Tuesday, November 19, 2013

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!

Tuesday, November 5, 2013

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.