Posing With a Deep Sea Mystery: A student poses with one of two oarfish that washed up on California shores earlier this month. Giant oarfish (Regalecus glesne), the world's longest bony fish are generally thought to live in deep water and exceed 10 meters in length. Image: CSUF Photos/Flickr
The US media reported gleefully this month that two real-life sea monsters had hit the beaches of southern California. But the two huge — and dead — giant oafish have prompted an equally delighted reaction among the world’s ichthyologists, who are keen to know more about these little-studied animals.
Giant oafish (Regalecus glesne) are generally thought to live below 200 meters of depth and can exceed 10 meters in length, which makes it the world's longest bony fish.
The first of the California fish was found off Santa Catalina Island on 13 October. The second washed up on 18 October near Oceanside. Biomechanicist Misty Paig-Tran now has most of the Oceanside oafish in a freezer at California State University in Fullerton.
“Lots and lots of research is going to come out of this one specimen,” says Paig-Tran, who was offered the specimen because she is working on deep-sea fish. “You get a little giddy inside to know you have a 14-foot-long entire fish.”
Rare observations of oafish in the sea by divers or submersibles have shown that they hang vertically, head upwards in the water column. But most knowledge about them comes from specimens that wash up on shores. In this case researchers speculate that currents conspired to take these fish — thought to be relatively weak swimmers — out of their comfort zones and beached them.
Russ Vetter, director of the Fisheries Resources Division of the Southwest Fisheries Science Center in La Jolla, California, says that most previous specimens of oafish were found partially decomposed and could be properly studied only at the level of bone structure. But the Oceanside specimen — measuring a little more than 4 meters long — came to Vetter’s team in very good condition.
Several parts of the Oceanside fish have already been claimed by different scientists. Vetter says that the heart has gone to a collaborator of his who studies cardiac function; the gills are being looked at by a respiratory physiologist, and the stomach and other tissues are being analyzed to determine the fish’s diet.
“In most cases the scientists involved have ‘day jobs’ in basic science or biomedicine but retain the curiosity for the odd offshoot of evolution such as the giant oafish,” says Vetter.
The rest of the fish, chopped into nine pieces for ease of handling, now resides in Paig-Tran’s freezer. The fish has already been X-rayed; once it has sat in the freezer for two weeks to ensure that it is properly preserved it will be run through a computerized tomography (CT) scanner. Paig-Tran will use the CT scans to make a three-dimensional model of the fish.
“We’ll have a really good idea of her anatomy before we ever cut into the fish,” she says. The X-rays have already shown some unusual bone structures.
Adam Summers, a biomechanist at the University of Washington in Friday Harbor, is interested in the head of the oafish. He says that the upper jaws of oafish are unusual in how far they protrude from the head during feeding. Summers says that his work focuses on “how it is that animals are able to do the cool things we see them doing”, and he is “always hoping for extreme outliers like this oafish”.
Earlier this year another large and poorly understood deep-sea fish, a six-gill shark (Hexanchus sp.), ended up in his lab and provided insights into the brains and jaw structure of these massive predators. “It has been a good year for oddball finds,” says Summers.
Genetic data from the oafish will also be useful to researchers. One major question is how many species of these animals exist. Some scientists believe that there may be two separate species, and DNA samples could enable biologists to answer that question, says Milton Love, a fish researcher at the University of California, Santa Barbara, who coordinated distribution of samples from the fish found near Santa Catalina Island.
“The excitement from the point of view of scientists was due in part to the freshness of the specimen,” Vetter says. “In fact, I took a bit home to try on the grill.”
Vetter says the fish’s taste was not bad, but “I wouldn’t cross the street if a restaurant had a sign out for it”.