A team of scientists including Ben Frable of UC San Diego’s Scripps Institution of Oceanography in La Jolla discovered a fish with a different stripe.
The new species — whose females have red stripes — was found living among volcanic rubble at a depth of about 70 feet during an expedition to the remote islands of the Revillagigedo Archipelago off Mexico’s Pacific coast.
The fish, called Halichoeres sanchezi, or tailspot wrasse, is likely endemic to those islands, meaning it is found nowhere else on Earth, according to Scripps Oceanography. This is described in a paper published on February 28 in the journal PeerJ.
The species was discovered in November 2022 during a trip organized by marine scientist Carlos Armando Sanchez Ortíz of the Universidad Autónoma de Baja California Sur to better understand the diversity of fish in a group of islands about 250 miles south of down The fish is named for Sanchez Ortiz.
“In the eastern Pacific Ocean, we are isolated from offshore islands [that] facilitate fish diversity,” said Frable, Scripps collection manager. “They are a landing place for young fish and there are some species that only live there because of the weather and the ocean. We decided to go there because, while it has been visited many times, no intensive survey and documentation has been done in long time. We wanted to hit that and take detailed pictures.”
As an added incentive, there is the possibility of discovering new fish.
Sanchez Ortiz collected a specimen during last years excursion that he could not identify, and he wants to further explore the area to find more of the fish and determine if it is related to another species that lives nearby. Costa Rica or a new species, Frable said.
So for two weeks on a dive boat, the team, along with Frable, collected samples and took pictures of different types of fish in the area – all while keeping an eye out for any new ones.
On the last day of the expedition, Frable said, “we dived right off one of the islands near an underwater canyon. We went to have fun and see sharks and manta rays.”
While some of the scientists are enjoying themselves, others are collecting fish. The team reassembled on the boat to examine what had been collected.
Ben Frable of the Scripps Institution of Oceanography in La Jolla helped discover and describe a new species of fish.
(Screenshot by Ashley Mackin-Solomon)
“There’s a fish that looks like a different kind of fish but has a different face,” Frable said. “Others thought it was the mysterious fish we were looking for. So we went down and found them near some big rocks. We found that they are really common there.
Wrasse, Frable said, can change from female to male later in life, and males and females look very different. Thus, different specimen samples are required to cover males and females at different life stages.
After collecting all but one sample of what it needed, the team returned for another dive.
“We’re running out of time and air, and we only have time for one last walk,” Frable said. “As soon as we got to the bottom, a photographer spotted the fish we needed. We chased it and caught it.”
After taking photos and tissue samples, work began to determine if it was a new species or something that existed elsewhere.
“We compared the genes and, lo and behold, this thing was different. So it was described as a new species,” Frable said.
The eight specimens of the new species collected by the team ranged from about an inch in length to about six inches.
Smaller females are mostly white with reddish stripes along their upper half and black patches on their dorsal fin, behind the gills and near the tail fin.
Frable described the males as “orangey red above, fading to a yellow belly with a dark band at the base of the tail.”
“We didn’t expect to find a new species … and for a place that scientists have visited, the possibility of easily finding one is really amazing,” Frable said. “These discoveries are not uncommon. There are 300 to 500 new species of fish described every year around the world.”
But this one, he says, “because it almost disappeared and I was in the water myself at the time, makes it very special for me.”
“I was involved in the description of 10 new species of fish in my career, but many of them were collected before I got involved, and my involvement came from presenting the fish,” he said. “It was really special because we were there, saw the fish, did the work. Being involved from start to finish was really great and very satisfying.”
Little is known about the contribution of the new fish to its local ecosystem. Since Frable’s mission is to document the diversity of the fish, further exploration of the species and its role will be conducted by another team.
“But we took the first step,” Frable said. “That made me happy.”
Identifying new fish species is important to a more comprehensive understanding of the ocean environment and how to protect it, he added.
“In trying to have a healthy ecosystem, documenting what’s there and how much there is,” Frable said. “New species help facilitate that because, if you’re not recording the true diversity of a site, you don’t know the full extent of what it is. So this is the missing piece of the puzzle.
“I thought we had discovered a lot about the world, but we see how dynamic it is. We will learn much more about the diversity of life as this work continues.” ◆
