Skip to main content Accessibility help

Autoecology of the heart urchin, Echinocardium cordatum, in the muddy sediment of the Seto Inland Sea, Japan

  • Yasuo Nakamura (a1)

Population density, biomass, seasonal growth and gonad index of the heart urchin Echinocardium cordatum were monitored in muddy sediments of the Seto Inland Sea, Japan, from July 1998 to July 2000. Rates of sediment ingestion by the urchin were also measured. Juveniles settled in winter and their growth in the first year was rapid. Individual somatic mass in terms of ash-free dry weight (AFDW) increased from about 0·1 to 40 mg while the test length increased from about 2 to 20 mm. At the end of the second and third year (early December), somatic mass averaged 90 and 120 mg AFDW (test length=30 and 33 mm), respectively. The gonads of both year-classes matured during this period and spawning followed within two months. Individual E. cordatum (test length=29–34 mm) ingested sediments at rates of 14–43 mg wet weight per hour. Population density (28 m−2) and AFDW biomass (2·8 g m−2) of E. cordatum (test length [ges ]15 mm) were high at the start of monitoring (July 1998), remained relatively constant through the next spring and rapidly decreased to <2 m−2 and <0·2 g AFDW m−2, respectively, by December 1999. When abundant, E. cordatum comprised about 60% of the macrobenthic biomass in the study area and its annual production in AFDW reached about 1·5 g m−2 y−1, suggesting substantial contributions of the urchin in material cycling through the sediments.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of the Marine Biological Association of the United Kingdom
  • ISSN: 0025-3154
  • EISSN: 1469-7769
  • URL: /core/journals/journal-of-the-marine-biological-association-of-the-united-kingdom
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed