Fri, November 16, 2018 11:00 AM - 12:00 PM AQUATIC ECOSYSTEMS RESEARCH LABORATORY (AERL). Speaker: Prof. Matthew G. Burgess
Assistant Professor
Environmental Studies Program
University of Colorado Boulder
Location: AERL Theatre (120), 2202 Main Mall, UBC
Understanding tradeoffs and synergies between stakeholder objectives is a major focus of environmental science. In fisheries, it is conventional wisdom that ending overfishing of target fish stocks offers a synergy between fishery profits, food production, and the ecological health of these target stocks. In contrast, it is conventional wisdom that there is a tradeoff between maintaining fishery profits and conserving marine mammal, turtle, and bird species caught incidentally as fishery bycatch. Using theoretical and empirical evidence, I will argue that situations exactly opposite to these conventional wisdoms might be common, especially in coastal waters of the developing world. With bycatch, we find that unsustainable mortality on marine mammal, turtle, and bird species often goes hand-in-hand with overfishing of target stocks. Thus, reducing fishing pressure in these fisheries could solve both problems. In contrast, we find that classical single-species models used to manage target stocks can sometimes significantly overestimate the food production available in an ecosystem. Indeed, once species interactions are accounted for, we find that there can be a strong tradeoff between target stock health and food production, because the highest-yielding fishing strategies often involve depleting predator fish. We find less severe ecosystem-level tradeoffs between profit and target stock health, because predators often fetch the highest prices. Our findings carry implications for managing ecosystems for the triple bottom line of economic, social, and ecological objectives. They also offer generalizable lessons about when resource management for multiple objectives can be made simpler, and when additional complexity is needed.