Latitudinal variation in life-history traits in Eurasian perch

Few studies have examined multiple life-history traits across a latitudinal gradient to test whether variation in growth rate and mortality schedules induces trends predicted by life-history theory. We collected data for the following life-history traits for 75 Eurasian perch (Perca fluviatilis) Populations: growth coefficient (K) and asymptotic body length (L-infinity) from the von Bertalanffy growth model, size at ages one and two years, specific juvenile growth rate, instantaneous adult and juvenile mortality rates, life span, age and length at maturity, and reproductive life span and investment. All life-history traits except L-infinity were significantly correlated with latitude. In general, growth rates, mortality rates, and reproductive investment decreased with latitude, whereas age at maturity, size at maturity, and life span increased with latitude. Populations could be grouped into two categories based on variation in L-infinity: stunted (small sized) vs. piscivorous (large sized). Four trait-latitude relationships differed between these two types: the growth coefficient (K) and the juvenile growth rate were larger, and age and length at maturity were lower in the stunted populations compared with piscivorous populations. Perch from southern populations tend to grow fast and experience high juvenile and adult mortality rates. As predicted from life-history theory, this selects for an early age and small size at maturity and relatively large investment in reproduction. The opposite pattern was found for northern populations.