McMurdo Fish May Prove to be New Species

By Emily Stone, Sun staff

You can count the variety of visible animals at McMurdo Station on one hand, so the idea that a new species would wander up to station might initially seem absurd. But there’s a whole world living next door to us in the ocean that still yields many surprises — such as the mysterious fish found in front of the station last summer.

Paul Cziko and Kevin Hoefling spotted the fish immediately. It was a purplishgold color against a big brown rock. And it looked like nothing the two divers had ever seen before.

Nor does it look like anything anyone has recorded seeing before. A year after the divers caught the mystery fish, they’ve done enough research that they’re convinced it’s a new species. Cziko is working on a paper to submit to a peer-reviewed journal, which, if accepted, will introduce the new species to the rest of the world.

The men saw the fish during a dive at the McMurdo Station jetty in November 2004. They were in about 15 meters of water collecting fish eggs for Art DeVries’ fish biology group. They didn’t have a net with them, but Hoefling was able to catch the fish in his hands and Cziko put a mesh bag around it so they could bring it to the aquarium.

They showed the fish to DeVries, who has about 40 years of experience with Antarctic fish, yet he’d never seen this type before. That’s when Hoefling said he started wondering if they’d found something new.

“You just wouldn’t think, ‘I’m going to find a new species today,’” said Hoefling, who is a diver with the group. He is back at station this summer working as a flight line mechanic since DeVries’ project isn’t doing field work at McMurdo this year.

Cziko and Hoefling looked through “Fishes of the Southern Ocean,” the bible of Antarctic fish species, and didn’t find anything that resembled their fish. Hoefling took pictures and videotaped the fish in the aquarium. Cziko, a visiting research specialist at the University of Illinois with DeVries, planned to look into the issue back home.

He took up the project again about a month ago. With only 300 or so species of fish in the Southern Ocean, it was relatively easy to see that the fish didn’t resemble much that was already cataloged, he said.

“There was only one that looked even remotely similar,” Cziko said. That fish, Cryothenia peninsulae, had been caught during only one expedition in 1975, off the Antarctic Peninsula. About 20 fish were caught in the course of a few days.

The next step was to ask museums for samples of Cryothenia peninsulae to compare the known species to the mystery fish. Museums around the world collect plant and animal species to document past and present biodiversity, and to help scientists with their research.

Four samples arrived by UPS, and Cziko did a series of comparisons between the fish. He counted the scales and bones in its fins and calculated body measurement ratios, such as how big the head and fins are compared to the body.

About 90 percent of the measurements were the same between the two fish. But there were some important distinctions.

The mystery fish is much larger — 32 centimeters compared to 15 centimeters at the same life stage. The mystery fish has a large pit between its eyes, which is used to sense movement in the water around it. The pit is wider than the other species’ pit and has a slight ridge in the middle. The new fish also has an unusual coal-black lining of its mouth and gills.

Cziko said he’s done about 80 measurements comparing the new fish and the Cryothenia peninsulae. He’s confident that they’re in the same genus but are different species. He’s hoping to write up his paper in the next month to submit to the journal Copeia, a publication that focuses on research about fish, amphibians and reptiles.

If the panel decides to accept Cziko’s theory that the fish is a new species, he and Hoefling will get to choose a name for it. They have some ideas, but nothing they’re set on yet.

They both want to pick a name that’s descriptive and will help other researchers quickly identify the fish if they see it, rather than naming the fish after a person. For example, many Antarctic fish bear the name of polar explorers and scientists.

The giant Dissostichus mawsoni is named after Australian explorer Douglas Mawson who sailed with Ernest Shackleton and was part of the first ascent of Mount Erebus. Trematomus bernacchii is named after Louis Bernacchi, who was part of Robert F. Scott’s 1901 foray to Ross Island. And Pagothenia borchgrevinki honors Norwegian Carsten Borchgrevink, the commander of the British Southern Cross Antarctic Expedition of 1898, which established the first winter station on the continent. The custom is not entirely dead, as DeVries has a fish named after him as well, the Paraliparis devriesi.

Cziko and Hoefling said they may focus on the pit in the fish’s head, its iridescence or black gills and mouth. The genus, Cryothenia means “from the cold” in Greek.

The jetty where the men found the fish is a short walk from the station’s main science building and is one of the most heavily fished and dived spots in all of McMurdo Sound. There were 1,701 dives at the jetty between 1989 and the end of last season, according to Dive Services Supervisor Rob Robbins, out of a total of 10,097 U.S. Antarctic Program dives in that time.

Hoefling said he has dived at the jetty hundreds of times in his six seasons diving here, so he was particularly surprised to find a new fish there. Cziko said he suspects the fish was attracted to the large, flat rocks that provide a safe place to lay eggs.

The fish’s characteristics, like the fact that it’s naturally buoyant, suggest that it may not spend much time on the ocean floor, making it hard for divers or trawling nets to catch it. This might explain why it hasn’t been spotted before, Cziko said. The discovery highlights how many species there may be in the oceans that we don’t yet know about, Cziko said.

It’s impossible to fully understand human impact on ecosystems without knowing what is living in the oceans to begin with, he added.

“We still don’t know everything,” he said.

NSF-funded research in this story: Jaakko Putkonen, University of Washington.