The UC Santa Barbara researchers who dissected tissue from the mysterious 18-foot oatfish that washed up last month on Catalina Island found some interesting parasites along for the ride. From the UCSB release:
"Our findings say that these are actually majorly parasitized fish," said Armand Kuris, professor of zoology in the UCSB Department of Ecology, Evolution and Marine Biology...
"In this little piece of intestine that we had, we found quite a few of these rather large larval tapeworms. One of them was about 15 cm (6 inches) long," said Kuris. They found a couple dozen specimens of two species in the small segment, along with two juvenile roundworms. And, unexpectedly, grad student Sara Weinstein found the hooked proboscis of an adult spiny-headed worm embedded in the intestine as well.
The life cycle stage in which these parasites were found is important, explained Kuris, because such parasites live out their life cycles in different hosts. The larval tapeworms, which hadn't yet developed their telltale segments, for instance, will stay in their larval stage indefinitely until the oarfish gets eaten by a shark, whereupon they resume their maturation inside the shark. The spiny-headed worm, on the other hand, was an adult, indicating that the oarfish ate the organism –– probably krill or some deep-water crustacean –– that hosted its juvenile form.
"These (findings) tell you about what the natural enemies of the oarfish are," said Kuris. The species it feeds on also indicate where the elusive oarfish is likely to live or hunt for food.
Cropped photo: UCSB/Sonia Fernandez