Genetics analysis reveals this fish is actually three species in one

The orange-spotted grouper, one of the most commercially important types of fish in the Arabian Gulf, is actually three different and distinct species, geneticists from New York University report in research appearing in the latest edition of the Marine Pollution Bulletin.

Remi Ketchum, a graduate of NYU Abu Dhabi, and her colleagues sequenced the mitochondrial DNA of 140 different tissue samples collected in four markets. They discovered that the grouper, currently marketed as a single species (Epinephelus coioides), is actually three.

In addition to Epinephelus coioides, the species Epinephelus areolatus and Epinephelus bleekeri are also being sold throughout the United Arab Emirates, the study authors explained earlier this week in a statement. While they look similar, they are genetically distinct from one another, associate professor of biology and study co-author John Burt explained.

“This has important implications for fisheries management, as earlier management efforts, which had assumed there was just one species, need to be broadened to account for possible differences in the biology of these three species,” he added. Their work will help generate molecular markers that can be used to identify and monitor the different species.

Findings could lead to improved efforts to protect the species

Epinephelus coioides is currently marketed throughout the UAE as hammour, and is so popular that even when it was believed to be one species, it was reportedly overfished at six times levels deemed to be sustainable. The NYU-led study could help improve conservation efforts.

“This work provides a much needed snapshot of the genetic makeup of grouper species in the UAE,” said NYUAD Assistant Professor of Biology Youssef Idaghdour. “With the rates of climate change, overexploitation and other environmental pressures in the region, biodiversity and genetic variation of marine species are under severe threat. These findings reinforce the importance of genetic monitoring for sustainable management practices.”

“From a highly informative mitochondrial DNA marker, we were able to tell that these three species have levels of genetic diversity that are similar to other critically endangered grouper species and that there are two species that remain underreported in the UAE,” added Ketchum. “I hope these findings will aid fisheries management and also prompt people to choose a more sustainable fish for consumption.”

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