Luciano Chiaramonte
Dr. Bartholomew’s lab researches salmon diseases but is primarily focused on the myxozoan parasite Ceratomyxa shasta, which occurs naturally in the Pacific Northwest. This parasite is particularly problematic for salmon populations in the Klamath River of Northern California. Ceratomyxa shasta has a complex lifecycle, requiring a salmon/trout and a polychaete worm host to complete its lifecycle. Luciano Chiaramonte's research is focused on the effects of temperature on the development of the parasite within its hosts and the longevity of the free living parasite stages. Laboratory experiments consist of polychaetes being administered parasite spores at various temperatures to see if transmission varies with temperature. Infected polychaetes will also be incubated at various temperatures to determine differences in time to development of the spores which can infect fish. Spores taken from both infected worms and fish will be held at various temperatures to see how long they remain viable. Once the effects of increased temperature on C. shasta are determined, predictions for climate change scenarios can be made.
Another component of Chiaramonte's research pertains to thermal refugia on the Klamath River, a critical summer habitat for juvenile salmon. Due to high temperatures in the Klamath River, outmigrating juvenile salmonids are required to use cool tributary water to survive the summer. Chiaramonte examined one of these thermal refugia, the Beaver Creek confluence, for the potential to provide disease protection for fish when mainstem parasite levels are high. He found evidence that the area of cool water created by the tributary was not only highly used by juvenile Chinook and coho, but also contained a lower density of C. shasta than the mainstem of the Klamath River. Therefore, fish seeking thermal refuge are exposed to less C. shasta in cooler water temperatures, which have previously been shown to slow disease progression.
Currently, Chiaramonte is monitoring the Willamette River to detect seasonal patterns in C. shasta abundance and to identify any areas in the river with higher parasite levels, a phenomenon observed on the Klamath River. Water samples are taken weekly from established sampling sites and the resulting C. shasta concentrations determined using quantitative polymerase chain reaction (qPCR).