The Common seal (Phoca vitulina)
The Common seal or Harbour seal as it is sometimes called, is not as common as the Grey seal around UK waters. However, we are privileged to have about 40% of the European population of Common seals, (accounting for 5% of the worlds population) around our coasts, about 50,000-60,000 individuals.
Globally speaking, Common seals are doing well and are widespread across the north Atlantic, Baltic, North Pacific and North seas. Across the North sea alone, there are thought to be 30,000 individuals. Of all the pinnipeds (walruses, true seals and eared seals) Common seals are the most abundant. Generally found going clock-wise around the UK starting from northern Ireland, around the coast of Scotland (which includes the Shetland Islands, Hebrides and Orkney) to the Themes estuary in the south east. Although there are pockets of seals, both Common and Grey’s on the Welsh coast, particularly around the Pembrokshire coast and Skomer Island. And in places along the Cornish and Devon coast in the south west of England. Scotland is particularly important, as 85% of the UK’s Common seal population live there.
Range of Common seals around the UK
Of our two native seal species (the Grey and Common seal), the Common seal is smaller in build. Adults can reach 1.85 meters (6 foot) in length and weigh 132 kilograms (290 lb). Overall colouration varies from location to location being anything from a brown, sandy, grey/brown to dark grey colour, dappled with dark spots. Common seals can be distinguished from Grey seals by their more rounded ‘dog-like’ head, lacking external ear flaps and the nostrils making a ‘V’ shape.
The Common seal gets the name ‘Harbour seal’ because their preference is to swim close inshore, around headlands, bays, estuaries and harbours. They may even swim some distance up rivers.
For the most part, Common seals are solitary animals, only coming together in small groups when they haul-out on their favourite marks, where they usually stay within 5-20 km, 3-12 miles.
The seals like to bask on rocks, beaches, mud and sand banks – arching their body and keeping head and tail off the ground – unlike the Grey seal which just flops.
Common seals spend a vast majority of their time in the water - looking for food, resting on the seafloor and drifting with the tidal currents – diving to depths between 10-150 meters 85% of the time.
Their diet consists of fish and crustaceans such as; Cod, Herrings, Sandeels, Flatfish, Sprats, Mackerel, Crabs, Octopus and Squid. They eat about 3-5 kilograms of food a day, which keeps their thick layer of blubber – a natural protection from the cold water.
Females give birth in the inter-tidal zone ( the area between low tide and high tide) in June, July and August. Usually to a single pup, weighing in at 8-16kg, which they take sole responsibility for. Within hours of birth, the new born pups are able to swim and dive in the cold ocean, as they were already born with their adult coats.
The young are weaned after a short 2-6 weeks and then have to fend for themselves.
The males play no part in bringing up the young and usually remain in the sea at this time, hustling and bustling each other – competing to mate again with the females.
Moulting takes place in August, not long after breeding. At this time the males come ashore or even mate with the females in the water. Once this is done, they return to the water where most of their time is spent. Although, mostly sedentary, Common seals can travel great distances – up to hundreds of kilometers.
Common seals will mingle with Grey seals and both species can be seen together. Blakeney Point – off the Norfolk coast, is a good place to observe them.
Their life span is between 25-35 years for females and 20-25 years for males – should they survive the trials of being drowned in fishing nets or catching diseases like phocine distemper virus (PDV), which Common seals can succumb to. Killer Whales and Sharks are natural threats to seals too. Even off the UK coast, Killer Whales have been seen attacking seals off the Scottish coast.
Since 1st February hunting for seals is now illegal in Scotland from under part six of the Marine (Scotland) Act 2010. Common seals around the UK are protected by schedule 5 of the Wildlife and Countryside Act (1981), the Conservation of Seals Act (1970) and the EU Habitats and Species Directive (1992).
Common seals are curious creatures and will take an interest in boats, divers and surfers. It can be quite startling when a large seal approaches you at high speeds (in seal terms)! They are fairly harmless if given their space. Care should be taken if encountering females on land during the breeding season, as they need peace and quiet while raising their young.
By Andrew Searle
Copyright, Andrew Searle 2012 @ Stonecirclesandnature.com
Sources; mammal.org.uk, jncc.defra.gov.uk, marlin.ac.uk, whaledolphintrust.co.uk
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