[From the Dublin Penny Journal, Vol. 1, No. 10, September 1, 1832]
The Gillaroo is a species or variety of trout not merely peculiar to Ireland, but found only in some of the lakes of the Shannon and the western part beyond it-a wild but romantic region, in which the lover of the picturesque, the antiquary, the naturalist, and the angler, will equally find sources of pleasure, and such as he could hardly meet with elsewhere.
The fish from which the accompanying sketch was made was nineteen and one-half inches long, five and four-tenths thick, twelve and six-tenths in circumference, and weighed four pounds. It was caught with a worm, on the seventh of August, 1824, in a deep hole near the mill at Cong, in the county of Mayo, a spot of singularly romantic beauty.
This hole or pool, is a portion of the river which connects Lough Mask with Lough Corrib, and whose course for the greater part is subterranean. Here we may descend into a cavern festooned with foliage, and see the fisher boy, plying his rod beneath a living rock of sixty feet in thickness. We shall give a sketch of this extraordinary scene in a future number.
The peculiarities of the Gillaroo trout are so accurately described by Sir Humphry Davy in his charming little book, Salmonia, that we gladly present the passage to the reader, in preference to any thing we could ourselves offer.
"Poiet.-I have heard various accounts of the excellent fishing in some of the great lakes in Ireland. Can you tell us any thing on the subject, and if the same flies may be used in that island?
Hal.-I have been several times in Ireland, but never at this season, which is considered as best for lake-fishing. I have heard, that in some of the lakes in Westmeath, very large trout, and great quantities may be taken in the beginning of June, with the very flies we have been using this day. Wind is necessary; and a good angler sometimes takes in a day, or rather formerly took, from ten to twelve fish, which weighed from three to ten pounds, and which occasionally were even larger. In the summer after June, and in the autumn, the only season when I have fished in Ireland, I have seldom taken any larger trout; but in the river Boyle, late in October, after a flood, I once had some sport with these fish, that were running up the river from Loch (Lough) Key to spawn. I caught one day two above three pounds, that took a large reddish brown fly of the same kind as a salmon fly; and I saw some taken that weighed five pounds, and heard of one that equalled nine pounds. These fish were in good season, even at this late period, and had no spots but were coloured red and brown-mottled like tortoise shell, only with smaller bars. I have in July, likewise fished in Loch Con, near Ballina, and Loch Melvin, near Ballyshannon. In Loch Con the party caught many small good trout, that cut red; and in the other I caught a very few trout only, but as many of them were gillaroo or gizzard trout as common trout.
Poiet.-This must have been an interesting kind of fishing. In what does the gillaroo differ from the trout?
Hal.-In appearance very little, except that they have more red spots, and a yellow or golden coloured belly and fins, and are generally a broader and thicker fish; but internally they have a different organization, possessing a large thick muscular stomach, which has been improperly compared to a fowl's, and which generally contains a quantity of small shell-fish of three or four kinds; and though in those I caught the stomachs were full of these shell-fish, yet they rose greedily at the fly.
Poiet.-Are they not common trout which have gained the habit of feeding on shell-fish?
Hal.- If so, they have been altered in a succession of generations. The common trouts of these lakes have stomachs like other trouts, which never, as far as my experience has gone, contain shell-fish; but of the gillaroo trout, I have caught some not larger than my finger, which have had as perfect a hard stomach as the larger ones, with the coats as thick in proportion, and the same shells within; so that this animal, is at least now a distinct species, and is a sort of link between the trout and char, which has a stomach of the same kind with the gillaroo, but not quite so thick, and which feeds at the bottom in the same way. I have often looked in the lakes abroad for gillaroo trout, and never found one. In a small lake at the foot of the Crest of the Brenner, above 4000 feet above the level of the sea, I once caught some trout, which, from their thickness and red spots, I suspected were gillaroo, but on opening the stomach I found I was mistaken; it had no particular thickness, and was filled with grasshoppers: but there were char which fed on shell-fish in the same lake.
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Poiet.-You spoke just now of the gillaroo trout, as belonging only to Ireland. I can, however, hardly bring myself to believe, that such a fish is not to be found elsewhere. For lakes with shell-fish and char are common in various parts of Europe, and as the gillaroo trout is congenerous, it ought to exist both in Scotland and the Alpine countries.
Hal.-It is not possible from analogies of this kind to draw certain inferences. Subterraneous cavities and subterranean waters are common in various countries, yet the Protius Anguinus is only found in two places in Carniola, at Addilsburg and Sittich. As I mentioned before, I have never yet met with a gillaroo trout, except in Ireland."
We shall only add that the giliaroo trout is frequently taken of six or seven pounds weight, and that it is considered by many as a great luxury.