When the giant trawler Atlantic Dawn, fresh from Norway's shipyards, made its triumphant homecoming voyage up the west coast to Killybegs last autumn, there to be greeted with flags and a pipe band, I was not among those who stood on headlands for a glimpse of the world's largest fishing vessel, built at a cost of €80 million.
Having to catch more than €2 million worth of fish on each trip, with nets twice the size of London's Millennium Dome, in order to make a profit, seems to me to speak for everything that's wrong with human impact on the sea.
Too voracious to admit into Europe's depleted fisheries, the Atlantic Dawn has been banished to a base in the Canary Islands, from which it hunts the fish off Mauretania, in West Africa, catching and freezing more in a day then 10 local fishing boats would net in a year. In compensation for such plunder off one of the poorest countries in the world, the EU will pay the Mauretanian government €480 million over the next five years.
As fish stocks dwindle across the north-east Atlantic, each new direction of the industry seems to wreak ecological havoc.
I have written here of the reckless exploitation of long-lived, late-maturing, deep-water fish ("orange roughy", now on Irish hotel menus, which can live for 70 years) about whose population dynamics almost nothing is known. Now the drive for albacore tuna and swordfish, to which Irish trawlers have been recruited by Bord Iascaigh Mhara, is causing quite unsustainable casualties among schools of dolphins and porpoises.
Concern about "cetacean by-catch" helped prompt an EU ban on drift-netting for tuna and swordfish that came into force this year. The new alternative is "pair-trawling", in which two trawlers sift the sea with a net the size of a football pitch stretched open between them.
In 1998, Bord Iascaigh Mhara (BIM) carried out a study of the technique for the EU Fisheries Directorate. It reported that on a 40-day trip, four pairs of trawlers hauled their nets 313 times and 145 dolphins and pilot whales were trapped. Most of these were taken in only 10 hauls, one of which caught up 30 animals.
A similar British study, by the Sea Mammal Research Unit, found just as unacceptable rates of by-catch among Scottish pair trawlers, with one haul killing at least 20 cetaceans.
"It would appear," the BIM report concluded, "that the majority of cetacean by-catches in pelagic trawls are isolated incidents, when relatively large numbers can be captured. With increasing experience in the tuna fishery, and by observing a number of simple fishing practices . . . it is firmly believed these by-catches will be reduced to negligible levels." In the early months of this year, however, more than 1,000 dolphins were washed up dead on the beaches of south-west England and Brittany, most with wounds and net marks strongly suggesting by-catch as the cause of death.
Pair-trawling by UK boats - not for tuna and swordfish, but schooling mackerel and sea bass - has been held to blame, amid angry protests from cetacean conservationists.
Research continues on the use of underwater "pingers" - acoustic devices - to warn dolphins away from trawl nets, and the use of release hatches to help them escape. Meanwhile, the EU Fisheries Commissioner, Franz Fischler, is under some pressure to ban pair trawling, as has happened already (though not always from concern for dolphins) in the US, Canada and Spain.
The real test of Irish pair-trawling skills and discipline will come this summer, as trawlers from Castletownbere steam out to compete with French boats in the hunt for schools of albacore tuna, perhaps 200km to the south-west. These metre-long relatives of the great Atlantic bluefish tuna migrate northwards from Mediterranean latitudes, following the spread of warmer surface water up to, at times, the level of Dingle Bay.
Finding tuna, as one French skipper has said, "is a trade of patience and a hunting full of maybes". The same BIM study that reported on dolphin by-catch ("some incidental catches", it remarked, "as with most other pelagic fisheries, would seem inevitable"), discussed the use of remote sensing technology to take some of the maybes out of the fishing effort.
A marked rise in the number of dead cetaceans washed up on our west coast would clearly bring fresh demands for action. Ireland purports, after all, to have declared a sanctuary for whales and dolphins in its offshore waters. But such a declaration, as the Irish Whale and Dolphin Group (IWDG) is always ready to point out, carries responsibilities in scientific monitoring and conservation.
At the end of the 1990s Dr Simon Berrow, a founder of the IWDG, took part in the first international scientific attempt to quantify marine mammal by-catch in ordinary pelagic trawling - in the upper layers of the open sea - by Irish, British, French and Dutch boats fishing from Biscay to the Celtic Sea. Their study confessed to being "compromised in France and Ireland by some fishing fleets and ports not wishing to co-operate" - a monitoring problem unlikely to grow less.
Not every dolphin killed at sea ends up washed ashore: some estimates, indeed, suggest that only 10 per cent of the total by-catch reaches land.
Independent programmes of by-catch monitoring are urged in a new study of sea-mammal strandings on the Irish and Welsh coasts of the Irish Sea, over four years of the 1990s, which was led by Emer Rogan of UCC (another leading figure in IWDG). It found that entanglement had killed about 10 per cent of the stranded cetaceans, most of them harbour porpoises.
Observers monitoring the by-catch of porpoises in the bottom gill-net fishery of the Celtic Sea found a total kill of 2,200 animals, or more than 6 per cent of the local porpoise population. This is probably more than natural replacement can stand. If you want to watch cetaceans while we still have them, log on to http://iwdg.ucc.ie for a list of weekend events.