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Scotland's seal population
23/04/2009
A new study offering a fascinating insight into Scotland's seal population has been published today.
The Special Committee on Seals (SCOS) Report for 2008 shows that:
- Scotland has more grey seals than previously estimated but that common seals are still in decline
- It is now estimated that there are around 164,000 grey seals in Scotland, more than previous reports suggested and 90 per cent of the estimated UK mean population
- There are a minimum of 20,000 common seals in Scotland. The localised decline in the Northern Isles and Firth of Tay is continuing and has spread to Strathclyde
- The main causes of these local reductions are unclear at present but predation by killer whales in the Northern Isles and competition for food supplies with grey seals could be significant factors
Environment and Rural Affairs Secretary Richard Lochhead said:
"This important report provides a valuable insight into the behaviours of one of our most fascinating marine mammals. I'm confident it will also help ensure that a better balance is struck between seal conservation and sustainable fisheries and aquaculture in our forthcoming Marine Bill.
"Our seas are among the most biologically productive in the world. While it's unlikely that any single cause is responsible for the decline in common seals, it would seem that competition for food supplies with the larger, more numerous grey seal could be a significant factor.
"We have already taken decisive action to provide additional protection for common seals and introduced additional monitoring and research to look at probable causes.
"We also know there are concerns about several aspects of current seals legislation, which is almost 40 years old. So we are currently considering options for new measures in the Marine Bill, they will also provide flexibility to accommodate such wide variations in the status of Scotland's two native seal populations.
"Our proposals will significantly increase protection for seals but allow for limited seal management for fisheries and fish farms under licence. They recognise the need for increased protection in respect of declining common seal numbers but acknowledge the continuing need to defend fisheries and fish farms from seals."
Professor Ian Boyd, director of the Sea Mammal Research Unit at the University of St Andrews, said:
"We are getting mixed messages from our studies of seal populations. On the one hand, we still have healthy populations of grey seals even though the increases of the 1990s are not being sustained. On the other hand, the causes of the recent decline in the common seal population are not understood.
"However management recently introduced in the Moray Firth as a result of research sponsored by the Scottish Government is beginning to pay off."
The SCOS Report 2008 provides scientific advice on matters related to the management of seal populations for the year 2007.
This revised grey seal figure of 164,000 does not represent a sudden increase in their numbers by 44,000. It reflects the use of an improved seal population model based on the best scientific advice available and revises previous underestimates of numbers. Analysis of grey seal pup production in 2007, which is the basis for all population modelling, indicates the underlying population trend is stable or increasing slowly.
The minimum figure of 20,000 for common seals is based on seals found ashore during the surveys and the total population, including seals at sea, probably lies somewhere between 32,000 and 38,000. The local declines in common seal numbers since 2000 now stand at 50 per cent in the Firth of Tay, between 40 and 50 per cent in Orkney, and over 40 per cent in Shetland. The latest surveys show common seal numbers in Strathclyde down by around 25 per cent since 2000.
A team of research scientists, led by Andrew Foote from the University of Aberdeen, studied the behaviour and feeding habits of killer whales around Shetland over the last two summers. Using over a decade of sightings data they found a clear correlation between the common seal pupping season and peak killer whale sightings. Mr Foote is happy to be approached by the media for comment - 07986 408639.
Competition with larger and more numerous grey seals may be an important factor in the decline of common seals. In 2007 Sea Mammal Research Unit aerial surveys indicated the presence of increasing numbers of grey seals amongst common seals on haul out sites in a number of areas.
A seal conservation order has been in place since 2007 to protect common seals against shooting in the Northern Isles and along the east coast. A major research programme is also underway to seek to establish the proximate causes of these localised declines and inform future action.
It is unlikely that any single factor is responsible. It is already clear that local shooting and disease do not explain the significant reductions reported. It is considered that predation by Killer Whales is a factor round the Northern Isles whilst competition for food supplies with the larger and more numerous grey seals is likely to be a significant factor across Scotland as a whole.