NEW ZEALAND FISHES

Evening Post, Volume CIX, Issue 119, 22 May 1930, Page 6

NEW ZEALAND FISHES

ACQUIRING DATA

ATLANTIC 'SAKMO-V

.■; Aecliiiiatisation in ?fcw Zealand has |irQvided striking instances of developments o£ plants aiid animals ia their new surroundings. Pishes do not loud themselves to. observation as readily, as blackberry and rabbits, however, and tho greatest', difficulty faced by the Ohief inspector of Fisheries (Mr. A, B. Hefford) when he took over the duties from tlio lato Mr. L. J?. Ayson, was the lack of data on wliicli to base tlio response of acclimatised fishes to their new habitat.

■. ■ Pisciculture .has beconio an oxaet scieueo in America, but there is 110 guarantee, that the imported salmon \?ill, strictly,:, follow tlioLt American jtiaijits, ,;0.1'.•. show the saino ' annual 'growth.. 'This. can. only be found out by examining' specimens at various stages of growth' over n. comparative period. The following' report, regarding a 1-llb Atlantic salmon from tho Waian Eiyer, forwarded to the Soutliland Acclimatisation Society by Mr. Hefford, shows how tho life history of tho flali is told;from Us scales:— ~ "The sealo.'shows pretty clearly two winters andj-at,the.edge, the beginning of ;i third winter. 'The zones of differing growth v rate ;: are: so- clearly shown in? this ;"speeimeii • tlii<fc I think there caii-bo'.no mistake about.its interpretation. Its total ..length is IGJ inches.,(it may have shrunk a trifle since it was first caught). Tho position of tho winter zones shows that it was about a quarter of its final length at the. completion of i)^ first winter, and about half its final length at the completion of its'second winter.

"The life history of tho fish then would appear to be as follows:—l 927— Spring (or.thereabouts),"hatched out. 1928—Just over 4 irfches-in length at the end of the winter of this year. 1929—Between 8 and I) inches long at tho end of this winter. . 1930—Caught at tho end of April when tho third winter band :is just boginnhnj to show. During the preceding year good growth .has taken place. -.-.'- ---'-'The fish is a male, very nearly ripe with fully developed milt very near the running stage. It is remarkable that its nnderjaw is so little developed, but with grilse this is no uncommon feature. The stomach is1 crammed with halfdigested insect larvae, among . which may be distinguished fragments of cphemcrido and at least one caddis,".