Coral Disease Recurs
An outbreak of the coral disease known as Montipora White Syndrome (MWS) has again been detected in the reefs of Kaneohe Bay. In March of 2010 an outbreak of MWS killed over 100 colonies of rice coral. Now the disease has reappeared and is killing even more than before, having already affected 198 colonies.
A rapid response team of scientists led by Dr. Greta Aeby of the Hawaii Institute of Marine Biology has been dispatched to document the outbreak. But can it be stopped?
“In corals, like humans, you’re never going to get rid of disease,” says Aeby. “The amount of death from these outbreaks is what we’re trying to restrict.”
One hopeful idea involves the response team using bone saws to surgically remove lesions from infected colonies, a method that has been successfully utilized in other areas like Australia. However, funding is still pending to get the operation below sea level.
“We have a grant proposal in, if it gets funded, we’ll do a trial period to see if it will work,” says Aeby. “We already know what happens if we don’t intervene. [MWS] will kill the colony, and go from colony to colony.”
Having already studied MWS for several years, Aeby’s team knows it is an infectious disease caused by pathogenic bacteria that affects only rice corals. Rice corals are one of the most abundant corals in the state, and, according to Aeby, they make up about half the corals in Kaneohe Bay.
Due to the northern end of the bay’s open exposure to open ocean and water circulation, the majority of the outbreaks are occurring in the southern end of Kaneohe Bay. However, Aeby notes that another notable reason for the disparity is the huge difference in human population between the north and the south bay.
“Any time you have humans, you have fertilizer, pesticides, herbicides, oil drips from their cars,” she says. “You have all this stuff on the land, and when it rains, that tends to run into the bay.”
Aeby also says that coral diseases have long been predicted to occur more frequently on reefs due to chronic stress from humans and seawater temperature changes from global climate change.
“What we’re seeing here in Hawaii is that the reefs are starting to follow the same pattern as what happened in the Florida Keys in the 1980s,” says Aeby. “We’ve been putting these chronic stressors on them for decades, and it’s starting to show.”
Aeby also encourages anyone interested in helping out to join the Eyes of the Reef Network, which is comprised of regular reef users (including regular divers, snorkelers, scientists and fisherman) who voluntarily monitor and report the state of the reefs that they frequent.