~ by Dr. Sarah D. Oktay, Director, University of Massachusetts Nantucket Field Station ~
One of the many luxuries that Nantucket visitors can experience is the chance to see a humpback whale, and just a few weeks ago we had one cavorting very close to the island in the shallow water to the west of the spit of sand that leads to Great Point. Humpback populations on the western side of the Atlantic Ocean are doing well which enables us to encounter more of them offshore and unfortunately we also see some deceased individuals wash ashore too like the 25 foot juvenile who was found dead around Thanksgiving last fall off Miacomet beach. The past two years have been boon years for spotting humpbacks with some Stellwagen Bank and east of Nantucket tours seeing 10-40 humpbacks in one day in 2014 and large groups of humpbacks with some right whales and finwhales for good measure cropping up this spring off the Cape. Marine mammal and fishery experts suspect that an increase in sand lance populations is fueling these large numbers of humpbacks visiting New England. I first learned about the sand lance/humpback connection in a Boston Globe article from last May which reported a plethora of humpback whale sightings (https://www.bostonglobe.com/metro/2014/05/22/spike-sand-lance-fish-population-draws-bumper-crop-humpback-whales-stellwagen-bank/sY5mfuT3nvhDgXbAaOPQLM/story.html) with what may be a record 40 animals seen in one day near Stellwagen Bank National Marine Sanctuary which is a rich feeding ground for whales about 25 miles east of Boston, just north of the tip of Cape Cod.
For several years, the UMass Boston Nantucket Field Station has collaborated with the Center for Coastal Studies (CCS) in Provincetown (http://coastalstudies.org/). CCS scientists are New England area experts on a variety of marine mammals. Information about their programs which include some very long term studies on a large number of individual humpbacks can be found at http://coastalstudies.org/programs/humpback-whale-research/. From the CCS site: “The cornerstone of our research is the Gulf of Maine humpback whale population, which has been under continuous study since the 1970s. CCS is the only institution to routinely monitor this population across its feeding range in both U.S. and Canadian waters. Our Gulf of Maine Humpback Whale Catalog is a synthesis of more than three decades of research on unique individuals. It combines detailed data on life history, behavior, spatial distribution, human impacts and laboratory studies such as molecular genetics. The catalog is the foundation of our Gulf of Maine research and is meticulously curated and updated to maintain its unique scientific value. New techniques for determining pregnancy, health, age and relatedness in large whales are also being developed and ground-truthed with these data.” Most recently the Center for Coastal Studies has started to record whale breathing in the field in the wild above their blowholes! How cool is that? And last but not least, at the end of April, CCS was involved in freeing a severely entangled humpback whale ( http://www.capecodtoday.com/article/2015/04/28/224260-Center-Coastal-Studies-frees-humpback-whale-Race-Point#sthash.2GaOarbn.dpuf). Their team is one of the best trained disentanglement teams in the country.
So let’s start at the beginning and learn a bit more about this gentle giants. From the American Cetacean Fact Sheet we find that the scientific name for a humpback whale is Megaptera novaeangliae. Humpbacks are in the class Mammalia; order Cetacea (Marine Mammals), Suborder Mysticeti (from a translation error from Aristotle for “the mouse, the whale so called”) and Family Balaenopteridae (Baleen Whales). The humpback whale is one of the rorquals, a family that also includes the blue whale, fin whale, Bryde’s whale, sei whale, and minke whale. The term “rorqual” is French, which itself derives from the Norwegian word røyrkval, meaning “furrow whale.” Rorquals have two characteristics in common: dorsal fins on their backs, and ventral pleats running from the tip of the lower jaw back to the belly area. These ventral pleats are longitudinal folds of skin that allow the mouth to expand immensely when feeding. The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head.
The long pectoral fins give the humpback the genus name, Megaptera which come from the Greek word “mega” for “giant” and “ptera” for “wing” (very “dinosaurian” sounding). The humpback whale’s flippers are the largest appendage of any animal at up to 5m in length! The humpback whale was first identified as “baleine de la Nouvelle Angleterre” by Mathurin Jacques Brisson in his Regnum Animale of 1756. The common name is derived from the curving of their back when diving. The species name means “New Englander” and was probably given by Brisson due the regular sightings of humpbacks off the coast of New England.
The long black and white tail fin (fluke), which can be up to a third of body length, and the pectoral fins have unique patterns, which make individual whales identifiable. Several hypotheses attempt to explain the humpback’s pectoral fins, which are proportionally the longest fins of any cetacean. The two most enduring mention the higher maneuverability afforded by long fins, and the usefulness of the increased surface area for temperature control when migrating between warm and cold climates. Humpbacks also have “rete mirable,” Latin for “wonderful net” a heat exchanging system of closely aligned arteries and veins, found in humpbacks, sharks, and fish and used to transport heat or oxygen or stabilize and control metabolism.
The shape and color pattern on the humpback whale’s dorsal fin and flukes are as individual in each animal as are fingerprints in humans. This unique morphology that can be observed by sight allows scientists to create photo-identification inventories of individuals in order to not only identify them but also track their movements and monitor their populations. This ability to distinguish humpback whales provides information about their population, migration, sexual maturity, and behavior patterns. A photographic catalog of all known North Atlantic whales was developed and is currently maintained by College of the Atlantic (http://www.coa.edu/nahwc.htm)
Adult male humpback whales measure 40-48 feet long (12.2-14.6 m) and adult females are slightly bigger averaging 45-50 feet (13.7-15.2 m) long. They weigh 25 to 40 tons (22,680-36,287 kg). Humpback whales feed on krill, small shrimp-like crustaceans, and various kinds of small fish like sardines and herring. Each whale eats up to 1 and 1/2 tons (1,361 kg) of food a day. These baleen whales have a series of 270-400 fringed overlapping plates hanging from each side of the upper jaw, where teeth might otherwise be located. These plates consist of a fingernail-like material called keratin that frays out into fine hairs on the ends inside the mouth near the tongue. The plates are black and measure about 30 inches (76 cm) in length. During feeding, large volumes of water and food can be taken into the mouth because the pleated grooves in the throat expand. As the mouth closes, water is expelled through the baleen plates, which trap the food on the inside near the tongue to be swallowed.
