| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1993: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1992: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1991: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Research Abstract |
The anguilliform fishes comprize more than 600 species of the 147 genera and the 19 families in the world. The larvae seem to play an important roles in the biological production in the oceans because their larvae are one of the most dominant ichthyoplankons in the oceans. However, their larval biology is one of the most undeveloped fields of study owing to their larval forms "leptocephalus larvae" extremely different from the body forms of their adults.
In this study, the anguilliform larvae which were collected by the TV Nagasaki Maru and Kakuyo Maru, Faculty of Fisheries, Nagasaki University, and were deposited in Faculty of Agriculture, Kyushu University, Shimonoseki University of Fisheries, and Seikai Regional Fisheries Research Institute, Fisheries Agency, were investigted from the stand points of exploring their morphology, classification and distribution. The larvae which were collected by a commercial trawl net for young sardine in Miyazaki Prefecture, were used for physiological study. The outline of the results currently obtained are as follows :
The anguilliform larvae which totaled more than 2,000 speciments belonged to Congridae, Nemichtidae, Muraenesocidae, Ophichthydae, Muraenidae, Anguillidae, Serivomeidae, Dysommidae, etc., and the prominent species were Ariosoma spp., Gnathophis spp., Nemichthys spp., Anguilla spp., etc. The spawnings of Anguilla japonica, and A.marmorata and/or A.celebesensis seemed to occur in the waters east of Luzon, the Phelippines, in the early summer.
Swimming abilities, responses to water flow and light, oxygen consumption, and origins of rings on otolith were determined for the leptocephalus larvae and elvers of Conger myriaster, Muraenichthys gymnotus, and Muraenesox cinnereus, and a possibility of culture of C.myriaster using wild leptocephali was presented.
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