UC Marine Council
Human and Natural Causes of Variation of Forage Species on Nearshore Rocky Reefs
- Author(s): Levenbach, Stuart
- et al.
Rocky reefs along the coast of California provide important habitat for at least 125 species of fish, yet they are heavily impacted by humans. These reefs are naturally dynamic and can change from a forested state with many fish, dense stands of giant kelp and foliose algae and abundant forage food for fish, to unforested "barrens" that are generally lacking in kelp, macroalgae, fish and their forage food. Despite its name, a "barren" reef can support a diversity of habitat types, including patches containing understory foliose algae that harbor small invertebrates used by many fish for food. Depth, rates of sedimentation, topography and other physical factors can be responsible for some of this spatial variation. However, variation in intensity of grazing, mediated by refuges for algae from urchins, could also permit algae to persist on heavily grazed reefs. This proposal outlines research that seeks to identify the natural and anthropogenic factors that influence the distribution and abundance of benthic species assemblages on deforested reefs. Specifically, interactions among algae, invertebrates and fish will be explored, in light of different regimes of sedimentation. The research addresses important issues pertaining to fisheries and management of these important ecosystems.