Determining climate-growth relationships in a temperate fish: a sclerochronological approach

Otoliths of fish can provide long-term chronologies of growth. Differences in the width of the annual growth increments can reflect the effects of environmental variability on somatic growth rate. We used generalized linear mixed models (GLMM) to evaluate the influence of region, sea surface temperature (SST), El Niño–Southern Oscillation events, and recruitment on the otolith growth of King George whiting (Sillaginodes punctatus), a commercially and recreationally important fish species in southern Australia. Growth increment data spanned 25 years (1985–2010). The optimal model demonstrated that mean winter SST was negatively correlated to growth, and as the winter SST increased the average width of the growth increments declined. However, the temperature effect was very weak (r²: 0.0006). There were no regional growth differences and recruitment was not correlated with growth. Understanding long-term temperature-growth relationships is crucial for disentangling the effects of climate change and other parameters on fish growth, and thus predicting how populations will change in the future.