Endurance at intermediate swimming speeds of Atlantic mackerel, <i>Scomber scombrus</i> L., herring, <i>Clupea harengus</i> L., and saithe, <i>Pollachius virens</i> L.

Abstract

Endurance and swimming speed were measured in mackerel, herring and saithe when they were induced by the optomotor response to swim at prolonged speeds along a 28‐m circular track through still water in a 10‐m diameter gantry tank. The maximum sustained swimming speed ( U ms was measured as body lengths per second ( b.l.s −1 ) for each species and for saithe of different size groups. Herring with U ms of 4.06 b.l.s −1 (25.3 cm, 13.5°C) were the fastest, mackerel U ms was 3.5 b.l.s 1 (33 cm, 11.7°C) and saithe (14.4°C) showed a size effect where U ms at 25 cm was 3.5 b.l.s 1 and at 50 cm 2.2 b.l.s 1 . When swimming at speeds higher that U ms , all three species showed reduced endurance as speed increased. How the curved track reduces the swimming speed is discussed.