Parrotfish—brightly colored, roving vegetarians of tropical oceans—are a precious element of the marine ecosystem in the Caribbean waters off the coast of Belize. It’s not because schools of resplendent parrotfish add a swirling rainbow of colors to the turquoise waters, although they do that too.
Instead, they have a much higher calling—playing an essential role in protecting the health of the world’s second largest barrier reef system. Insatiable plant eaters, parrotfish spend most of their lives munching on grasses, and most importantly for the health of the reefs, algae, which if left unchecked can strangle the life out of coral.
In the fall of 2017, Hayley Goss and Jacob Jaskiel were in Belize collecting seagrass blades from underwater meadows in the warm, shallow coastal waters of the western tropics. Goss and Jaskiel, student researchers at Boston University, weren’t thinking about plastic pollution in the ocean when they put on their snorkel gear and dived down to the seafloor, snipping away at the seagrasses—a species called T. testudinum—swaying in the underwater breeze of the currents. Instead, they were thinking about salad dressing.