Climatic effects on the growth of a temperate reef fish from the Southern Hemisphere: A biochronological approach

Increments in the hard parts of marine organisms (otoliths, skeletons, shells) can provide long-term chronologies of growth analogous to tree rings. For the first time in the Southern Hemisphere, we use a dendrochronological (tree-ring analysis) approach to develop a multidecadal chronology of growth for a temperate reef fish, Girella tricuspidata, from the coast of northern New Zealand. Growth patterns in the otoliths of this species were strongly synchronous among individual fish over a period spanning 27 years (1980-2006). We then compared our otolith chronology to climatic records and found strong positive correlations of growth with sea surface temperature, and weak negative correlations with the multivariate El Nino Southern Oscillation (ENSO) index. Strongest correlations were found between summer sea surface temperature and otolith growth. This relationship was consistent across all years and explained 44 % of the variation (y = -2.0 + 0.1785 × temperature, r ² = 0.4367, P = 0.0002) in the G. tricuspidata growth chronology. Our study illustrates how otolith chronologies provide remarkable records of annual growth patterns over decadal time scales that will be useful for forecasting the likely effects of climate change on marine ecosystems.