- The Japanese Society of Fisheries Science
- Fisheries science (ISSN:09199268)
- vol.68, no.1, pp.104-116, 2002 (Released:2009-03-31)
The predation pressure on the siphons of the bivalve Nuttallia olivacea by the juvenile stone flounder Platichthys bicoloratus in the Natori River estuary, Miyagi, was estimated from both sides of the predator-prey relationship to analyze the specific relationship in which predators remove a part of the prey. Feeding experiments determined the feeding rate required to achieve the growth of juvenile stone flounders in the field. A juvenile cropped siphon tips at a mean of 56 per day from March to early July. The siphon tips that a juvenile consumed in a season amounted to 6375 pieces (6.2 g). In terms of predation, the duration since the last cropping in the field from the regeneration of cropped siphons was analyzed. The mean cropping rate of 0.211 times a day per clam in an area of intensive predation indicated that a clam was cropped 25.8 times (22.1 mg) in a season by fishes. The mean cropping rate by juvenile stone flounders was estimated to be 0.160 times a day. Of the 25.8 croppings, 19.5 (16.9 of the 22.1 mg) could be attributed to juvenile stone flounders. The results proved that a juvenile stone flounder preyed on approximately 370 clams in a season.