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.
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.
Humpback whales are the best documented great whales, and we know a great deal about their lives, because they are so easy to tell apart. We don't have to "tag" them. We have a natural tagging method of simply photographing the underside of their tail, which is usually raised before a deep dive. The coloration ranges from all black (what we call Type 5) to all white (Type 1). Most are a mixture of black and white and unique to each whale like a fingerprint for a person. So by photographing the fluke pattern we can get a positive identification for each individual humpback whale. Over 4,000 individual humpbacks have been documented this way in the northwest Atlantic Ocean alone. They, like the fin whales, are each given catalog numbers, computer codes and field "names." Researchers see many of the same individuals year after year - some for over 20 years!
|Pick the Humpback whale (Megaptera novaeangliae) fluke|
College of the Atlantic's Allied Whale
Spoon, a very large female, was first sighted in 1977. She has be seen again every year except 1978. In the summer of 1986 she traveled all the way to Brier Island Nova Scotia to feed. The first calf she was seen with was born in 1983, a male given the name Regulus. Six years later she had another male calf named Vesuvias, and two years after that another calf named Fork. In 1995 she had her fourth known calf.
Most of the humpbacks of the Northwest Atlantic give birth in December and January down south in warm tropical waters. The baby whales are born without a protective blubber layer and probably wouldn't survive in colder waters up north her. The largest breeding ground for these whales is a place called Silver Bank, which is far south in the West Indies, just above of the Dominican Republic. If, in fact, this is where Petrel gave birth, she and her calf swam about 2000 miles to come here this summer! Other humpbacks swim even twice as much distance, to feed farther north in the waters near Greenland and Iceland. West Coast humpbacks have a similar migration, feeding in Alaskan waters and traveling south to breed around the Baja and Hawaii.
Since it is August, this calf is about 7 months old. At birth it was 12-15 feet long, and has been nursing constantly, drinking up to 50 gallons of Spoon's milk each day, gaining several hundred pounds every week, and growing about 1 and 1/2 ft in length every month! It is now about 22 feet long.
There are about 350 plates of baleen, hanging very close together like a comb, on each side of the upper jaw. In the very front of the mouth the plates are only about 6 inches long. In the back of the jaw they grow to a length of about 2 1/2 feet.
The mouth is huge, but the throat is so small it is said that a humpback would choke on a grapefruit. For this reason, and because they don't have teeth to chew large fish, their diet is made up of only small fish like sand lance, herring, mackerel, capelin, and even tiny shrimp-like crustaceans called krill.(LINK - National Marine Fisheries Service)
Humpbacks whales sometimes blow underwater bubbles that rise to the surface when they are feeding. It is believed that the rising bubbles confuse and concentrate the fish into a dense bunch so the whale can get more in each mouthful. The bubbles may also camouflage the whale so the fish can't see it coming toward them.
This calf, being only about 7 months old, is probably still nursing and hasn't begun feeding on its own. As soon as Spoon stops feeding, they will join up, as mothers and calves have a very close relationship. In fact it is the only really lasting bond of a baleen whale. They do not live in family groups, or pods, like the toothed whales. Sometimes they group up to feed or travel together, but it is only temporary.
Often young calves have gray areas on their flukes, which may change quite a bit during their first year or so. It is important to photograph and pay attention to any black parts. They will probably remain the same. In a year or two a permanent black and white pattern will appear and will be this young whale's "fingerprint." This calf has already been given a catalog number, but it won't be give a name until next spring. In April researchers on the East Coast will meet to look at the fluke patterns of the previous season's calves and unknown whales. Names will be suggested and voted on then.
Greater shearwaters can skim to close to the water surface because of small thermal updrafts caused by the difference in the water and air temperature, and also by the wind riding over the waves. By letting their broad wings ride on these updrafts they can glide inches above the surface without actually touching the water. They feed on small fish and crustaceans.
