SHORT COMMUNICATION THE ROLE OF THE PECTORAL FINS IN STATION-HOLDING OF ATLANTIC SALMON PARR (SALMO SALAR L.)

• Main Authors: G. P. Arnold, Paul W. Webb, B. H. Holford
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1990
• Subjects: Yama; Atlantic salmon; Salmo salar
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.5550; http://jeb.biologists.org/content/156/1/625.full.pdf

Benthic fish resist downstream displacement in a current by balancing drag, the force orientated downstream, with the friction force. The friction force is n(Wo—L), where n is the friction coefficient, Wo the weight force of the fish in water (N), and L the lift force (N) acting on the body and fins (Arnold and Weihs, 1978). Above a critical speed, friction is insufficient to counteract drag and the fish must either swim or seek shelter from the flow. This note reports tests of the commonly proposed hypothesis (e.g. Kalleberg, 1958; Keenleyside and Yama-moto, 1962; Jones, 1975; Wankowski, 1981) that the pectoral fins are important to station-holding in Atlantic salmon, acting as hydrofoils generating negative lift. Parr were obtained by electrofishing in the River Frome and were transported by road to Lowestoft in insulated containers. Fish were held in tanks with an underwater gravel filter, continuously aerated and flushed with water at 10-11 °C. Parr were fed daily on chopped fish. Station-holding parr were observed in a flume (Arnold, 1969) on both a smooth (Perspex) and a rough substratum. The rough substratum was subrounded gravel