Growth and Mortality of Post-larval Echinoids

Growth and mortality rates and maximum sizes are examined for 16 urchin species using, primarily, values from the literature. A positive correlation exists between the Brody-Bertalanffy growth constant K and the instantaneous natural mortality rate M: those urchins which approach maximum size very rapidly also have a high mortality rate. It is proposed that this relationship is the result of the way particular species allocate resources. Those species in which individuals grow rapidly and expend a large fraction of their resources on reproduction have less to spend on maintenance. The result of this allocation is that these individuals suffer a decreased probability of survival. Predictable recruitment success is suggested as the factor which determines whether a species can persist with fast rowth and short life.