Salmon

Press, 18 March 1989, Page 24

Salmon

Sir,—l would like to ask Dr Peter Todd, of the Ministry of Agriculture and Fisheries, to elaborate on the statement made in “The Press” on March 11 by giving the number of salmon straying to Tentburn from the Rakaia River over the last three years and also the number straying from the N.Z. Salmon Company salmon farm at Tentburn to the Rakaia River over the same period. Would he also publish the authority for these figures and how they were obtained?— Yours, etc., - C. J. BERRY. March 14, 1989.

[Dr Todd replies: “In 1985 17 salmon from other hatcheries strayed into Tentburn, 220 in 1986, 54 in 1987 and 26 in 1988. This contrasts with 137 Tentburnorigin fish straying into east coast rivers in 1986, 395 in 1987 and 1029 in 1988. All are minimum estimates. Tag information from fish returning to Tentburn is supplied to MAFFish by the N.Z. Salmon Company in confidence, and all tags from stray fish are given to us for verification. Tags from fish straying from

Tentbufn are recovered by anglers and from other hatcheries. Details on the method of tagging and data analysis has been published in a MAFFish publication (N.Z. Fisheries Technical Report No. 2) which is available from the Freshwater Fisheries Centre in Kyle Street, Riccarton. The above information only relates to hatchery strays, but there has been concern about wild fish being attracted into Tentbum. The only reliable way of identifying wild from hatchery fish is from the scales, which reflect the different life history patterns, much like tree rings. Analysis- of a sample of fish in March from the farm showed that 1.9 per cent were wild. Further samples from angler-caught Tentburn fish will be taken to verify this. Based on the straying derived from this season, and assuming that it was similar -in previous years, approximately 180 wild salmon strayed into Tentbum in 1986, 230 in 1987 and 170 in 1988. Total returns reported by the company for the same years are 9700, 12,000 and 9000 respectively. Large numbers of salmon can be expected to return to Tentburn based on the several millions of fish released over the past three years. However, all returns of salmon, hatchery and wild, have been affected by the catching of salmon at sea and poor ocean conditions.”]