They were recently discovered to use am ingenious “bubble net” technique to encircle fish that they drive into the net in order to herd large groups of fish into a tighter ball that they can then swim underneath and engulf in one big swallow. They usually do this as a group but can do it alone if needed. These video links shows the awesome beauty and precision of this method of corralling fish: http://www.pbs.org/wnet/nature/fellowship-of-the-whales-video-cooperative-feeding/5324/ and http://www.arkive.org/humpback-whale/megaptera-novaeangliae/video-08b.html. If the second one reminds you of the sandworms in Dune, you are not alone, that is the first thing that came to mind when I saw that amazing video; the sheer size of their mouths and the massive pleats are hard to miss.
Because their feeding, mating, and calving grounds are close to shore and because they are slow swimmers, the humpback whales were an easy target for early whalers. The International Whaling Commission (IWC) gave them worldwide protection status in 1966, but there were large illegal kills until the 1970s. Population estimates vary from 35,000 to 70,000 individuals depending on the source. The humpback whale completes the longest annual migration of any mammal, travelling from polar regions to the tropics and back each year. The humpbacks we see spend their spring, summer and fall months in northern waters. Late in the year, humpbacks migrate to the waters of the West Indies where they mate and bear their calves. There are about 550 humpback whales in the Gulf of Maine, many of which frequent Cape Cod waters. The National Oceanic and Atmospheric Administration in April of this year proposed to remove a majority (10 of the 14 groups) of the world’s populations of humpback whales from the endangered species list, including the West Indies population that swims in Cape waters (from http://www.capecodtimes.com/article/20150604/NEWS/150609767. It is important to remember that all marine mammals are protected under the 1972 Marine Mammal Protection Act and humpbacks would remain protected under that Act.
Concern about the population revolves around protecting females and their calves from entanglement and unnecessary death. Females typically breed every two or three years. The gestation period is 11.5 months, yet some individuals have been known to breed in two consecutive years. The peak months for birth are January, February, July, and August. There is usually a 1-2 year period between humpback births. Both male and female humpback whales vocalize, however only males produce the long, loud, complex “songs” for which the species is famous. Cetaceans have no vocal cords, so they make their famous songs by blowing air through their nasal cavities (basically glorified snoring!). The humpback whale lifespan ranges from 45–100 years which gives them plenty of snoring time. Whales in the same population sing the same song.
There are many theories for why males sing. They may be trying to impress a female, warn off another male, find other whales to set up a hunting group, or use it for echolocation. Perhaps they are bored. I highly recommend that you go online and listen to one of the many audio files of humpback whales songs if you are one of the two people in American who have not heard them. Their eerie, haunting songs have captivated researchers and the public for years. Humpbacks whales’ spectacular breaching maneuvers, their curiosity and “friendliness” in approaching whale watching boats, and their amazing feeding behaviors have made them an ideal whale for ecotourism, and whale watching provides an fan of whale watching and I highly recommend taking a trip on Shearwater Excursion (http://shearwaterexcursions.com/) boats that go east off Nantucket. Captain Blair Perkins is extremely knowledgeable and a big friend of science as his company provides the Nantucket Field Station with year-round research vessel access.
Boaters who see marine animals including whales and sea turtles in distress are encouraged to call the MAER hotline at 800-900-3622 or report the animal to the United States Coast Guard via VHF 16. Callers are asked to stay with the animal at a safe distance until help arrives. Since 1984, the Center for Coastal Studies has freed more than 200 large whales and other marine animals from life threatening entanglements, using techniques developed by Center staff. For many years, CCS was the only organization on the east coast of the United States to be federally authorized, by National Marine Fisheries Service, to disentangle large, free swimming whales, such as the humpback and the critically endangered North Atlantic right whale. CCS rescue work is done under NOAA authorization (http://coastalstudies.org/programs/whale-rescue/). Currently here on Nantucket a group of several organizations are working with NOAA to obtain authorization to respond to simple on land (not off shore) strandings. In the meantime, all seal strandings (when the seal is obviously distressed or wounded) and dolphin, whale and other cetacean reports and calls should go to the MARINE MAMMAL STRANDING HOTLINE: 866-755-NOAA (6622).
You can learn more about local education efforts to protect whales and teach the public about them from the Nantucket Marine Mammal Conservation Program http://www.nantucketmarinemammals.org/ who can often be found at a booth at the downtown Sustainable Nantucket Farmer’s and Artisan’s Market. New England is home to many museums dedicated to learning about whales from the hunts of years ago to the protection and science of their biology and behavior. Our local Nantucket Historical Association’s Whaling Museum on Broad Street is one of the finest in the country. New Bedford also has an excellent whaling museum. You can see a humpback whale’s skeleton and learn more about them at the Whale Center of New England’s free, public Visitor’s Center located near the Gloucester Maritime Heritage Center. Go to http://www.nmfs.noaa.gov/pr/species/mammals/whales/humpback-whale.html to learn more about humpbacks than you ever thought you could! Other New England whale information links can be found at http://www.barharborwhales.com/whale-links.php. Portions of this article were originally published in July 2011 in this publication.