April 15th, 2016, Sanya, China – The sun was already high and hot over our heads when the final Nature Conservancy Scientist arrived at Sunny Bay for China’s first extensive coral nursery project. Dr. Phil Kramer, a boisterous and overworked senior scientist on The Nature Conservancy’s (TNC) Global Oceans team, was already geared up to get in the water and survey the nursery site. Kemit Amon-Lewis, one of the managers of the TNCs Caribbean sites, had already arrived to aid Jun in a haphazard acquisition of materials to construct the coral tree nursery for the Park Hyatt Sunny Bay resort – a feat in itself, as material availability varies across continents. The next day TNC staff and volunteers like myself were spread across a grass hill cutting PVC pipes. This coordinated effort across land and sea would take only a week, and indeed could take only a week – TNC’s Board of Trustees was scheduled to explore Sunny Bay the first week of May.
What is a coral nursery? Why install one? Why is TNC, specifically, invested in installing coral nurseries? While I introduced the project briefly when I introduced Sanya, these questions warrant a more rigorous answer.
A coral nursery is a structure that takes coral fragments and raises them into the water column to protect them from predators, algae and sediment. While they take many forms (one of the early fathers of coral restoration Baruchevitch prefers suspended nets), coral trees are the most popular method for building out coral nurseries. They’re cheap and relatively easy to build, and can be adjusted for different ocean conditions. For example, given that Sanya reportedly experiences major storms in the winter, the trees in Sunny Bay were rigged with heavy-duty shackles and duckbill anchors, which are near-impossible to remove. They can be customized for things like tree height/depth of light penetration, number of fragments per tree, and are easy to monitor if you want to pay attention to coral genetics.
To that end, there are several reasons why one might install a coral tree nursery. The primary function of a coral nursery is to grow more coral fragments than are currently being produced on the reef. A local reef might have low recruitment (i.e. low number of new individual corals), or there might have been/will be a bad bleaching event, or you might just be growing coral for sale. Mainly, one hopes the growth of more coral will either maintain or enhance local reef health. The process of installation is in itself a good educational tool, and a local coral nursery is a great way to teach folks about coral conservation. In the case of the Sunny Bay resort the developer hoped to offset some of the damage done by local construction, as much as he and his partner are genuinely concerned about global coral conservation. TNC has, historically, employed trees in the conservation-education model, and in fact lead the charge in large-scale coral restoration.
Actually TNC, alongside Obama’s American Recovery and Reinvestment Act (ARRA), is one reason why coral trees have emerged as the iconic coral restoration technique in the United States. As you might recall, after the Great Recession Obama implemented ARRA as a stopgap for further job loss and economic deterioration. As part of that package, the ARRA allocated funds to government organizations like NOAA to promote infrastructural development. The Nature Conservancy (TNC) received a $3.3 million, 3-year grant from the National Oceanic and Atmospheric Administration (NOAA) to expand on existing acroporid restoration work. The TNC-NOAA Community-Based Habitat Restoration grant program has been funded though 2015 as a regional effort designed to aid the recovery of populations of Acropora corals throughout Florida and the USVI. TNC maintains this project provides social and economic benefits for local communities in addition to long-term ecological habitat improvements. As Kemit explained it, ARRA funding allowed TNC to deploy coral nurseries “at scale,” enabling TNC staff to work out kinks as well as reach a critical capacity of coral specimen, which are healthiest in dense communities. See this post for how such restoration efforts feed in to TNC’s company goals.
Managing coral tree nurseries is akin to managing a small farm plot. Unlike a greenhouse (the coral equivalent of which was recently reported upon in one of my favorite podcasts, The Adaptors), site managers can’t control the water temperature or salinity – specific environmental conditions. But they can adjust the height of trees the way one might adjust fertilizer, or “plant” different species of coral fragment among the trees as warranted by the season. There are pests (fireworms are a problem in the Caribbean), and symbionts (algae-eating fish), and those random environmental incidents that can undo weeks of hard work.
Personally, I like coral trees because they produce “clean” results and are really useful in explaining the hard science behind coral restoration. There are certainly cheaper and lower-maintenance designs, like concrete pucks or table nurseries, but these forms are susceptible to storm damage, algal growth, and theft. Coral restoration, Dr. Kramer confirmed, had a reputation of being pseudo-science for a solid two decades (more on this coming), and it was only through the concerted effort of groups like TNC that coral restoration has new methodologies and good numbers justifying the implementation of nurseries. Coral trees allow you to track genetics, growth and predation rates, and enact a certain degree of environmental control – typically a challenge in marine science.
There is also something to be said for maneuvering between trees at 10 meters, an underwater forest in its own right. You can set a team of divers loose, scrubbing and adjusting and collecting data, dividing tasks amongst trees, doing good work in a single dive. Gleaming rows of PVC get lost in the distance. As ever, I wonder where the line lies between knowing what you’re doing and everything looking like you know what you’re doing. Science can’t even say.
p.s. all underwater photography property of TNC/Mono.