Building upon the success of 2017’s pilot coral spawning project, headed by Jenny Mallon as part of the Caribbean-wide reef restoration research project of Dr Anastazia Banaszak at the Integrative Reef Conservation Research Laboratory at the National Autonomous University of Mexico in Puerto Morelos, this summer we expanded to involve more volunteers and to cover a greater reef area and several coral species in our spawning observations.
Planning and preparation for this once a year event started months ago, leading up to a flurry of activity here in Akumal making spawning collection nets, disinfecting equipment, filtering sea water for our tanks, planning dives at three monitoring sites and preparing the laboratory for assisted fertilisation and incubation of the coral larvae. Volunteers from Akumal Dive Center and Operation Wallacea were trained in advance of the spawning with a short course presented by coordinator Jenny Mallon, following Dr Banaszak and her research group’s ‘Guide to Coral Reproduction’.
Night dives to observe and collect coral spawning
We monitored for spawning of Elkhorn and Staghorn Acropora species, Brain coral Diploria labyrinthiformis and were lucky enough to report an incidental observation of the iconic Pillar coral, Dendrogyra cylindrus, spawning. At the end of a week of night dives, we finally observed Acropora palmata spawning, collected gametes and fertilised the collected samples in our on-site laboratory. Due to the timing of the full moon this summer very few monitored sites in the Caribbean produced spawn, so we were relieved that Akumal was one of the sites to show sexual reproduction in the Acropora population.
Each night, after sunset, three trained teams monitored for Acropora palmata (Elkhorn, Cuerno de Alce) and Acropora cervicornis (Staghorn, Cuerno de Ciervo) at distinct sites within Akumal. Divers and snorkellers looked for signs of eminent spawning, known as ‘setting’ whereby hermaphroditic gamete bundles are pushed forward to the mouth of the polyps on a portion of the branch. This year setting occurred the day before spawning, nearly an entire week after we expected it to.
Making baby corals for reef restoration
The gametes collected from distinct colonies at different sites were were cleaned and fertilised, and we continued to monitor larval development round the clock for the following week.
As the larvae were developing, we retrieved the substrates designed by SECORE International and made for us by Dr Banaszak’s team in Puerto Morelos. The substrates had been conditioned in Expedition Akumal’s coral nurseries accumulating biofilm including Crustose Coralline Algae (CCA) which promote coral larvae settlement. The substrates were placed in the coral larvae tanks awaiting the larvae to settle on them. The larvae have now settled, metamorphosed into primary polyps, and have been transferred into the coral nurseries where they will to sequester symbiotic microalgae, Symbiodinium spp., which they require to photosynthesize.
Meanwhile, we were able to share the importance of Expedition Akumal’s reef research with local children from Hekab Be Biblioteca. Many knew how integral the reef is to this community and were delighted to see a video of the larvae swimming taken with our microscope.
Local support for the Expedition Akumal spawning project
To celebrate the success of our project we donated t-shirts printed with Expedition Akumal’s “DESOVE 2018” logo to the Akumal Dive Center employees who volunteered extra hours each night to support lead biologist Jenny Mallon in the field acitivites she trained and conducted for this project.
The project was made possible by the consistent support from Hotel Akumal Caribe who on top of their usual genorisity also extended to provide food and accomodation for volunteers and visiting scientists.
Thanks to the extra support from Operation Wallacea volunteers, local and visiting volunteers for their hard work and long hours which have resulted in successful fertilization of Acropora palmata as part of Expedition Akumal’s reef restoration intitiative.