Rhythmic Distribution Patterns due to the (Diel and Tidal Cycle) of the Megabenthic Animals on a Jangbongdo Macrotidal Flat, Incheon, Korea.

초록

Temporal fluctuations of abundance in macro- and megabenthic animals were studied in intertidal area. Trawling was performed to examine the community structure and rhythmic (diel and tidal) distribution patterns in the megafaunal assemblages on the Jangbongdo tidal flat, Incheon, Korea. Trawl tows every 3h throughout 24h tidal cycles and megabenthos were sampled on the extensive intertidal flats. The fauna were collected by modified otter trawl and sampling from 8 to 9, June 2000. The macro- and megabenthic animals comprised a total of 60 species, including 6,309 individualds and 67,835 gWWt in biomass. As a result, we found somewhat rhythmicity of species composition and abundances. The abundance patterns showed two different categories relating to diel (day/night) and tidal (ebb/flood) cycle. Especially, in terms of day/night sampling, dominant species fall into 3 categories ; 1) nocturnal species seen only or mostly at night (the Crangonid and Penaeid shrimps, the Portunid crabs, and the Scorpaenid fishes) 2) diurnal species seen only or mostly during the day (the Loliginid cephalopods, and the Engraulid fishes) 3) species showing no obvious pattern with the Sciaenids, Hexagrammids, and Callionymids fishes, and the Temnopleurid echinoderms.