Ontongeny of feeding between of first-feeding Atlantic salmon (Salmo salar)

Coughlin, D. J.  1991.  Can. J. Fish. Aquat. Sci. 48:1896-1904.


Abstract:

Feeding strikes of Atlantic salmon (Salmo salar) alevins preying upon Daphnia are described using video recording of synchronous lateral and antero-ventral views.  Based on examination of characteristics such as aiming inaccuracy and capture distance, it is demonstrated that feeding behavior significantly improves during the first 2 wk after initiation of exogenous feeding.  With increasing experience, young salmon tend to capture prey more quickly and with greater accuracy.  First-feeding alevins use a body-ram feeding mode, relying on their swimming motion to overtake and capture prey.  After 7-10 d of feeding, the fish change to a suction feeding mode that effectively uses suction generated by expansion of the orobranchial chamber to pull in prey from a distance.  Also, feeding behavior of alevins raised on a commercial salmon feed lags developmentally behind the behavior of fish raised on live food.  This lag time is short (2-3 d), indicating that despite reports to the contrary, hatchery-raised fish do not require a long time to learn to capture prey effectively in the wild.