When we think about zoos and aquariums, a few things come to mind: a family day, observing animals, and learning something new. As visitors, we only view a fragment of zoo and aquarium operations. Behind the animals we see, presentations we watch, and things we learn is a complex network of scientists, conservationists, and animal experts with various concentrations and specialties. The reach of accredited zoological facilities stretches far beyond the entrance turnstiles.
Last year, National Aquarium staff members had the opportunity to travel to the Riviera Maya, the Caribbean coast of Mexico, to help restore coral reefs. Many Caribbean reef systems have been decimated over the last few decades due to human activities like pollution and over-fishing.
One key reef-building species, elkhorn coral (Acropora palmata), has become critically endangered. A complete die-off of this species would seriously complicate any chance of regrowth. This has a direct impact on area biodiversity and sustainability within the ecosystem. In an effort to conserve this species and the ecosystems it supports, SECORE International, a nonprofit organization based in the US and Germany, has brought experts from around the world together to reproduce and outplant healthy corals throughout the Caribbean.
The reproduction of coral works in a few different ways. When coral pieces break off from animal activity, waves, or storms, it’s known as the process of fragmentation. During this asexual reproductive process, those fragments may land in conditions suitable for attachment and develop into new genetically identical colonies. This process is delicate and healthy attachment and success is not likely without suitable substrate, good lighting conditions, and water flow.
Another reproduction process is called broadcast spawning, where eggs and sperm are released. During these annual events, typically following a full moon, the released gametes drift to the surface and fertilize. Larvae begin to descent from the surface in search of an area to settle after a few days.
The National Aquarium team traveled to the Yucatán Peninsula during one such event to collect elkhorn gametes and raise the larvae to help restore local reefs. The team’s focus was to create successful breeding techniques that made genetic diversity and operational sustainability a priority. Simple tools were utilized to create the specialized equipment needed for a coral nursery including vinyl tubing and plastic salad bowls.
The SECORE team sought to mimic the natural process of broadcast spawning by collecting eggs and sperm during the annual spawn. From there, they were to fertilize the eggs and raise them in a lab environment where they’re free from predation. The controlled environment ensures optimal chances for successful fertilization. This project must adhere to strict timing. Once the larvae are mature enough to begin settling, they are then introduced to specialized tiles where they’ll have good places to attach. Once the larvae have established themselves on the tiles for a couple weeks, they’re transferred back to the shallow waters of the reef.
SECORE and local partners in Curaҫao were able to report an exciting milestone in January of this year. The first lab-bred colonies of the threatened Caribbean coral (A. palmata) reached sexual maturity and spawned this past September. This news offers hope to SECORE researchers and coral conservationists that these types of projects can help to rebound these threatened species.