Selena McMillan

image of Selena McMillan with kelp


As a marine ecologist, I am interested in the trophic interactions between primary producers and their consumers. Interactions between the giant kelp, Macrocystis pyrifera, and its grazers is a subject well studied in southern California, but greatly overlooked in central California. However, an understanding of the strength of trophic interactions is essential to determine the overall dynamics of the kelp forest community.

Studies of grazing on the giant kelp Macrocystis pyrifera have mainly focused on conspicuous herbivores such as abalone and urchins that can devour entire kelp forests. The purpose of my study is to evaluate how the most abundant kelp forest herbivore in central California, the turban snail (formally of the genus Tegula), affects the productivity, reproductive output, and survivorship of Macrocystis pyrifera within central Californian giant kelp forests. Three turban snail species Promartynia pulligoChlorostoma montereyi and C. brunnea, preferentially graze Macrocystis in this region. The effects of these grazers were investigated using experimental field manipulations of Macrocystis sporophytes at Stillwater Cove, Carmel, California. By comparing ten treatment levels of Macrocystis (sporophytes stocked with a gradient of lesser to greater densities of C. brunnea), differences in growth rate, sporophyll production, and mortality were analyzed.

image of Chlorostoma grazing kelp

 This project represents the first study of grazing on whole-sporophyte physiology in central California. The research will increase the understanding of the interactions between the Chlorostoma brunnea and its preferred food source, Macrocystis pyrifera. With this information, conclusions may be drawn regarding the importance these intermediate-sized predators have in regulating kelp density and what role they may have in the overall health of Macrocystis pyrifera over time.




Contact info:

Selena McMillan
Moss Landing Marine Laboratories
8272 Moss Landing Rd.
Moss Landing, CA 95039-9647
Phone #: 831-771-4421
Fax #: 831-632-4403