Data data everywhere

So now that we’re back from the field what to do with all the data that we collected. Well the first obvious step is to transfer the data from the many data sheets we used in the field to spreadsheets so we can actually use that data in our future analyses. But that’s not terribly exciting so lets just leave it at this: after a couple of days of tirelessly entering data into excel sheets we finished and now its time to start analysing it!

The first thing we decided to look at is changes in recruitment. As you might remember from my last post recruitment is when a fish metamorphoses from its larval phase (usually floating around on the ocean currents) to a recognizable juvenile form on the reef. Our dataset now includes 2002-2004 (pre-lionfish) and 2013 (post-lionfish). So while we won’t be able to say with absolute certainty that any changes we observe are due to lionfish; we can say that lionfish are a prime candidate for any shifts in the fish community structure. Other potential candidates are things like hurricanes and coastal development. To my mind lionfish are really the number one candidate because the time post hurricane before the 2002 surveys is about the same as the time post hurricane before this years surveys so you would expect the populations to have changed in a similar manner. Coastal development is unlikely to be much of a factor because Turneffe is still for the most part undeveloped. There have been a couple additions (a Coast Guard base next to the field station for one) but for the most part from what I’ve heard not much has changed, its not like a big town or resort complex suddenly showed up.

So without further ado here is a very rough graph of what our data looks like!

Fish community plot

I know its pretty rough and complicated (I’m just learning how to code in R and haven’t really figured it out enough to make it do what I want completely!) but still you can get some pretty cool info out of it. Basically the the circles represent where all of the different survey years cluster towards as far as species composition (the purple four letter codes represent species so HAGA = Halachoeres garnoti or the Yellowhead wrasse). The small circles are each individual site coloured to match the year. So looking at this you can see that CHCY, the fish formerly known as the Blue Chromis, is negatively correlated with the 2013 data since its very far away from that circle. HAGA on the other hand is positively correlated to the 2013 data etc. So looking at this we can see that the three survey years before the lionfish invasion (black, red and green for 2002, 2003 and 2004 respectively) all have very similar fish community structure where as the new 2013 data has a somewhat different community structure.

So yeah cool stuff right! I haven’t even begun to figure out what all of that could mean in terms of what’s going on with the fish communities, or why some fish are positively and other negatively correlated to lionfish. But this is definitely a cool start to what will continue to be an interesting story to pull apart in the future.


Home Sweet Home

Well after just 15 busy days, filled with diving (40), lionfish dissections (~250 between the four of us), 1 lionfish sting (to yours truly), science, and providing a food source for the local mosquito and sand flea populations, I’ve made it back to Texas, my new home for the next 2 years.

In Belize we stayed on Turneffe Atoll at the University of Belize’s Calabash Caye Field Station.


My primary goal while there was to start to get a feel for the type of research projects I could do for my Master’s thesis. In addition to that we gathered data and performed experiments for a few other studies. One set of these studies is continuing some of the research my advisor was performing about 10 years ago (long before the lionfish made it to Belize) looking at interconnectedness of fish from different parts of the Mesoamerican Caribbean. The part of that research we could do while in the field involved counting IMG_0082various key species of fish recruits (new fish leaving the larval phase and landing on the reef). We also collected two different species the bicolor belize_2013054damselfish (Stegastes partitus right) and the masked/glass goby species complex (Coryphopterous persomatus/hyalinus it’s impossible to tell these species apart in the field so most people just lump them together. left). Why these two species? Well for one they are both super abundant on the reefs so its possible to remove some of them without impacting the local populations. Another reason is that they aren’t used for any economic purposes, so removing them isn’t taking them away from a fisherman who needs them to make money. Lastly they are super easy to catch. The masked/glass goby occurs in big clouds all over the reef so you can basically just scoop them up in an aquarium net and catch a whole bunch.

My advisor catching masked/glass gobies The bicolor damsel, like most damselfish is quite territorial so they tend to stay in the same place on the reef where you can spray them with clove oil (basically a fish anaesthesia made from cloves, just like what you might cook with, and ethanol). The clove oil slows the fish down a bit so you can catch them.

Of course we also collected lionfish from our sites for our research (and just doing a good IMG_0060deed!) We used two basic methods to do this. One uses two hand nets basically exactly the same as in the above picture but replace the gobies with a lionfish. The other was your basic pole spear of science. The choice really just came to how big the fish was (small fish are much harder to hit with a spear). Using the nets you would then carefully remove the lionfish from the net and put it into the collection bag. With the spears we built PVCbelize_2013030 containment tubes so you wouldn’t have to handle the fish at all to minimize stings (and it was a great success since only I was stung and that only happened once!).

Once we gathered all of the data and fish we needed it was time to go back to the lab to perform dissections and preserve everything. First things first we dissected the lionfish getting all their length and weight measurements and looking to see what they had been eating by cutting open IMG_0020their stomach. This one had 16 fish in its stomach, and that’s not even the most we saw! We preserved some of these fish in ethanol (particularly when we found either of our other study species, they seem to like the goby) so that back in Texas we can try to do some genetic and otolith work on them for another study (more on that in a future post). We also removed the two sagittal otoliths (calcium deposits in the brain that act as a balance organ and can be used to determine age of the fish and with some cool chemical techniques determine the point of origin of new recruits). Because the gobies and damselfish we collected are so small (less than 2.5cm) we preserved the whole fish in ethanol to bring back to the lab in Texas where we have some nicer equipment for removing the otoliths (by nicer I just mean a dissecting microscope). With all of the fish we collected lionfish, damselfish, and gobies we took a fin clip to preserve for DNA work back in Texas. There will be more on the otolith and DNA work in the future.

And that’s basically what we did in Belize. Here are a few miscellaneous pictures I took on some of the dives unrelated to the research and one of the lab group doing our safety stop, and no my hair isn’t usually that in the way while diving!


Our hut on TurneffeIMG_0010

Lionfish hunting a fairy bassletIMG_0111

Big/old barrel sponge with some creole wrasse and sunshinefish around itIMG_0109

Part of a large school of black jacksIMG_0105

Sponges and some coral with blue chromisIMG_0096

Yellowhead jawfish checking to see if the coast is clearIMG_0078

Pair of four-eye butterflyfish. I imagine the one in the back saying “wait up honey” since they form mated pairsIMG_0022 (2)

Cleaner goby on some coralIMG_0032

Hungry hungry parrotfishIMG_0023 (2)

Coral war!IMG_0007