August 4 – Visit Chapmen, brooder workshop and second spawning dives!

Since there was no spawning the past night and thee was no lab work, we had time to visit the Chapman research vessel. It’s a former NOAA ship, used for  fishery and marine resource research. Substation Curacao N.V. purchased the ship and refurbished it to operate with the Curacao Substation in tourism and science. Laureen Schenk gave us a tour on the ship, which was an interesting experience!

Brooder workshop

In the afternoon, one part of the group did a fun dive, while the other part got instructions from Mark Schick on how to handle and maintain the kreisels in the coral nursery. After that, they joined the Brooder workshop taught by Valérie Chamberland and Bob Snowden. Contrary to broadcast spawners which release both eggs and sperm, with brooders, sperm is released by the coral polyp which fertilizes the eggs inside another polyp. In the end, completely developed larvae are released, ready for settlement. Brooders may release larvae all year round, which is very useful for coral propagation and research. In the brooder workshops, participants learn everything about this group of corals, as well as how to collect and treat the larvae.

Press coverage

Meanwhile, Claartje Visser was interviewed by Dolfijn FM, a Dutch radio station, about the SECORE Foundation and especially on what is currently going on in Curacao. So far, we have had good local press coverage, which we think is important to inform the local people about the dramatic situation of the Elkhorn coral and what can be done to help coral reefs! Dirk Petersen and Mike Brittsan gave an interview to the Amigoe (Dutch newspaper) and several other newspapers published articles about the SECORE Foundation, the public lecture evening and the workshop.

Pre-spawn!

After dinner everyone got ready for the second spawning dive. Since at least some spawning was expected, everybody was excited. Unfortunately, when we arrived at the Sea Aquarium dive site, the water turned out to be very rough due to the tropical storm Ernesto (which is currently passing by 200 miles North of Curacao). For safety reasons, we decided that only the most experienced divers would enter the water. The rest of the group stayed on shore, following the dive lights that shone through the waves. After what seemed a long time waiting, the first divers surfaced and excitedly reported on the pre-spawning they witnessed.

At the Sea Aquarium site, about 13 colonies were partly staging, but only small patches mostly in the center of the colonies did stage – a typical sign for a pre-spawn. The term “staging” describes the phenomenon when egg-sperm bundles become visible at the mouth of each polyp. Typically for the Elkhorn coral, the bundles stay at the mouth for several minutes before they are actually released . This gives us time to set the nets and get ready to collect the spawn.

This night, staging took longer than usual time (30 min) and the colonies finally started  to release the bundles at 9.45pm. Since the water conditions got worse and worse, we decided to leave the water at 10pm when the corals still spawned. Within the heavy surge it was almost impossible to place the nets in the right position to catch the gametes, but each team still managed to collect some!

First laboratory work and night shifts

Back in the laboratory, Dirk Petersen and Valérie Chamberland demonstrated to the participants how to work with the gametes to create a batch culture. This sort of culture is simply a mix of gametes from different colonies for producing a maximum of larvae and genetic diversity. In addition, we will also perform cross-fertilization in the coming days to look at specific genetic crosses and their influence on the performance of the resulting larvae.

Spanish Waters

Meanwhile at the Spanish Water site, the divers also suffered from the rough conditions, but they did manage to collect a nice amount of spawn! Since coral sperm is only viable for a short period of time, the dive teams at Spanish waters performed fertilization directly at the beach and returned to the laboratory at the Sea Aquarium.

Observation protocol

Region: Curacao
Dive Sites: Sea Aquarium
Principle observers: Dirk Petersen, Valérie Chamberland, Mark Vermeij
Date of spawning observation: Aug. 4, 2012
Sunset time: 7pm
Monitoring start time: 9pm
Monitoring end time: 10pm
All species monitored: Acropora palmata
Depth: 3-7 ft
Approx. monitoring area: 30x50m
Species that spawned: Acropora palmata
Time Set: 9.15pm
Time Spawn: 9.45 up to 10pm
Approx. % of corals monitored that spawned: 5%
Environmental date (i.e., conditions, tide, moon rise time): rough surge, partly cloudy
Notes: –

Region: Curacao
Dive Sites: Spanish Waters
Principle observers: Mark Schick, Bob Snowden
Date of spawning observation: Aug. 4, 2012
Sunset time: 7pm
Monitoring start time: 8.45pm
Monitoring end time: 10.10pm
All species monitored: Acropora palmata and Acropora cervicornis
Depth: 3-7 ft
Approx. monitoring area: 30x20m
Species that spawned: Acropora palmata
Time Set: 9.10pm
Time Spawn: 9.15 up to 9.45pm
Approx. % of corals monitored that spawned: 3%
Environmental date (i.e., conditions, tide, moon rise time): rough surge, partly cloudy
Notes:

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