Grey seal usage maps for MORL/BOWL developments - Phase 2 delivery

Esther Lane Jones, Jason Matthiopoulos

Research output: Book/ReportBook


Grey seal (Halichoerus grypus) telemetry data from 1992‐2008 were combined with aerial survey data from 1988‐2009 to produce maps of estimated total, at‐sea, and hauled‐out usage in
a study area surrounding the proposed Moray Offshore Renewables Ltd (MORL) and Beatrice Offshore Wind Farm Ltd (BOWL) wind farm developments.

Temporal and demographic (age‐class and sex) information on seals were aggregated to produce the spatial maps. The usage maps in this (Phase 2) report utilise developments in the software used to produce the maps. As such, there have been several key changes:

1. The Phase 1 report showed tracks that had zero and non‐zero aerial survey counts associated with them. To improve transparency between the number of tracks shown in Table 1 and Figures 1 and 2, and the usage maps (Figure 6, 7 and 8), only tracks that were matched to non‐zero aerial survey counts were used in the final analysis. This explains why 7 tracks shown in Table 1 and Figures 1 and 2 of the Phase 1 report do not
feature in the corresponding Table 1 and Figures 1 and 2 of this (Phase 2) report.

2. Additional data have become available since the Phase 1 report was submitted. This has resulted in 11 additional tracks being incorporated into the final analysis (Table 1; Figures 1 and 2).

3. The second driver in the differences between total and at‐sea usage maps (Figures 6 and 7) is the development of a new null usage model (see Null (Accessibility) Model). This is a bespoke model using only telemetry tracks from the analysis, and therefore represents a more accurate picture of null usage at the study site. In the Phase 1 report, a generalised null usage map was used.

4. Because the total and at‐sea usage appear graphically similar, a hauled‐out usage map was included to give a clearer understanding of where the differences in total and at‐sea
usage occurs.
Original languageEnglish
Place of PublicationFife, Scotland
PublisherSMRU Consulting
Commissioning bodySea Mammal Research Unit
Number of pages18
Publication statusPublished - 1 Dec 2011


  • Grey Seal
  • Halichoerus grypus
  • Wind farm developments
  • Scotland


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