Newly exploited area (10³ km²) for each latitude class, averaged over each decade.

<p>Newly exploited area defined as ocean cells where primary production required to sustain fisheries catch exceeds the threshold percentage of primary production. Results based on three exploitation thresholds (10%, 20% and 30%) are presented. Black dots at the base of each histogram represent the mean latitude of the distribution. The dots for each exploitation threshold are fitted with a linear regression; jointly, they suggest the southward expansion of 0.7 to 0.9 degree per year.