Humpback Whales and Silver Banks

Humpback whales are beautiful. They are acrobatic, they sing, they are charming and gentle. You can easily become enchanted by seeing their sleek black bodies glide through the water with the graceful movement of their long, white pectoral fins which appear lovely aquamarine blue when close to the surface. Their flippers are the longest of any whales, making them look almost like angels as they move. You may gasp involuntarily when you see their huge flukes lift out of the water majestically, allowing you to see their beautiful, unique markings. You may scream or shout for joy when you watch them raise their full bodies powerfully out of the water to breach. Tears may come to your eyes when you hear their haunting songs, or watch their grace of movement, a grace surpassing that of any human ballerina. And your heart may swell when you feel their trust in coming so close to you.

Facts about humpback whales:

Humpback whales are marine mammals of the order cetacea. They are different from their marine mammal cousins of the pinniped order in that as cetaceans they must live entirely in the water. Pinnipeds such as harbor seals and sea lions live in the water but also regularly haul out on rocks and land for long periods. Cetaceans cannot do this. As a mammal they must come to the surface to breath air, but they must remain in the sea. Humpbacks also belong to the suborder Mysticeti, meaning that instead of having teeth they have baleen. Other baleen whales are gray, blue, fin, right and minke whales. Odontocetes, or toothed whales, include killer, sperm, pilot whales and dolphins. The species name for humpback is Megaptera novaeangliae, meaning "Big Winged New Englander." The common name, humpback, is derived from the "hump" of the dorsal fin on it's back, and the hump that is created when they arch their backs to dive.

Status and Population:

Humpback whales are endangered. Between 1905 and 1965, whaling reduced their numbers from about 115,000 to a present estimate of 15,000 - 20,000. There are approximately 10,600 North Atlantic Humpbacks, the whales we see in Silver Banks. Distribution & Migration: Humpbacks are found in all the world's oceans. Most of them follow a regular migration route, summering in cooler waters for feeding, and wintering in tropical waters for mating and calving. It is believed that approximately 3,000 to 5,000 humpbacks travel through Silver Banks each winter.

Physical Description:

Length: Adult males 40-48 feet, adult females 45-50 feet. At birth: 12-15 feet. Weight: Adults 40-50 tons (about one ton per foot). At birth: 1 ton (2,000 pounds).

Dorsal (Back) Fin: This is the fin on the whale's back that we often see when they glide or float near the surface of the water. It is situated about 2/3 of the way from the mouth toward the back of the body. The shape of each humpback's dorsal fin is unique and helps with identification. Pectoral Fins (Flippers): The longest of any whale, about 1/4 to 1/3 the length of its body. On North Atlantic Humpbacks, the color is usually white, with some black markings. On Pacific Humpbacks, the color is often all black. Fluke (Tail): Can be 18 feet wide and is serrated and pointed at the tips.

Fluke Markings:

When a humpback dives deeply (called "sounding"), it usually lifts its fluke upward, exposing black and white markings on the underside. These markings are unique to each whale. Considered the "fingerprints" of humpbacks, the markings make visual identification of individuals fairly easy. "The discovery of this interesting fact changed the course of cetacean research forever, and the new form of research known as "photo-identification," in which individuals are identified, catalogued, and monitored, has led to valuable information about such things as humpback whale population sizes, migration, sexual maturity, and behavior patterns." (American Cetacean Society Fact Sheet)

Head, Mouth and Throat:

The top of the humpback's head as well as the lower jaw have a number of round, bump like knobs called tubercles, each of which has a stiff hair. At close range, these knobs make their heads look very cucumber-like. It is believed that the hairs may provide a sense of touch, but the purpose is not known for sure.

From the tip of the mouth to the navel, they have about 20-35 ventral grooves, allowing their mouths to expand tremendously while feeding. This makes their entire lower jaw area look so blown up it appears pelican-like.

Inside their mouths, humpbacks have baleen plates instead of teeth. Baleen is composed of keratin (what human fingernails are made of), and is situated in the whale's mouth in plates, hanging from each side of the upper jaw. Each plate is about 30 inches long, black in color, and fringed on the ends. Each humpback has about 270-400 of these fringed overlapping plates. When they feed, they take in large amounts of water along with their small prey (thanks to those expanding throat grooves), pushing the water out with but their tongue but keeping the food trapped in the mouth (thanks to the fringed baleen).

Breathing:

Humpbacks use their blowholes for breathing, not their mouths. Like all baleen whales, humpbacks have two blowholes, while toothed whales have one. When a whale exhales, a mist called a blow or a spout rises above the surface about 20 feet. A whale will usually blow several times before diving. Seeing these beautiful spouts is what allows us to locate the whales' position from quite a distance. Up close one can hear the peaceful "whoosh" sound of the whale breathing. But even from far way, even from land, a whale spout is an awesome sight.

Feeding:

Humpback whales feed on krill, tiny shrimp-like crustaceans, and small fish such as sand lance (in Stellwagon Bank in the Gulf of Maine) and herring (in Alaska). Each whale eats up to 1 and 1/2 tons of food a day. Humpback calves drink about 120 gallons of milk from their mothers each day.

Mating and Breeding:

Mating, giving birth and nursing occurs only in the warm, tropical waters, such as Silver Banks in the Caribbean, that humpbacks travel to in winter months every year. They reach sexual maturity and begin to mate at about 6-8 years of age or when males reach the length of 36 feet and females reach about 40 feet. Females typically bear a calf every 2-3 years with a gestation period of 12 months. Calves nurse on mother's rich milk of about 40% - 60% fat content. Calves are weaned to solid food at about one year old.

For more information on the natural history of humpbacks, see books on humpback natural history, videos on humpback whales, visit our links to American Cetacean Society and the Center for Coastal Studies.

Silver Banks:

A humpback mating and nursery area, Silver Banks is located about 90 miles north of the Dominican Republic in the Caribbean Sea. It is a 75 square mile shallow coral reef area which derives its name from large amount of Spanish gold and silver lost in ship wrecks in the 1600's. The "banks" are not a pile of silver, however, but rather an underwater plateau of limestone. It is believed that the whales choose this area for birthing and nursing because numerous coral heads which break the surface provide protection from ocean swells.

It is estimated that between 3,000 - 5,000 humpbacks pass through Silver Banks between December and mid-April each year, making it the largest breeding and calving grounds, often called a nursery, in the world.

In 1986 the Dominican Republic declared Silver Banks a whale sanctuary. In 1996 the sanctuary boundaries were enlarged to include Samana Bay and the north and east coastline of the Dominican Republic and was renamed "Sanctuary for Marine Mammals of Dominican Republic."

Because it is not a highly populated vacation spot such as Hawaii, you will not see large numbers of whale watch boats or fishing charters in the area. The vessel for this trip, Bottom Time II, holds a special license issued by the Dominican Republic Whale Commission to be there. Only three to four vessels hold this license which allows travel and mooring in the waters of this sanctuary. These vessels must adhere to strict guidelines of non-invasive travel near the whales.