Long-term collection of benthic and benthopelagic organisms from a deep-water inlet offshore from Okinawa, Japan

Abstract

Deep seawater facilities inadvertently collect organisms from suction inlets and, thus, may serve as unique biological platforms. Organisms collected from a depth of 612 m offshore from Okinawa, Japan, were archived from 2000 to 2006. Of the total of 633 individuals collected, 550 specimens were examined and taxonomically identified; the remaining 83 samples were too seriously damaged to examine. As a result, a total of 63 species were identified, and taxa comprised 34 fishes, 23 crustaceans, 5 mollusks and 1 echinoderm. Although a weak tendency of year-to-year increase in the catch number was apparent, it should be confirmed by monitoring for a longer term. No clear seasonality for the catch number and species composition was observed. A significant decline in the number of the pleurobranchid Pleurobranchella nicobarica and an increase in the benthopelagic holothurian Enypniastes eximia were recorded during the study period; these variations may imply that unspecified environmental changes have occurred. © Inter-Research 2008.