A male tailspot wrasse with a vermillion coloration is shown here. If the wrasse grow up and live long enough, they will become males. (Photo by Alasdair Dunlap-Smith)
A small, orange-vermillion colored fish has been named a new species after a team of divers from Southern California and Mexico found the wrasse in deep water on volcanic and rugged rocks near the remote Mexican Revillagigedos Islands in the Eastern Pacific Ocean.
Halichoeres sanchezi, or more commonly tailspot wrasse, and its discovery in the Marine Protected Area were recently announced in a scientific journal by Benjamin Victor, an Irvine-based marine scientist who has helped name and discover more than 80 new species, 13 of those in the wrasse family.
Wrasse are a colorful group of fish that includes 600 species; many of the tailspot’s relatives are common in home aquariums, says Victor.
Declaring a new species is not an easy process. It required at least six months of DNA research, and then it took six months for Victor to write up the discovery in the journal. The announcement of a new species is not made public until it is published in a scientific journal.
Through his research, Victor discovered that the tailspot wrasse is currently only known to be found near those islands, but that could change if El Nino worsens.
The tailspot discovery is unique because most new tropical fish species are usually found preserved in jars in museums and then “described” as new, Victor said.
“To actually have the first one of a species collected live,” he said, “it’s very unusual.”
The eight specimens of the new species collected by the team ranged from one inch to nearly six inches in length.
Females are mostly white with reddish horizontal stripes along their upper half and black patches on their dorsal fin, behind their gills, and near their tail fin.
“This species is unusual among wrasse, where the male is almost always more colorful,” says Victor. “In this species, the female is more colorful.”
The first photos of the unknown fish were taken in 2013 during an expedition by the Reef Environmental Education Foundation, and no one on the team was knowledgeable enough to identify the species.
“We looked at the pictures and thought no one had seen it before,” Victor said. “We don’t know what it is.”
The mystery lingers until 2022, when a new expedition to the Revillagigedo Islands, sometimes called the Mexican Galapagos, is planned to conduct a survey of the ocean around the islands, which have not been surveyed for 20 years, said Victor.
And there’s the mysterious fish to watch out for.
The area is rugged with rocks and large lava fields; huge Pacific rollers barrel through the clear blue water. Most of those who dive there do so for research, but some visit to admire the wide range of marine life, especially giant tuna and manta rays, in waters protected from fishing.
The expedition to the islands took two days on a boat from Cabo San Lucas. It was organized by professor and marine scientist Carlos Armando Sánchez Ortíz of the Universidad Autónoma de Baja California Sur. The wrasse’s official name, Halichoeres sanchezi, includes a nod to Sánchez.
The trip also included researchers from UC San Diego’s Scripps Institution of Oceanography, the Natural History Museum of Los Angeles County, the Smithsonian Tropical Research Institute, the Ocean Science Foundation and the University of Central Florida.
Over the course of two weeks, the group surveyed all four islands during 30 research dives that produced more than 5,500 photographs and 900 specimens representing more than 100 fish species. The researchers also took tissue samples for DNA analysis.
Victor said that it wasn’t until the second to last day of the trip that Sanchez came up with a fish believed to be a juvenile of the mystery species.
“When he brought it to the ship in a bag, we all said, ‘That’s it!’ Victor said. “It’s a strange looking wrasse, and it’s a baby.”
A dive team immediately returned to search for an elderly man, he said.
“Juveniles are often identical in related species,” he said. “Males differ because they perform mating displays, which are the first to change when a new species splits from an ancestral species. Men need to discover the difference about what is unique for that species and that makes it a new species in science.”
On the last day of the trip, a group of divers descended 70 feet. There, they found what they needed.
“That’s the only adult; we were just so lucky,” said Victor.
Since its discovery, the fish has been documented and photographed and is now preserved in the Colección Nacional de Peces in La Paz, Mexico. Other specimens are stored in the Scripps’ Marine Vertebrate Collection and the Natural History Museum of Los Angeles County, where they can be examined by researchers around the world.
After analyzing the DNA of the new species, Victor determined that the new tailspot wrasse was related to the golden wrasse, a species that lives between Baja and Ecuador.
“We found that it was 2% different in the DNA sequence,” he said. “And we can interpret how many years separated. When it reached the islands, it adapted to its new conditions.”
For Victor and the other researchers, the new species discovery is like a “canary in the coal mine,” and they will use it to monitor the ocean’s warming conditions, he said. Mexican scientists will also continue to study fish in the area of the islands and determine if their populations have encountered “disastrous effects” of El Nino, he said.
“It’s a small population, about 1,000, in a very vulnerable area,” Victor said, but added, “They haven’t been declared an endangered species and haven’t been put on the list since they officially existed last week.”
But the damselfish, a plankton feeder also found in the area, is gone, he said, likely due to climate change and its effects on the upwelling ecosystem of the eastern tropical Pacific. A sister species to the extinct damselfish migrated to cooler waters and is now found on Catalina Island.
“It shows us the damage human-caused climate change is doing to species,” Victor said. “If El Nino continues, all these fish will move here, and we’ll start seeing more and more tropical species in Southern California.”
