The Giant Oarfish

The Giant Oarfish

Welcome to "On the Line", a NOAA Fisheries podcast.

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Host: I'm sure you've heard about this already, because the story's been everywhere in the news. In the last two weeks, not one, but two giant oarfish have washed up on beaches in Southern California. The oarfish is a leviathan from the deep sea, a part of the planet that's as mysterious to us as an alien world. Oarfish are huge—they can grow to 25 feet or more—and, like any movie alien worth watching, they can hover in place and they radiate a bioluminescent glow.

Like that other movie monster the Giant Squid, oarfish live and die in the darkness of the deep sea, so we know very little about them. But every now and again the sea coughs up one of these creatures, exposing it to the light of day and to the poking and prodding of scientists. One of scientists who examined the the oarfish that washed up this week is Russ Vetter. Dr. Vetter is a geneticist and physiologist with NOAA's Southwest Fisheries Science Center. That's where he and other scientists necropsied this strange and startling fish. We've got Dr. Vetter On The Line today talk to us a bit about the oarfish. He discusses the animal's biology and also hypothesizes about how two of them ended up on the beach.

I started our conversation with the obvious question…

Host: So first of all Russ, what is an oarfish and do they taste good?

Russ Vetter: I haven’t cooked it yet but I brought a piece home. It’s very very watery and by all reports very disgusting. So what is an oarfish? It’s a kind of fish that once you’ve seen one you never forget it. The striking nature of this long sinewy fish is what many people say gave rise to the original notion of sea serpents and that’s because it’s general body shape is to have a large head and then this long tapering body that can be well over 20 feet long and then the dorsal fin which goes from the very tip of the forehead all the way to the tip of the tail is a beautiful bright orange and then the pectoral fins are thin ribbons and they’re tipped by light emitting organs so from beginning to end this has all the qualities you would want in a sea serpent.

Host: Have you ever seen one live?

Russ Vetter: I have not seen one live but I would recommend anybody who has an interest in fish or the ocean to take a look at some of the video that’s available because it just turned literally and figuratively our notion of how the fish swam 90 degrees. So if you go in a museum or think of them as a sea serpent you would orient them horizontally but in real life they’re actually hanging in the water column vertically and they’re motionless except for this long ribbony dorsal fin that’s allowing them to maintain their vertical position in the water.

Host: Wow. This is the second one in a week that has washed up in California so what’s going on?

Russ Vetter: So without any evidence, and I’ll stress that, it seems reasonable to me based on the freshness of the fish that it must have stranded or died fairly close to where it eventually washed up. So if you see the videos of the fish and you see what poor swimmers they are perhaps an ocean current swum in and brought some more oceanic water close to the beach. That would be what I would say would be a working hypothesis, some place you would start.

Host: Yeah. So I heard that you necropsied the fish yesterday so what’s a necropsy and what did you learn from it?

Russ Vetter: Well I mean a necropsy when you have a body of knowledge like human pathology, or even nowadays marine mammal pathology, you’re looking for an explanation of the cause of death. When you’re working with a rare fish that very few people have seen and touched even it’s much more of a shot in the dark so because it was so fresh one of the main objectives of the necropsy was to get tissues preserved the way that people need them preserved and get them into the hands of all these experts.

Host: So you’re shipping a bunch of stuff all over the country, all over the world.

Russ Vetter: All over the world.

Host: Really? So what kind of research will this yield?

Russ Vetter: I take pains to say it’s not a primitive fish. It’s actually a highly evolved highly advanced fish. And when you see some very unusual fish your first guess and it’s usually correct is that they have a very specialized ecological niche as opposed to say a generalist fish like a bass that just looks like a fish. So this one is so unusual and there doesn’t seem to be a lot of living relatives so we don’t really know how this fish evolved and who its closest living relative might be so the DNA will allow us in comparison with the DNA of other fish to determine what its nearest living relative was and how it might have gotten to be the way it is. Some of the tissue samples – it’s literally a truism that you are what you eat so with careful chemical analysis of the lipids and the proteins we should be able to tell what it’s diet is and where it fits kind of in the food chain.

Host: Just a moment ago you mentioned the creature’s ecological niche so what is its ecological niche and how does being so big help it to exploit that?

Russ Vetter: Well that’s a very important question and if I were to say I knew the answer with certainty I would be lying but typically the ocean is divided into the epipelagic where things like sardines and anchovies and whales live and more importantly where sunlight reaches plankton and you get primary productivity. And below that is probably the least explored part of the ocean which is not on the bottom, that’s the benthic zone, but what we call the mesopelagic and those animals form this huge band of life that generally moves up at night to feed on phytoplankton and krill and then moves down in the daytime to avoid predation.

And typically these animals tend to be small and not very strong swimmers but occasionally fish in that system or invertebrates in that system tend to reach huge sizes so that’s the realm of the legendary giant squid and in this case the realm of the giant oarfish so what triggers one line of fish to become extraordinarily large? Who knows? But as I say when I did the dissection you could put your hand into the mouth, around the mouth, down the throat and not even scratch your skin so whatever these fish are doing it’s not based on large teeth and aggressively biting large prey. It’s based on systematically filtering the water for smaller food particles.

Host: So tell me why is this interesting to you as a scientist?

Russ Vetter: Well I mean I think it’s often been said that this mesopelagic portion of the ocean is the least explored ecosystem left on Earth but all of our other work that we do here very often involves electronic tagging of fish and what we’ve found is that many common fish on the dinner table like swordfish or mako sharks or blue sharks of tunas spend a lot more time diving down to this food layer than we originally thought. We originally thought all these fish spent most of their time in the surface layer but from our electronic tagging, a huge number of swordfish and big eyed tuna and all kinds of fish will routinely go to 300 – 400 meters every day and so we really hadn’t thought that much about the vertical aspect of the ocean. We thought tunas was moving from one place to another horizontally looking for schools of fish so it’s becoming a bigger part of our view of how the ocean works.

Host: Before I let you go Russ paint me a picture. What was the scene in the necropsy suite?

Russ Vetter: Oh it was fantastic. Sometimes you forget that everybody’s a, every scientist is a kid at heart even if they may be doing bookkeeping or something now. I mean everybody came down and everybody participated so that was great.

Host: Great. Thanks Russ.

Russ Vetter: All right.

Host: Nice talking to you.

Russ Vetter: Bye.

Host: You know, when I think of Dr. Vetter and his colleagues in the necropsy suite, meticulously dissecting the strange fish that washed up on the beach, I get an image in my mind that's straight out of a Sci Fi movie, it's that scene where scientists examine the body of the big-eyed, green-skinned alien that stumbled out of his space ship and died because he couldn't breathe our oxygen-rich air. Who knows if we'll ever discover life on a distant planet. But if we do, will it be any more strange and fantastical than the life forms we have right here on Earth, hidden in the darkness of the deep sea?

As always you can get more of this story on our website, that's www.fisheries.noaa.gov/podcasts. There you'll find some photos from the necropsy, and a link to a video of an oarfish. So take Dr. Vitter's advice, and check that video out.

Thanks for listening. Join us again next time for more stories about ocean life and ocean science. I'm Rich Press, and you're listening to "On The Line".

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You have been listening to the NOAA Fisheries’ podcast, "On the Line". Join us next time for a first-hand look at the people and the science behind managing our nation’s fisheries. For more information, visit NOAA Fisheries at www.fisheries.noaa.gov.

"On the Line" is a production of the NOAA Fisheries Office of Communications.