During the first week of February humpback whale females give birth after being pregnant for 11 months. Newborn calves are 13-16 feet long and grow quickly feeding on the milk of their mother.
Humpback whales are a favorite amongst whale watchers due to their acrobatic, highly visible surface activities and their tendency to stay close to the coast.
Humpback whales are a favorite amongst whale watchers due to their acrobatic, highly visible surface activities and their tendency to stay close to the coast. The first time I encountered a humpback whale, I never even saw it. Instead, I heard and felt it. I was aboard a 12-foot boat directly over a submerged humpback off the coast of Maui. Placing my ear on the floor of the boat, I could hear and feel the vibrations of the whale singing below. I knew this whale was a male as only male humpbacks sing, often in long complex songs, and only within their breeding grounds.
Humpbacks grow up to 60 feet and weigh 40 tons.
Humpback whales spend their spring, summer, and fall feeding in cold, high-latitude waters where prey is plentiful. During the winter, most individuals migrate to warm-water breeding grounds to mate and give birth—a round-trip of up to 10,000 miles. Since prey is scarce in these breeding grounds, the only individuals feeding are newborn calves on their mother’s milk. The whale I heard off Maui probably migrated from the coast ofAlaskawhere he spent his summer feeding. In the Northwestern Atlantic, humpbacks migrate between feeding grounds off New England and eastern Canada and breeding grounds in the West Indies. This migration route passes through New Jersey’s ocean waters and some humpbacks swim very close to our shore to feed on small fish like herring and sand lance.
Humpbacks may use several fascinating hunting methods, including “bubble netting.” To begin, a group of whales dives below a school of fish and use their blowhole to blow bubbles in a circular pattern. As the bubbles rise, they form a “cage” around the fish, causing the fish to school within a tighter formation. Finally, the whales swim upward through the bubble net with their mouths wide open, capturing a large mouthful of fish.
Humpbacks grow up to 60 feet and weigh 40 tons. Their long flippers are knobbed along the leading edge, distinguishing them from other large whales. Humpbacks also have knobs, or tubercles, on their chins and snout, giving them a somewhat grizzled look. They are generally dark above and white below. Their dorsal fin is variable in appearance. When humpbacks dive, they roll their backs until their tail flukes rise out of the water before sinking beneath the surface. The underside of each humpback’s flukes is unique and scientists use photographs of them to track individual whales over years and across oceans. Because of this, they are one of the best studied whale species.
Despite all these challenges, humpback whales are increasing in abundance throughout much of their range.
Grooves on the underside of their throat and belly enable humpbacks to expand their bodies to swallow enormous amounts of water and food. Instead of teeth, its mouth has great plates of horny baleen which extend from the upper jaw. After swallowing a large gulp, they use their tongue to push the water through the baleen to strain out the food.
Like the other great whales, humpbacks were hunted to near-extinction. Commercial whaling ended in 1966 and in 1970 humpbacks were listed as federally endangered. New Jerseyadded humpbacks to their endangered species list in 1973. Although their numbers have rebounded better than some other whale species, they have not returned to their pre-whaling level.
Despite the ban on hunting, humpbacks still face a number of threats, all of which are caused by humans. The greatest threats to humpbacks are entanglement in fishing gear and ship strikes, but offshore development, pollution and oil spills, overfishing of prey species, and climate change destroy habitat and displace whales. Noise pollution from ship traffic, offshore construction, or use of active sonar by the military may negatively impact whales by disrupting behaviors associated with communication, feeding, navigating, etc.
Despite all these challenges, humpback whales are increasing in abundance throughout much of their range. There is still no commercial hunt for humpback whales although several countries are interested in hunting them again. The population today remains endangered and any such hunt would set back decades of recovery.
By Michael Davenport
Harbor Seals in New Jersey Story Map
Use interactive web-mapping and multi-media to learn about harbor seals in New Jersey. Where they live in the world, where they are frequently seen in New Jersey, information about their ecology, as well as threats to their survival. Also profiles two seals which live at Jenkinson’s Aquarium in Point Pleasant Beach, New Jersey: Luseal & Seaquin.
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