Lee's phenomenon in the western subspecies of the Australian salmon, Arripis trutta esper

Abstract

Lee's phenomenon is apparent in scale readings of the western subspecies of A. trutta esper. A hypothesis involving a progressive eastward decrease in growth rate of fish from juvenile areas coupled with the progressive entry of these fish into the adult fishing area is advanced to explain the appearance of the phenomenon.

The phenomenon can be included under the effects of biased sampling, although not in the normally accepted sense. Here it is apparently caused in the adult fishery by the selective arrival of fish with progressively slower growth rates, and in juvenile areas by the selective departure of faster-growing fish.

If the hypothesis is correct this type of situation may occur in other species exhibiting a cline in growth rate that migrate from nursery areas to a separate spawning or adult area.