The effects of temperature on ''S-strike'' feeding of larval herring, Clupea harengus L.

Both Manx autumn-spawning and Clyde spring-spawning stocks of Atlantic herring were reared at a range of temperatures (Manx 10 and 13 degrees C; Clyde 5, 8 and 12 degrees C). The behaviour of larvae, feeding on Artemia nauplii at a range of test temperatures (7.0, 10.0 and 13.0 degrees C for Manx and 6.8, 9.3 and 13.0 degrees C for Clyde herring) was recorded using a high speed video system at 200 frames per second. The maximum velocities of feeding 'S-strikes' (measured during frame-by-frame analyses) were positively correlated with body length, capture time and attack distance. In contrast to burst swimming speeds reported elsewhere, strike velocities showed only a weak relationship with test temperature. Both strike behaviour and velocity altered as larvae developed and both were modified by rearing temperature.