On the reefs of Guam - this year's coral restoration work
Photos: representatives of this year's team left) Underwater World Guam: Curator Mike McCue; mid) Aquarium of the Pacific: Assistant Curator Danny Muñoz, Curator Dr. Sandy Trautwein, and Senior Aquarist Janet Monday; right) University of Guam: Coral Reef Ecologist Dr. Laurie Raymundo
This workshop is part of our collaborative Project Guam aimed at restoring (sexual coral restoration) and protecting coral species of local concern, together with UnderWater World Guam, University of Guam, Aquarium of the Pacific (USA), Columbus Zoo and Aquarium (USA), Henry Doorly Zoo (USA), and Horniman Museum and Gardens (UK). Guam is located near the Coral Triangle, and its reefs feature great biodiversity. Yet today, Guam's reefs are in bad shape. The usual suspects, such as overfishing, pollution, and diseases, in addition to frequent crown-of-thorn seastar (Acanthaster sp.) outbreaks, heavy sediment loads caused by land run-off, and pressure applied by highly developed tourism are giving the reefs a hard fight. Increased efforts have been made to account for the alarming status of Guam's coral reefs by establishing marine preserves―still many coral reefs need protection, and public awareness is poor.
Photos: on the island of Guam left) touristic beach with hotels in the background; mid) deforested hills cause land erosion; right) degraded reef site
Coral gametes―egg-and-sperm bundles―were collected from parent colonies of two branching corals; one in the lab: Acropora digitifera, and one on the reef: A. abrotanoides. Both coral species are reef-building corals, essential for Guam's reefs. “Luckily the corals really cooperated well for us this year”, tells Mike McCue, Curator at UnderWater World Guam. “The corals we had transferred to the lab decided to spawn the night before we expected spawning on the reef, where we also wanted to collect gametes. This worked out perfectly for us, as conditions were really too rough to dive that night. With no one in the water, the whole crew was able to focus their efforts in the lab.” There, A. digitifera gametes were collected by gently skimming them off the surface of the water of the culture tanks.
“The waves let up a bit the following night,” continues Mike, “so everyone was able to concentrate on the gametes that we collected directly from the spawning corals on the reef.” The reef is the 'house coral garden' of the University of Guam's Marine Laboratory and it is located just behind the lab. “It was the biggest spawning event I’ve seen on Guam yet, with at least five different species releasing billions of sperm and eggs into the water column”, describes Mike. “As we came up to the surface at the end of the dive, we were engulfed in a thick layer of spawn that had accumulated as far as we could see. The water was also packed with tons of small animals that were already feeding in the mess, like little bustling worms, crabs, shrimp, and other swirling creatures, all gorging themselves on the feast.”
“We collected A. abrotanoides gametes in situ using specialized cone-shaped nets”, explains Dr. Sandy Trautwein, Curator at Aquarium of the Pacific, who traveled from Long Beach California, USA, with her staff to participate in this year's work. “This event is very significant since A. abrotanoides has never been cultured in this way before, so the Aquarium of the Pacific is thrilled to participate in this research.” The team successfully fertilized the gametes of both species in the lab right after each spawning event and cultured the resulting tiny coral larvae.
Photos: spawning work in the lab left) spawning colony of Acropora digitifera; mid) skimming coral gametes off the water surface; right) collected egg-and-sperm bundles; below) fertilization work
“A few days later, we settled them on special tiles (SECORE Seeding Units, larval settlement), and we are planning to transfer them to a floating nursery within the next two weeks”, says Mike. “Additionally, tiles with corals from the previous year’s spawning event were planted back to one of our local reefs. Hopefully these corals can help to rebuild Guam’s reefs that are in trouble.” Sandy adds, “as we scattered the one-year-old coral tiles onto the reef, we saw at least two colonies of Acropora surculosa that had been outplanted during the workshop in July 2014. What an amazing feeling to know that the Aquarium of the Pacific helped in restoring this little piece of reef!”
Some settlers from last year went on a long journey. They had already made their home on settlement tiles in 2015, and 24 of those tiles were then carefully hand delivered to the Aquarium of the Pacific. Sandy and her team also took back coral larvae of each of the two species. “All the tiles made it home safely”, assured Sandy, “and the larvae have settled on tiles in one of our tanks. We are currently highlighting the SECORE tiles on our daily Behind-the-Scenes Tours for the public. They will be put in a new exhibit explaining our joint effort in Project Guam and the general need to protect corals reefs around the globe.” The nonprofit Aquarium of the Pacific’s 1.6 million annual visitors will then have the opportunity to learn more about the project through this exhibit.
Photos: shipping corals to the Aquarium of the Pacific left) packing corals on settlement tiles; mid) coral larvae go on a journey; right) ready-packed coolers
“All the parties involved are looking forward to a long term partnership with SECORE’s Project Guam, hoping to truly make a difference for coral reefs worldwide”, emphasizes Mike. “We were a smaller team than usual this year, which was nice, as we worked together very closely. In addition to the SECORE crew, we owe a really big thank you to Samuel Nietzer and Mareen Moeller, PhD students from ICBM- University of Oldenburg, Germany, who have been working with spawning corals in Guam for many years now. They helped guide us through several new techniques for fertilizing and settling the coral larvae, even while still busy with their own research. We couldn’t have done it without them!”
Work so far has been on a fairly small scale, but all of the SECORE partners are committed to continue to expand on the work in Guam; especially Mike McCue and his team have been quite persistent. Sandy and the Aquarium of the Pacific team have also been determined in their efforts, traveling to Guam now for the third time in the course of this project to aid in the effort. “The Aquarium of the Pacific is honored to help with SECORE International coral reef restoration in Guam and looks forward to assist with future coral spawning events”, emphasizes Sandy.
Photo: good coral cover on a dive site at Tumon Bay, Guam
Photos by Mike McCue (UnderWater World Guam), Danny Muñoz and Sandy Trautwein (Aquarium of the Pacific), Paul Selvaggio (Pittsburgh Zoo and PPG Aquarium), and Dirk Petersen (SECORE)
by Carin Jantzen