Appendix A. A description of the construction of coastal zones, a figure showing construction of the coastal zones, and a figure showing stranded specimens of Rhizostoma octopus.
Construction of coastal zones
Using ArcView 3.2 (ERSI, Inc.) a 15-km buffer was created around the coastline of the entire study area, with any sightings beyond this limit removed from the analysis. To achieve this, 20 km long straight sections were drawn continuously around the coastline of the study area (Fig. A1a). Both ends of each section coincided with the coastline and none of the sections overlapped. Fifteen-kilometer buffers were created around each section resulting in the definition of 61 separate coastal "zones" (each zone representing an area of 20 km × 15 km) (Fig. A1a). These combined zones accounted for ~72% of all turtle records within the Irish Sea (n = 103) and a spatial coverage of ~25% of the entire survey area.
|FIG. A1. Construction of coastal zones (a) Shows how 20-km segments were used as a baseline along the coast and how these were overlaid with circles of 30-km diameter. (b) Shows resultant coastal zones in detail (20 km × 15 km).|
|FIG. A2. Stranded specimens of Rhizostoma octopus collected from: (1) Whitford Sands, Carmarthen Bay (2003: n = 198) (2004: n = 56) (2005: n = 22); (2) Llanbedrog beach, Tremadoc Bay (2003: n = 41) (2004: n = 141) (2005: 85). Stranding data were collected on a number of occasions throughout each year between the following dates: (2003: 20/0614/10) (2004: 09/0424/12) (2005: 03/0114/02).|