Growth of different year classes of smelt Osmerus eperlanus L. in Lake Tyrifjorden, Norway

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Erik Garnås

Abstract

Smelt Osmerus eperlanus L. were collected during spawning run in May in Lake Tyrifjorden in southern Norway. Age determination was carried out by otoliths. Fish length (Y) and otolith radius (X) were correlated (r = 0.954). Calculation of growth was carried out for 610 mature smelt of age 1 + to age 6+, by using the regression model Y = 81.39 X + 17.95. Females were significantly longer than males, except those of age 4 + and 5 +. The smelt grew about 60 mm in first year and from 20-30 mm in second and third year of growth. Then the growth decreased gradually. The eldest smelt caught were five smelt of age 7 +. Back-calculation of growth indicated differences in growth rates between the year classes, with an apparent steady decrease in yearly growth rate of younger year classes. Natural mortality caused by strong size selective predation from other fish species, is considered to be the cause for this growth pattern.

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How to Cite
Garnås, E. (1982). Growth of different year classes of smelt Osmerus eperlanus L. in Lake Tyrifjorden, Norway. Fauna Norvegica, 3, 1-6. https://doi.org/10.5324/fn.v3i0.6137
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