Simple solutions to complex problems in fisheries

Event date: Thursday, June 05, 2014, at 12:00 PM
Location: RW 432

Speaker:  Matthew Burgess

Host:  Mark Fitzpatrick <mark.fitzpatrick@utoronto.ca>

Fisheries science faces a challenging combination of complexity and data
limitation that often leads to disconnects between theoretical research -
which seeks to capture as much complexity as possible - and empirical
research - which is constrained to the simplicity of the available data.
In this volume, I present studies aiming to reconcile theoretical and
empirical approaches to assessing the current status of fished populations
and designing management plans in two ways: i) by using concise mechanistic
theories rooted in measurable parameters to develop new predictive
assessment tools; and ii) by using ecological and economic theory to
develop insights whose applications are not data-dependent or system
specific.  My research provides several important insights for assessment
and management in fisheries: 1) Combinations of biological and
socioeconomic conditions that eventually lead to extinction or overfishing
can often be empirically identified decades before high harvest rates and
large population declines occur, allowing for preventative management. 2)
Though there is concern that harvest value which rises as a harvested
species is depleted can lead to its profitable extinction, this threat most
often also requires catch-rates to be substantially robust to declining
abundance.  Because range contraction often buffers population densities
against abundance declines, habitat destruction may exacerbate threats of
overharvesting. 3) Assessments based on single-species population models in
multispecies fisheries can often provide reliable estimates of sustainable
yields and harvest rates in populations with high vulnerability to
overfishing, but often significantly overestimate sustainable yields and
harvest rates in populations with lower vulnerability.  However,
single-species assessment frameworks can nonetheless be used to identify
conditions leading to such bias, and estimate bounds on its magnitude.  4)
Diversification of fishing fleets often leads to fewer population collapses
in both managed and un-managed fisheries; and increases the positive impact
management can make on fishery yields and profits.  The studies in this
volume provide new perspectives on theoretical-empirical synergies in
fisheries research, and maximizing the information value of fisheries data
through theoretical concision and ecological abstraction.