Healthy Reefs, Healthy Fish

Red grouper are habitat engineers, creating complex habitat that enhances biological diversity.

• Red grouper help expose hard substrate that creates settlement sites for sponges, corals, anemones and other species. 
• The presence of more red grouper can increase both species richness and an abundance or reef fish.

Other habitat engineers include goliath grouper and golden tilefish. 

When coral growth rates were compared between reefs with high fish biomass (total quantity or weight of organisms in a given area) and low fish biomass, scientists found the following:

• Coral reef sites with high fish biomass have higher coral growth rates, likely due to nutrient availability created via fish excretions.
• Large numbers of schooling fish create nutrient hotspots and a site with less algae cover and more crustose coralline algae cover, a seaweed important for coral settlement.

This research indicates that a coral reef restoration strategy should include planting nursery-raised corals on existing nutrient hotspots at high fidelity sites with a high biomass of fish.

Commercially and recreationally important reef fish, including mutton snapper, use a variety of habitats throughout their life cycle. Oyster reefs, seagrass beds, mangroves and coral reefs provide food, nursery grounds and shelter.

• Seagrass and mangrove habitat are particularly important for mutton snapper during the juvenile stage.
• As mutton snapper grow, coral reefs become the supporting habitat for food, nursing grounds and protection from predators.