Monday, February 22, 2016

Madagascar: A momentous day on the water

Dr. Salvatore Cerchio is a marine mammal biologist who has studied free ranging populations of cetaceans around the world for more than 30 years. He is currently a Visiting Scientist at the New England Aquarium, with a guest affiliation at the Woods Hole Oceanographic Institution. In November 2015, he went off the grid to study Omura's whales off the coast of Madagascar. 

Now that we are at our field base and have the “lab” set up in one of our bungalows, we are ready to start field work. With each year that I return to Madagascar to study Omura’s whales, I am never quite sure what we will find… this is because we know so little about this species, that we don’t yet know how reliably and consistently we will be able to find animals. Is this population here all year round? Do the same individuals use this habitat around Nosy Be from year to year? Do they range much farther in Madagascar than this immediate region, and will they sometimes be very far from Nosy Be?

Prior to my arrival this year, I heard numerous reports from friends and local tourist operators that there were many whales sighted in early and mid-October, in conjunction with swarms of what people referred to as “tiny shrimp”.  This was very encouraging, however, they seemed to thin out right before I got here and were nearly absent during our set-up week.  This made the team a bit nervous…

… and then our first day on the water proved to be momentous…

Omura's whale surfaces after feeding lunge

Out on the water by 7:50 and within one hour we find our first Omura’s whale of the season quite close to Sakatia! These whales are relatively small, show very little of themselves at the surface, and don’t put up a prominent blow like larger whales, so can be a bit tough to find. But this first morning the sea is very calm, making it easier to find them. And as soon as we sight our first animal we see at least two others in the vicinity. We have found an aggregation!

A series of images showing side lunges

And what’s more, they are feeding! This is fantastic because we really hoped to focus more on feeding behavior this year, particularly to document what they are feeding on. So the previous reports of “tiny shrimp” were indeed tantalizing — and it seems that the swarms of these zooplankton, what we believe to be a tropical species of krill, or euphausiids, have returned.

Plankton tow
Close up of krill

By the end of the nearly 10 hour day we have worked with four different Omura’s whales, done two plankton tows in the vicinity of feeding whales collecting good samples from the krill swarms, and collected a “poop” sample from the fecal plume of a nearby whale. [The right whale researchers also collect fecal samples to study a whale's reproductive and stress hormones, among other things.] Truly a remarkable first day!!

Collecting a fecal sample

The good weather holds out for the rest of the week and we are treated to full days of work with whales, more feeding, and more plankton, and poop samples. Two major highlights to mention: First our first mother-calf pair of the season, first seen deep in the bay to the south on our second day out, and then again three days later. The mom was feeding at the surface, making several rolling lunges in which her pectoral fin and fluke came out of the water, while the calf meandered around nearby. Very mellow and tolerant, she gave us some great opportunities for underwater video to document her feeding behavior.

Omura's whale mom feeding with calf nearby

Mom and calf surfacing

The second exciting moment came when we recognized a whale while on the water from previous years. Upon return to base that night, a check of photos verified that this was in fact a female that we first photographed in 2012 within an aggregation of four whales, and then in 2013 with a calf, and now in 2015 again without a calf. This female clearly considers Nosy Be her home!

Finally, to close out the first week, we deploy our four SoundTrap recorders, in a relatively tight diamond-shaped cluster about 2km apart from each, outside of Sakatia. This first deployment will be for two weeks, in part to test the new units, and in part to use the close spacing as an “array” and attempt to locate singing whales through an acoustic triangulation technique.

All in all, an amazingly successful first week for a field season!  An excellent start!

— Sal Cerchio

Saturday, February 13, 2016

Madagascar: Traveling to Base Camp

Dr. Salvatore Cerchio is a marine mammal biologist who has studied free ranging populations of cetaceans around the world for more than 30 years. He is currently a Visiting Scientist at the New England Aquarium, with a guest affiliation at the Woods Hole Oceanographic Institution. In November 2015, he went off the grid to study Omura's whales off the coast of Madagascar. 

Getting to Madagascar from Cape Cod (my home) is a bit of a process. After a 4 a.m. wake up, 3 flights, 4 airports, and 28 mostly sleepless hours, one finally arrives in Antananarivo (more commonly referred to as simply “Tana”), and with any luck in possession of all of one’s luggage.

This was not one of my lucky trips… the Rubbermaid crate with most of my equipment appears to have been left in Johannesburg. In fact, during the 11 years I have worked in Mada, I think about one or two in every 10 bags gets lost in transport! So far they have always turned up in Tana later, and on this occasion I was pleased to be able to return to the airport and pick up the crate the very next day. And an added bonus – with all of the equipment still in it!! That was a great relief, because this year I was carrying four precious remote acoustic recorders, each about the size of a soda can, cutting edge technology called SoundTraps manufactured by Ocean Instruments New Zealand.

