The study of fisheries involves far more than fish.  Dynamics that emerge from exploited ecosystems are functions of environmental conditions, biological interactions, and human behavior. I apply a wide range of methodologies to one overarching question: what drives variability in aquatic communities and how can this knowledge be used to improve predictions of change?

Complex dynamics of aquatic communities

Changes in population abundances can happen rapidly and unexpectedly, often imposing serious economic and conservation impacts.  For example, the decline of Atlantic cod during the 1990s cost tens of thousands of jobs and the failure of the fishery to rebound, despite strict catch limits, stymies managers.  My research investigates vulnerability to rapid shifts, quantifies the impact of harvesting on community stability, identifies community-level interactions to inform ecosystem-based management, and quantifies predictability in communities. I use nonlinear time series forecasting models to characterize complexity and produce short-term population forecasts for fisheries.

Socio-ecological feedbacks in fishery systems

Over 1 billion people depend on fish for protein, and fisheries provide employment for hundreds of millions.  Fisheries represent complex systems of human and natural interactions: fishing effort is shaped by economic, political, and regulatory concerns, while the number of fish caught is driven by climatic, biological, and technological variables.  I seek to understand the feedbacks that shape fisheries systems, from natural variation in fish abundance to the effect of market forces on fisher behavior to the role of fisheries resources in social wellbeing. Dr. Cullen Hendrix (Korbel School of International Studies, University of Denver) and I are exploring these relationships in East Africa.  Our research is funded by a NSF Coupled Natural-Human Systems grant.  In collaboration with the National Fisheries Resources Research Institute (NaFIRRI) in Uganda and Dr. Les Kaufman (University of Boston), we seek to understand links between fisheries, food security and civil conflict in the Lake Victoria basin.  (read more…)

Food web ecology and predator-prey dynamics

A third branch of my research investigates top-down effects of predation and changes in diet diversity through time.  As the relative abundances of prey species in aquatic communities change, we must predict whether and how predator diet will change.  Diet studies are especially useful in poorly observed systems, such as aquatic environments, where interaction strengths are difficult to quantify. I combine field data collection, statistical analyses, bioenergetic models, and population dynamics models to investigate the impact predators have on the systems in which they forage.  My research examines:

– Temporal and spatial variability in diet
– The impact of prey quality on predator     foraging effort
– Prey regulation through top-down mechanisms
– Predator decisions given variable prey and environmental conditions