Monday the Marine Science interns were on a mission to understand the secret lives of butterflyfish. We know that they belong to the Family Chaetodontidae, which literally means “hair-tooth” or bristle-tooth. This is perfect to describe their mouth which is a coral eating machine. The interns found out this morning that they will eat plankton, mollusk eggs, worms and soft and hard corals.
So why study butterflyfish? These species are territorial, specific to a given reef with strong site attachment. They also have a life span of an average of 12 years and are important Corallivores on the reef. In some areas of the Pacific, butterflyfish have been used as an indicator species for the quality and quantity of coral coverage, based on their territory sizes.
In a paper by Raymundo et al. (2009) it was noted that the density of coral-feeding chaetodontid butterflyfishes, was positively associated with disease prevalence. This may be because these butterflyfish are acting as a vector for disease transmission between and among colonies. This is a question that the MSI’s were up for trying the protocol!
The interns investigated into which of the coral species in Bermuda is most affected by one of the major diseases documented, Black Band Disease. In a Masters thesis by Khuel (2010) it was noted that Diploria strigosa is the most susceptible when looking at brain coral species. In the coral disease surveys the interns took East of North Rock this trend in their data was noted. D. strigosa and Eunicea were being the most fed upon coral/minute by the butterflyfish.
The interns saw and followed both the spotfin and the foureye butterflyfish and had to be quick to keep up with them!!
Here are some notes from the interns!
Notes from Eliza: At one point I spotted six foureye swimming all together! It was very interesting to see that when two mates could not each other they would franticly look for each other until they could find one another. Also, they did not eat very much. The parrot fish that we tracked ate much more in one minute than the butterfly fish ate in ten minutes. Overall it was a really cool experience!
Notes from Michael: Tracking a Butterfly fish’s bite count isn’t easy! From studies they are very territorial and claim from very small to large areas (10-300m^2). Following one takes skill and lots of patience. The trickiest part of this was to follow different fish, not the same one – unless you found a different species. Another factor is when the swim under reefs and rocks, you would have to guesstimate or neglect the bites they may have taken while there.