A couple of Crown of Thorns Starfish! Their spines are poisonous, so we have to be very careful when handling them.
I may be getting lazier since the days have been busy…So here’s excerpts from my ISP journal for your enjoyment! Sorry that they’re so to the point. It’s hard to keep track of every single thing that’s going on! Also…I haven’t done my two month photo yet. It’s delayed, but it’s coming!
A bit about our study species:
Crown of Thorns starfish (Acanthaster planci) is a voracious predator of live coral. The species can becoming extremely detrimental to the reef when they occur in large numbers–this is called an outbreak. Controlling them is problematic because they have a limited number of predators, being covered in venomous spines. Being starfish, they have the ability to regenerate their body parts quite readily; they only need one arm in order to regrow. Past methods of killing them are ineffective, expensive, and/or cause harm to the reef or other organisms. Jairo has developed a method of causing a sort of allergic reaction within them, that is contagious to other crown of thorns. It has a 100% death rate, and in other locations this was generally within 24 hours. We will be replicating an experiment he conducted successfully in the Phillipines to make sure it will affect the (larger) crown of thorns in Australia.
4/3/13
Met Jairo, Catalina, and Simon in the morning and learned about four different projects we would be working on
– Injecting COTS in nally bins with two different solutions in two concentrations, measuring approximate time to death. Five starfish for each site of injection/solution
– Collect sperm and eggs of COTS and look at fertilization rates at different pH – includes watching fertilization under a microscope
– A transmission test in the lab, with three setup tanks: two treatments and one control. All three have the same coral, fish, and echinoderms inside. An injected COTS will be placed inside the two treatment tanks and observed, once every three hours, to see if there is transmission to any of the other organisms–evidenced by things like blackband disease, lesions, or rotten tail.
– Upon completing the transmission lab test (expecting that it will be successful), we will inject COTS in the field and place GoPros in the field to watch their movements–what eats the COTS when its sick, what it does, etc
We immediately began working, and have been pulling on average 8-9 hour days.
This includes snorkeling to find COTS, collecting organisms for the transmission tests, doing injections and cleaning out dead COTS.
4/8/13
Today we compiled the first set of results for the Bile Salt injections. It looks like the most effected injection sites are the base and middle of arm. We will continue to do injections over the next couple of days, now also to see the efficiency of the old gun now used to control COTS and the new one Jairo is developing from a fertilizer gun! We started the transmission experiment yesterday, and have been watching it since. Mucous has appeared on the COTS and some of the enchinoderms—this could just be stress due to their habitat rather than getting the disease, but we shall see! We will continue to work on this for the next week.
We also learned about a number of other projects we will be helping other people out with (but not writing about). This includes completing genetics on the COTS in order to understand whether outbreaks originate from one group of related starfish or if they are from a number of groups. There will also be some people coming in starting Wednesday through Sunday who will need our help with their projects. We are supposed to collect 150 COTS in order to complete all of these projects. At this point, we may have around 50. We are having trouble finding good places to collect since the active outbreak is on the outside of the sheltered areas, making it difficult to snorkel or dive there. Hopefully, we should be able to get enough for all our experiments.
Time’s a flying! Most of the other SIT students are only now going to their ISP locations around Australia. We gained an extra week here on LIRS, which meant we were working through our final papers and exam, but we also get more time to work with our advisors! It’s likely we will also have more time to work on our ISP papers/presentations and have it all done before we’re back in Cairns!
lianinspring 