Age and longevity in fish, with consideration of the ferox trout

In the first part of this paper, we review the evolutionary aspects of age and longevity in fish and then summarize the theory of maturity due to Ray Beverton. This theory allows one to predict age at maturity (and thus a put ative point for the onset of senescence) from information on growth rate an d mortality rate. We illustrate the application of this theory with data on tilapia species and then discuss the limitations of the theory. In the sec ond part of the paper, we develop an individual based model for the ferox t rout. This is a morph of brown trout Salmo salar that is an exception to th e common notion that caloric restriction extends lifespan, in the sense tha t ferox trout achieve long life by eating more, not less. The model allows one to identify the role that ecological and biochemical adaptations play i n the longevity of the ferox trout. (C) 2001 Elsevier Science Ltd All right s reserved.