A newly identified species of Antarctic dragonfish, known as Akarotaxis gouldae or the Banded Dragonfish, has been found in the waters off the western Antarctic Peninsula. This species is named in tribute to the Antarctic research and supply vessel (ARSV) Laurence M. Gould, which has recently been retired, along with its crew. The discovery underscores the hidden biodiversity and the delicate condition of the Antarctic environment.
A newly identified species of Antarctic dragonfish, Akarotaxis gouldae or Banded Dragonfish, has been found in the waters off the western Antarctic Peninsula by researchers from William & Mary’s Virginia Institute of Marine Science (VIMS). This species is named as a tribute to the recently decommissioned Antarctic research and supply vessel (ARSV) Laurence M. Gould and its crew, reflecting the hidden biodiversity and vulnerable state of the Antarctic ecosystem.
As described in the journal Zootaxa, Akarotaxis gouldae was first identified through genetic testing. Larval samples gathered while trawling for zooplankton off the coast of Antarctica were initially considered to be Akarotaxis nudiceps, a closely related species. However, upon comparing their DNA with that of Akarotaxis nudiceps specimens from various collections including VIMS, Yale University, and the Muséum national d’Histoire naturelle in Paris, significant differences in mitochondrial gene regions indicated that these larval samples represented a unique species.
Lead author Andrew Corso conducted this research while earning his Ph.D. at W&M’s Batten School of Coastal & Marine Sciences at VIMS, under the guidance of faculty advisors Eric Hilton and Deborah Steinberg. With the DNA findings as a foundation, Corso and his team sought adult Akarotaxis gouldae specimens from various ichthyology collections worldwide. Significant morphological differences became clear when comparing the adult samples of the two species.
“There are two distinct bands on the sides of adult Akarotaxis gouldae that are absent in Akarotaxis nudiceps, which surprised us, as this species was already present in collections but had slipped through the cracks,” said Corso. “While genetics alone is becoming the standard for distinguishing fish species, our discovery highlights the significance of studying early life stage morphology and the value of natural history collections like those at VIMS and other organizations.”
Genetic analyses also provided insights into the species’ evolutionary history. Using a method known as time-calibrated phylogeny, Corso and coauthor Thomas Desvignes from the University of Oregon estimated that Akarotaxis gouldae started to evolve as a separate species around 780,000 years ago, a period when much of the Southern Ocean was under glaciers.
“This method essentially looks at the rate of genetic mutations to trace a species’ evolutionary background,” explained Corso. “We theorize that a population of dragonfishes might have become isolated in deep trenches beneath glaciers, feeding on nutrients pushed by moving ice. Once the glaciers receded, this isolated population developed enough differences to become reproductively distinct from Akarotaxis nudiceps.”
Newly discovered, yet potentially at risk
Currently, there’s limited understanding of Antarctic dragonfishes due to their remote habitat in the Southern Ocean and their tendency to live in deep waters during adulthood. Previous studies indicate these fishes may protect their nests in shallower coastal regions, while their larvae remain closer to the surface. Investigations of female ovaries reveal a constrained reproductive capacity. Although Akarotaxis nudiceps is found in various waters around the southern continent, data from larval samples indicate that Akarotaxis gouldae is primarily restricted to waters surrounding the western Antarctic Peninsula.
Dragonfishes play a critical role as prey for many species, including Antarctica’s well-known penguins, whose populations have significantly declined in recent years. A study conducted by Corso in 2022 linked rising water temperatures and reduced ice coverage in the Southern Ocean to decreasing populations of Antarctic silverfish.
“Akarotaxis gouldae has one of the most limited ranges of any fish endemic to the Southern Ocean,” stated Corso. “This restricted distribution, along with their low reproductive rates and the presence of larval stages in shallower areas, indicates that this species is vulnerable, particularly to the krill fishery.”
The waters around the western Antarctic Peninsula are actively targeted by the international Antarctic krill fishery, managed by the Conservation of Antarctic Marine Living Resources (CCAMLR). Commercial fishing vessels often trawl for krill in the top 250 meters of water, and CCAMLR has highlighted the challenges in accurately identifying bycatch of young fish during these operations.
“Given our limited knowledge of this region’s biodiversity, we believe caution should be exercised regarding resource extraction until we better understand the effects on the overall ecosystem,” added Corso.
Highlighting research while honoring a scientific legacy
The ARSV Laurence M. Gould is named for Laurence McKinnley Gould, the chief scientist on the first expedition to Antarctica. While it’s easy to think Akarotaxis gouldae was named in tribute to this notable geologist, the researchers chose instead to recognize the vessel for its significant scientific contributions and the efforts of its crew.
The ARSV Laurence M. Gould supported the U.S. National Science Foundation’s Antarctic Program from 1997 until the recent non-renewal of its charter in April. It was one of two U.S. ARSVs dedicated to researching the Southern Ocean. Although plans for a replacement vessel are underway, the U.S. National Science Foundation noted that the charter wasn’t renewed due to financial factors and shifting research priorities.
The ARSV Laurence M. Gould and its crew have been instrumental in supporting Antarctic research conducted by VIMS and other organizations. Corso’s advisor, Steinberg, focuses her long-term research on the impact of climate change on zooplankton populations around the western Antarctic Peninsula, which affects the marine food web. Such research depends on regular collection intervals that must adapt based on the availability of vessels like the Gould.
“The retirement of the ARSV Laurence M. Gould is a setback for scientific exploration in Antarctica,” remarked Corso. “Antarctica is warming faster than any place in the Southern Hemisphere, and there’s immense biodiversity in the area that we are just beginning to uncover. By naming this fish after the vessel, we aim to honor its scientific legacy while raising awareness about the need for more resources to study this unique ecosystem.”
