富山湾のホタルイカ漁況

摘要

To clarify the structure of catch fluctuations patterns of firefly squid (Watasenia scintillans)in Toyama Bay, Japan Sea, we examined yearly and daily fluctuations of catch by areas, relation betweendaily catch and sea temperature, and body size changes of squid during 1982 to 2001. Annual yieldswidely fluctuated from 473 to 3,895 tons with average of 1,655 tons from 1982 to 2001. When defining afishing season as the period from the first to the last days with over one-ton daily catch, the maximumduration of fishing season in Toyama Bay was from early March to middle July. The potential and opti-mum sea temperature for squid fishing seemed 9-15°C and 11-13°C, respectively. The west part asShinminato and the east part as Namerikawa and Uozu of Toyama Bay showed distinct patterns in annualand daily catches. These differences in catch pattern could correspond to bottom topography. There were7 days time lags in average of years of rich yield from Shinminato to Uozu in daily catch correlation,which suggest eastward movement of squid. Body size of squid generally increased through a fishingseason. However, the detailed examination of changes in mean body size with a known growth rate indi-cates an occurrence of several recruitments during a season every year. This was also supported by anoccurrence of several peaks in daily catches for every year and area.