EVOLUTION OF THE LIFE-HISTORY OF ARCTIC CHARR SALVELINUS-ALPINUS

Arctic chaff Salvelinus alpinus life histories are very variable, both within and between localities. In some lakes we find more than one ph enotype (in Lake Thingvallavatn there are four), each phenotype having a characteristic life history. In spite of this, the life histories o f 44 populations of Arctic chaff from throughout its range of distribu tion can be described accurately by a number of dimensionless indices made up from some common life-history descriptors (age and length at m aturity, theoretical maximal length, instantaneous rate of natural mor tality). This is contrary to what we previously have found for Brown t rout Salmo trutta and we discuss this difference. We also test a new m odel which seeks to predict reproductive effort based on information o n relative length at maturity (L(alpha))/L(inf)) and age at maturity. The model did not fit the observed reproductive investment data.