Open Access Senior Thesis
Bachelor of Arts
Dr. Evie Wieters
2019 Kathy Liu
Many different types of marine benthic herbivores or “grazers” inhabit coastal intertidal zones and play a crucial role in inter- and shallow subtidal ecosystems. Chile has one of the most diverse intertidal zones, but many intertidal grazers are exploited for human consumption. Marine protected areas (MPAs) and marine management and exploitation areas (MEAs) are promising tools for Chile to combat over exploitation of these grazer and other marine resources. This study surveyed the impact of sites with contrasting management on the diversity and abundance of all intertidal grazers and their impact on the size frequency and shell length-body weight allometry of the keyhole limpet Fissurella crassa, the chiton Chiton granosus, the scurrinid limpet Scurria araucana, and the pulmonated limpet Siphonaria lessoni, four of the most abundant intertidal grazers. Data was collected from three sites: an open access site in Las Cruces, Chile, a limited removal management area in El Quisco, Chile, and a no-take marine reserve at the Estación Costera de Investigaciones Marinas (ECIM) in Las Cruces, Chile. Field experiments examined species diversity and abundance at each site and length and weight measurements were also collected from the four previously mentioned species. A total of 6 different families and 21 different species were observed across all sites. Site diversity and the abundance of 17 species among sites were not significantly different. However, the lengths and length-weight relationships of some species were significantly impacted by human disturbance. The results show F. crassa and C. granosus having the lowest abundance in the open access site and the longest lengths in the marine reserve reflecting their exploitation by humans. All species’ individual body weight increased with increasing length as expected, but shell length-body weight allometries varied among sites for F. crassa and C. granosus. Their body mass was highest in the management area or marine reserve suggesting there is a behavior response to management areas needing further research to pinpoint the mechanism. This study demonstrates that protected marine areas have the potential to be greatly beneficial, especially to exploited species, but their creation is not enough, they need to also be effectively managed and enforced.
Liu, Kathy, "Role of managed marine areas on the diversity and individual responses of rocky intertidal shore grazers in Central Chile" (2019). Scripps Senior Theses. 1514.