Life history dynamics of the limpet Patelloida alticostata in intertidal and subtidal environments

Abstract

Population dynamics and reproductive biology of the acmaeid limpet Patellojda alticostata were investigated on a rocky intertidal platform and on an adjacent shallow subtidal reef in New South Wales, Australia. The intertidal population had a higher density than the subtidal population. Intensity of recruitment of juveniles to the intertidal region was also greater. Growth rate of individuals was higher in subtidal reqons and inversely correlated with population density. In contrast, mortality rate was pos~tively correlated with density; intertidal individuals had an annual mortality rate of 80 % whilst subbdally this was only 36 %. The maximum and mean sizes of subtidal individuals were therefore much greater than those in the intertidal area. Both populations spawned at similar times of the year: March, May and October. Two different estimations of reproductive effort of individuals from the 2 populahons indicated that individuals had similar investments despite the large differences in other populabon characteristics. It was concluded that this species does not conform to any generalised theory concerning life history patterns. Nonetheless, the discovery of the large flexibility in responses of neighbouring populations will be important in any examination of the role of this species in the structure of the New South Wales marine community.