FISH RESEARCH

Press, Volume LXXXIV, Issue 25445, 17 March 1948, Page 6

FISH RESEARCH

VALUE OF HATCHERIES QUESTIONED

“ FRY LIBERATIONS ONLY A DROP IN BUCKET ”

From Our own reporter TEMUKA, March 16. Doubts were cast on the value of hatchery work and the liberation of trout fry by Mr D. F. Hobbs, senior freshwater fisheries officer of • the Marine Department, when he met members of the South Canterbury Acclimatisation Society at Temuka last evening. x , x “Do not imagine for a moment that 1 am belittling the work and enthusiasm that-has gone into the hatchery business,” said Mr Hobbs. “Research shows that 98 or 99 per cent of the fry goes west in the first year of their life —that is, it takes a million fry to produce 150,000 yearlings, and these 150,000 yearlings dwindle down to about 2000 two-year-old fish.* A single angler might take 350 fish of an average weight of lib in a season, said Mr Hobbs, and when shags, eels, and other natural enemies were taken into account, it would take a quarter of a million fry to produce that quantity of fish.

Hatcheries, he said,-, were able to handle only a very small fraction of the total number of eggs produced, and the fry placed in rivers by acclimatisation societies were few compared with naturally-produced fry. Anglers often credited the introduction of fry into rivers with the improvement in fishing, but this was more often than not the result of exceptionally favourable seasons, he said. Mr J. H. Smillie: It appears that the liberation of fry is only a drop in a bucket. Mr Hobbs: That is the position. Of course, one way is not necessarily the best for all waters. In the case of some waters it is a good policy to hatch fry and to liberate them in land-locked lakes, especially where they are devoid of land-locked tributaries, without spawning grounds, and were also devoid of eels. If fry were introduced in areas where eels were prevalent, it just meant feeding the eels. There were good, spawning areas in 4ome lakes, but it was not reasonable to allow the fry to be slaughtered by eels. Lake Alexandria, he said, was & great fishing lake. It was possible that the weight of eels mignt be less than the weight of trout, out the reverse might be the case. It was certain, howeven, that there was a great weight of eels, and eel and trout flesh were produced from the same food resources. Need to Control Eels The desirability of controlling eels in nursery tributaries was emphasised by Mr Hobbs, who said that any place where young trout were in good abundance was a happy hunting ground for eels.

Mr Smillie: Our ranger might be better employed in killing eels than in raising fry? • Mr Hobbs: There is one priority T hat u seB that spawning hsh get a fair chance. Often field officers were called in and tied down to hatcheries at a time when poaching was most prevalent, and it was questionable whether this was the wisest e ' , Th ? eradication of shags and eels—natural enemies of the trout—was important, and fish salvage was work of high priority. Many societies, he said, spent many hundreds of pounds fob hatcheries but £inon w ?, uld to spend £so ° or 1 n a flstl transportation outfit. Fish salvage was something that should to h g atch n work eQUaI considera «<>“ ehmrman H - B - Timmings): The present council did not build the £ at1116 production of fish costs us only the rangers wages. 1 doubt if we are justified in closmg it, even if X^^°a a . ccept - the theory that artificial ?weS g wH°h a y aste of time aompa£r natural propagation. for M La H 4 b e dS: A DO bo n o O shortly 0 MaS 'nepa'iS Ston a onTe n evid e d ng" d “ ake your de -'