Scale Character and Growth Rate - A study on small fat herring from North Norway
Soeprapto, Mahhargo
From the mean values it can be seen that herring of the "Southern-type" in both years have the same growth rate as those of the "Northern-type". The conclusion must be, therefore, that the correlation, "N-type" - slow growth -, "S-type" - faster growth -, as revealed by an analysis of mature winter-herring, is due to the dominance of fastgrowing "S-type" herring of southern origin in the composite "S-type" winter-herring, and vice versa, a dominance of slow growing herring of northern origin in the composite samples of "N-type" winter-herring. This conclusion is not incompatible with the observations made by Marty (1956), that growth rates tend to decrease when the stock is rich and the observation of Østvedt (1958), that a rich stock seems to be dependent on a rich influx of "N-type" herring. Admittedly it is a weakness pertaining to the present material that the "S-type" herrings are few in the samples and it would be worthwile investigating fat herring from the waters of Møre-Trøndelag to see if any significant difference in growth-rates of "S" and "N"-type can be discerned there. The strong dominance of the year-class 1918 as II-group in 1920 shows that a rich year-class of herring under such circumstances as then prevailed, may be recognised at the early stage of II-group, a point well worth noting for routine survey purposes.
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Эту запись предоставил Institute of Marine Research