Sustained voluntary swimming speeds of 5 species of juvenile estuarine fish were determined in a laboratory circular flume, 2.5 m in mean circumference. Successful tests depended on the fish's ability to avoid downstream displacement through positive rheotaxis. The following swimming speeds, in body lengths (BLjsec, were measured: 3 to 6 em Atlantic menhaden (Brcvoortia tyrannus), the species of primary interest, swam 5 (at 13 C) to 11 (at 30 C) BLjsec; striped mullet (Mugil cephalus), 3 em, swam 8 (at 15 C) to 12 (at 25 C) BLjsec; pinfish (Lagodon rhomboides), 4 em, swam 11 BLjsec (27 C); spot (Leiostomus xanthurus), 4 em, swam 6 BLjsec (25 C); Atlantic croaker (Micropogon undulatus), 7 em, swam 5 BLjsec (30 C). An evaluation of the apparatus and implications of the data for predicting impingement of juveniles on power plant intake screens are included.
