West Scotland.

Year	Number of sightings	Mean number per sighting	Range in sighting
2004	43	1	1–3
2005	411	1	1–70
2006	293	1	1–37

3b. Tagging Basking Sharks and Photo-ID

Through our surveys, we encountered 19 Basking Sharks under varying conditions. We were able to order our two satellite tags and the company kindly rushed our order for us to have the tags by early August. This unfortunately was late in the season. Despite allocating large portions of time for tagging, the weather was atrocious and proved too hazardous for both the shark and the team for tagging and sadly suitable conditions to apply a tag did not arise again in August or September. Some of the sightings were clustered in weeks when we had other obligations. The tags have now been deactivated and stored for winter to be used at the beginning of the next season in summer 2007. Our photo-ID database has grown considerably, however, partly thanks to our Observer Network. Fins differ considerably between individuals and a good photo will help to identify who is who.

3c. Food resource: Zooplankton Profile

We have analysed many of the zooplankton samples that we took routinely in the Clyde Sea Area over 2004 and 2005, as well as opportunistically when Basking Sharks were being observed. The routine surveys involved six stations in an area that included the north of the Isle of Arran to Lamont Shelf, an area that could be surveyed in a day and where Basking Sharks are known to frequent. Standard zooplankton sampling techniques were applied: two samples were taken at each station, hauled vertically from 25 m, for each of two mesh sizes, coarse and medium, to capture the zooplankton of most interest as a food resource.

Discussion

We have had a 27% increase in the number of observers, who are key in our coverage of sightings of Basking Sharks. We have distributed a large number of leaflets, newsletters, stickers and logging sheets to raise awareness of the project to provide information on Basking Sharks and their conservation issues. One of these issues is the danger of basking sharks becoming entangled in fishing gear.

Summary for Clyde Cetacean Monitoring Programme

The number of minke whales appears to have increased in 2006, but the pod of 27 bottlenose dolphins that visited the Clyde Sea Area in 2004 and 2005 did not return this year. The number of harbour porpoises may have increased, according to casual remarks, but they are not reported as regularly or as consistently as whales and dolphins. Without the reported numbers and locations, the number of harbour porpoises and any possible increase cannot be assessed.

A rare visitor to the Clyde Sea Area appeared in Loch Long in October and the humpback whale remained from the 9th to 13th, when it left. The team went out to gauge its health status as it had been reported that a commercial RIB had been harassing it. We worked with the HM Naval Base Clyde MOD and the Strathclyde Marine Police Unit to try to raise awareness of the Scottish Marine Wildlife Watching Code for the public to visit the whale. We remained most of the day with the whale, and its dive pattern and breathing rate appeared normal. The following photographs are of our special visitor.