Herbivore Stocking - Mission: Iconic Reefs

HERBIVORE STOCKING: GRAZERS HELP CLEAN THE REEF

Photo by Jay Clue

M:IR integrates non-coral species with key ecological functions to facilitate and reinforce ecosystem recovery and resilience. Herbivores, such as long-spined sea urchins and Caribbean king crabs are part of the strategy that will reduce nuisance algae that compete with corals for habitat. At all seven sites, scientists will remove nuisance species like algae and snails, and reintroduce sea urchins and crabs to help keep the reefs clean and healthy.

Caribbean King crabs are natural grazers, feeding on algae that can consume healthy corals. A clutch of eggs contains thousands of potential offspring.

Funded in part by NOAA, Mission: Iconic Reefs partner MOTE MARINE LABORATORY & AQUARIUM created the first ever land-based Caribbean King Crab hatchery at Moteʼs Aquaculture Research Park near Sarasota that will allow for the production of this native herbivore which will be stocked onto degraded reefs along with coral outplants. The crustaceans are large native reef herbivores that consume algae, which competes with corals, slowing down and removing their ability to reproduce or killing the coral outright.

After stocking, these reef grazers significantly reduce algal cover leading to a benthic community that promotes a more abundant and rich fish community. This increases the survival of coral outplants and clears space for natural coral recruitment. The four-year project implemented in 2023 represents a science-based and scalable pathway to transformative and functional restoration.

Long-spined sea urchins (Diadema antillarum) suffered die-off in the 1980s, but as natural grazers, they play an important role in the coral landscape, consuming benthic algae and detritus for sustenance. The urchins are being raised in cages until they are large enough to be released onto the reef.

Additionally, research partners at University of Florida are aquaculturing long-spined sea urchins. Once very abundant on Floridaʼs reefs until the population was impacted by disease in the early 1980s, these urchins also eat algae, creating open space on the reef for corals to settle. Since the large die-off, there has been a significant shift from a coral-dominated reef to an algae-dominated one.

Video courtesy Wildlife Nation with Jeff Corwin Expedition Florida and HEARSTMPG.