Abstract
Habitat modelling for UK grey and harbour seals permitted construction of realistic distributions for areas where telemetry data were available, and to predict distributions for areas where direct observations were sparse or absent. Maps were produced for each species, showing habitat preference scaled to population size.
Both grey and harbour seals show a preference for shallower water (consistent with a central-place forager spending much of their time close to the coast). Grey seals prefer tidally stratified areas where the water column remains vertically well-mixed all year. They show preference for the potential between the surface and bottom temperature to be 3.6°C (with a near-bottom year-average temperature of 9.7°C, and show slight preference for substrate with increasing levels of sand (and subsequently decreasing levels of gravel). Harbour seals prefer areas with a near bottom salinity of 33.7 psu and increasing sea-floor slope. Harbour seals spend much of their time close to the coast,
where mixing of the water column (that may influence prey distributions) is known to be primarily driven by salinity. Water column mixing, near bottom temperature and salinity, and sediment may all be associated with the distribution and concentration of prey that are utilised by grey or harbour seals.
The methodology will allow predictions based on the current models, e.g. for future scenarios including local seal population change, or changes in environmental variables such as sea
temperature. The resulting maps can also be updated when new data become available, including seal telemetry or new environmental data.
Both grey and harbour seals show a preference for shallower water (consistent with a central-place forager spending much of their time close to the coast). Grey seals prefer tidally stratified areas where the water column remains vertically well-mixed all year. They show preference for the potential between the surface and bottom temperature to be 3.6°C (with a near-bottom year-average temperature of 9.7°C, and show slight preference for substrate with increasing levels of sand (and subsequently decreasing levels of gravel). Harbour seals prefer areas with a near bottom salinity of 33.7 psu and increasing sea-floor slope. Harbour seals spend much of their time close to the coast,
where mixing of the water column (that may influence prey distributions) is known to be primarily driven by salinity. Water column mixing, near bottom temperature and salinity, and sediment may all be associated with the distribution and concentration of prey that are utilised by grey or harbour seals.
The methodology will allow predictions based on the current models, e.g. for future scenarios including local seal population change, or changes in environmental variables such as sea
temperature. The resulting maps can also be updated when new data become available, including seal telemetry or new environmental data.
| Original language | English |
|---|---|
| Publisher | Marine Scotland |
| Commissioning body | The Scottish Government |
| Number of pages | 18 |
| Publication status | Published - 2015 |
