Impact of environmental temperature on the lifespan of octopods

Recent studies on the life history of cephalopods have challenged the paradigm that all coleoid cephalopods have a single reproductive cycle and a short lifespan. Although lifespan has been investigated in several octopod species, few studies have considered their life-history traits in relation to environmental conditions via a comparative approach. We tested the hypothesis that octopod lifespan is correlated with habitat characteristics. For that purpose, life history and environmental data of 25 incirrate octopod species and the vampire squid Vampyroteuthis infernails were compiled from the literature. Regression analysis showed that the relationship between age at maturity and average habitat temperature was best described by a negative power function (r(2) = 0.86). The depth ranges of occurrence (minimum-midpoint-maximum) were positively correlated with time to reach maturity, with maximum depth showing the best fit (r(2) = 0.47). Using literature data and our analyses, we estimated that octopods living in polar and deep seas mature after 3 to 5 yr. The reviewed and estimated instantaneous relative growth rates ranged from 0.1% body weight (BW) d(-1) in the Antarctic species Pareledone charcoti to nearly 6% BW d(-1) in the temperate species Macroctopus maorum. Our analyses suggest that low water temperatures (<5 degrees C) result in an extended ontogenetic development, potentially as a result of reduced metabolic rates and constraints on protein synthesis, which increases the lifespan of octopods living in cold environments.