Ecology of fishes of Kasaoka Bay as observed from the catch of pound nets

1) 内湾における魚類の生態を明らかにすることを目的として，瀬戸内海中央部の笠岡湾において，湾内に極めて濃密に設置される桝網の漁獲物を，ほぼ周年にわたって調査した.
2) 桝網漁獲物中に出現した魚類は48科83種に達した.この外，頭足類11種，甲殻類11種，剣尾類1種をえた.
3) 漁獲物の組成では魚類が数量共に首位を占め，個体数，重量はそれぞれ，全漁獲物中の82%および72%に達した.漁獲量には季節的変動があり，夏期に多く，冬期に少ない.
4) 期間中ひきつづいて，かなり大量に漁獲された魚類4種(テンジクダイ，スズキ，マルアジ，イシモチ)について，その出現時期，湾内における成長，その他二，三の生態的事項について述べた.
5) 出現時期および数量から，笠岡湾内に出現する魚類は，昼態的に次の三者に分類することができる.
i) 湾内に定住するもの:テンジクダイ，ヒイラギ，アミメハギ，マハゼ，サツパ等.
ii) 湾内に一時的に滞留するもの:
a. 産卵のため成体が来遊するもの:魚類ではみるべきものが少ないが， トウゴロイワシ，ダツ科の2種(ダツ，テンジクダツ)等がある.
b. 幼期にのみ来遊し，湾内で成育するもの:マルアジ，スズキ，イシモチ，マコガレイ，イシガレイ， トカゲエソ，アカカマス等.
iii) きわめて稀に出現するもの:クロアナゴ，サンマ，ギンカガミ等.

1) Almost year-round investigation was carried out on the catch of masu-ami, a kind of pound net, in Kasaoka Bay located in the central part of Seto Inland Sea.
2) A list of species found in the catch was presented, in which 83 species of fishes belonging to 48 families were contained, with 11 species of cephalopods, 11 species of crustaceans and I species of Xiphosura.
3) Characteristics in the composition of the catch of masu-ami were shown. Among the animals caught fishes dominated in number and weight, comprising 82% and 71% of the total catch, respectively. The catch per haul fluctuated with seasons, being greater in summer and smaller in winter.
4) Growth as deduced from length-weight measurements and weight-length relationships were described on several fishes captured abundantly during the present investigation.
5) On the basis of seasonal occurrence and abundance, the fishes of Kasaoka Bay can be grouped into the following three ecological categories.
i. Year-round "residents" : Apogon lineatus, Leiognathus nuchalis, Rudarius ercodes, Harengu/a zunasi, Acanthogobius fiavimanus, Callionymus richardsoni, etc.
ii. Temporary "visitors":
a) Those coming to spawn: Allanetta bleekeri, Ablennes anastomella, etc.
b) Those visiting the area in their young stages only : Decapterus maruadsi, Lateolabrax japonicus, Argyrosomus argentatus, Limanda yokohamae, Kareius bicoloratus, Saurida elongata, Sphyraena pinguis, etc.
iii. Infrequent or accidental "visitors": Conger japonicus, Cololabis saira, Mene maculata, Lateolabrax latus, etc.