Climate change is altering the ecology of the world's coral reefs and, in turn, affecting fish feeding behaviors and food availability for millions of fish that rely on reefs for their main meals.
NYU Abu Dhabi, located on the shores of the Arabian Gulf, has a unique opportunity to better understand fish diets in water temperatures that are as high as conditions predicted for the next century elsewhere in the world. The Arabian Gulf heats up to 37 degrees Celsius in the summer months, the same as human body temperature.
To find out more about the diets of local fish, NYUAD student and faculty researchers analyzed the stomach contents of three different fish species seasonally over a year long period. Their research provides the first detailed description of what fish in the southern Arabian Gulf eat, and shows how their diets change when sea temperatures fluctuate from cool at the start of the year to extremely hot in the summer.
- Sample period: one year, with samples collected seasonally
- Fish types analyzed: Arabian angelfish, Dark damselfish, and Paletail damselfish
- 146 stomach content samples processed
- Samples sequenced using next-generation metagenomics approach
It's unusual to see fish eat so much coral
Professor John Burt, principal investigator of the NYUAD Marine Biology Lab, said one of the most interesting research findings is that coral is the major component of the diets of all three reef fish species.
“It’s fascinating because none of these species are known to consume coral in any meaningful quantity in other regions,” he said.
“Our study provides some amazing insights into the unusual nature of fish diets in the thermally extreme southern Arabian Gulf, allowing us to start making predictions about how reef fish diets in other parts of the world might shift as climate change makes those areas warmer,” Burt added.
The research also made some interesting conclusions about the diets of Arabian angelfish, Burt said. Elsewhere in the world, angelfish are mainly known to specialize on sponges, but off the shores of the UAE, sponges account for only a very minor portion of their diets.
“Sponges are fairly rare in southern Arabian Gulf reefs, so it appears that angelfish are switching their diets away from their preferred food to one that is much more common here: coral,” he concluded.
Diets of damselfishes also changed dramatically over the course of the year, the study found, fluctuating from periods where they mainly consumed coral to periods when their diets widened to include a suite of other organisms, particularly in the spring. Broadening diets by season might be a strategy to build up energy reserves quickly before the onset of the summer heat, Burt said.
The research, published in Frontiers in Marine Science, was a Capstone project led by NYU Abu Dhabi alumna Rasha Shraim, a biology major in the Class of 2016.
The project used next-generation sequencing approaches to examine fish stomach contents rather than traditional microscopic surveys, which is also unique.
“Traditionally, researchers would have to pore over microscopes and visually sort through and try to identify small and partially digested pieces of foods. The metagenomics approach used in this study proved to be a fast and effective means of quickly identifying the materials in stomachs, including a wide variety of items that could never be identified using traditional approaches,” Burt added.