Age determination, reproduction and growth of the sea urchin Hemicentrotus pulcherrimus in Oshoro Bay, Hokkaido, Japan

Yukio Agatsuma, Akifumi Nakata

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

The age of the sea urchin Hemicentrotus pulcherrimus in Oshoro Bay at the northern distributional limit of the species was ascertained by counting black bands in charred genital plates after etching. Consequently, the seasonal growth of two year-classes was monitored and the seasonal changes were related to the reproductive cycle and water temperature. A black band at the edge of the genital plates was found in more than 50% of the sea urchins from September to November. No statistical difference of the test diameter and body weight forming the bands between the estimated and actual values showed that the band is formed annually and can be used as a chronometer. The sea urchin grew rapidly for one and a half months, from late August to late September or early October when water temperature reached a maximum of > 20°C, then began to fall while the gonads increased in size prior to maturation. Growth ceased during October to November with initiation of gonadal maturation and the peak of black band formation in genital plates. Spawning occurred from March to May, later than in southern Japan. The annual cycle of growth and reproduction of H. pulcherrimus may be flexibly adapted to surbarctic waters.

Original languageEnglish
Pages (from-to)401-405
Number of pages5
JournalJournal of the Marine Biological Association of the United Kingdom
Volume84
Issue number2
DOIs
Publication statusPublished - 2004 Apr 1

ASJC Scopus subject areas

  • Aquatic Science

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