We spent most of yesterday afternoon being dragged around by a boat through the turquoise waters off of Great Abaco Island in the northern Bahamas, occasionally free-diving to the bottom to practicing sucking up imaginary whale poop with a turkey baster and a slurp gun. Excuse me?!!!
Map of Bahamas: The star shows the Bahamas Marine Mammal Organization location in the Bahamas.
Perhaps a bit of background explanation is in order. This week, the New England Aquarium, in collaboration with the Bahamas Marine Mammal Research Organization (BMMRO) [More about this organization in this post], is starting a new research project on the potential effects of noise on beaked whales and sperm whales in the Bahamas. The project is funded by the US Navy's Office of Naval Research (ONR), which has been supporting research on the potential effects of sound on marine mammals for several years because of concerns over the environmental effects of military activities on the environment. Modern civilization has moved into the oceans - the low frequency drone of constant shipping traffic, the booming of offshore seismic exploration, recreational boat traffic, and sonar pings from fishing and military activities all contribute to making the ocean much noisier than it was in the past. For marine species that hunt and communicate using sound, this rising tide of background noise could make it harder for the animals to find food or each other, raise stress levels and affect their health or reproduction in subtle ways.
The BMMRO field station on Great Abaco Island-our home for 11 days
We're doing this research in the Bahamas for three reasons. First, there's a Navy testing range here - the Atlantic Underwater Test and Evaluation Center, near Andros Island in the Bahamas. Second, there are Blainville's beaked whales and sperm whales living here that have been studied for two decades by our collaborators at the Bahamas Marine Mammal Research Organization. Third, the water in the Bahamas is so clear that it's possible for a snorkeller to keep the whales in view even when the whales are diving a hundred feet below the research boat.
Beaked whales are notoriously difficult to study - many marine biologists go their whole careers without even getting a glimpse of a beaked whale. (More about beaked whales in a later post.) But our collaborators at the BMMRO have discovered that a slowly towed snorkeller can keep the beaked whales in view during the whales' long shallow dives, and can signal where the whales are going to the boat pilot. That means the boat can slowly follow the beaked whales, allowing the swimmers to spot and collect one of their fecal samples.
Roz being towed in snorkel gear to collect beaked whale fecal samples.
So why are we trying to get fecal samples? Our NEAq research team has previously shown that it's possible to measure reproductive and stress hormones in whale feces - it's the first proven method for measuring stress in a free-living whale. (Reproductive hormones are good for lots of things too – from determining maturity to pregnancy tests! - more about this in a future post.) And we need to collect hormone samples from a relatively un-disturbed population of whales to establish baseline hormone levels, before we test stress level on animals that have been exposed to underwater sounds. Our ultimate goal in this research project is to compare fecal stress hormone levels from beaked whales and sperm whales that live on vs. off the Navy testing range, to try to determine whether the noise disturbance from Navy exercises are having any detectable effect on the whales.
Scott rigging a slurpgun for towing.
Yesterday, our first full day here, we spent most of our time building and testing our gear. NEAq researcher Scott Kraus built an ingenious rigging system so that we can tow two snorkellers simultaneously, one on each side of the boat (to maximize our chances of spotting the whales and collecting the samples). Then we - Scott, Rosalind Rolland, myself (Kathleen Hunt), and our BMMRO collaborators Diane Claridge and Charlotte Dunn - spent much of the rest of the afternoon taking turns being dragged around by the tow rope, testing how fast we could be dragged before the turbulence got too rough, and practicing free-diving to collect imaginary fecal samples (hence the slurp guns and turkey basters - about which we'll have more later). Our gear seems to be working well; now we just need to find some whales. Stay tuned!