Comparison of habitat use during early life stage between ayu Plecoglossus altivelis and ice goby Leucopsarion petersi along the sanriku coast of Japan, as determined from otolith microchemistry

摘要

The habitat use and migration of ayu Plecoglossus altivelis was compared to that of ice goby Leucopsarion petersi using otolith microchemistry analysis. Both species were collected along the Sanriku Coast. Otolith Sr: Ca ratios of ayu fluctuated strongly along the life history transect in accordance with the migration (habitat) pattern from fresh water to sea water. The Sr: Ca ratios of the center region averaged 3.2×10−3; thereafter, the ratios increased sharply, averaging 9.2×10−3, and were maintained at the higher levels until the outermost regions. By contrast, the Sr: Ca ratios of ice goby showed consistently high values along the life history transect of the otolith, ranging 9.0×10−3 in the center to 9.2×10−3 in regions outside the center, with further increases around the otolith edge. These findings indicate that ayu shows a typical amphidromous migratory pattern, while ice goby does not show the anadromous migratory pattern previously reported. The use of a freshwater environment during the early developmental stage in ice goby along the Sanriku Coast was less prominent than that of ayu in the same region.