Life is again stirring in the seas around us

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Here we are awaiting another tourist season on the Wild Atlantic Way, writes Marie Louise Heffernan. People come for a sense of wilderness, and perhaps the unexpected. Remote ledges with screaming sea birds, thousands of hectares of soft bog or waves crashing down on deserted shorelines.

In the seas around us, life is stirring. This time of year the seashore is very green and brown and as the year pushes on the fronds of the seaweeds (pepper dulse and serrated wrack, for example) will swell up with reproductive follicles, turning yellow in the process, before releasing new life to the sea.

The wild Atlantic Ocean west of us, from Killary to Mannin Bay, is internationally important for marine mammals. The sea here encompasses a large range of marine features echoing the drama of land above, including cliffs, reefs, islets and valleys. A population of bottle-nosed dolphin lives in this area. This population is estimated at a minimum of 123 dolphins, with possibly up to 200 individuals living in this western corner of Ireland.

Bottlenose dolphins have few distinguishing features; they have white bellies and ventral areas but are uniform grey on their head, sides, tail and dorsal area They feed on squid and a range of fish species and give birth to their calves in the summer months, normally June to August. Calves are very small and pale in comparison to the larger darker adults.

I was lucky enough to encounter a pod in summer four years ago off the Mayo coast. The young ones, just one month old, were being protectively kept away from our boat while adult dolphins wove their way at three different depths, riding the bow of the wave streaming from the boat. I sometimes see them from White Strand off Renvyle, playfully jumping in front of Cramp Island, or further offshore, close to the mouth of Killary harbour.

However, bottlenose dolphins are not the only marine mammal of interest to grace our waters. Seals are also often seen in the seas around us. We have two different variety of seals here; there is the common seal and grey seal and despite their similarities they do prefer very different habitats.

The common seal is the smaller of the two seals. Common seals are generally cuter in appearance, with round faces, double chins and v-shaped nostril slits. They prefer sheltered coastal areas with a sandier coastline and calmer waters than the habitat of the grey seal. In north west Connemara they are often seen hauling out on in Mannin Bay and can often be seen in small groups of seven or eight individuals on sand and mud banks at mid tide.

Common seal numbers counted at Mannin Bay in 2003 were 33 adults and 3 pups recorded.

The Grey seals are more regal in appearance, with longer faces and straight slits for their noses. They prefer areas of more exposed rocky coastline than that of the common seal species. Haul out sites can be found on areas of rocky coasts or on steep sandbanks. Traditional breeding sites to which individuals will visit every year for the mating and pupping seasons are generally to be found on uninhabited islands.

In north west Connemara the seals breed on Inishgort, which is located relatively close to Inishbofin Island. The breeding population on Inishgort is large with the population estimated at around 850 individuals in 2005.

Common seals and Grey seals pup at different times of year, perhaps in response to food availability. Common seals pup during June on secluded sandy beaches. In contrast the grey seals pup in December on the islands and the young have pure white fur covering them. Grey seal pups are weaned after losing their baby coat at three to four weeks of age. The pups live off these fat reserves whilst learning to feed, which may take several weeks. I spotted a young pup at White Strand in 2004 and it quickly jumped in the water as I approached.

Common seals generally feed on herring, hake, sole and also octopus and squid in deeper waters. Grey seals tend to feed on bottom dwelling prey items such as crustaceans, flatfish and lobsters, but will also hunt for cod, herring and whiting. Grey seals are also known occasionally to snatch resting seabirds.

The seals and dolphins here in these north west Connemara waters are resident species but occasionally we also get some more glamorous varieties of marine mammals passing through. In 2010 a Killer Whale was seen between Inishturk and Clare Island. In December 2011 a sperm whale was washed up on Omey Island and in 2013 five Minke whales were spotted out off this coastline. So keep your eyes peeled – for who knows what we will see off our shores this year?

  • Marie Louise Heffernan is a chartered environmentalist and founder of Letterfrack-based Ecology Centre – see www.theecologycentre.ie