The Feeding Behavior of Coral Reefs

The feeding behavoir of all life on the coral reef is a true synergy of plants, plankton, invertebrates and fishes in a food chain of predator and prey with a strong diet of balance both on and off the reef.

Forming the base of the reef and the base of the food chain is the living coral feeding in a symbiotic relationship on algae known as zooxanthellae which takes in carbon dioxide and through photosynthesis emits oxygen to the living coral polyps providing life and colour. This limestone column shaped coral creature attaches itself to each other and then to a surface though a tissue connection at with one end and grows out the other end to develop and entire colony which will eventually form a reef. Absorbing calcium in the sea they build themselves up through depositing a calcium carbonate, limestone, around their base as they grow. Within the colony as coral polyps dies off their limestone skeletons continue to support the growing community as a reef is forming. The intricate coral structure shapes over time trapping rock, sand and grasses and creates a home to a sustainable bio-diverse system and structured food-chain within the reef.

The feeding behaviour within the coral reef is based on the structure of the coral, sand, sediment and sea-grasses all of which are important parts of the food cycle in the reef. The grasses filter sediment, release oxygen and provide protection to young sea life and stability to the reef itself. Within the ecosystem are many varieties of fishes. Herbivorous fish make up about a quarter of life in the shallower water of the reefs where light levels promote algal growth, with Carnivores being the largest population in the deeper waters of the reefs.

Herbivorous fishes include Nomadic varieties which have the ability to forage wide areas and have stronger jaws and teeth adapted to scraping algae off the corals and excreting sand back into reef. Many Herbivorous fish stay in groups offering protection from predators as they graze the grasses and sandy areas. They also have an adapted ability to hover in the waters and flexibility in small spaces. Sedentary herbivores actually care for the algae gardens preventing other herbivores from totally destroying the grasses.

Carnivorous fishes make up about half of the reef’s species and rely on capturing invertebrate prey for their food making for a more solitary hunter existence and a need for protection themselves from other prey. They must have abilities to self camouflage, swim precise and have adapted abilities allowing them to reach in to pull out prey from hidden spaces with strong jaws able to penetrate shells. For self protection while hunting these carnivorous fish often have chemical protecting abilities, spiny plate like armour and protective exteriors.

Many predators have adapted to nocturnal lifestyles to be able to eat the many invertebrates feeding in the sand flats at sea grass beds at night. These preys have evolved with large mouths and the ability to suck in the sea and close their jaw expelling the water in the mass feast. Others school-up for feeding travel off reef in groups traveling along bottom trails. Sponges also offer a diet to some fish having strong jaws and overlapping teeth needed to penetrate the tough sponge materials.

Planktivorous fishes feed on planktons as juveniles in schools for protection above or near the reef, but with some of these species growing very large they eventually forage alone not worrying about predators. Moray eels have adapted bodies able to hide in elongated spaces waiting almost motionless for unsuspecting prey grabbed with expandable jaws to suck in the fish.

As the reef provides many natural methods of protection few species venture far from the ecosystem providing all their food needs. Larger predators stray farther as they have a greater ability to protect themselves and swim faster and have many developed strategies to pursue, stalk and ambush their prey all in the complex dance of the feeding behaviors of coral reefs.