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ID 23480
file
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title alternative
On the food habits of Nibea albiflora in the Seto Inland Sea
creator
Nakai, Kazuo
Kakuda, Shunpei
Gushima, Kenji
NDC
Fishing industry. Fisheries
abstract
瀬戸内海の中部で1977年3月から'79年6月までの間に採集した323尾のコイチについて、空胃またはそれに近い状態にあった個体120尾を除き、体長49~435mmの203尾の個体の胃内容物の種類とその個体数を明らかにした。さらにそれらの中で胃内容物が未消化であった個体153尾については、各個体の胃内容物全重量と餌生物の種類別重量を測定した。得られた結果は次の通りである。

1) 胃内に出現した生物は魚類、甲殻類(橈脚類、アミ類、クマ類、端脚類、オキアミ類、十脚類、口脚類)、腹足類、頭足類(十腕類)、多毛煩、螠類、藻類であるが、出現頻度、個体数、重量のいずれについても特に多い魚類とエビ類が最も重要な餌生物であり、次いでアミ類が重要である。

2) 胃内容物組成は、出現頻度では魚類51%、エビ類52%、アミ類23%、個体数比では魚類17%、エビ類58%、アミ類20%、重量比では魚類46%、エビ類33%、アミ類1%であった。

3)コイチの成長に伴って胃内容物の種類組成が変化するとともに、餌生物の種類数は成長とともにやや減少する傾向がある。重要な餌生物は、体長40~79mmの0年魚ではアミ類、小型エビ類(主としてテッポウエビ類、ヒラツノモエビ、エビジャコ、クルマエビ科のエビ1種)、小型魚類、体長80~139mmの0または1年魚では魚類、エビ類(主としてアキアミ、テッポウエビ類)、体長140~199mm の1年魚では魚類、エビ類(主としてテッポウエビ類、エビジャコ)、そして200mm以上の成魚では魚類であって、中でも体長200mm以上の個体になるとイカナゴが極めて重要である。

4) 捕食者であるコイチと被食者(エビジャコ、魚類)の大きさとの関係については、大きいコイチほどより大きい餌生物を捕食する傾向が認められる。そして両者の関係は、コイチとエビジャコよりもコイチと魚類との間でより明瞭であって、被食魚類の全長は捕食者であるコイチの体長の約1/5~1/3である。

5)瀬戸内海中部に生息するコイチとシログチの胃内容物について比較、検討した結果、両種の食性はほぼ等しく、同海域の底魚群集の中での食地位は魚食性魚類に次いで高位にあり、魚類・甲殻類食性とすることができる。
abstract
The food habits of Nibea albiflora, which is one of the most important fishing resources in Bisan-seto of the Seto Inland Sea, were studied through the qualitative and quantitative analysis of their stomach contents. Stomachs of 323 fish collected in the central regions of the Sea during the period from March '77 to June '79 were examined, although 120 of them were found to be empty. The stomachs of the remaining 203 fish with a standard length ranging from 49 mm to 435 mm were analyzed individually. The prey items were identified, counted and weighed damp with the total length of the prey (fishes and shrimps: Crangon affinis) being measured. This study is one of a series of studies on the fishery biology of N. albiflora in the Seto Inland Sea. General conclusions obtained in this study are as follows:

1) The prey items found in the stomachs were fishes, crustaceans (shrimps, hermit crabs, crabs, mantis shrimps, euphausiids, amphipods, cumaceans, mysids, copepods), gastropods, cephalopods (squid), polychaetes, echiurids (Urechis unicinctus) and algae.

2) The most predominant prey items in the stomachs in terms of occurrence were shrimps (52%), fishes (51%) and mysids (23%). In terms of numbers, the most numerous item was shrimps (58%), with mysids (20%) and fishes (17%) being less important. In gravimetric terms, the major prey items were fishes (46%) and shrimps (33%), and U. unicilzctus constituted 12%.0 The main species of shrimp consumed were Acefes japonicus, Aljlzous Brevicristatus, Alpheus japonicus, Latreutes planirostris, Crangon affinis, and a species of penaeid shrimp, but Lucifer reynaudi and Athanas lamellifer were less dominant. The most important species of fish consumed was the sand eel (Amnzodytes personatus).

3) The number of prey items in the stomachs decreased gradually with growth of N. albiflora, with the frequency of occurrence and weight of each prey item also changing with the size of the predator. The 203 sample fish were divided into four standard length groups: less than 80 mm, 80-139 mm, 140-199 mm, and greater than 200 mm. The major foods were mysids, small shrimps (mainly alpheid shrimps, L. planirostris, C. affinis, a penaeid shrimp) and small fishes in the < 80 mm size group, fishes and shrimps (mainly Ac. juponicus, alpheid shrimps, C. afjinis) in the 80-139 mm size group, and fishes and shrimps (mainly Ac. japonics, alpheid shrimps) in the 140-199 mm size group. Fishes were the most important prey item in the > 200 mm size group, and sand ell was dominant in the stomachs of N. albiflora greater than 260 mm length.

4) The prey size of fishes and shrimp (C. affinis) appeared to increase with incresing predator size. Size preference was more clear in fish prey than shrimp. The total length of fish prey in the stomachs was 1/5-1/3 of the standard length of the predator.
journal title
Journal of the Faculty of Applied Biological Science, Hiroshima University
volume
Volume 26
issue
Issue 1・2
start page
89
end page
98
date of issued
1987-11
publisher
広島大学生物生産学部
農林水産研究情報センター
issn
0387-7647
ncid
SelfDOI
language
jpn
nii type
Departmental Bulletin Paper
HU type
Departmental Bulletin Papers
DCMI type
text
format
application/pdf
text version
publisher
department
Graduate School of Biosphere Science
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