SAIPAN – Although bleaching remains a major challenge, divers and snorkelers are also affecting the coral reefs in the CNMI, according to Kaylie Anne Costa of the Coral Nursery and Restoration Project, and marine biologist Dr. Lyza Johnston of Johnston Applied Marine Science.
"We see impacts from divers and snorkelers at some of the tourist destinations, though the diver-specific impacts are limited mostly to the roped entry and exit routes at Laolao Bay and Obyan Beach," they added.
With researcher D'amy Steward of Healthy Oceans, they were recently on Saipan to conduct a presentation on their research project in the Saipan lagoon through the Asia Pacific Academy of Sciences, Science Education and Environmental Management.
At Managaha, they said, snorkelers have flattened most of the nearshore corals by standing on them, and there was also evidence that people had been feeding the fish "which changes their behavior and can cause an imbalance in the local ecology."
They added, "There is also some concerns that overuse of these areas may be contributing to some of the red flags ... at the Grotto and some of our other high-use beaches."
Costa and Johnston said typhoons Soudelor and Yutu caused some direct damage to the reefs, but the biggest impact to coral from the storms "was probably all of the marine debris – a considerable amount of building materials, including tin roofs, and green debris like tree limbs, can still be found both in the lagoon and out on the forereefs."
"Storms aren't trivial," they said, "but the biggest threat ... (are) the major bleaching events caused by extremely warm waters that occurred in 2013, 2014 and 2017."
Reefs have 'declined drastically'
In their study, Costa and Johnston said the coral reefs in the CNMI have "declined drastically over the last five years due predominantly to mass bleaching events, which occurred in 2013, 2014 and 2017."
They said they are still in the beginning stages of developing a restoration program for the CNMI, adding that they have so far installed 10 trees in the Saipan Coral Nursery.
Those trees have a maximum capacity of 100 fragments each, or 1,000 coral fragments in total, they said.
Costa and Johnston said they have fragmented 40 parent colonies from five different species in the lagoon and shallow forereefs of Saipan.
The nursery currently houses 400 coral fragments, they added.
"We hope to double this number in a few months once the corals are large enough to be propagated," they said, adding that they will break each fragment in half and keep both halves in the nursery so they can grow out again for another few months.
In the near future, they said, they hope to create a volunteer program to get the community involved in the nursery.
They said they want to train volunteer divers and snorkelers from the community to help with nursery maintenance, including removing algae, propagating corals and outplanting activities.
At present, Costa and Johnston said the community can help preserve the coral reefs by spreading the word about their importance; introducing more eco-friendly practices into their daily lives; and practicing reef-safe diving.
"Saipan's remote location and lack of a readily available scuba-certified labor force will create challenges as the nursery grows beyond what can be managed by a small team," they said.
They added that cleaning and outplanting in particular are relatively dirty jobs that many nurseries achieve through partnership with universities or specialized volunteer groups, but the CNMI doesn't currently have an equivalent.
"We are hoping to be able to scale up our efforts in the near future, using corals that have survived the recent bleaching events and are therefore more resilient to thermal stress," Costa and Johnston said.