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Feeding Fish and Island Nations: IntelliReefs as Marine Restaurants

Updated: Nov 11, 2020

IntelliReefs Ocean Buffets

The results from our fish behaviour study in Sint Maarten indicate that fish are feeding off the IntelliReefs every 15 seconds (publication in preparation). This is nearly 4x higher than other healthy natural and artificial reefs using the same methods.

As reef loss continues to accelerate around the world, fish are losing valuable food sources and their homes. One of the fastest ways to combat these pressures is by deploying additional hard substrate into degraded reef systems to quickly build back three-dimensional habitat and provide healthy surfaces for fish populations' food source - benthic marine plants and animals - to settle directly on.

Several species of Caribbean fish feeding and resting on pilot IntelliReefs in Philipsburg, Sint Maarten.

IntelliReefs are cast from bioenhancing proprietary mineral mixtures called Oceanite. Our mixtures are chosen to enhance the growth and development of desired species and can be completely customized to site and function - including pH values. Unlike Portland cement, the pH of Oceanite mineral mixtures is customizable, which allows us to create ideal growth conditions for target species by fine-tuning and controlling substrate pH.

Portland cement and 3D printing binders can burn animal tissues when they come into contact with it because it has a pH around 12. Oceanite mixtures can currently attain a pH as low as 8.1, corresponding directly to the surrounding ocean’s pH value.

The porosity of the material provides more surface area for animals to live in the crevices, creating a living substrate that is unparalleled in marine construction materials. Within months, Oceanite can foster nearly 100% coverage of a healthy benthic coral reef community, feeding fish populations quickly.

In November 2018, the IntelliReefs team deployed 3 pilot Oceanite structures off the coast of Philipsburg, Sint Maarten to compare the recruitment of marine life between the natural reefs and IntelliReefs artificial reefs. Our researchers analyzed the animal and plant community directly on the structure and the fish community that feed on and shelter inside the IntelliReefs. We found that fish are feeding off the IntelliReefs approximately every 15 seconds. This is nearly 4x higher than other healthy natural and artificial reefs using the same remote monitoring methods. Fish species have different feeding preferences: some only feed on plankton and small fish, others are purely vegetarians, and others still are omnivores, eating whatever they can find. Many of the foods that fish depend on grow on hard substrates and can be difficult to find on degraded reefs. IntelliReefs promote rapid, healthy, biodiverse growth of the species that feed fish on coral reefs.

How Additional Habitat Creates Food for Fish

Around the world, both coastal and inland communities rely on the ecosystem services that coral reefs provide. It is estimated that reefs generate an annual revenue of over $11.9 trillion from fisheries, ecosystem services (i.e. storm protection, medicine, etc.), tourism (Coral Reef Education Institute). Globally, fisheries alone from coral reefs are conservatively estimated to be worth around $5.7 billion (Scripps Institute of Oceanography). The fish that grow and live on coral reefs are a significant food source for over a billion people worldwide and contribute to both local and global food security and economies.

Schools of fish sheltering on a coral reef in Raja Ampat, Indonesia.

Coral reefs are large structures, built over hundreds of years, and as they deteriorate due to warming and acidifying waters, coastal erosion and runoff, and increasing frequency and intensity of storms, they are losing coral cover and their three-dimensional structure. On healthy coral reefs, erosion of coral structures is balanced by the accretion of new coral skeletons by healthy colonies.

The result of prolonged and severe reef degradation is that reefs around the world are being flattened. This leaves fish populations on the reefs without food and shelter, making them more vulnerable to predation, disease, and fishing.

IntelliReefs have been found to not only provide non-toxic, pH balanced additional habitat to shelter fish, but also grow healthy, vibrant reef communities with nearly 100% cover of marine organisms for fish to feed on within months of deployment.

Although they are often called the "rainforests of the sea", coral reefs are made predominantly from animals instead of plants. Coral reefs are highly complex, living structures comprised of many colonies of corals. These colonies are made up of many tiny individual animals that grow together, called coral polyps.

Over hundreds of years, these colonies deposit massive reefs underwater, which humans rely on for food, storm protection, and tourism. Each polyp has a mouth surrounded by stinging tentacles that immobilize planktonic prey and bring them to their mouths. Many coral species are also photosynthetic, and have tiny microalgae living in their tissues. The algae convert sunlight into nutrients, which are then delivered to the corals. As coral colonies grow, they deposit a strong calcium carbonate skeleton. Over time, these skeletons build up massive reef structures that can span for kilometres and house thousands of species.

Close-up of coral polyps under ultraviolet light.

Much like birds that flit from tree to tree on dry land, fish seek complex habitats underwater that offer a high amount of vertical relief. This provides them with shelter from predators, as well as a place to lay eggs and rear young in relative safety.

Fish are attracted to the structure of coral reefs for another reason; for dinner. On hard-bottomed substrates in marine environments, animals and plants fastened themselves to rocks, bedrock, and volcanic deposits. These marine species are anchored to the seafloor, and are known as the benthic community. Many fish on reefs rely on these animals and plants as their primary food source.

As overfishing and reef degradation intensify around the world, the compounding effects of biodiversity and species loss will be felt by over a billion people (13% globally) who rely on reefs for food and economic security. While many countries have deployed artificial reefs to address these issues, the vast majority of man-made underwater structures are not large enough, durable enough, or biologically viable enough to make a real difference on an ecologically relevant scale. The biological and physical benefits of IntelliReefs address the most pressing conservation concerns globally. Contact IntelliReefs today to discuss your marine conservation needs and for a direct consultation.

A blenny sheltering in a coral.

Photo credits:

  • Title photo by David Gross / Coral Reef Image Bank.

  • Schools of fish sheltering on a coral reef in Raja Ampat, Indonesia by Jayne Jenkins / Coral Reef Image Bank.

  • Fish sheltering under coral knoll by Grant Thomas / Coral Reef Image Bank.

  • Close-up of coral polyps under ultraviolet light by Ramona Osche / Coral Reef Image Bank.

  • School of squirrelfish with diver on reef by Yen-Yi Lee / Coral Reef Image Bank.

  • Several species of Caribbean fish feeding and resting on pilot IntelliReefs in Philipsburg, Sint Maarten by Emily Higgins / IntelliReefs.

  • A blenny sheltering in a coral by Cristina Mittermeier.

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