Small schooling fish require carefully tailored management to balance catches and collapse risks

Forage fish are small, densely schooling fish at the heart of many marine ecosystems. These fish, including sardines, anchovies, menhaden and their kin, consume tremendous quantities of plankton and also provide abundant food for top marine predators such as larger fish and whales. A key characteristic of these species is their dramatic fluctuation in numbers between high “bonanza” periods and low “collapse” periods, which make them hard to manage. A new study now looks at which kinds of management rules offer the best trade-offs between high and stable catches and minimizing the risk of collapses. It turns out that aiming for stable catches results in more severe collapses, and that early detection of impending collapse is of great importance in averting bad outcomes in terms of catches and collapses. Furthermore, no single management rule was appropriate for all forage fish species. Instead, rules need to be tailored for each species individually. The new paper appears in the journal Fish and Fisheries and was authored by SAFS PhD student and current postdoc Margaret Siple, SAFS professor Timothy Essington, and CSIRO scientist Éva Plagányi.

The management strategy evaluation approach simulates both the management rule and the underlying changes in numbers of the fished population.

 

 

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