open access

https://hdl.handle.net/2115/55299

Abundance and growth trajectory of Japanese sandfish (Arctoscopus japonicus) juveniles in Mutsu Bay

日本語

日本海北部系群

2012-04-25

日本魚類学会

魚類学雑誌

59(1)

21-35

Although spawning of Japanese sandfish (Arctoscopus japonicus) does not occur in Mutsu Bay, juveniles of the species were first discovered in the bay in June 2003 (following the initiation of yearly sampling in 1991), also being collected in subsequent years. To better understand the function of Mutsu Bay as a nursery area and the growth characteristics of the early life stages of the sandfish population, their abundance and otolith microstructure were investigated. Juveniles distributed along the sea floor in temperatures of 7.4–10.0˚C were sampled in June 2010, measuring 32.4–62.7 mm in standard length some 100–145 days after hatching, an indication of their having hatched from January 14 to February 27 (24% and 76% of juveniles hatched in January and February, respectively). June sampling surveys, conducted each year, revealed that high juvenile abundance in the bay occurred only when adult sandfish had been abundant in the Sea of Japan, off Akita and Aomori Prefectures. The origin of the juveniles in Mutsu Bay may have been the eastern Sea of Japan population, distributed off the northwestern coast of Honshu Island, the Tsushima/Tsugaru Warm Current possibly conveying the larvae and juveniles into Mutsu Bay. Median hatching dates did not differ between sampling stations in Mutsu Bay, although relatively small juveniles with narrow otolith increment widths occurred in the inner part of the bay in June 2010. Such slow-growing juveniles may have been early arrivals to Mutsu Bay from the hatching area, thereby experiencing colder water in the bay from a young age than later arrivals.

学術雑誌論文

Version of Record

0021-5090

AN00063212