| |
Assessing the biological impacts of groundfish surveys: a
metapopulation approach
Derek Olson*
Research Abstract
Adequately
monitoring the health of depleted fish stocks is crucial to the
development and evaluation of rebuilding strategies, as well as to
the prevention of additional stock collapses. It is also critical,
however, for monitoring programs to be as minimally invasive to
populations as possible so as to avoid compounding the problem of
depletion. Unfortunately, the spatially structured and patchy
distribution of some depleted stocks may pose challenges to
reconciling these competing objectives in the design of broad-scale
surveys. To appropriately balance information quality/quantity and
biological impact requires a critical evaluation of alternative
sampling strategies under a variety of scenarios of depletion and
stock structure. I propose to create a series of simulated fish metapopulations using the systems dynamics modeling software STELLA,
each characterized by a particular spatial structure, overall
abundance, dispersal rate, and suite of demographic parameters.
Metapopulations differing incrementally in each of these attributes
will be subject to a range of simulated sampling regimes, assessing
both the relative statistical performance and comparative biological
impact of the alternatives. This work follows increasing awareness
of the metapopulation nature of many fish stocks and of the
consequent need for attention directed toward the individual
subpopulations that comprise a stock. The results will help identify
survey programs that have low biological impacts on fish
populations, yet are effective for monitoring Gulf of Maine
groundfish.
*
Derek Olson is also a research assistant collaborating with the
Downeast Initiative
Back to Home page
|
|
