Moorea Reef Sharks Wrap Up (For Now)

18 November 2013

Well, the mission is now over! Today, Jeremy and Johann removed the camera poles and took detailed data on the sites where they had been deployed.  It was a memorable last dive with sicklefin lemon sharks! 

During the last two weeks, Jeremy and Johann continued collecting shark samples from the lagoon (including at the shark and ray feeding sites), along the forereef and in nurseries. In addition, a diversity of potential prey samples (including spotted eagle and sting rays) for stable isotope analyses were collected. In total, we collected 250 shark and prey samples in just a few weeks!

We now have a total of 15 days of stationary camera deployments (60 total cameras), totaling about 350 hours of recordings.  Johann and Jeremy also finished off the transects using the drone that will help us estimate total numbers of sharks and rays in the shallow habitats of the reef. Now the lab work begins - including going through all of that video!  We should have fantastic data!  Of course there is more fieldwork that needs to be done too.  We can't wait to be back...

We will post updates of the results as they come in!

Moorea Reef Sharks!

November 5, 2013

Its been a busy few days for Jeremy and Johann!  The stationary cameras have been deployed several times on the forereef. The cameras have recorded an impressive number of species including blacktip reef sharks and lemon sharks, hawksbill turtles, large predatory fishes (trevallies, groupers, emperor beams and some large pelagics too), and tons of smaller fish. A couple days ago, Jeremy and Johann had the chance to listen to amazing humpback whale songs when they were retrieving the cameras! Two males were singing about a kilometer away!

This week, the team started collecting samples from many fish species.  These will help us use chemical markers - stable isotopes - to better understand the feeding ecology of blacktip and sicklefin lemon sharks around Moorea.

Another major accomplishment this week was establishing sampling areas (transects) along the barrier reef that we will fly with the quadcopter to measure the distribution and densities of reef sharks and rays in shallow water habitats.  The first round of flights has already been completed!

Finally, two nights of net fishing resulted in collecting samples from four newborn blacktip reef sharks. Pup numbers are still low, but there should be many more births in the coming days!

In the upcoming weeks, Jeremy and Johann will continue working on all of these projects and try to deploy the shark-cam on adult blacktips!

The net is set in a nursery area for blacktip reef sharks.

Johann with a newborn shark.

Jeremy releases a baby shark after sampling.

A sickelfin lemon shark swims right in front of a stationary camera.

The quadcopter coming back to the boat.

Moorea Reef Sharks: Mike and Linda's last research day

October 27, 2013

Well the weather wasn’t kind to us on the last day for Linda and I.  We were going to do some quadcopter work but the wind was blowing 25 knots…at least…making conditions bad at best.  We did get in a little bit of snorkeling when we went out to check the conditions. We saw lots of sharks and rays and got some identification pictures for Johann…and then came across a humpback whale and calf inside the bay (a nice birthday present for Jeremy!).  The humpbacks are here for breeding and will travel south for the (southern hemisphere) summer to feed.  We were lucky enough to spend a bit of time with a mother and calf.  They were both pretty animated at times and we got to see tail slaps, pectoral fin slapping, a few spy hops and a couple breaches!  Truly amazing!  They even came close enough to see them underwater.  Last night when Johann and Jeremy were retrieving the cameras they could hear a whale singing in the distance!

Below are some pictures from the monitoring cameras and our snorkel.  Linda and I head back tomorrow but Johann and Jeremy have another three weeks of work.  We won’t keep up the daily updates for now but we will put together some highlights of the research.  Also look out for project based videos for elementary and middle school classrooms in the next couple months … and research results as soon as we have ‘em!

For you Finding Nemo fans....

Moorea Reef Sharks Day 7: shark cam trial

26 October, 2013

It was another great day of work in Moorea today!  We started out early, setting the stationary cameras again.  Finding the stakes was a bit trickier today with seriously reduced visibility!  But, Johann and Jeremy made fast work of it, and we soon ducked inside the lagoon to try to catch a blacktip reef shark to deploy the shark cam.  I still wasn’t totally happy with our design so while we waited for the sharks to show up (which took them what seemed like forever) I worked on it.  In the end, I was pretty happy with the field fix and I am now confident that the camera will come off when it is supposed to and that we have absolutely minimized the drag.  Even better, the new design puts the camera right in front of the dorsal fin so it isn’t causing drag on one side of the animal but not the other.

