There are two species of seals around Northern Irish  coasts, the grey seal  and the common or harbour seal. The grey seal is the most common. Both are true seals in that they have no external ears.  Leading a mostly aquatic life they  go to land  only to moult, rest and have young.  Both are sociable and form harems or colonies.

           These two species  are  quite easy  to distinguish from each other. The grey seal has a  larger head  with a sloping nose while the common seal  has a smaller round labrador type face with v shaped nostrils. The grey is mostly as the name suggests  of a grey colouration with dark blotches and spots with pale bellies.

Grey seal 

 The common seal varies  in colour from white to  dark brown, generally though they are grey with dark spots. Unlike the common seal ,grey seals have large colonies. One of the most important colonies is off  the Blasket Islands in  Co Kerry and  in Northern Ireland they can be spotted off Rathlin Island and around  Murlough Bay.  

Common seal

      Both species have a streamline torpedo shape  with four limbs called flippers armed with  small claws. On land they are ungainly  and move in a flopping style  but once in the  water they demonstrate  their agility and can reach speeds of 25 knots  and dive to depths of 300 metres.  They have very good vision with large forward-facing eyes. In areas of good light vision is used  but in deeper areas and in  poor light they rely on their sensitive whiskers to pick up movement from their surroundings.  Their lifestyle is to  spend half of their time resting and the other half  hunting  fish ranging from sand eels to cod and molluscs from squid to octopus . Seals emit clicking noises when hunting. They can remain submerged for  quite a long time. Around Ireland  this has been found to be usually about 10 minutes . During a dive they will close their nostrils and  on very deep dives they can reduce their  blood supply  and slow their heart  rate .

                                 Forty percent of  the entire world population of grey seals are around  the coasts of  Britain.  Grey seals breed in Autumn or Winter on offshore islands and moult from January to April, whereas common seals breed in June and July and moult soon after  giving birth. In both species the males are larger than the females and are called bulls.  Bulls reach maturity between 4-6 years. The females called cows  reach maturity between 3-5 years.  Grey seals are known as ‘capital breeders’ which means they spend little time with their pups, and both sexes will fast during this time  This  can last up to 50 days for  the  males in which they have to rely on their fat reserves or blubber for energy.  Male grey seals do fight to maintain very loose territories amongst groups of females. They have many partners but only a few will monopolise the females. Pregnancy is ‘ delayed’ which means that  the fertilised egg’s  development is delayed  until conditions are favourable. On average the pregnancy lasts for eleven and a half months.  Only one  white  pup is born, they cannot swim  and  the female nurses them for three weeks.  After this  period around about January,  she departs to the sea leaving them to fend for themselves. These pups stay on the land for another couple of weeks until they have completely shed their white fluffy coat to a more waterproof  one.

Grey seal pup

                    Common seals  like the greys  have delayed implantation although their pregnancy may be a little shorter, anything from 9 to 11 months. They give birth to one pup. These pups are grey and  can swim and dive a few hours after birth .They are nursed for 3-4 weeks.

Common seal pup

                                   In both species the males can live until 25 years while females can live until 30 to 35 years .They have  no major predators in our waters although there is always the potential of  shark and killer whale attacks. Sometimes large grey seal males will kill  both common and smaller grey seals as well as common porpoises .

                          All seals face an uncertain future. Climate change and the  warming  of oceans  is a major problem as is plastic pollution,  entanglement in discarded fishing equipment,  boat collisions, oil spills, the phocine  distemper virus  which was first recognised in 1988 in Europe where 60 percent of the North Sea common or harbour seals and a few hundred grey seals became infected and died. Starvation and  infection from bites are also a threat. Both species  are protected by law under legislation such as the  Wildlife ( Northern Ireland ) Order 1985 which makes it an offence to kill injure or take them. They are beautiful creatures and are one of the wonderful sights in our ocean and around our shores.

Seals written by Maureen Graham Hon Secretary