Diel variability in the catch composition of bottom trawl survey in the East China Sea
2005
Mizutani, T.(Mie Univ., Tsu (Japan). Faculty of Bioresources) | Harada, Y. | Yamashita, H. | Yamamoto, K. | Yoda, M. | Hiyama, Y.
Diel variability in the catch composition of a bottom trawl survey the East China Sea is analyzed using the results of sixteen (eight in the day and eight at night) operations. Of several fishes including the Japanese common flying squid, the average catch weight and number were larger at night. Of several fishes including sword tip squid and yellow sea bream, they were larger during the day. A small difference in average size between day and night was observed in Thamuaconus hypargyreus, Japanese horse mackerel, and male and female of Ovalipes punctatus. The average number of species caught was larger at night. It is also suggested that, by operating in both day and night, the number of species appearing in the survey catch can be increased without increasing the number of operations.
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