Publication Abstract

Exploring the sensitivity of fish population dynamics to possible ocean acidification driven changes in recruitment. 

Despite concern about possible impacts of ocean acidification (OA) on fisheries, little work has been conducted on how the physiological effects of OA might scale up to the population and ecosystem level. Although the direct impact of ocean acidification will occur at the cellular level it is the outcomes at the population, community and ecosystem level that are of societal concern. Understanding the potential impact of ocean acidification on fisheries requires extending beyond physiology to ecology and socio-economics.

Reproduction and early life stages have been identified as being particularly sensitive to OA. Acidification induced declines in fertilisation or larval development success would lead to a reduction in population reproductive output, so what would be the potential population level effects?

Within fisheries assessment and modelling reproduction is normally considered in the context of stock-recruitment (S-R) relationships. The most commonly applied of these are the Beverton-Holt and Ricker S-R relationships. This paper examines the ability of these S-R relationships to emulate reproductive acidification effects on population dynamics, and explores the sensitivity of fisheries production and management reference points to possible physiological effects of acidification.

Both relationships could be used to emulate changes in development success and planktonic food availability, however the nature of the Ricker relationship in particular forces specific assumptions about the mechanism of OA effects that may not reflect realistic processes. Fishery yield and management reference points showed a range of linear and non-linear responses to OA varying with assumptions of the mechanisms of effect.