Lionfish Sampling Day 9: End of the road

Today was a pretty epic day on the water. It is Saturday and the weather was perfect, so there were a ton of boats on the water today. Fortunately, none of them wanted to dive or fish in the same spots we were diving. We only had 2 sites to finish. It wasn't too difficult, but we did spend over three hours at each location. Each pair of divers spent almost an hour an a half on the bottom doing our surveys. We had a tough time finding graysby, so that was part of what took us so long. 

We saw a whole lot of cool things from the surface. We saw a sailfish jump out of the water super close to the boat. That was AWESOME! The water was also so calm and clear that we could see the other pair of divers on the bottom while we were sitting in the boat. It was a pretty incredible day on the water. 

This trip has been quite memorable overall. The general attitude has been extremely positive. Everyone was very organized and kept everything running smoothly. We worked together extremely well, staying on top of data, and working together like a well-oiled machine. This has been an extremely positive experience & I have learned a great deal. I have continued to hone my skills as a research diver, gotten to drive a boat, and generally had a god time working closely with a group of higly inteligent, highly motived marine scientists. Yay field reasearch!!!

Lionfish Sampling Day 8: Weather

The field sampling for this project occurs  four times per year for two years for a total of eight visits to each of the twenty sites. Each sampling period has its own unique challenges. The project began in January when both the air and the water were in the 60s. This sounds like a nice, warm temperature. However, it is quite cool to be wet for twelve or more hours per day, During the May sampling period, it was very windy, and the samplers were only able to visit fourteen of the 20 sites. 

Our routine during this sampling trip has been for two divers to go down and do their surveys while the other two divers remain on the boat and watch their bubbles. The divers on the bottom do not bring a surface marker with them. The two people on the boat have to constantly watch their bubbles in order to not drift away from the spot where the divers are working. During that time, we also prepare all of our gear for the next dive. 

The weather in July has been really nice overall. There is relatively light wind in July, leading to seas less than two feet. Most days have been sunny, and we make sure to wear pleanty of sunscreen when on the boat.  However, summer also means squalls, rain, and thunderstorms. The squalls aren't too bad but they are a pain. They bring wind that whips the water into a froth, significantly reducing our ability to see our divers when we are on the boat, and changing the direction of the wind, making the boat quickly float away from the divers. Rain adds a level of difficulty. It reduces visibility even further, and makes the divers even more difficult to see. 

Thunderstorms are the worst. One lightning strike can fry all of the electronics on a boat and even severely shock a person who is holding onto metal on the boat. Being at sea on an open center-consoled boat in a thundstorm is no bueno. Yesterday Chris and Joe came up just before a rainstorm started moving toward us and building energy to become a thunderstorm. We turned on the radar, took a look at the direction it was moving, and started heading south as fast as possible.  We ran south around the edge of the storm, spending several tense minutes unsure if we would make it away from the thunder and lightning. When we got past the south edge of the storm, we were able to wait out the weather and get back to pick up a few graysby. The radar was a great help to us since we could watch where the thunderstorms were moving, and how far away they were. 

Today the weather seemed to be acting aproximately the same. However, when we watched the rain showers, there was no lightning, so we were relatively safe. The showers stayed close to land, and never made it out to where we were sampling. Once we finished our sites, we did have to run back to the park through pelting rain that seemed very cold after our day of sunny, humid conditions offshore, and our week of diving four hours every day. 

As long as all goes well, we will finish our last two sites tomorrow and be done with this project for the month of July. It has been a really fun experience. I have learned a lot, and had a good time. I'm excited to get to participate in some research this summer. 

Lionfish sampling day 6-7: Graysby hunting

One of the four divers on this trip is a master' student at USF. His project is dealing with the diet of the predators on the reef and how they are impacted by the presence of lionfish. There are a few different ways to possibly answer this question. One way to analyze this data is the use of isotope analyses. The isotopes of nitrogen and carbon differ based on where their food is coming from.  If lionfish are having a significant impact on the native predators' ability to find food, the natives would shift their diet from their normal diet to different food. This shift would be present when the data is analyzed.

