Development of a new field-based approach for estimating consumption rates of fishes and comparison with a bioenergetics model for lingcod (Ophiodon elongatus)

Abstract

Development of quantitative tools to characterize the nature of predator–prey interactions is an essential component of the science supporting ecosystem-based management and conservation. A common constraint is our capacity to estimate the feeding rates of fishes at the temporal and spatial scales at which predation occurs. This study developed a new field-based modeling approach for estimating consumption rates of large predatory fishes that requires fewer assumptions and may be more flexible than other field-based methods. We compared the field-based model results with consumption estimates from a bioenergetics model for lingcod ( Ophiodon elongatus ), a top predator in nearshore rocky habitats along the west coast of North America. The models were used to determine population-level consumption of rockfishes ( Sebastes spp.) by lingcod in marine reserves and nonreserve areas in the San Juan Channel, Washington, USA. Based on these models, rockfish consumption by lingcod may have been 5–10 times greater in marine reserves than in nonreserves during fall and summer, 2005–2007. Understanding whether lingcod predation may limit the efficacy of marine reserves for rockfish recovery requires site-specific information on the abundance and size structure of lingcod and rockfishes.