Abstract
Spatial and temporal variation in the growth of a widely distributed temperate marine herbivore, Girella elevata, was examined using length-at-age data and multi-decadal otolith increment growth chronologies. In total 927 G. elevata were collected from three regions of the Australian south-east coast, extending 780km and covering the majority of the East Australian Current, a poleward-flowing western boundary current of the Southern Pacific Gyre and climate change hotspot. A validated ageing method using sectioned sagittal otoliths was developed to enumerate both daily (juvenile fish) and annual otolith increments. G. elevata exhibited great longevity with a maximum recorded age of 45+yrs. Spatial variation in growth from length-at-age data was observed with the highest growth rates within the centre of the species distribution. Analysis of otolith growth chronologies of 33yrs showed a positive relationship with the Southern Oscillation Index. Identifying links between life-history characteristics and variation in oceanographic conditions across latitudinal gradients may shed light on potential impacts of expected climate shifts on fish productivity.
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