Graysby looking angry at the world

One of the resident preditors on the reef is a small grouper species called the graysby. For the master's project, we are spearing 1-2 graysby on each site. On each site, once Kara and I finish with our surveys for lionfish and other prediators, we spend the remainder of our time searching for a few graysby to shoot for the project. We swim around the reef & try to sneak up on them and spear them with a pole spear.

The student, Joe, will analyze their tissues for the nitrogen and carbon. Currently, each of the reefs we are visiting have at least a few lionfish living on them, and they have been there for the past few years.  In another few months the National Park will begin regularly visiting each site to remove the lionfish they find. On future trips, the divers will collect 1-2 more graysby. These will be after the lionfish have been removed from the area. If the lionfish were having an effect on the diet of the native predators, Joe's analyses should find a change in the isotopes. If lionfish are not affecting the diets of native predators, the isotope signatures will be the same both now and in a year.  Of course, we will not know the answer to this question for at least another year or more. It will be very interesting to find out what type of effect the lionfish have on the native predators. 

Lionfish Sampling Day 5: Hunting for lionfish

Searching for lionfish while diving seems like the easist job on the planet. Lionfish are large. They have red and white stripes and long trailers all over all of their fins. It seems like they should be the most obvious fish on the reef. However, there are a few things that actually make them a little tough to spot. 

First, they really like to hang out inside of holes, under ledges, and generally anywhere kind of dark and dank. They group up in the best holes, sitting next to each other. They love to hang out upside-down inside of these holes. In order to spot them, you often have to hang upside-down, stick your head into a hole and then look really hard. No one ever expects to see a fish sitting on the ceiling, even under water. 

The second thing that makes lionfish hard to spot is those long, frilly fins. Although the fins look extremely obvious on their own, when looking for them among sea fans, sponges, algae and other organisms flowing in the current, it's really quite difficult to distinugish the fish fins from any of these other living things.  

The third thing that makes lionfish difficult to spot fact that those stripes are actually a form of disguise called "disruptive coloration." Many species of reef fish employ this tactic much like zebras in the grasslands. By disguising thier eyes, having irrregular vertical bars, and frilly fins, they blend right in with the background. Potential prey and predators never even notice that the lionfish is there until it's too late. 

These facts conspire to make a large and conspicuous-looking fish somewhat difficult to spot while trying to cover every inch of 3000 square meters of dense reef habitat. 

Lionfish Sampling Day 4: Working in Space

Each site we visit is marked with 8 floats attached to the bottom in precice locations. The floats also have livestock tags attached to to bottom in case the floats break off. Since the sites are only visited once every 3 months, there is a fairly high chance that at least one of the floats will  go missing. If this happens, we have to do our best to find the tag, clean it off, and replace the float. Today we visited two sites that hast lost several of their buoys. We were able to find the locations of the tags. We then replaced each of the missing floats with a new one.

Anytime I am doing this sort of work under water I feel like I am working in space, possibly doing critical maintenance on the Hubble Space Telescope or the International Space Station. Since we don't know what the state of the site will be I bring several extra floats and zip-ties along with me on each dive. While I am perusing the site for lionfish, I also keep an eye on each of the markers. If I arrive at a marker and the float is intact, I will clean it off, removing any of the plants or animals that have started to grow on the line or the float. If I arrive at the approximate location where the float should be and I don't see it, I will spend a few minutes searching for the livestock tag. I can often find it on the bottom. I then clean it off & thread a new float line through the spot where the tag is. This entire procedure makes me feel like I am in space. I can't see any of the gear that I'm carrying with me, but I know exactly where each piece of gear is. Each of the floats is buoyant, of course, and will float aways if you let go of it. Other gear is negatively buoyant, but I have to make sure to place it where I can see it to pick it up and not let it slide away. I also have a propensity to hold things in my mouth since I only have two hands. Of course, with a regulator in my mouth I can't use it for holding onto gear when I run out of hands. Much like space, I have to think hard about each move I am going to make before I make it. I have to hang on to all of my gear, and I have to make sure that I finished everthing completely and have picked up all gear before I move on to the next task. 

