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Bio

Presentation

Paper

Travis MacKenzie
Northwest Missouri State University

Subject Listing - Biology
Advisor: Dr. Peter Kondrashov

Saturday, Oral Session 7, Presentation 5, Karpen Hall 103

DISTRIBUTION OF GASTROPOD MOLLUSKS ON THE INTERTIDAL ZONE OF VANCOUVER ISLAND, CANADA

Over time gastropod mollusk faunas have gone through significant changes caused by non-biotic and anthropogenic factors. This study documents species diversity, ecological preferences, and intraspecific shell variation of native and invasive species of gastropod mollusks in the intertidal zone along the coasts of Vancouver Island, Canada. I collected samples of over 20 species representing eight orders and thirteen families of gastropod mollusks from eight localities. In order to document the species distribution and shell variability, the samples were cleaned, sorted by locality and then shells were identified and measured. An array of localities was sampled in order to understand how the species diversity varied in different habitats. Extensive intraspecific shell variation was documented in three species of gastropod mollusks: Littorina scutulata, L. sitkana and Nucella emarginata. Two species, Littorina scutulata and L. sitkana, were the most abundant gastropod mollusks at all the localities. Both Littorinas showed variation in color and sculpture. Nucella emarginata varied in color (including the presence or absence of spiral bands) and in the development of spiral ribs which were often reduced. Along with the native species of gastropods I discovered an invasive species, Batillara attramentaria (Japanese false cerith), in the intertidal mud flats of Comox harbor and Royston beach. Originally this species was only found in Japan and the Western Pacific, but had been brought to North America in the early 20th century with the import of the pacific oyster. Batillara attramentaria was abundant at both localities. In contrary, the native representatives of Cerithiidae, which are usually found in the same type of habitat, were extremely scarce or absent at these localities. As our study shows, the native gastropod mollusk fauna of Vancouver Island, Canada, is very diverse and abundant, but an introduction of a non-native species could jeopardize the stability of native mollusk populations.

Advisor: Dr. Peter Kondrashov, Assistant Professor, Biological Sciences, Northwest Missouri State University, Maryville, MO