When a cushion star eats a coral colony, it leaves behind a bright white skeleton
Cushion stars are placed in the cage with corals of different species on either side
A big component of being a marine biologist has been walking the isles of Lowes looking for materials to use for my experiments underwater... In this case I used A LOT of PVC pipe!
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Cushion stars eat coral, but we still don't fully understand what their preferred species of coral are. In the past, experiments have been conducted to determine this but they looked at only a handful of species. They were also conducted in a lab, and these artificial settings can sometimes affect how animals behave. Why do we want to know what coral species they prefer to eat? Different coral species experience different levels of stress. For example, cauliflower coral (Pocillopora meandrina) in Hawai‘i is more susceptible to bleaching (check this out to learn more about coral bleaching). Understanding what coral species cushion stars prefer to eat will let us know what management interventions to take during times of stress. For example, if they prefer to eat cauliflower coral and a bleaching event occurs, it might be important to manage cushion star populations during those times in order to minimize stress. Additionally, coral restoration efforts might be targeted to certain species if they are experiencing stress from multiple angles, such as bleaching and coral predation.
My current work is looking at what species of corals cushion stars prefer to eat. I am testing many more species than have been tested in the past and am conducting these experiments in situ (in the field). In order to determine their feeding preferences I have built cages made out of PVC and garden fencing material. I first collect cushion stars from the reef and leave them in the cages for a week without food, this ensures that they all have the same base "hunger level". I then zip tie coral of different species to either side of the cage and leave them for another week. Because I can't check on the cages every day, I deploy KiloCams. These are inexpensive cameras that are programmed to take pictures every 15 minutes (learn more about them here). These experiments will help me determine a hierarchy of prey choice. This will also answer questions such as what coral species they might switch to if their preferred species were to become very uncommon. * All work done for this project is under proper Special Activities Permits |
Figuring out how to cage cushion stars was... surprisingly difficult! Scroll through the slides below to see the different enclosure contraptions I tested out.