Genetic Study Reveals New Goliath Grouper Species

Genetic studies have revealed that the goliath grouper is not a single species as scientists once thought, but is in fact two distinct species. Researchers from the University of Hawaii, the Wildlife Conservation Society, Smithsonian Tropical Research Institute, National Marine Fisheries Service and Projecto Meros do Brazil studied goliath groupers from the Eastern Pacific Ocean and the Atlantic Ocean and compared their genetic composition. They found that although fish from the two regions look identical, their underlying genetic makeup differs enough to classify them as separate species.

According to Dr. Matthew Craig of the Hawaii Institute of Marine Biology and lead author of the study:

"For more than a century, ichthyologists have thought that Pacific and Atlantic goliath grouper were the same species, and the argument was settled before the widespread use of genetic techniques. The genetic data were the key to our finding: two species, one on each side of the isthmus."

The original scientific name, Epinephelus itajara now applies to the Altantic goliath grouper alone. The Pacific goliath grouper has received the new scientific name Epinephelus quinquefasciatus. Both species are exceptionally rare; the Atlantic grouper is already listed as critically endangered on the World Conservation Union's Red List of Endangered Species of Fauna and Flora. The Pacific goliath grouper may too be granted similar conservation status due to its scarcity.

Both species of goliath grouper are astonishing creatures— they can grow to more than six feet in length and weigh as much as 1,000 pounds. The Atlantic and Pacific lineages of goliath grouper are thought to have diverged when the Caribbean and Pacific oceans became separated some three-and-a-half million years ago when Central America emerged to form a land barrier between the two oceans.

Find out more: Genetics Reveals Big Fish That Almost Got Away (Eurekalert)

Photo © Rachel Graham / Wildlife Conservation Society.