Will SPR analysis help assess blue warehou?

22nd April 2013

An Australian breakthrough in stock assessment science looks to solve the problem of assessing data-poor fisheries and make assessment processes affordable. The approach estimates the proportion of spawning occurring relative to unfished levels rather than estimating sustainable catch levels directly, simply indicates whether fishing pressure should be incrementally increased or decreased until stocks and catches stabilize at management targets. The technique makes assessment possible with information about average maximum size, or size of maturity, and current size composition. Eliminating the need for information about stock structure, catch rate trends and biomass estimates the new approach promises to slash the cost of fisheries assessments worldwide.

Blue warehou is one of the three stocks (of more than 30 commercial stocks in total) in the fishery with a quota set that only allows unavoidable by-catch.  No targetting is allowed until the stock rebuilds.  Industry has worked to avoid blue warehou and CSIRO confirms that an analsysis of the fishery shows less and less targeting.  However, no targetted fishing means that it is very difficult to assess the stock’s abundance.  Thousands of length/frequencies collected by industry, the observer program and on previous fishery surveys may have the potential to feed into a future SPR analysis and provide a trend in abundance.

For more information on SPR analysis contact Dr Jeremy Prince.