Newly discovered rainbow-colored fish lives in the ocean’s ‘twilight zone’
By Ashley Strickland, CNN
Far beneath the waves surrounding the Maldives, there’s a living rainbow in the ocean’s “twilight zone.” Say hello to the rose-veiled fairy wrasse, a colorful species of fish that’s new to science.
The fish, which bears the scientific name Cirrhilabrus finifenmaa, was found living at depths ranging from 131 to 229 feet (40 to 70 meters) beneath the ocean’s surface.
The name honors the fish’s stunning pink hues, as well as the pink rose, the national flower of the Maldives. “Finifenmaa” means “rose” in the local Dhivehi language.
While hundreds of species thrive in the waters near and surrounding the archipelago nation, this is the first fish to be described by a Maldivian scientist — Ahmed Najeeb. A study describing the fish published Tuesday in the journal ZooKeys.
“It has always been foreign scientists who have described species found in the Maldives without much involvement from local scientists, even those that are endemic to the Maldives,” said study coauthor Najeeb, a biologist at the Maldives Marine Research Institute, in a statement.
“This time it is different and getting to be part of something for the first time has been really exciting, especially having the opportunity to work alongside top ichthyologists on such an elegant and beautiful species.”
A fish by any other name
The fish has a history of mistaken identity. Researchers first found it in the 1990s, but they thought it was an adult belonging to Cirrhilabrus rubrisquamis, or the red velvet fairy wrasse. This different species had only been described from a single juvenile fish found 621 miles (1,000 kilometers) south of the Maldives in the Chagos Archipelago.
Wrasses, a family of largely bright colored fishes, have been known to change in color as they transition from juveniles to adults, said senior study author Luiz Rocha, the California Academy of Sciences curator of ichthyology, in an email.
While the juveniles of many species look alike, it’s the adults who carry distinguishing characteristics, he said.
“A few months ago, Yi-Kai Tea (our first author) received (remotely operated vehicle) footage from Chagos showing adults, which were very different from the adults from the Maldives,” Rocha said. “That’s when we decided that the species from the Maldives was new and different from C. rubrisquamis.”
In their study, the researchers focused on the details of adults and juveniles, analyzing the height of the spines supporting their dorsal fins, counting scales and cataloging the colors of the adult males.
The rose-veiled fairy wrasse adult males have a unique color pattern including bright magenta, peach, orange-pink and dark purplish-red.
Discovering that finifenmaa and rubrisquamis were two separate species can help scientists understand the range of these fish, which becomes especially important when trying to protect them.
“What we previously thought was one widespread species of fish, is actually two different species, each with a potentially much more restricted distribution,” said lead author Yi-Kai Tea, a University of Sydney doctoral student, in a statement. “This exemplifies why describing new species, and taxonomy in general, is important for conservation and biodiversity management.”
The name may be new, but the rose-veiled fairy wrasse is already a target of the aquarium hobby trade.
“Though the species is quite abundant and therefore not currently at a high risk of overexploitation, it’s still unsettling when a fish is already being commercialized before it even has a scientific name,” said Rocha, also a codirector of the California Academy of Sciences Hope for Reefs initiative. “It speaks to how much biodiversity there is still left to be described from coral reef ecosystems.”
Exploring ‘twilight zone’ reefs
The Hope for Reefs initiative aims to research and restore coral reef systems. Last month, researchers from Hope for Reefs and the Maldives Marine Research Institute surveyed some of the Maldives’ twilight zone reefs.
These reefs can be 160 to 500 feet (50 to 150 meters) beneath the ocean’s surface and provide a unique environment for fish like fairy wrasses.
“It’s a really different environment: It’s darker (because the water functions as a filter absorbing light, so the deeper you go, the darker it gets) and colder,” Rocha said. “There are much fewer corals, and almost no algae (because of the lack of light), so the fish community is very different and most fish at this depth feed on plankton (tiny marine invertebrates that live in the water column).”
The recent dives, funded by an award from Rolex, show just how difficult it is to survey the largely unexplored twilight zone reefs — located below recreational diving limits. The divers must use rebreathers and helium mixed into the gas they breathe to avoid the negative effects of breathing oxygen under so much pressure, in addition to using an abundance of gear that requires a lot of training, Rocha said.
But it’s well worth it, according to the researchers.
“Diving there is like visiting another planet,” Rocha said. “We are always the first ones to see those reefs, and always find new species. It is very challenging, but also very exciting!”
During the recent surveys, the research team found more of the rose-veiled fairy wrasse as well as at least eight potential new species of fish.
The California Academy of Sciences and the Maldives Marine Research Institute are continuing their partnership to explore more Maldivian reefs in the future.
“Our partnership will help us better understand the unexplored depths of our marine ecosystems and their inhabitants,” Najeeb said. “The more we understand and the more compelling scientific evidence we can gather, the better we can protect them.”
“We hope to collect a few more specimens of the other eight new species we recently found,” Rocha said. “Additionally, we are closely working with our Maldivian partners to keep using Maldivian names in our species.”
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