Towards a Predictive Framework of Habitat Enhancement

Effectively managing fish populations in aging reservoirs is a Grand Challenge in Fisheries.  A common symptom of older reservoirs is the loss of structural habitat (trees, brush, etc.), and a common management response is to add natural and/or artificial habitat.  Despite a long history of habitat additions into reservoirs, the age-old question remains “do habitat additions attract existing fish or increase fish productivity (abundance, growth rates, maximum sizes, etc.)?”  We argue that this is the wrong question to ask when evaluating habitat enhancement projects.  Fish attraction is well documented in the previous research; we know that younger reservoirs with strong habitat infrastructure support increased production of fishes.  Therefore, we are developing a framework for habitat enhancement that predicts the quantity of habitat needed to affect change in a population.  We will discuss the theoretical framework of our proposed “habitat curve,” and describe ongoing field experiments to test these ideas.  Development of a predictive framework for habitat enhancement will provide strategic benchmarks for reservoir habitat projects.