Identification of three different species of grouper for sale at local markets will impact future conservation

Student and faculty researchers at NYU Abu Dhabi have used genetic testing to determine that one of the most commercially important fish in the Arabian Gulf, the orange-spotted grouper (regionally known as the hammour), is typically marketed and sold as one species, but the fish on sale are actually three distinct species.

Hammour are currently managed and sold as one species in local markets (Epinephelus coioides), and have been reported as overfished in the region at six times the sustainable level. In a new paper published in Marine Pollution Bulletin researchers at NYU Abu Dhabi, led by Class of 2015 graduate Remi Ketchum during her time at the University, offer new findings into the genetic diversity of the grouper in an effort to resolve the species composition of fish marketed throughout the UAE as hammour, to inform management strategies and to generate molecular markers that can be used for species identification and monitoring.

The researchers at NYUAD sequenced mitochondrial DNA from 140 tissue samples collected in four fish markets and analysed the data to reveal the presence of three distinct Epinephelus species being marketed and sold as one: hammour. In fact, the hammour on sale in the UAE is not only Epinephelus coioides, but also Epinephelus areolatus and Epinephelus bleekeri.

According to NYUAD Associate Professor of Biology John Burt, "This was the first application in the Gulf of genetic approaches to hammour, one of the most highly valued fish species in the region. The results were highly informative in showing us that what is being marketed as a single species hammour is actually three separate species. These species look similar, but are genetically distinct from one another. 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."

NYUAD Assistant Professor of Biology Youssef Idaghdour said, "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."

NYUAD Class of 2015 graduate Remi Ketchum said, "This study highlights the value of using genetic techniques on natural populations. 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."

According to Professors Burt and Idaghdour, the faculty researchers involved in the project, it's quite remarkable for this type of research to be led by an undergraduate student. "This breakthrough research was largely accomplished by the hard work and ingenuity of an NYU Abu Dhabi student," said Burt. "It is a rarity in most universities for an undergraduate student to produce research that leads to publication and we are extremely proud of Ms. Ketchum's efforts to further our knowledge of a species of such high economic and cultural importance to the UAE."

"Our initial aim was to focus on one species but in the process, Ms. Ketchum had a ‘Eureka' moment when she first looked at the genetic data and discovered the presence of three species in her collection. The results are a testament to what undergraduate student research can lead to" added Idaghdour.

Understanding the patterns of genetic diversity in fish species is essential for marine conservation as it enables researchers to determine the effects of overfishing and environmental pressures and informs the appropriate government bodies that manage species specific protection measures.