Saturday, September 20, 2014

Instruments deployed, heading home

Preliminary results from the benthic surveys
Yesterday we made our final two acoustic recorder deployments and carried out the last visual surveys. Over the last two weeks we successfully deployed instruments at 7 reefs and carried out visual surveys on 8 (one reef was already instrumented). Initial analysis of the benthic survey results suggest that we were successful in identifying sites that varied in the amount of coral cover, from sites with no coral to sites with around 80% coral. These biological differences among sites will be key to linking the acoustic records we collect to the organisms that live in each site.

This week's deployments were possible with the help of Lee James of Ultimate Whale Watching, who lent us his boat the Aloha Kai, a robust vessel that was ideal for the diving we were doing.

Now, we wait until January when we can retrieve the recorders and find out how these reefs may vary acoustically.

The Aloha Kai in harbor, prior to our last instrument
This work was made possible through a collaboration with Marc Lammers and Eden Zang of Oceanwide Science Institute, based here in Maui, and with funding from WHOI's Access To The Sea program.

Monday, September 15, 2014

One more mooring in the water

Crown of thorns starfish devouring a coral
Lots of three-dimensional structure at Honolua Bay, where
instruments were deployed on Saturday.
After Thursday's boat issues and some small fixes here and there, we hoped that the boat would be issue-free and run perfectly come Friday morning. Our hopes were dashed early on when, after putting the boat back in the water, it failed to start. Eventually we resigned ourselves to the fact that this boat needed a more thorough fix than something we could provide. A few hours of searching for boats ensued and ultimately we were offered two boats to borrow. So on Friday and then again on Saturday we went out on the Whale Trust's Charles B II, managing to deploy one recorder on each day. Saturday's deployment was in Honolua Bay, a popular snorkel and dive site. This site had lots of physical structure and many different fish species, although there was much dead coral overgrown with turf algae.

On Monday we are getting another boat that will help us continue to deploy instruments through the middle of this week. As a result of the generosity of several people, we may yet succeed in deploying all of the instruments that we initially planned on.

Octopus at Honolua Bay

Friday, September 12, 2014

Coral reef soundscape study: Maui, HI

EAR acoustic recorder boards
ready to program

Today marked the first field deployment of a project that has been several months in the making. I am in Maui, working with Marc Lammers and Eden Zang of Oceanwide Science Institute, which is based here in Maui. The purpose of this investigation is to comprehensively study coral reef soundscapes and link them to the biota on those reefs. To do this, we have selected several reefs from all along the west coast of Maui.

We are deploying two types of acoustic recording device: the EAR, developed by Marc, and the DMON, developed at WHOI. The last few months have involved tireless work on the DMON by Jim Partan, a WHOI engineer, and after some lessons learned from field testing in Palau last month, Jim has made the DMON as robust as possible. The first of many went in the water today and, a few months from now, we will see how they fared.

Back in business
Marc with the faulty
ignition coil
The first days of this expedition went very smoothly and involved pouring concrete moorings to affix the recorders to and preparing the instruments for deployment. Today was our first field day, and from the beginning, things felt a little different. To our immense dismay, the boat we are using did not start once in the water. After a few hours of peering into the engine compartment, with the help of a mechanic who happened to be at the boat ramp, we had identified what we thought at the time was our problem - a broken ignition coil. A quick trip to an auto parts store for the part and we were almost back in business. However, in our earlier attempts to start the engine, we had killed the battery! Back to the store for a new battery, and we finally made it out to sea.

Instruments deployed
We deployed our instruments on a patch reef and carried out visual surveys for coral cover and fish diversity right then. The recorders will be out for 4-5 months, and we hypothesize that the recordings will vary considerably among different reefs. But how different are the deployment sites in what lives there and their 3-dimensional structure? That remains to be seen.

Max Kaplan

A large turtle resting on the reef as we carry out our visual surveys

Friday, August 29, 2014

Back to port and headed home

Acoustic recorder deployed on a reef in northern Palau
(Photo: M. Kaplan)
After our rare opportunity to travel down to the remote Helen Reef, we headed to the very north of Palau - Kayangel - to collect visual survey data and water samples for seawater chemistry. Just like at Helen Reef, we had great support from local Rangers, who took us to our various sites on their boats during our time there.

