Tests show halibut is 20 years old

"IT required detailed scientific tests. Fish bones were scrutinised. Candles burned long into the night

"IT required detailed scientific tests. Fish bones were scrutinised. Candles burned long into the night. Now, the Marine Institute has been able to confirm that the giant halibut caught by a Donegal fishing vessel off the north west coast is all of 20 years old.

Scientists from the institute's Fisheries Research Centre (FRC) were able to "age" the 286 lb fish by studying the earstones or otoliths found in its head. Otoliths are bony structures which fish use for balance and which form growth rings similar to those found in tree trunks, according to two marine scientists, Dr John Joyce and Dr Paul Connolly.

Caught off Rockall by the Killybegs vessel, the Mary M, just over a fortnight ago, the monster was probably born in the deep waters of the Atlantic in 1976. Halibut are large, grey flat fish which frequent depths between 200 and 2,000 metres, and normally grow to about 706 lb or 320 kg. They can reach up to eight feet in length, though the record stands at 12 feet, according to the scientists.

The fish spawns in winter and early spring at depths of between 400 and 1,000 metres on the edge of the northern Continental Shelf. The females are larger than their male mates, and can survive for up to five decades.

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Few halibut are taken by trawl most are caught on hook and long line by passive fishing methods. The flesh is normally firm and of "excellent flavour", the two scientists say. However, the slow growth rate and late sexual maturity can leave the stocks prey to overfishing.

Remnants of this monster are still on the menu in Wright's Fisherman's Wharf restaurant in Howth, Co Dublin, which paid a quoted £1,950 for the specimen. Since a photograph of the catch appeared on the front page of The Irish Times earlier this month, there has been a great demand for it, the restaurant said yesterday.

Meanwhile, the decomposed body of a 30 foot whale was found floating near the uninhabited island of Inishinny, off the Donegal coast, at the weekend. Because of disintegration of vital organs, an Irish Wildlife Service source said that an analysis could not be undertaken and cause of death cannot be established.

There is some speculation that death may be due to choking caused by plastic wastes dumped in the ocean. An appeal has been made to the public who see any dead whales to report the matter immediately to the Wildlife Service. Boatmen have been warned to keep a look out for floating sea mammals at this time of the year.

Lorna Siggins

Lorna Siggins

Lorna Siggins is the former western and marine correspondent of The Irish Times