Life in the ocean can be rough. Days are spent searching for food, trying not to become food, or warding off fishhooks and nets. Then there are the hitchhikers: parasites. Parasites thrive in the ocean, and there are plenty of hosts for them to choose from. In fact, oceanic parasites may be more common than you think.
Very little is known about ocean parasites, but scientists do know they are quite a diverse bunch. A new video shot by the US Geological Survey off the coast of the northeastern US has revealed that one third of the fish they encountered were afflicted with some sort of parasite. Of these, as many as half had multiple and varying types of parasitic pals latched on.
How did the scientists do it?
Conducting more than 40 ROV (remotely operated vehicle) dives, researchers were able to observe fish playing host to dozens of organisms. There were two basic kinds of ocean parasites observed: isopods and copepods. Isopods are flat-bodies crustaceans, with seven pairs of legs, something like a wood louse. Copepods are eyeless crustaceans with six pairs of legs. These tiny creatures are more akin to water fleas.
While it was unclear if any of those observed were new species, the scientists were quite surprised by the number of them. Collecting samples is difficult because bringing infected fish to the surface would likely dislodge or kill the parasite, rendering study impossible.
What did the scientists say about ocean parasites?
“Seeing them in their natural condition is a bit of an eye opener that in fact parasitism is probably much more common in the deep sea than perhaps we had previously imagined,” says biologist Geoff Boxshall at the Natural History Museum in London. “Virtually nothing is known about their importance in the deep sea.”
While they may sound dangerous or undesirable, ocean parasites may actually be a sign of a healthy ecosystem. They can help keep fish populations in check without being an overwhelming threat.
