open access

https://hdl.handle.net/2115/43087

Seasonal occurrence and sexual maturation of Japanese pygmy squid (Idiosepius paradoxus) at the northern limits of their distribution

英語

thermal tolerance

2009-06

Oxford Journals

ICES Journal of Marine Science

66(5)

811-815

The distribution of aquatic animals is severely limited by water temperature. However, little is known about migration pattern, over-wintering and reproduction at the northern limits of their distribution. To investigate the sexual maturation of the Japanese pygmy squid (Idiosepius paradoxus) and its ability to survive during winter at the northern limits of its distribution, we conducted monthly collections at Usujiri in northern Japan and carried out low temperature tolerance experiments. Squids were collected only during four months in autumn and early winter. In autumn, all squids were large and sexually mature, and many egg masses were found on the surface of seagrass, whereas in early winter, only small immature squids were collected. A warm northward-flowing current reached near Usujiri in autumn. These results suggest that squids were transported by the current and some small squids were recruits that hatched at Usujiri. Field data and low temperature tolerance experiments showed that I. paradoxus can not survive in the low seawater temperature that occurs at Usujiri in winter. The migration pattern in I. paradoxus may differ from the major pattern where young fish are passively transported and never reproduce at the northern limits.

学術雑誌論文

Accepted Manuscript

This is a pre-copy-editing, author-produced PDF of an article accepted for publication in ICES Journal of Marine Science following peer review. The definitive publisher-authenticated version 66(5):811-815, June 2009 is available online at: http://dx.doi.org/10.1093/icesjms/fsp145

1054-3139