Common terns are nicknamed "sea swallows" and will dive from great heights to capture fish and shrimp and insects. They can be very aggressive in their breeding colonies and will often attack people who wander too close.
Wilson's Storm Petrels feed on tiny fish, shrimp and planktonic animals. They are also called "St. Peter's birds", named after St. Peter who was supposed to have walked on water. They flutter and hop over the waves, pattering with their webbed feet to stir up the food to eat.
Blue, fin, humpback, minke and sei whales all belong to a group of baleen whales that whalers named rorquals. This name comes from the Norwegian ror, tube, and hval, whale. These whales have a number of folds, or tube-like grooves on the throat and chest. We sometimes call them "gulpers" because when they feed they usually gulp a single huge mouthful of water and fish. As the water enters the mouth these grooves stretch, the floor of the mouth ballooning out to form an enormous pouch that increases by as much as 5 times the amount of fish and water they can take in. When they close their mouths those grooves contract forcing the salt water out through the baleen. The food is trapped inside.
Even though baleen whales don't live in families, they do sometimes travel together for a while. If two or more whales are traveling within 50 - 70 feet of each other, and performing the same behaviors, it is called an "association." These associations may be quite brief, lasting only a few minutes, maybe several hours, days, or even weeks.
The Basking shark, which can grow to a length of 45 feet, is second only in size to the giant Whale shark. Despite their size these sharks are almost completely harmless. They have 4 to 7 rows of very tiny teeth which are not used for feeding. 5 large gill openings circle the neck. Each opening has a gill arch covered with bristle like gill rakers. The gill rakers look like a whale's baleen. In fact the scientific name for the basking shark, Cetorhinus maximus, means "big whale- nosed" shark.
Basking Shark Slide Show
ceto = whale, rhinus = nose, maximus = big
Like baleen, the gill rakers are used to strain very small food from the water.
Fan was first seen in 1988. In 1993 she was seen with her first known calf, named Slant. The scars on her fluke reminded researchers of a spreading fan. These scars are from the teeth of orca (killer) whales.
Many orcas feed only on fish like salmon. But some prefer to hunt marine mammals like seals, dolphins, and even the great whales. About 15% of the humpbacks that have been identified have orca teeth scars on their bodies, fins, or flukes.
Crystal was born in 1980, when he was first seen with his mother, Salt. How old is he now? His mother was the first humpback whale to be given a "name." She has white scarring on her dorsal fin that looks like dry caked salt. Her first know calf was named Crystal, because he is a little piece of her, a "crystal of salt."
Crystal now has many brothers and sisters: Halos, born in 1983, Thalassa born in 1985, Brine born in 1987, Bittern born in 1989 and Salsa born in 1991. In 1992 Crystal's sister, Thalassa gave birth to a calf named Skeeter, so he is now an uncle!
Fan, Crystal, Salt, and Brine were seen on Stellwagen Bank during the summer of 1996.
After a long winter in the southern breeding grounds where there is so little food for the humpbacks, eating is their main activity all summer long. Their stomachs may hold up to a ton of food and these whales may eat as much as 3,000 pounds of fish (well over a million calories!) each day. They build up a thick layer of blubber, or fat, which will help them live through the next winter without food.
(LINK to "fat glove" activity)
This the "fluke print." The old whalers used to think that it was an oil slick left behind by the whale. It is a brief flattening of the surface water caused by the upward motion of the whale's tail when it dives. In fact, if a whale were traveling just beneath the surface we could follow its path by watching the trail of fluke prints, just like footprints.
When a whale "spyhops" one must wonder who is watching who. It appears that they are scoping out all activity above the surface. The visibility is poor in the water of the northern feeding grounds because of all the plankton. Whales cannot see very far beneath the surface. Their eyes are located at the side of the head, so then can look down, and out, but not very well in front . In fact their eyes are so far back on the side of the head that both eyes can never focus on the same thing at the same time. They are taking in two different images, and in only two dimensions.