Beautiful scenery in Madagascar: View of Nosy Be outside Hellville 

Next, onto Nosy Be after a couple days in Tana (which I always plan, just in case a bag doesn’t make it on my flight…).  A 2 hour local flight from Tana, Nosy Be is an island located on the northwest coast of Madagascar, and means literally Big (Be) Island (Nosy). A spectacular setting, lush and green in the wet tropical belt that includes the northwest and east coast rain forests, with dramatic mountains and rocky coasts, white beaches and various small islands scattered about the region.  It is one of the few infrastructure centers in Madagascar, and a center of the tourism industry due to its beauty, accessibility and relatively modern conveniences. I have worked here since 2007, and know the area well, so always greeted by familiar faces in a hotel I stay at each year in the working town of Hellville. Ah, Hellville…  in some ways aptly named, in other ways an exhilarating center of culture and real people, with an energetic central open-air market, a main strip with a litany of small, overstuffed and random shops, two small harbors and a variety of low to mid-range hotels, all amid the dirty streets and acrid smells typical of a least developed country.

Sal and Boris on Sakatia—with a chameleon friend!

Here I meet my team, headed by Boris Andrianantenaina. I have worked with Boris since 2010, and last year he just completed his Masters degree (DEA in the Malagasy system) on coastal dolphins of Nosy Be at the Institute of Fisheries and Marine Science (IHSM), University of Toliara. Boris is a brilliant and highly motivated young man, and manages the field work we do in Madagascar. Also based in Nosy Be, in the beachside town of Madirokely, are partners Les Baleines Ass’eau, a Malagasy NGO formed by brothers Tanguy and Arthur Guillemain who we began to work with in 2014 and have become essential support for our research.

Bringing necessary gasoline to fuel the field research

From Madirokely and Hellville, we spend a week setting up for the coming 4-week field season, buying necessary supplies, arranging for our boat rental, building moorings for our acoustic recorders, and meeting with our regional partners at the National Center for Oceanographic Research (CNRO). Finally we make our way aboard our 8m fiberglass boat from Hellville to our field site on Nosy Sakatia, with all of our equipment and 1000L of gas in tow.

Humpback dolphins | Photo: S. Cerchio

Sakatia is a small island off the west coast of Nosy Be, and a new base of operations this year chosen to be closer to the concentration of Omura’s whale sightings identified in the last 2 years. On the way we have a brief encounter with a pod of Indian Ocean humpback dolphins, the previous focus of our work from 2007 to 2012, so kind of like a welcoming party from old friends!

Research accomodations

We have a pretty nice setup Nosy Sakatia, renting two bungalows at Sakatia Passion, a tourist lodge on the beach that is undergoing renovations; this means there are no tourists right now and we were able to get a discounted price. The accommodations are a little rustic for some tastes (no hot water, for example), but actually quite luxurious for a field camp, with electricity and running water full time (really unusual), great food, and a somewhat finicky internet connection.  It's a slice of tropical paradise and I feel really lucky to be here for a little while!

A beautiful base to launch our field research

Now that we are set up and ready to go, next week we start the field work!!

Sal Cerchio

Wednesday, February 10, 2016

Madagascar: In Search of Omura's Whales

Dr. Salvatore Cerchio is a marine mammal biologist who has studied free ranging populations of cetaceans around the world for more than 30 years. He is currently a Visiting Scientist at the New England Aquarium, with a guest affiliation at the Woods Hole Oceanographic Institution. In November 2015, he went off the grid to study Omura's whales off the coast of Madagascar. 

The Omura’s whale (Balaenoptera omurai) is a recently-discovered species of baleen whale, first recognized as a distinct and ancient species in 2003. Previously confused with Bryde’s whale (B. edeni), at the time of its discovery it was known only from a handful a strandings and specimens from whaling, and never documented in the wild. Then in 2013, my team and I made an exciting discovery off the northwest coast of Madagascar: the first population of this rare and poorly understood species that could actually be studied, found off the northwest island of Nosy Be.

I have been conducting research on cetaceans in Madagascar since 2004, and studying coastal dolphins and cetacean diversity in the Nosy Be region since 2007. The work on Omura's whales began in 2013, when we started to see an unusual baleen whale during an effort to document diversity of cetacean species in the region. At first, with only a few brief encounters, we thought it was a Bryde’s whale, a common mistake. But then once we started to see them more frequently, we realized that this was something very special, and genetic verification confirmed that it was in fact Omura’s whale.

Since then we have published the first scientific study on the ecology and behavior of the species in Royal Society Open Science. In 2015, I joined the New England Aquarium as a Visiting Scientist, and currently the work continues through an international collaboration between the New England Aquarium, the Malagasy NGO Les Baleines Ass'eau, and the Madagascar Centre National de Recherches Océanographiques (CNRO). During 2015/2016, the work is funded by the U.S. Marine Mammal Commission, and focuses on studying feeding ecology, acoustic behavior, status and distribution of the population around Nosy Be.

In the coming blog posts, I will document some of the exciting happenings and discoveries of the November 2015 field season. Stay tuned!

— Sal Cerchio