Some fish parasites are on the rise, bringing with them risks to human health and fisheries-based economies. Now researchers have a new way to track their numbers—by digging into old records and museum samples.
Recent years have seen alarming outbreaks of disease in fish and other marine species, including one that caused a massive die-off of sea stars in the northeast Pacific starting in 2013. But it has not been clear whether this uptick in illnesses was due to an actual increase in the number of pathogens and parasites, or whether scientists were just noticing them more often because they were paying closer attention. Chelsea Wood, who studies marine parasites at the University of Washington in Seattle, set out to track how some parasites have changed over time—and had to get creative to find answers.
First, Wood and her team trawled through old journal articles to track the long-term change in two genera of parasitic nematode worms—Anisakis and Pseudoterranova—that infect a variety of marine creatures, including fish, shellfish, whales, and seals, and that can make humans sick if consumed in raw or undercooked fish or squid. Because of the public health concern, scientists have monitored these parasites over the past few decades.
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