Russell Markel

My dissertation examines the effects of over-exploitation of marine predators on nearshore food web structure, dynamics, and productivity. I am focusing on what I call the collateral effects of trophic cascades on nearshore fish communities resulting from sea otter predation via changes in grazer and kelp populations. This research is based on evidence that extirpation of sea otters significantly decreases regional-scale production of kelp and other macroalgae through dramatic expansion of sea urchin populations. Kelps provide important habitat for many ecologically and economically important fishes and fuel parallel food chains through production of detritus. The objective of my research is to quantify how recovery of kelp forests following sea otter re-introduction affects the population dynamics of organisms that depend on kelp for structurally complex habitat and/or kelp-derived detritus for some portion of their life history. The organisms that I am focusing on to investigate and quantify the ‘kelp effect’ are the nearshore Pacific rockfishes (Genus Sebastes).