It looks innocent enough. No teeth or fangs, no vague resemblance to some of the more voracious inhabitants of the Atlantic Ocean. Yet the little dog-whelk, Nucella lapillus, is a serious predator on inshore coasts, writes Lorna Siggins.
The Hannibal Lecter of the rocky shoreline is particularly partial to other shellfish, mostly barnacles and mussels. Do mussels feel pain? If ever they do, it must be at the unfortunate point in their lifecycle when a hungry dog whelk approaches, and begins to secrete acid to soften the mussel's shell.
Mercilessly, it then drills a hole through which the soft parts of the mussel can be extracted, and consumed. Small surprise that, between its feeding bouts, Nucella lapillus spends "long periods resting", according to Dr Gillian Bishop.
The animal is one of a number which Dr Bishop analyses in great detail as part of a major study of a south-west marine habitat. When Matt Murphy and his late wife, Eileen, established Sherkin Island Marine Station in 1975, one of the first projects was the selection of a number of rock shore sites for investigation. Dr Bishop was among six volunteers involved, as the station's first marine biologist.
The year before, the oil tanker Universe Leader had spilled about 2,600 tonnes of Kuwait crude oil into Bantry Bay, and a second spill of about 460 tonnes of heavy crude oil occurred six months later, in January 1975. After the two accidents, seashore monitoring sites established as part of Whiddy oil terminal pollution control measures were surveyed to establish whether any damage had occurred to the flora and fauna.
The marine station's opening in Roaringwater Bay couldn't have been more timely. As Bishop notes, it focused attention on the fact that both Roaringwater and Long Island bays had no similar industrial threat hanging over them - and should, therefore, be described and studied so that naturally occurring changes in the marine plant and animal communities could be recorded.
In the summer of 1975, the first transects were established and surveyed on Sherkin and several other islands in the bay. It was the start of a 20-year project with which Dr Bishop was closely associated. Year after year, as the Murphys established close links with British and Irish universities, the number of sites grew to over 60. It was decided that seven shores on Sherkin would be sampled every month between April and October, while the remainder would be inspected annually.
Murphy knew that collecting the information wouldn't be sufficient, and was also conscious that he had been criticised for not publishing data. His response was that a single "snapshot" would tell very little. The analysis which he asked Dr Bishop to carry out after 20 years proves he was right.
Towards the end of the 1980s, something startling occurred. Barnacle populations "crashed", and began to recover only towards the end of the 1990s. This hit the dog-whelks, who depended on them for food. The dog-whelks put so much pressure on mussels that they also declined. And seaweed cover was reduced.
It may be that barnacle populations were particularly high in the early 1980s when the scientific studies started. However, Dr Bishop clearly believes that a natural environmental event occurred which may be linked to changes induced by the Gulf Stream. As yet, there is no sign of a full recovery, and it is only a matter of time before the effects spread to other parts of the island's marine ecosystem. "Clearly, the rocky shore communities of Sherkin are under stress," she writes, "and the populations are in transition as a result of those forces." Significantly, this would not have been noted without the years of patient recording in all weathers. "Today we realise that working to understand individual species cycles, and the dynamics of 'connected' species in the rocky shore habitat, is not only important in itself, but can contribute significantly to understanding climate change," Bishop says.
The marine station intends to do its own bit, It has plans to interpret data from some 145 sites inspected annually, extending from Cork harbour to Bantry Bay. In the interim, it has presented a wealth of detailed information on seven south-west shorelines. The Ecology of the Rocky Shores of Sherkin Island: A Twenty-Year Perspective by Gillian Bishop (Sherkin Island Marine Station, 2003) is dedicated to the memory of Eileen Murphy, late wife of the station's owner, Matt.
Far north of Sherkin, meanwhile, the Killybegs Fishermen's Organisation is marking its 25th birthday this year. It has planned a series of celebratory events and one of the first is the publication of a calendar depicting people involved in the industry at "work" and, more significantly, "play".
"Well, it's for a great cause, and we don't mind people having a laugh at our expense," the KFO chairman and former skipper, Mr Martin Howley, explains, without giving too much away. And the "cause" or causes are very worthy - the Royal National Lifeboat Institution (RNLI) and Killybegs Community Hospital.
Proceeds from the calendar will go to these two organisations, and copies are said to be selling fast at €10 in local shops, or €15 including postage and packing. More details from Kevin Shields, KFO Project Office, telephone 074- 9151844.