All humpback whales have bumps the size of a large orange on top of the head in front of the blowhole. It is said that some whalers used to call these bumps "stovebolts" because they thought the bumps held the whale+s head together, just like the bolts on an old cast iron stove. Each bump, or knob, is a large hair follicle that has one or two bristle-like hairs growing out of it. Whales probably use these hairs very much like a cat uses its whiskers. They can feel the water movement, and maybe even sense fish nearby.
The most outstanding physical feature of a humpback whale is its enormous flippers which can reach up to 1/3 the total body length. Each flipper, or pectoral fin, is 12 - 15 feet long and can weigh up to a ton (2000 pounds). The genus name for humpback refers to these flippers - Megaptera novaeangliae. mega, big & pteron, fin or wing, nova, new & aeangliae, England. Although the humpback whale is found in all the major oceans, the first one described scientifically was seen along the Maine coast in 1846, so its genus name translates into "Big winged New Englander."
These huge flippers, the largest of any whale, are used for steering and balance, herding fish, guiding young calves, pounding the surface to show power or stun fish. Inside the flipper is a bone structure similar to a human hand. They even have finger bones! This is one of many traces whales still have of their ancient land ancestors.
(sketch of bone structure)
"Lobtailing," yet another spectacular behavior of the humpback whale, may occur for similar reasons as flipper slapping. There are several thoughts as to why whales "breach," flipper slap and lobtail.These active behaviors would certainly would help knock off some of the barnacles that collect on their bodies.They might also help in digesting their food. Maybe they are territorial statements to the arrival of a new whale, and are sometimes seen when two whales together separate. They could be a form of communication, because the sound of a breach splash travels a tremendous distance, and when a whale jumps out of the water, occasionally other huge splashes are seen in the distance, as if responding to that sound. These behaviors at times may also be play. All mammals have play activities, and young whales have been seen active when they are only a few weeks old. Whatever the reason for these bursts of energy, a humpback breach is said to be the singe most spectacular behavior of any animal on earth!
Millions of tiny plants and animals, most too small to see without a microscope, live in the ocean. Most of this ocean life is called plankton, from the Greek word, "planktos," meaning wanderer. Plankton usually drifts, being carried by waves and current. Some of the animals in the plankton swim quite well but, because of their extremely small size, they usually swim vertically in the water.
Plankton is made up of plants (phytoplankton) and animals (zooplankton). The greatest amount of planktonic life are plants and they are called "primary producers" because they use the sun's energy to make their own food through the process of photosynthesis.
The biggest amounts of plankton are found in shallow, coastal waters, and places in the ocean where there are banks and ledges. It is here that there is the greatest amount of upwelling, currents of water bringing rich nutrients from the bottom up to the surface and sunlight.
The least amount of plankton is found in warm tropical seas. In these areas, where there is little or no plankton, the seas are clear and blue. Seawater that is rich in plankton is green.
The gills of fishes strain the tiny organisms of plankton. The largest fish, the 40-foot whale shark, feeds entirely on plankton. Even some of the world's largest mammals, the baleen whales such as the blue whale and right whale, feed by sifting tons of planktonic animals called krill. Krill can grow to be 2 inches long, but most plankton are so small that you would need a magnifying glass to see them.
INFO on copepods, comb jelly
The energetic White-Sided Dolphins range in size from about 6.5 - 9 feet, and can be seen from Cape Cod all the way to Greenland. They are very social and always found in groups, some as large as several hundred individuals.
Dolphins and porpoises are all whales belonging to the family of Cetacea, just like the huge baleen whales. Dolphins are mainly fish eaters, enjoying sand lance, herring, hake, smelt, and short-finned squid. Like all toothed whales, dolphins have the ability to "echolocate." They are constantly sending out rapid clicking sounds that bounce off objects and, like an echo, return to the dolphin. The returning echo helps them locate each other, know how deep the water is, find fish to eat, and "see" our boat.