Humpback Whales are the most acrobatic of the great whales. This
is why it is a favorite of Odyssey Science Intern, Judith Scott.
Photo: Iain Kerr
December 11, 2001
Perspectives - Odyssey Science Intern
This is Judith Scott speaking to you from the Odyssey in Western Australia.
Before working onboard the Odyssey as the Science Intern, I worked for Cape Anne Whale Watch, an organization based in Massachusetts that is affiliated with The Ocean Alliance. I feel so fortunate to have had the opportunity to experience working in such different parts of the world, with two species of whales that are totally different in so many ways. I have always been passionate about whales and marine conservation and to be able to work directly with these animals in their own environment while educating the public, is the experience of a lifetime.
It is my job to help keep the acoustic arrays and other equipment we use for tracking sperm whales in good working order. The system we use on the Odyssey for finding and tracking whales is very different from the way whales are found on most commercial whale watch vessels.
While working for Cape Ann, we observed humpback whales in the Stellwagen Bank National Marine Sanctuary. When out with whales we took data on behavior, identified individuals by the marks on their flukes, noted group associations and also feeding styles.
Sperm whales and Humpback whales require different habitats for feeding and therefore are tracked in different ways by the two vessels I have worked on. We searched for humpbacks visually, whereas on the Odyssey, we search for sperm whales acoustically.
Humpback Whales are Baleen Whales, belonging to the order called Mysticetes. We generally look for Humpback Whales at the surface using one or a combination of three indicators. One of these is seeing a lot of birds in a concentrated area, which may indicate the whales feeding on sand lance at the surface. Humpbacks have several unique ways of feeding, the most spectacular of which is bubble net feeding. The whales blow a series of bubbles under the surface, in a line, a circle, or a column, around a school of fish, which frightens them into a concentrated ball. The whale then rises underneath the school with its mouth open and consumes the fish. It is an incredible sight to see a whale rising up with its mouth open and up to a third of its body out of the water. This is one of the reasons humpbacks are a favorite of mine and of whale watchers.
We also look for is a lot of white water at the surface. A huge splash indicates a whale doing some sort of surface activity - breaching, flipper slapping or lobtailing. Although this is a way of locating many species of whales, humpbacks are one of the only species of large whale that performs this behavior quite regularly, which is another reason why they are so enjoyed by human observers.
Humpbacks are also a migratory species. They spend the summer months feeding in colder waters and then migrate thousands of miles to their breeding grounds in the winter. The humpbacks here in Australia have just completed their southern migration from the shores of northwest and northeast Australia to Antarctica, where they spend the southern hemisphere summer gorging on krill. This pattern is mirrored in the Atlantic where the humpbacks spend their summer off Cape Cod and the winter in the Caribbean. This set migration pattern enables researchers and whale watchers to find high concentrations of humpbacks in known areas. This makes their location much easier to predict than the sperm whales we are researching on the Voyage of the Odyssey.
Judith Scott is from England and she is the current Odyssey Science Intern.
CLICK HERE to meet some of the other crew members of the R/V Odyssey.
Photo: Iain Kerr
In addition, the last thing we are looking for when spotting Humpback Whales, is the blow or exhalation of the whale at the surface. This can be seen from a great distance in the large whales depending on the weather conditions.
We are also able to find Sperm whales visually, but our most important tool for looking for these toothed cetaceans is the acoustic array, which allows us to hear them underwater. Scientists can also use an array to listen to the songs of male humpback whales, however on a whale watch, this is not a reliable method of locating them.
Unlike Humpback whales, Sperm whales are Odontocetes meaning they belong to the toothed whale family. These include all the dolphins and porpoises, Sperm Whales, Orcas, Pilot Whales and other species. As well as having teeth for feeding, they also use echolocation.
Sperm whales make very loud and regular click sounds when they are below the surface of the water. Scientists believe the animals use sound as an acoustic flashlight', a focused sound beam which enables to navigate and detect prey items.
The habitat in which Sperm whales hunt, as well as their preferred prey could not be more different to that of the Humpback Whale. Sperm whales eat squid, which are found in the open ocean and at depths of up to two miles. This means that they spend much more time under the surface than humpbacks do. They can stay submerged for over an hour whereas the humpback whales in Cape Cod Bay that Cape Anne Whale Watch observes, will usually stay underwater for an average of 6-8 minutes.
Given that they are only at the surface for a small percentage of their time, we use an acoustic array, an underwater microphone system that allows us to track sperm whales while they are clicking below the surface. When the clicking stops, they have returned to the surface, no longer needing to echolocate and can now be found visually, usually by their blows.
This system means we can locate and track sperm whales throughout the day and night, something that would not be possible with humpbacks observed on Cape Anne Whale Watch. With the historic whaling charts of sperm whale grounds as our guide, we drag our array behind the Odyssey, searching for Sperm whales with our ears not our eyes. Hopefully using this method, and improving it over time, we can learn more about the lives of these incredible animals.
Log by Judith Scott