January 10, 2023 — Katherine Maslenikov carefully plucked a young walleye pollock specimen from a glass jar full of ethyl alcohol. The critter’s eye and insides were missing, some carefully packed in a nearby vial labeled “inner organs.”
Maslenikov is the steward of the millions of fish specimens dating back to the 1800s neatly organized in a massive library of jars hidden in the basement of the University of Washington’s fisheries teaching and research building.
In their flesh are thousands of parasites — worms and other critters that lived off their host — that could reveal a hidden effect of climate change. Researchers fished out more than 17,000 parasites of the nearly 700 fish they studied. But as they moved to newer samples, they found fewer and fewer of the passengers.
In a study published Monday, scientists concluded that warming water may have caused some parasite populations in Puget Sound to plummet. The research suggests parasites may be especially vulnerable to global warming.
“It’s really our first peek into what parasites have been up to over the past couple of decades,” lead researcher Chelsea Wood said. “It’s a warning. It suggests that there might be more loss of parasite biodiversity than we previously anticipated.”
The loss of parasites could have implications for the long-term stability of Puget Sound ecosystems, according to the study, now the world’s largest and longest data set of parasite abundance.