Coral Spawning 2005
Flower Garden Banks
"The Texas
Caribbean"
The timing of this years trip was set to coincide with the annual coral
spawning event in the Gulf of Mexico which occurs each August eight days after
the full moon. Eric Borneman lead a team of aquarist "helpers" to
collect egg bundles released by the corals and maintain them in a temporary
holding tank while the ship was at sea. The following information provides an
introduction to this project, outlines the process, and offers insight into this
next generation method of coral collection.
The concept began as a research project initiated at the Rotterdam Zoo in 2001.
It was designed to
examine coral reproduction and breeding techniques in closed systems. Dr. Dirk
Petersen and his colleagues shared their results with other public aquariums and
institutions. In the 3 years that followed they formed an international network
known as SECORE (SExual COral REproduction). SECORE held its first workshop in
June 2005 hosted by the Rotterdam Zoo, the Netherlands. It was here that Eric
Borneman worked out the techniques for egg collection.
Dive team members included Tim McRae, Eric Borneman, John Dawe, and Michael
Janes.
During a mass spawning event eggs and sperm are released into the open water
column. It is here where the eggs are fertilized then set adrift in the currents
with the potential to form young coral larvae. The eggs are collected by funnel
shaped nets. As the net narrows toward the top a small catch vessel is attached.
As the eggs are released by coral polyps they drift upwards into the catch
vessel.
The plan was to transplant the collected eggs with seawater held
in the catch vessels into large ice chest coolers kept on the upper deck of the
boat. The two coolers contained clean seawater gathered earlier in the day and
used battery powered air pumps to aerate the water.
The seawater was constantly stirred to keep the eggs from coalescing
along the sides of the cooler and to ensure their chances for fertilization.
During the next 30 hours the eggs were diligently cared for and
checked for cellular multiplication as a sign that the eggs would develop into
viable coral larvae. A stereomicroscope was used on board the boat to monitor
the progress of the eggs. As the cells multiplied the initially spherical eggs
took on an obvious change in shape that appeared lobed like.
After 20 hours the coral larvae were ready to settle out of the
water onto a hard surface. Ceramic tiles were placed on the bottom of the ice
chest coolers. These tiles had the appropriate surface features, texture, and
biofilm to act as a functional substrate for the corals to settle onto.
Once the boat was back at dock and the ice chests with young
corals safe loaded into vehicles they were taken to Eric's Houston area lab. The
tiles were transferred to grow out tanks. They were monitored for development
and survival rates were calculated.
This process has been successfully preformed in the research
arena and similar techniques are now being used in commercial coral farming operations.
This noninvasive technique is an opportunity to rescue coral eggs from the rapid
decay they would otherwise experience in the ocean as only a few of the eggs are
intended to survive fertilization, settlement, and eventually develop into
mature coral colonies. In the years to come it is highly likely a large portion
of the live corals sold in the aquarium trade could be grown from collected
eggs!
