The abundance of food organisms and feeding habits of larval and juvenile Japanese flounder were examined during the period from May to August in 1999August in , 2000August in and 2001 at the sandy Ohama beach, the central Seto Inland Sea. The food organisms collected with a sledge net consisted of 40 families from 18 orders, dominated by mysids, crangonids and gammarids. The mean densities of mysids, crangonid shrimp (Crangon spp.), gammarids and fish were 2.74, 6.74, 2.91 and 0.15 individuals/m 2 , respectively. The main prey of the flounder (n = 202; range of total length 9.80-75.95 mm) was mysids and small crangonid shrimp (<14 mm in body length). Prey fish availability was low, as the density of fish was low. The small crangonid shrimp was abundant, and the large crangonid shrimp, which could prey on larval flounder, was not abundant. The crangonid shrimp was important not as a predator for the flounder but as prey. The flounder preferred epifaunal mysids, Nipponomysis ornata and Anisomysis ijimai, to sand-burrowing mysids, Iiella oshimai, and avoided crangonid shrimp.

The occurrence and distribution of larval and juvenile Japanese flounder Paralichthys olivaceus and major demersal fish from May to September were examined at seven sandy beaches at the central Seto Inland Sea. The flounder appeared from late May to August and were mainly collected at a depth of 2-5 m. Settlement of larval flounder was seen from late May to late June. A total of 6412 individuals of 17 species representing 12 families were collected in the study area. The dominant fish species were Favonigobius gymnauchen (56.0%), Tarphops oligolepis (8.1%), Rudarius ercodes (7.8%), P. olivaceus (7.3%), Repomucenus spp. (7.0%) and Heteromycteris japonica (3.3%). The catches of flounder differed among beaches and months. The number of flounder in June at Ohama Beach, where the most flounder were collected, was 22.6 individuals per haul (400 m 2 ). The density of the flounder correlated negatively to that of F. gymnauchen.