A Day on a Whale Watch
Assumed teacher materials:
nautical chart, Gulf of Maine or other & enlarged simplified
version to track trip
(Instructor can highlight entire course of the trip beforehand to use as reference)
Globe or world map
Stellwagen Bank poster
Herring gulls are common along the coast, especially in harbors and around areas where there are fishing boats. At times they soar overhead like hawks, with a call that is loud, clear, and sort of sounds like a bugle. About 50 cm (20+ inches) long, with a wing-span of 120 cm (4 1/2 feet). They are mostly scavengers, feeding on discarded rubbish, dead fish and garbage.
Black-backed gulls are larger, with a length of 60 cm (2 feet) and wingspan of over 150 cm (5 fee)t. Their call is a low pitched "kow-kow." They are predators who eat live things. Frequently, in the case of gulls, even rob eggs from nesting colonies.
Harbor seals are the most common seal seen in New England. The scientific name (Greek phoca, seal, & Latin vitulus, calf) means "sea calf" or "sea dog." In fact the little head resembles that of a cocker spaniel with an upturned nose. They are 135 cm to 160 cm (4 1/2 - 5 feet) long and weigh 68 to 113 kilograms (150 to 250 pounds) from feeding on fish like herring, squid, sand eels and mackerel. Sometimes they flap their flippers on the water and blow bubbles. They also make sounds like snorts, snarls and burps both in water and on land.
Double-crested cormorants are the most common of all cormorants. They are fish eaters that dive from the surface and swim underwater. They're over 2 feet long with a wing span of 4 feet or more. Cormorants are different from other sea birds in that they don't have oil in their feathers to shed salt water. So, with all their diving, they can become quite waterlogged. The only way they can dry off is to stand on land or on a rock and stretch their wings out in the sun and wind.
Cormorants can dive deeply and catch fish, but are unable to actually swallow the fish while underwater. They have to bring their catch to the surface to swallow. Years ago Chinese fishermen, watching this behavior, found a way to make the cormorant help them with their own fishing. They slip a rope noose around the bird's neck. The cormorant dives, and brings a fish to the surface. The Chinese fishermen then tighten the noose, preventing the cormorant from swallowing, and snatch the fish out of the bird's mouth to keep for their own. Every 13th dive, the fishermen let the cormorant swallow its catch.
Stellwagen Bank National Marine Sanctuary covers 842 square miles of open ocean, stretching between Cape Ann and Cape Cod at the mouth of Massachusetts Bay. Beneath the surface is a geological formation that makes this part of the Gulf of Maine very productive and worthy of special protection.
Underneath the waves, the Bank rises up from the ocean floor leveling off at an average of 30 meters (100 feet) below the the water's surface. The Bank is made up of sand and gravel deposited during the last Great Ice Age.
Stellwagen Bank National Marine Sanctuary
Minke whales are small whales whose blows are almost invisible. They are almost always alone, move quickly, and do not often come near boats. The average length is 8 to 9 meters (25 - 28 ft) and they weigh 8 to 9 metric tons (9 or 10 tons). In their mouths are between 280-300 baleen plate. The longest reaches a length of 27 cm (11 inches). They are also called the "little piked whales" and "sharp-headed finners." Since the Middle Ages, Norwegians have hunted minkes for food.
There is now a scientific ban against all commercial hunting of whales, but the Norwegians and a few other nations continue to hunt and kill the minke for scientific research.
Whales can be divided into two major groups: Odontocetes and Mysticetes. Odontocetes are the toothed whales. There are over 60 species of Odontocetes which include: porpoises; dolphins; the orca (killer whale); and only one great whale, the sperm whale. Mysticetes, which comes from the Greek word meaning "mustache.", are the baleen whales. All of the other great whales, including the blue whale, fin whale, Bryde's Whale, Sei whale, minke whale, Gray whale, Bowhead whale, and the right whales are baleen whales. Instead of teeth these whales strain their food through hundreds of plates of baleen.
Just like our fingernails, and animal hooves and horns baleen is made of a protein called keratin. Like our fingernails, baleen keeps growin. It hangs down from the gums on each side of the upper jaw. The inner edges fray into coarse hairs which strain very small food from the water. Baleen is soft and flexible in the whale's mouth (push against your own fingernail!). When dried out it becomes stiff and hard so the whalers called it whalebone, even though it is not bone at all.
(LINKS for odontocetes)
(LINKS for mysticetes)
When studying wild animals it is important to be able to distinguish individuals, to tell one from another. Minke whales have a white band on their flipper, but only scars, and the shape of the dorsal fin make them look different from each other. Because of this we know very little about their population numbers, migration, or social behavior.
We can see the blow of a large whale no matter what the air temperature is. Some people think whales are squirting water. What we are really seeing is a combination of highly compressed warm air from the lungs, mixing with oil and moisture in the blowhole, as well as surrounding sea water. It is coming out at a tremendous blast, about 300 miles per hour! This is because whales exchange almost all the air in their lungs each time they breathe, about 85 - 90%, so they don't have to breathe as often as we do. We only exchange about 12 -15% of the air in our lungs each time we take a normal breath.
Fin whales can be up to 85 feet long! The scientific name of this whale, Balaenoptera physalus (Latin balaena, whale, and Greek pteron, fin, and Greek physa, bellows) refers to the tall dorsal fin, up to 2 feet, and the very high blow.
The fin whale is the only asymmetrically (uneven) colored whale known. On the right side of the head the lips and part of the baleen are white or pale gray. The lips and baleen of the left side are all dark. The white color of the right lip continues over the back as a broad, pale wash that sweeps up from the corner of the jaw to behind the blowhole. On most finbacks the color becomes two stripes called chevrons that spread forming a wide V along the back and upper side. Over recent years it has been discovered that the color and shape of the chevrons can vary a great deal among different whales. By photographing these chevrons, about 750 individual fin whales have been identified. Each new whale is given a computer code, catalog number, and some are given field names, like "Tracks" for some specific scar, or shape of the dorsal fin.
Fin whales are one of the fastest whales, and have been given the nickname of "greyhounds of the sea." Also fin whales, along with the blue whale, have the deepest and loudest voices of any animal on earth, and can communicate with one another over thousands of square miles!
Both of these humpbacks are down on deep "sounding" dives. The length of time that a baleen whale will stay down holding its breath depends on what it's doing. The average dive time is anywhere from 4 to 10 minutes although they can hold their breath much longer. Usually there is no need to do this, whether they are cruising or even feeding. Their diet is made up of small schooling fish that most often swim up at least mid-water during the day.