Pollution, climate change, and poor land use practices can create environmental conditions that foster coral disease and coral bleaching, support the spread of invasive species and threaten reef health. Detecting the early signs of any of these events on our local reefs requires a wide network of observers providing regular reports of conditions throughout the region. The Eyes of the Reef network has been designed to provide reliable reports on coral bleaching, disease, invasive species and changing reef conditions throughout Hawai‘i.
Coral Bleaching, Disease and Growth Anomalies
There are many natural and human factors that negatively affect corals and coral reefs. These negative factors generate stress. Consequences of stress include coral bleaching, greater susceptibility to disease, diminished growth and reproduction, and partial or complete mortality. Repeated exposure to stress decreases the likelihood of coral recovery. Coral disease, bleaching and predation are indicated by changes in coral color, a loss of tissue with bare skeleton exposed or abnormal growths or protuberances.
Crown-of-Thorn Sea Stars (COTS)
COTS are unusually large sea stars that can grow to almost a meter in diameter. They have up to 19 arms, with the entire upper surface covered with sharp venomous spines and can move up to 20 meters an hour. COTS feed on coral by pulling its stomach out and using digestive enzymes to kill the live coral, leaving the white calcium carbonate skeleton. COTS are normally present in small numbers on coral reefs, but when outbreaks occur they can take over coral reefs quickly.
Marine Invasive Species
Marine invasive species are recognized globally as a major threat to marine ecosystems, and locally are responsible for millions of dollars worth of damage to vital and important Hawaiian coral reefs as a result of diminished fisheries and lowered property values. These biological invasions dramatically affect reef ecosystems, causing a complete change in biodiversity and a shift from coral to algal dominated reefs. Human-caused changes to natural reef communities, such as overfishing, increased nutrients, sediments and pollution, make them more vulnerable to invasive species. Hawaiian reefs have experienced considerable damage from both introduced and native algal and invertebrate invasive species.
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