Two days later, we were back in port in Koror. From there we continued our data collection on local boats.

Feather star (Photo: M. Kaplan)
I was able to collect approximately two-week long recordings at three reefs, in addition to a 24-hour recording on a northern reef. These data, when examined in the context of the visual survey and water chemistry data, will allow me to make inferences about links between sound production at these reefs and the physical, chemical, and biological environment present there.

Over the course of approximately 20 dives, I was able to see some great marine life, some of which I have included here. Palau's reefs are some of the nicest that I've seen. In many places I saw large fish, which are rare in many parts of the world. Palau is working to protect these resources, and is currently planning to ban commercial fishing in all of its territorial waters. If they proceed with these plans, Palau's marine resources will continue to be a big draw for tourism. Of course, increasing numbers of visitors bring with them other environmental problems.

The expedition ended with a trip to a Jellyfish Lake, an enclosed saltwater lake with very dense swarms of non-stinging jellyfish (photo below).

I am grateful to Anne Cohen and her lab for inviting me along on this great trip, the boat drivers at PICRC, and the Captain and crew of the M/V Alucia, whose hospitality and vessel support was instrumental in making this trip a success. This trip was also an opportunity for me to field test the acoustic recorders that I will be using next week in Maui, when I deploy them for approximately 4 months. While most of the recordings were flawless, a couple glitches highlighted some areas for further improvement. Without the hard work of Jim Partan and Walter Zimmer, these recorders would not exist in their current form and I am especially grateful for their engineering efforts.

Max Kaplan

Moorish idol (Photo: M. Kaplan)
Moray eel (Photo: M. Kaplan)
Octopus (Photo: M. Kaplan)
Sea cucumber (Photo: M. Kaplan)

Whitetip reef shark (Photo: M. Kaplan)
Jellyfish in Jellyfish Lake, Palau (Photo: M. Kaplan)

Saturday, August 16, 2014

Helen Reef

Helen Island (M. Kaplan)
After departing Koror on Wednesday and a 30 hour steam south we arrived at Helen Reef, close to the equator and very remote. Other than three rangers that inhabit Helen Island, a small sandy island at the top of the reef, there are no other people for miles. The rangers are tasked with monitoring reef conditions and guarding against illegal fishing activity.

The rangers were also extremely helpful, taking us in their boats to a range of sites around the reef where we collected coral cores, tissue, and water samples.

After a short day-and-a-half stay we had to depart again, this time heading to the very north of Palau's archipelago. We would have been happy to stay for a few more days to further explore the beautiful reefs. One of the rangers we spoke to told us that he had been there for five years. Perhaps we wouldn't have wanted to stay quite that long.

A view from the island (M. Kaplan)

Monday, August 11, 2014

Palau: Out to Sea

Coral reef in Palau replete with juvenile fish (M. Kaplan)
It's day 3 of the Cohen Lab Palau expedition and we are heading out to sea. Since arriving on the night of August 8, we have been busy deploying instruments and collecting coral and water samples on reefs around the island of Koror, Palau. Many of the reefs that we've dived here so far are in excellent condition, and the ones that aren't have largely been affected by natural disturbances (El Nino surface water warming, typhoons, etc.).

A shallow coral lagoon in Palau (M. Kaplan)
I am on this expedition to help collect water samples to study the carbon chemistry and nutrient fluxes of reefs here, which display a natural gradient in acidity as one moves inshore and into shallow lagoons. The fact that corals can thrive in these low pH environments is surprising, given that most experiments and field studies have shown that corals struggle to maintain and grow their calcium carbonate skeleton in low pH waters.

Acoustic recording device (left) &other instruments
(M. Kaplan)

I've also been given the opportunity to collect coral reef acoustic recordings while here. My PhD research is focused on exploring links between biological sound production on coral reefs and the species assemblages present - in other words, what is the link between the sounds produced on a given reef and the fish and invertebrates that live there. Luckily, visual survey data is available for many of the reefs we are going to on this trip, courtesy of the Palau International Coral Reef Center.

At the moment we are preparing to head out to sea, first to collect offshore water samples and then to head south to some of Palau's more remote reefs. This is a rare opportunity to sample in some of these areas, and in part because access is so infrequent we are bringing fuel and a boat for the three rangers that live on one of these remote reefs.

 Max Kaplan