Daily Archives: February 22, 2011

Hook nosed sea pig

Radio silence has been a tad prolonged this time, so apologies for that. I wasn’t able to get out and about last weekend so I’ve delved into the archive to write about the grey seal. The Latin name for this one of our native seal species – the other being the common seal (Phoca vitulaina) – is Halichoerus grypa – or ‘hook nosed sea pig. Which is a wonderfully descriptive piece of taxonomic nomenclature! It is the only seal to be classified in the Halichoerus genus.

Grey seal relaxing in the Menai Strait between
Anglesey and
North Wales

The grey seal is almost twice the size of the common seal and is immediately distinguishable by the long ‘hooked nose’ compared to the stubby rounded snout of the common seal. Males are around 2.1m in length and females 1.8m, weighing approximately 230kg and 150kg respectively, the female is therefore much smaller than the male.

Distribution of the grey seal is across the northern Atlantic Ocean with breeding colonies in northern Europe and North America. They are fish eaters feeding predominantly on cod and sand eels but are opportunists and will take a range of fish caught at depths down to 70m including molluscs and crustaceans and they fast during the breeding season.

Grey seal watching me watching it off the Farne Islands, Northumberland

Around two thirds of their time is spent at sea, but they will haul themselves onto rocks, usually on uninhabited islands but also on some isolated mainland sites between tides and also come ashore to breed. This occurs at various times around the UK and while the females are nursing pups the males will also come ashore to mate. At this time the males may get into territorial battles with other males resulting in scarring to their necks. The pups which are white, suckle milk that is 60% fat for approximately 3 weeks during which time they will gain 2kg per day that is mostly sequestered as a subcutaneous layer of blubber providing essential insulation when the young go to sea.

Grey seals were the first mammals to be protected by legislation – the Grey Seal Protection Act of 1914 – and since 1960 the UK population has increased to 120,000 individuals, around half the world population. They are affected by ‘seal plague’ – phocine distemper virus – although of individuals known to have succumbed to the disease only 10% were grey seals.

These delightful animals can be seen all around the UK coastline from the south west, Wales, Scotland and the east coast of England and due to the increase in numbers they have attracted the inevitable hatred of fishermen who claim that they are responsible for declining fish stocks, and they have also been implicated in damaging the nets of offshore fish farms and passing on parasites. The link with parasites is a complex one and further studies are required to establish the link between seals and transmission of parasites, or not.