The identification of the spatial boundaries of exploited stocks is a fundamental requirement before any assessment or modelling can be contemplated, and therefore lies at the basis of resource management. SIMWG was established in order to:
review new methods for the definition and investigation of stock structure,
update and disseminate findings on stocks relevant to the ICES remits
provide other ICES expert groups with advice on how to interpret patterns of population structure based on currently available data
Traditionally, exploited stocks have been assessed and managed according to geographical features and ICES subdivisions (e.g. "lines on a map"), in order to facilitate decision-making and agreements among countries. As more research is conducted, it is evident that only a fraction of exploited resources are organized, through space and time, according to such subdivisions. In reality, biological stocks are far more dynamic and complex. SIMWG work is aimed at minimizing mismatches between true biological stocks and traditionally perceived management areas. Its contribution strives to play a significant role in the formulation of improved approaches to define stock units and promote evidence-based management approaches.
For decades, scientists of diverse backgrounds have proposed – and successfully employed – a wealth of methodologies to identify biological units in space and time. For this reason, SIMWG members include a number of experts in disciplines such as ecology, genetics, life-histories, tagging, chemistry, morphometrics, sclerochronology, parasitology and statistics. The biodiversity of fish is such that different blends of methodological approaches are necessary to comprehend the nature of spatial structure of the hundreds of species subjected to exploitation. Given the reliance upon so many techniques and philosophies – as well as their integration – stock identification is a field in rapid advancement. In 2013, a new edition of the book Stock Identification Methods: Applications in Fishery Science will be published, representing the state-of-the-art of the discipline.
The participants of the 2015 SIMWG meeting in Portland. From left to right: David Secor, Richard McBride, Greg Decelles, Christoph Stransky, Steven Cadrin, Stefano Mariani, Lisa Kerr, Doug Zemeckis.