SECORE scientists collecting sperm and eggs from staghorn coral.
High resolution (Credit: SECORE)
The circle of life — it’s not just a song in an animated movie. For many NOAA researchers the circle of life starts with coral reefs. Why? Coral reefs — a critical part of the ocean ecosystem — teem with sea life that relies on them for survival. And this sea life is important to our economy, providing millions of people around the globe with food, coastal storm protection, and jobs.
Unfortunately, coral reefs are threatened by a growing number of natural and man-made stresses. These threats range from very localized and potentially manageable events to global phenomena that we are still attempting to understand affecting entire oceans.
The elkhorn and staghorn corals — both listed as threatened under the Endangered Species Act — are particularly at risk due to difficulties reproducing. That’s why the NOAA Fisheries Southeast Region Protected Resources Division is working closely with partners on two fronts to ensure successful reproduction and the continued survival of these important species.
These two Caribbean species of branching corals reproduce both sexually (eggs and sperm released in the water in many locations, or broadcast spawning) and asexually (broken fragments reattaching themselves to new coral, or fragmentation).
Four year old elkhorn coral grown from collecting sperm and eggs, fertilizing and settling in the laboratory, and placing back on the reef at approximately 2 weeks old.
High resolution (Credit: NOAA)
Sexual reproduction has not been successful in recent years because of extremely low numbers — populations are less than 3 percent of historic levels. That means individual corals are probably too far apart for eggs and sperm to encounter each other in the water column.
Although asexual reproduction through fragmentation is a natural part of the corals’ life history, this strategy is not as successful as it once was. Broken fragments are not reattaching and growing into a new coral colony because the degraded reef habitat is dominated by macroalgae and sediments.
To enhance sexual reproduction, NOAA Fisheries is working with SECORE (SExual COral REproduction), a non-profit initiative of public aquariums and coral scientists, which collects eggs and sperm from Caribbean reefs during the annual spawning event, assists with fertilization, and sends microscopic baby corals to zoos and aquariums around the world to grow.
Field nursery growing staghorn corals. Inset: Close up of coral “nubbins” created from a collected fragment.
High resolution (Credit: Coral Restoration Foundation)
SECORE has been growing baby threatened corals successfully for several years and this year they will begin growing baby corals in tanks receiving natural seawater from an adjacent reef in Curacao. Baby corals large enough to be attached to a reef in the ocean will help improve wild populations.
Complementary efforts to assist with asexual propagation are being conducted with partners from The Nature Conservancy, Coral Restoration Foundation, NOVA Southeastern University, University of Miami, Florida Fish and Wildlife Conservation Commission, Mote Marine Laboratories, and the National Park Service.
Staghorn coral colonies on Molasses Reef, Florida Keys approximately 3 years after their transplantation from the field nursery.
High resolution (Credit: NOAA)
Researchers are collecting orphan coral fragments and some from attached colonies and are bringing them into field nurseries throughout Florida and the U.S. Virgin Islands to grow. Nursery-grown corals placed back out on the reef will supplement the wild population, increasing the likelihood of threatened corals being close enough together for successful sexual reproduction. These partners were awarded $3.3M through the American Recovery and Reinvestment Act to support their efforts to improve genetic diversity and increase numbers of threatened corals, while also creating blue-green jobs.
Both projects work together to boost natural reproduction in extremely diminished wild populations, and ultimately rely on our continued efforts to address the myriad threats affecting threatened elkhorn and staghorn corals.
The U.S. Senate created Endangered Species Day, and recognizes it by resolution as the third Friday in May every year.