IMIS

Feeding rates and selection of the oyster drill Urosalpinx cinerea were investigated with several long term temperature alteration experiments. Oyster drill prey selection was assessed in terms of prey (oyster) size and shell thickness. Drills fed on oysters with thinner shells 86% of the time and selectively preyed on smaller (1 g wet weight) oysters during colder months and larger (10 g wet weight) oysters during warmer months. Analysis of U. cinerea seasonal feeding patterns showed virtually no feeding during winter months (January to March) and a significant increase to over 1 gram of prey tissue per week during summer (July to September). A nine month experiment compared feeding rates of U. cinerea at two different temperature levels: ambient seawater (control) and temperatures elevated 4 °C above ambient. Oyster drills showed a 60% increase in feeding rate in the warmer treatment, especially during late summer, fall and early winter. Both temperature manipulation and annual feeding experiments revealed a significant temperature dependence of U. cinerea feeding rates. Seasonal or long-term seawater temperature changes related to climate change could strongly affect the predator–prey relationship between U. cinerea and its prey.