TE ANAU SALMON

Evening Post, Volume CX, Issue 42, 18 August 1925, Page 3

TE ANAU SALMON

LIFE HISTORY READ FROM

SCALES

(FROM OUR OWN CORRtBPOMDIKT.)

LONDON, 30th June.

A correspondent recently sent fo "Tho Field" gome salmon scales from fish caught in Lake Te Anau, with a request that thft editor should, if possible, throw some light on their life history from reading the scales.

"It is curious," says "The Field," "that, although attempts were made to establish Atlantic salmon fry in New Zealand waters as early as 1868, without counting an attempt some four years earlier, when the ova all died on tlje voyage out, it is only in the last year or two that any authentic Salmo salar seem to have been caught. These were, no doubt, the result of stocking by Mr. C. L. Ayson, the Dominion's Chief Inspector of Fisheries, between 1908 and 1910, when he imported ova from a number of our rivers here, including the Tay, Test, Dee, and Wye, as well as wine from Irish waters. A question which lias aroused considerable interest in New Zealand, as well as in this country, is as to whether these fish are now breeding in Dominion waters,, and whether they run to sea or have became lake-feeding fish."

The scales sent are from three fish caught in Lake Te Anau on 28th March, , 1925, the particulars of which are as follow ;_l ' (1) Weight 7|lb, length 301111, girth 12|in; hen. Very little spawn and very undeveloped. Fish in poor condition. -. (2) Weight 51b 2oz, length. 24in, girth. 12inj.hen. Spawn well developed. • •• (3) Weight Sib, length 23in, girth ll|in ; cock. Milt well developed. . Fish No. 1 appears to have two spawning marks, so that it would, seem certain ■tjiat-these salmon are spawning in New Zealand waters, but the,question of their migration to salt water is more difficult to determine. There appear to be'practically no definite "winter bands" on tho scales, which may mean either that they ! are lake-feeding fish, or that the food | supply in the Southern Pacilic does not vary much between summer and winter. ■ MR. J. A. BUTTON'S OPINION. We asked (continued "The Field) Mr. ,T, Arthur Hutlon his opinion of theso scales, and lie Jia«- kindly written us as follows :—

"1 have received a fair number of scales from these so-called Atlantic .salmon, and I firfd them most difficult toread, and yours are no exception to th» rule. There seems to be no well-defined 'winter band/ and the growth of tlm scales generally is quite different from what one finds in this country. It give* one' the impression,.that the fish fiavß poor food supplies, which may indicato that they do not go to the sea at all^ and content themselves with what they find in the lakes. Most of the fish seem very long and thin, for instance, your No. 1. which was 30Jin long, weighed only 7J'"" A eataon of this length, ought to weigh at least lOj-lb to 111b.; The other two are distinctly better shaped. - ' _

"As regards the life history of'tlie fish, I hardly like to express a positive opinion. One really requires a representative collection to enable one to form any sound ideas about this point. By this I mean a collection of several hundred sets of scales from fish of all sizes and caught at different times of the season.' Judging from the description of these three'fish, they were just about to spawn, and therefore can hardly be regarded us 'representative.' Anyhow, for whatever they are worth, my 'guesses' as to tha life of these fish are as follow-:—

"No. 1. —Two (possibly three) year*' river life followed by what looks like two years of. sea or lake' feeding, outsids which 1 take is to be a spawning mark. Then there is another period of rapid feeding, with a second spawning mark, followed by a further zonp of wideP rings.

" No. 2,—Two years' river life, with' what looks like two years of sea or lake feedins;;'no spawning mark " No. 3.—Two (possibly three) yeare' river life, with apparently two years' rapid feeding. Outside this there seems to-be a check in growth, wk'ch may represent a winter's slackened feedinjr. This iii surrounded by a further of wider rings. No spawning mark*.

" The above must be taken witli a rood deal of caution, for I really do not. know enough about these New Zealand fish to be able to* give p.n opinion worth much. 1'