Distribution and migration of a catadromous sculpin, Cottus kazika, larvae and juveniles in the Yura estuary and neighboring waters, facing Wakasa Bay.

概要

論文の詳細を見る
To clarify the early life history of <I>Cottus kazika</I> (Cottidae), we examined the distribution, migration, growth and food habit of larvae and juveniles collected by various methods from the Yura estuary and neighboring waters in western Wakasa Bay from November 1993 to May 1994, and from January to June 1995. Collections using an aqualamp in the rocky shore yielded mostly yolk-saclarvae, which tended to occur synchronously with the spring tide. This tendency was supported also by the back calculation of the hatching date estimated from otolith microstructural increments. Most of the larvae and juveniles were collected in the 5 m depth areas (mean salinity about 34 ppt) with a beam trawl (from 3.5 to 30m depth). We collected no <I>C. kazika</I> larvae and juveniles by oblique tows of alarva net in coastal areas of 10 to 50m depth. In wading areas of the surf zone, many larvae and juveniles were collected, particularly at the lowest salinity (mean about 26 ppt) station nearest to a river mouth. Mean size of larvae and juveniles were greater in the surf zone than in the 5 m depth areas. Food habits changed with growth, and differed between habitats. Pelagic larvae fed on copepods in 5m depth areas. Settled larvae and juveniles chiefly fed on mysids in 5 m depth areas, and gammarids in the wading areas of the surf zone. Thereafter, juveniles fed on tanaidaceans and trichopteran larvae in the estuary.
日本魚類学会の論文