Publication Abstract

Scaling from physiology to ecology: the sensitivity of population dynamics to acidification effects on reproduction and early development.

 

Physiological studies on the effects of ocean acidification (OA) have lead to concern over possible negative impacts of OA on marine ecosystem dynamics and the goods and services society derives from the oceans, such as commercial fisheries. However, whilst the effects of acidification operate at the cellular level, it is the expression of these effects at the population, community and ecosystem level that are of societal concern. Scaling from physiological studies to population and ecosystem level effects requires explicit consideration of ecology as well as physiology.

Experimental studies suggest that reproduction and early development are particularly sensitive to physiological impacts of ocean acidification. Within fisheries modelling and assessment reproduction and early developmental stages are typically considered within the context of stock-recruitment (S-R) relationships. This study examines the ability of commonly applied S-R relationships to emulate acidification effects and the potential implications for population dynamics, fishery productivity and management reference points.

The two most commonly applied S-R relationships are the Beverton-Holt and Ricker relationships. Key features of these relationships are the maximum larval survival rate and the ‘larval’ carrying capacity of the system. OA could potentially impact both of these features through direct impacts on larval development or indirect impacts on planktonic prey availability. Although impacts on larval survival and carrying capacity can be independently emulated with the Beverton-Holt relationship, these affects can not be independently emulated within the Ricker relationship.

A simple population model incorporating a Beverton-Holt S-R relationship was applied to examine the sensitivity of population dynamics to changes in larval survival or carrying capacity. At full reproductive capacity a population is sensitive to changes in carrying capacity, but relatively insensitive to changes in larval survival. Conversely when reduced below full reproductive capacity, population dynamics become sensitive to changes in larval survival and relatively insensitive to carrying capacity.

W. Le Quesne

European Marine Biology Symposium, Edinburgh, 23-27 Aug 2010.