Looking for the best larval restoration site in the Bahamas
Here is her report.
I was excited but not completely sure what to expect on our Bahamas scoping trip to determine the best prospects for a spawning site to address our 2018 Acropora research goals. SECORE is collaborating with Dr. Craig Dahlgren (Perry Institute of Marine Science) and Dr. Nicole Fogarty (Nova Southeastern University) to investigate the potential for the Acropora hybrid (Acropora prolifera) for large scale outplanting and to implement larval restoration in the Bahamas. These hybrids form naturally, likely when the two parental species are in skewed abundance so eggs encounter sperm from the opposite species prior to their own. A phenomenon known as ‘hybrid vigor’ may confer added resilience to hybrid corals. Dr. Fogarty has focused much of her research career on the ecology of Acropora prolifera, observing it to be sometimes in high abundance in stressful habitats. Our collaborative project aims to test the success of hybrid larvae (compared to the parent Acropora palmata) in restoration.
Thus, we need to identify a workable spawning site with both parental species - elkhorn and staghorn corals - available. With the benefit of Craig’s extensive local knowledge and logistics, we were headed to check potential sites on two islands, Abaco and Andros. Our criteria included robust Acropora palmata (elkhorn coral) AND Acropora cervicornis (staghorn coral) colonies at the same, accessible spawning site.
photos: left) Abundant robust elkhorn corals at Sandy Cay reef, Abaco. (Margaret Miller); mid) Collaborator Dr. Nicole Fogarty takes samples on a Abaco reef. (Margaret Miller); right) SECORE Research Director Dr. Margaret Miller and a NSU grad student preserve biopsy samples. (Nicole Fogarty)
First stop: Marsh Harbor, Abaco. After an early flight over from Fort Lauderdale with the NSU team, Craig picked us up at the airport and we headed out to Sandy Cay Reef via a rental boat. We snorkeled around this patch reef and were treated to a lovely, abundant stand of Acropora palmata, but only a few spawnable-sized Acropora cervicornis, and several hybrid colonies mixed in. Thus, our conclusion was “not perfect” due to low abundance of Acropora cervicornis, but a very workable site and excellent Acropora palmata.
Photo: A Acropora hybrid (Acropora prolifera) at Sandy Cay reef, Abaco. (Margaret Miller)
The NSU team collected a few biopsy samples from all three species across the span of the reef to determine that there is adequate diversity in the populations there to provide for successful larval production. We enjoyed our stay at the Kenyon Research Station operated by Friends of the Environment, Abaco.
The next morning we ran around in the boat specifically looking for sites that would be amenable for deploying the in situ larval pools. On advice from the FoE folks, we examined a mooring that is just south of the potential spawning reef, of appropriate depth, and reasonably protected from the incoming swell so we think this will be a workable option, though it will require extensive boat access to tend the pools during deployment. That afternoon we flew back to overnight in Nassau and meet our charter flight to Andros the next morning.
Andros: We were privileged to be hosted by Small Hope Bay Lodge dive resort in Andros. We hoped, based on Craig’s observations here in 2015, that there would be more extensive Acropora cervicornis stands available. In fact, we were disappointed in this regard. One site we visited clearly had been affected by recent hurricanes with many fragments of both Acropora spp. The good news is that these fragments were re-growing well, but will require a few years to provide a good spawning stock. The other site where Craig had previously observed an extensive healthy Acropora cervicornis patch, was still intact (indicating hurricane damage was not the primary culprit), but was ~ 80% dead. Although Acropora palmata was still present at a range of sites here, our overall determination is that Abaco provides us a better option. We will be making more specific plans for summer 2018 at Sandy Cay reef, Abaco for our Bahamas Acropora efforts.
Photos: left) The scientists on their charter flight to Andros (Nicole Fogarty); mid) Mostly dead staghorn corals at Aquarium Reef, Andros. (Margaret Miller); right) Regrowing elkhorn coral fragments that broke off during recent hurricanes (Margaret Miller)
After another overnight in Nassau, we bid farewell to the NSU team and I proceeded with Craig on to visit Cape Eleuthra Institute on an early morning flight. I was looking forward to visiting this facility which will host two new PIMS research staff focused on coral restoration, and also scoping plans for the mixed species boulder coral spawning and larval culture anticipated for Sept 2018. After shuttling back to Cape Eleuthra Institute from the airport and a bit of paperwork, we headed out to a reef site that, as promised, hosts a great diversity of boulder corals, including three or four which we hope to collect and culture larvae. This site is around a ‘blue hole’ which may help moderate temperatures.
I was also excited to see an abundance of Mycetophillia ferox, a rare threatened species of which I had seen very few in my previous experience. We also visited several other nearshore reefs, finding plenty of head corals, including a more accessible site that will be good for monitoring for Diploria labyrinthiformis (Grooved brain coral) spawning starting in the next couple of months. We also visited a marina that could have served as a good site for the in-situ pools, but for the regular patrol of bull sharks that are attracted to their fish cleaning stations.
photos: left) The Island School of the Cape Eleuthra Institute. (Margaret Miller); mid) A shallow Acropora reef off the East side of Eleuthra (Margaret Miller); right) Sharks in the Cape Eleuthra Marina. They convinced the scientists that the marina was not a good place for their in-situ pools. (Margaret Miller)
Sunday morning, we headed out early to hit a slack tide at a back reef hard bottom site with an extensive stand of Acropora cervciornis. This site generally has very strong currents and so is not a great candidate for spawning, but this was indeed the most extensive Acropora cervciornis stand we observed on the trip. We got a great look at the wet lab and re-vamped outdoor tank facility at Cape Eleuthra Institute and brainstormed on restoration-related projects for the new staff to tackle, including brooding coral larval collection and experimental outplants from the local coral nurseries.
Overall, a fantastic week island-hopping. We now have a great start to more specific planning for Bahamas spawning operations for summer 2018. Thanks to Craig for arrangements and the folks at Small Hope Bay Lodge (Andros) and Cape Eleuthra Institute for taking such good care of us!
Margaret Miller, SECORE Research Director