Lionfish Sampling Day 3: The ups and downs of small boat sampling

All of our sites are located 10-15 miles offshore in somewhere between 50 and 80 feet of water. To get there, we are using a 26 foot catamaran with two 115 horsepower outboard motors. It is a great work boat for four divers. There is lots of space to store gear and get ourselves ready. The boat is wide, and there is a lot of deck space. The T-top provides a fairly large amount of shade, and the boat is very easy to maneuver. Each day we bring out pleanty of food to eat between dives, and we take turns at the helm. 

However, working on a small boat requires quite a bit of pre-planning and organization. We have a total of 24 Nitrox tanks. We can only bring 12 out on the boat with us at one time because of the amount of space on the boat and the number of hours in a day. The two divers who are about to go on the boat get their gear ready on the back corners of the boat, while the other two people bring their gear to the bow when they get out of the water. Since the sites we are working at are 300 feet long and the current is relatively strong, the pair of divers who stay on the boat don't anchor. They "hold station" by watching the divers' bubbles & driving the boat so that it stays close enough to the divers to pick them up when the dive is over.  This can be extremely easy if the wind is calm and the waves are small. It gets much more challenging when the wind is blowing the tops off of the waves, and the current is running several knots. Anything above about 15 knots of wind makes this an impossible task and requires that you cancel diving for the day. Fortunately we have yet to have a day like that. 

By managing our air consumption pretty religiously, we can make the tanks that we have last about 2.5 days. Today was our "tank day." We sampled for two twelve-hour days, and today we were only on the boat from 7:30 am until 1 pm. Then we ran the tanks up to the dive shop to get all of our tanks filled. This is still work, but it's a bit easier since we just bring the tanks to the shop and then let the shop workers fill them. However, we do have to lift those 38 lb steel tanks into the back of the truck, and then unload them at the dive shop, load them back up to take them back, and then unolad them back at the National Park. 

Since conditions were a bit marginal and we were trying to complete a deep site, we were only able ot finish half of the surveys we needed to. Tomorrow will be another full 12-hour day. We will again attempt to complete three sites. I always say "attempt" because you never know what will happen on the water on any given day. It's always an adventure. 

Lionfish Sampling: Day 2

The study we are working on is a  BACI (Before and After Control Impact) study. In short, the goal of the study is to determine how frequently lionfish will need to be removed in order to return the area to a "natural" state, or that before the lionfish were introduced.

There are a total of 20 sites within the study. Each is approximately 100 meters long & situated along the edge of the reef in 50-80 feet of water. Each site is sampled four times per year. During the first year of the project everything is left as is. All lionfish are left in place, despite their invasive nature. During these sampling trips we are merely observed  During the second year, each site will receive one of three different treatments. Three of the sites will have lionfish removed from them on a monthly basis. Three will have lionfish removed every four months, and the remainder will not have lionfish removed. Researchers will continue to return to the sites four times per year to count numbers of lionfish remaining and numbers of other types of fish species present. If the lionfish are having a substantial impact on the populations of other fishes, the researchers would expect to see an increase in all types of native fishes on the sits with the most frequent lionfish culls. However, if the impact is somewhat lower, the researchers would not expect to see much difference in fish populations between sites with monthly lionfish removals and those with removals 3 times per year. This study will determine how frequentlly the National Park should be culling lionfish in order to maintain the populations of native fishes in a natural state. It will be a couple of years before we have an answer to this question.

Counting Lionfish

Both yesterday and today, we completed three surveys of lionfish, other predator fish, and prey species.  Of course, completing the dives is only a small part of the entire process of working in the field. These are at least twelve hour work days. We get up around 6 am, leave the house by seven, arrive at the park around 7:30, load the boat, and drive out to the first site of the day. Each pair of divers spends approximately 1 to 1.5 hours on the site, searching for their fish (lionfish/predators or prey species), then we move on. We arrive back at the park around 7 pm, and head back to our rental house. This is a great group of people, so we work together to make dinner, and then clean all of our gear, and ready for the next day. It's an exhausting schedule, but it is also a great deal of fun. You get to know people extraordinarily well working so closely with them. 

My office for a couple of weeks

Tomorrow will be a shorter day of sampling. We plan to only sample one site and then come back in to get our tanks refilled at a local dive shop. This will also give us a chance to rest up a little bit, watch the World Cup final, and generally recouperate for another couple of twelve hour days.