Table 2. Results of boat-based surveys of basking sharks in the two study areas.
| Firth of Clyde | Inner Hebrides | Areas Combined | ||||||
|---|---|---|---|---|---|---|---|---|
| Year | Distance (km) | Time (h) | Individual Sharks Photo-ID | Distance (km) | Time (h) | Individual Sharks Photo-ID | Individual Sharks Photo-ID | Number of Re-sights |
| 2004 | 601 | 96 | 1 | 138.5 | 30 | 0 | 1 | 0 |
| 2005 | 1123.5 | 181 | 12 | 226 | 49 | 20 | 32 | 3 |
| 2006 | 406.5 | 54 | 1 | 226.5 | 39 | 27 | 28 | 0 |
| 2007 | 299.5 | 32 | 1 | 646 | 82 | 143 | 144 | 3 |
| 2008 | 440 | 38 | 0 | 685 | 71 | 239 | 239 | 10 |
| 2009 | 64 | 11.5 | 0 | 343.5 | 48.5 | 16 | 16 | 0 |
| 2010 | 125 | 19 | 0 | 507.5 | 95 | 231 | 231 | 10 |
| 2011 | 0 | 0 | 0 | 400 | 71 | 177 | 177 | 27 |
| Totals | 3059.5 | 431.5 | 15 | 3173 | 486 | 853 | 868 | 53 |
Shown are the distances covered (km) and duration (h) of dedicated boat-based surveys of the Firth of Clyde and Inner Hebrides study areas over the period 2004–2011, together with the numbers of separate individual basking sharks (of all fin grades) photographed and catalogued (Photo-ID) each year and the numbers of re-sightings (Re-sights). All re-sightings occurred in the Inner Hebrides. Note that the numbers of separate sharks photographed does not include re-sightings. The total number of photographed encounters is obtained by summing the number of sharks photographed and the number of re-sights. The total number of sharks recorded during surveys was higher again, since many of the sharks encountered could not be photographed in the available time.