Grey Seals are a familiar sight to kayakers and walkers down at the Calf Sound, whether in the water or 'hauled out' on the rocks of Kitterland. But how populous are they and what are the threats to their numbers? Eleanor Stone, Marine Officer for the Manx Wildlife Trust, set out to find answers to these and other questions when she undertook the first comprehensive survey of Seal pups in the area. Based on the Calf of Man during whelping season, she was able to gauge roughly the number of new pups and gain an overview of Grey - and Common - Seal activity.
What informed your decision to carry out an official survey of the Calf's Seal population?
Seals are counted on the Calf by the wardens and a couple of surveys have been done round the whole of the Isle of Man, but there hasn't been a dedicated survey to look at pups on the Calf. When I started my job, one of the things I was keen to set up was a photo ID and pup study on the Calf, partly because it hadn't been done. Seals are doing pretty well overall in Britain, but with all the pressures on the seas, it's important that we keep monitoring the top predators.
Approximately how many 'Greys' are there around the Calf?
I'm not sure how many there are around the Calf specifically, although probably in the region of a hundred or so. Around the Isle of Man, there are probably about 500 resident, which is only a tiny percentage of UK population. But Seals travel far and wide - between Ireland, Scotland, Wales and England - and the Isle of Man is an important stopping off point in the Irish Sea.
Can you estimate the number of new pups per annum?
It's a bit difficult to know for sure but there were 27 visible from land this year, with probably that number again hidden from view in caves.
How badly was the Isle of Man Seal population hit by phocine distemper?
Oddly, the phocine distemper virus only affected Common Seals, and was devastating to their population. It didn't really affect Grey Seals, though. Common Seal populations are still slowly recovering, which may be why we see so few of them round the Isle of Man.
Roughly how many Common Seals are there in Manx waters?
I didn't see any when I was there, although you do see the odd few throughout the year. There is now also a Common Seal pup at the MSPCA that was found abandoned. The best places for Commons are further north in the Hebrides and they tend to prefer sandy shores for pupping on, rather than rocky coasts.
What other threats are there to Seal numbers?
The biggest threat to Seal populations is collapsing fish stocks from overfishing. Seals eat a wide variety of fish, so they haven't been too badly affected so far, but this could be a serious problem as more and more fish species become depleted. There are also threats from entanglement in fishing gear and pollution of the sea.
How will you follow up your findings so far?
I hope to go back to the Calf next year to do a pup count again and see if the same areas are being used for pupping. I was also doing photo identification of the mothers and males so that next year, I will be able to see if it's the same Seals that come back.
Pictured: A newborn Grey Seal pup.
