Abstract
The bioturbation rate of a tube-building maldanid polychaete, Eulymene sp., collected in Koajiro Bay, was measured by a video observation system. The length and volume of fecal pellets, and defecation interval were measured from more than 80h of video records taken for 17 specimens. Thus, the defecation rate was estimated as 782mm3 day-1 worm-1 for each individual. From the results of observations and the density of the worms in the field, the bioturbation rates in situ were estimated. At a station in Koajiro Bay, the amount of sediment reworked by a population of this species was estimated as 291.84cm3m-2 day-1 in August, 1992. This would amount to a cover about 0.292 mm thick on the bottom sediment. The bioturbation rate of this species was middle level in Japanese littoral waters.
