1995 Fiscal Year Final Research Report Summary
THE ADAPTATION OF THE FIREFLY SQUID ON THE SEMI-ABYSSAL LIGHT ENVIRONMENT.
| Project/Area Number |
06839025
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
海洋生物学
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| Research Institution | KONAN UNIVERSITY |
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Principal Investigator |
MICHINOMAE Masanao DEPARTMENT OF BIOLOGY,FACULTY OF SCIENCE,Konan University ASSISTANT PROFESSOR, 理学部, 助教授 (60068145)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Tidal cycle / Firefly squid / Light environment / Vertical migration / Squid bihavior / Deep-sea spectrum |
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| Research Abstract |
In the spawning season, large shoals of the firefly squid, Watasenia scintillans, enter the fixed shore net settled near the coast of Toyama Bay of the Japan Sea. This squids live at the 200 m depth in the daytime. They move up near the coast at night. We found around the sunset an intense scattering layr at 10 m depth near Yokata port of Toyama on the fish school finder, which was specially designed for searching squid by Furuno Elec.Camp. (Nishinomiya). The squid population in the layr was estimated more than 5 individuals per 1 m. This dense layring of the squid appears to be the specific behavior characteristic of the firefly squid in spawning season. Daily vertical migration of deep-sea animals may depend mostly on the underwater light intensity and its spectrum. We measured the spectral intensities of the underwater light from surface to 200 m depth where and when they were found and tried to estimated the relation of the critical intensith for their vertical migration and their vision.
On the other hand, we investigated the influences of tidal cycles on the vertical migration for the spawning of the firefly squid. The tendency was found in the fishing records of the last five years at Yokata port that the amount of squid caught in the fixed shore net was closely relating to the tidal cycle and the largest amount was at the major tide. This tendency was observed in other ports of Toyama. However, this tendency was not clear at Namerikawa and Uozu of the eastern part of Toyama Bay.
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