Fishing for climate: establishing a harvest industry on a range-extender to protect a reef ecosystem

The climate driven range extension of the Longspined Sea Urchin, Centrostephanus rodgersii, in south-eastern Australia led to the establishment of a population off the island state of Tasmania to increase from zero to almost 20 million within four decades. Extensive overgrazing resulted in 15% of the eastern coast becoming unproductive urchin barren, with predictions barrens could increase to more than 50%. Commercial fishing has become the champion control measure, with harvest subsidies applied as a key tool to accelerate the industry. Catches of this range extending species have increased to in-excess of 400 t pa; Tasmania’s third largest wild harvest fishery. Habitat recovery in some heavily fished areas is now being documented. The pros and cons of commercial fishing as a control measure of an invasive species are discussed, as are the strategic industry manipulation measures available to maximise ecosystem benefits. Spatially variable subsides can be successfully applied to direct fishing activity to areas of ecological, commercial and recreational importance, while ‘Take-All’ harvests (including the removal of “undersized” individuals) can be used as a tool to maximise ecological benefits. While commercial fishing is seen as the primary control measure, the importance of the integration of a suite of control measures to address fishery limitations and maximise ecological benefit is discussed.