Genetic testing shows that one of the most commercially important fish in the Arabian Gulf, the orange-spotted grouper, is actually three distinct species.
Currently sold as one species (Epinephelus coioides) at local markets, the fish have been reported as overfished in the region at six times the sustainable level.
In the Marine Pollution Bulletin, NYU Abu Dhabi researchers led by 2015 graduate Remi Ketchum, offer new findings into the genetic diversity of the grouper in an effort to resolve the species composition of fish marketed throughout the United Arab Emirates as hammour, to inform management strategies, and to generate molecular markers that can be used for species identification and monitoring.
The researchers sequenced mitochondrial DNA from 140 tissue samples collected in four fish markets and analyzed the data to reveal the presence of three distinct Epinephelus species: not only Epinephelus coioides, but also Epinephelus areolatus and Epinephelus bleekeri.
“These species look similar, but are genetically distinct from one another,” says associate professor of biology John Burt. “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.”
“This study highlights the value of using genetic techniques on natural populations,” adds Ketchum. “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.
“I hope these findings will aid fisheries management and also prompt people to choose a more sustainable fish for consumption.”
Youssef Idaghdour, assistant professor of biology, adds: “This work provides a much-needed snapshot of the genetic makeup of grouper species in the UAE. 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.”
Source: New York University