So many parasites, too few hosts? How has parasite burden of fishes changed in an overfished sea? Increasing demand for fish as a food resource has led to decades of overexploitation. With declining fish abundance and diversity, the fate of fish parasites is unknown. Using preserved fish from the University of Washington Burke Museum, that were collected from ~1900 to present, I am: (1) Quantifying the diversity, abundance, and richness of parasites in 10 different fishes of Puget Sound, WA over a century-long period, (2) Comparing how these metrics vary among fishes and over time, and (3) Linking shifts in diversity, abundance, and richness of fish–parasites with host and parasite life history traits.
Do dietary shifts of fishes drive changes in their disease burden? Persistent commercial harvest of fishes has led to “fishing down the food web”. How has this phenomenon impacted the diets of fish? I predict that trophic downgrading is occurring, such that fishes - deprived of their high-trophic level prey by intensive fishing - have responded by eating down the food web themselves, with the diets of high trophic-level fishes becoming similar to those of lower-trophic level fishes. Many abundant lower level food items are reservoirs of parasitic disease. Consequently, a fish eating down the food web may carry higher disease burden of complex life cycle parasites. By subjecting museum specimens to compound specific stable isotope analysis, I am: (1) Quantifying the trophic position of 5 fish species of Puget Sound, WA, USA over the past 100 years, (2) Associating the parasite data of the concurrent project (see above) with changes in trophic position, and, (3) Linking detected change in parasite burden with fish traits and environmental change.
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