山口県萩市見島沖合における表中層トロール（天鷹丸232次航海）漁獲物の多様性

Diversity of Fishes Caught (T/V Tenyo Maru’s 232nd voyage) by Sea-surface and Mid-water Trawl Off Mishima Island, Japan Sea

Creators Tanoue Hideaki

Creators Fujiwara Kyoji

Creators Nakahara Takashi

Creators Ogawa Masahiro

Creators Hata Kazuhiro

Creators Enoshima Taketomo

Creators Gotou Hiroshi

Creators Kokatsu Masaki

Creators Ito Takafumi

Creators Takahashi Hiroshi

Creators Komatsu Teruhisa

Creators Mohori Masahiko

Sea-surface and mid-water trawls, to which a small submarine bathythermograph system (SBT) was attached, were carried out from August 1 to 4, 2015, in inshore areas off Mishima island, Hagi, Yamagushi Prefecture, by the training vessel “Tenyomaru” of National Fisheries University (voyage 232). The numbers of species caught at four research stations (St. 1-4) were 7 (76.1 kg in catch amount), 4 (69.2 kg), 11 (168.5 kg), and 10 (52.7 kg), respectively. Diversity indices of fishes caught at each station, as measured by taxonomic distinctness (Δ^+), were 0.79, 0.89, 0.74, and 0.79, respectively. There was no critical difference in water conditions, such as water temperature, salinity, and dissolved oxygen with conductivity-temperature-depth (CTD) measurements among the four research stations. However, the SBT record indicated that the mouth of the net was not sufficiently open at St. 2, causing a difference in the diversity of fishes caught between St. 2 and other stations.

[ISSN]0370-9361