Moorings deployed

One of our large (~200 pound) long-term moorings (Photo:M. Kaplan) 

Today marked the final day of fieldwork. The morning was spent rebuilding a few of our acoustic recorders, which were not doing exactly what we wanted, but we were still able to get out and complete 3 dives this afternoon. We deployed four longterm moorings in addition to two that were deployed a couple days ago, with a total of 18 instruments measuring the soundscape, temperature, salinity and ambient light intensity. These instruments are distributed across the 6 moorings at 3 distinct sites. Late today we also retrieved some short-term acoustic recorders that were deployed at our last site.

Retrieval of our short-term recorders (Photo: A. Mooney)

In total we've collected nearly 300 hours of acoustic recordings over the past 10 days. We poured around 600 pounds of concrete to make our long-term moorings, and the plan is for those instruments to record intermittently for approximately 4 months; we will retrieve these recorders in August. These data will help us characterize differences in the soundscape between sites over a long temporal scale and may allow us to correlate variability in sound production with variability in environmental conditions.

Between Aran and Max, 40 dives were completed over the last 10 days, comprising around 1600 minutes underwater. In addition to instrument deployment, we conducted a number of visual surveys so that we can characterize what is living at our three sites.

This research project is off to a successful start - for that we owe thanks to a number of collaborators, whose work was truly instrumental in allowing us to achieve all that we have here in St John. Our engineers - Dan Bogorff, Steve Faluotico, and, in particular, Jim Partan, whose tireless work in the weeks leading up to the project allowed us to deploy all of the instruments we wanted. We also thank David Mann for quickly sending us some replacement circuit boards for malfunctioning instruments, and all of the volunteers at the Virgin Islands Environmental Resource Center where we have been based.

Aran about to deploy a mooring (Photo: M. Kaplan)

We have almost a 3-week break from fieldwork now - but check back here during the first week of May - Aran and I head to Hawaii for the last of four melon-headed whale tagging expeditions. Details of that project can be found under the tab "Hawaiian Odontocetes" at the top of the page.

Max

(Photo: A. Mooney)

Our first acoustic recordings of a coral reef

A recorder about to be recovered using a lift bag (Photo: M. Kaplan)

Over the last two days we have deployed, retrieved, and redeployed 4 acoustic recorders. Late last night we looked at our first 24-hour recordings from one of our deployment sites - Tektite. This site has the most coral cover of our three sites and we expect that it will also have the most complex soundscape. A quick look through the recordings suggests a strong background noise produced by snapping shrimp, with a number of low-frequency fish sounds on record throughout the 24 hours. By deploying 4 recorders at each site, we're hoping to be able to better characterize the spatial variability in sound production within a site, and to compare that variability between sites.

Max recovering a lift bag at the surface (Photo: S. Zacarias)

After an overnight data download, the recorders were redeployed this morning at a site with intermediate coral cover. They will be recovered tomorrow and then redeployed the following day at our site with the least coral cover. In the meantime, we've been working on getting our long-term moorings ready for their 4-month deployment. This afternoon's quick trip back to the hardware store means that we now have (hopefully) all that we need to make sure our instruments are secure for their long underwater deployment.

Aran with two recorders during our redeployment this morning (Photo: M. Kaplan)

A typical reefscape encountered during our visual surveys (Photo: M Kaplan)

In addition to instrument deployment we've been carrying out visual surveys of the benthic cover and fish diversity over the last few days, in order to better characterize our sites. These surveys involve line transects, video and photography, and allow us to take a closer look at what species live on the reef and how abundant they are.

A visual representation of some fish grunts recorded during our first deployment. 

Recorders down

 Acoustic recorder #1 on the reef. It's the size of a coffee can.

Big day. The first set of digital acoustic recorders were deployed today. Very exciting as this is our main goal. We put four of these new recorders, updated and advance by WHOI's Jim Partan (thanks Jim!), on our 'best' reef: Tektite. We're hoping to examine spatial variability of sounds within this healthy reef.

We also had the chance to survey a few new reefs including Booby rock and an area just to the north of Booby rock. Booby rock was filled with a forest of soft corals but not much hard coral. The site to the north was a rubbly reef that will like act as our third comparison site (i.e., limited and dead coral).

Overall it was a great day. Four dives. Two new reefs. Explored Tektite extensively and deployed our new recorders. Pretty awesome. Now to finish prep for tomorrow.

Aran and Max resting between dives.