Studies on the Stocks of Some Economically Important Marine Fishes caught around Amakusa IV. Some observations on the round-herring, Etrumeus micropus (Temminck & Schlegel)
1949 Volume 15 Issue 3 Pages 122-124
Details
1949 Volume 15 Issue 3 Pages 122-124
The present work was carried out at Tomioka from September in 1946 to February in 1948 to make clear some biological charaeteristics of the round-herring, Etrumeus micropus (Temminck & Schlegel), fished around Amakusa. The appearance of the said fish is very long at Tomioka, but its main fishing season is after July. The catch measures mostly from 30mm to 150mm in total length, but some of those, which were caught in September and October, reach over 170mm to 200mm.
The average number of vertebrae for each group lies from 53.71±0.0368 (S. E.) to 54.04±0.0552, and varies according to the advancement of the season, showing a maximum at the latter part of July and a minimun in that of September.
The coefficient of variability of total length is from 4.74 to 21.94 in a range, and becomes nearly minimum, when the average number of vertebrae is maximum or minimum.
Further, we computed the values of k and n in a formula, W=kLn (W, body weight in g; L, total length in mm), and obtained 2.15×10-6 and 3.251, respectively. Then, we calculated the value of k for each group, making n egual to 3.251, and got 1.96×10-6-2.37×10-6. Such a value of k indicates a seasonal variation, becoming minimum in August. This variation of k is comsidered to be closely related to that of total length.