For a while it looked like the sharks were going to win again today.  Four sharks came and went, sniffing the bait and then leaving, for more than an hour before a big female finally bit.  Jeremy got it to the boat and we quickly measured it, took identification photos and samples, then put the camera on.  The release went smoothly and the camera rode perfectly on the shark.  She showed no reaction at all to the camera, slowly cruising away.  Unfortunately, my desire to make sure the camera came off was a bit over-zealous and it detached before the dissolving link was gone.  However, the video showed that the system will work and I am really encouraged by the lack of reaction to the tag.  One more set of tiny tweaks to the attachment and we will be in serious business!!

After getting the camera back it we returned to CRIOBE to refill tanks.  Jeremy and Johann headed back out to get the stationary cameras and Linda and I managed to squeeze in a snorkel since our days are disappearing fast!  The fish life on the snorkel was amazing.  The diversity is wonderful to see and although the coral isn’t what it used to be before the cyclone and the crown-of-thorns starfish outbreak there are signs of a robust recovery everywhere!  We did have one entertaining encounter with a triggerfish that decided it did not like us in its territory…or really didn’t like it’s reflection in the camera lens!

 In the early evening we planned to head out to a nursery area but the weather thwarted us again.  That’s the breaks of fieldwork though!

View from the back of a blacktip reef shark swimming over a shallow sand flat.  There is a whipray in the upper right corner of the picture.

The shark cruises out into a deeper channel in the lagoon.

The shark cam floats to the surface after releasing from the shark as it swims slowly away.

Triggerfish attack!  This triggerfish really didn't like its reflection in the camera lens! Or maybe it was my swimsuit.  It successfully chased the intruder away!

Moorea Reef Sharks Day 6

October 25, 2013

Before I get to the sharks…er or attempt to work with sharks…I give you a photo of our alarm clock!  Now…the myth is that roosters wake you up at dawn.  Well, here on Moorea they aren’t bothered by technicalities like daylight…5am and dark is fine for them.  And 530.  And 0600, but by then we are up and having coffee anyway.

 

Our alarm clock during one of its rare quiet moments

Well, you can’t win ‘em all!  We had a beautiful start to the day and were poised to catch a shark to deploy our shark-cam.  But, before one of the three sharks circling the bait could take it a large tourist boat came over and anchored right next to us.  We tried to find another spot, but we couldn’t catch a shark before it was too late in the day to deploy a camera.  We’ll give it another go tomorrow!  We did, however, have a really nice test flight of the quadcopter.  The ‘copter has a video camera mounted to it and we will be able to use it to assess shark abundances on the shallow reef and in nursery areas.  Today was about making sure we could retrieve it from the boat and picking the best speed and altitude to fly!  The test was a success and involved no unintended plunges into the Pacific Ocean.

Getting ready to leave from CRIOBE

Getting ready to fish for sharks

Jeremy preparing the quadcopter.  

Test flight!

View of our boat from the quadcopter.

The day started so calm and sunny...

Landing the quadcopter safely!

We were going to go a nursery area tonight, but we were thwarted by a tropical downpour that is still going on!  But the silver lining is that it gave us time to review the footage from the stationary cameras we deployed and retrieved yesterday. 

The rain got even worse than this!

The cameras really did an amazing job, recording for almost seven hours and providing high-quality video.  Check out the pictures for a sample – lots of sharks (especially the site closer to the feeding site), tons of fish, turtles, and dolphins!  In addition to basic numbers of reef species, we will also be able to investigate the behavior of the sharks and fish. 

This blacktip reef shark was at the site far from the shark feeding spot.  There are a lot of sharks here!  Just way more near the places they can get a free meal. 

Spinner dolphins (at the top of the frame)

Mike and Jeremy very happy to see no leaks in the camera housing!

Ok, so I got distracted and had to take a picture of the lemon shark while Jeremy finished installing the camera!

Pufferfish swimming right past the camera.

Sicklefin lemon shark caught on the stationary camera.

Another lemon swimming through.

Hawksbill turtle

So, after a fairly slow afternoon today, we will have an ambitious plan for tomorrow.  Of course, that assumes that the rain slows enough to see more than four feet in front of you.  Anyway… the plan is deploy the stationary cameras, catch a shark to deploy a shark cam and collect samples, collect samples from other sharks, retrieve shark cam and stationary cameras, go to a nursery area to sample, then collapse.    There aren’t a ton of days left for Linda and I so we need to pack them full!  Of course, the work will continue for another month with Jeremy and Johann…and hopefully for years after that!