Naturalist’s Corner: Humpback Whales
Posted July 22, 2020
Written by Kyla Isakson
Humpback whales (Megaptera novaeangliae) are large baleen whales, known as mysticetes, that live in all major oceans. The scientific name Megaptera novaeangliae translates to “big winged New Englander.” Humpback whales can be up to 17m (56ft) long, which is equal to 1.5 school buses! Their bodies are dark with white spots and patterns on their pectoral fins, undersides, and tails, which are also called flukes. The patterns on the underside of their fluke are unique to each whale and can be used to identify individuals. Researchers photograph, identify, catalog, and track whales to learn more about their behavior and life, a process known as photo-identification. The underside of a whale’s fluke can be seen easily because they experience positive buoyancy, which means that whales are less dense than water, so they tend to float. To break this buoyancy, they lift their tails out of the water and dive deeper into the water.
The population that we see in the Gulf of Maine and Cape Cod Bay migrate from their wintering grounds in the Caribbean to feed in our cold waters. Food is much more abundant here in the north because cold water is pushed up from depth to deliver nutrients to the surface waters, a process known as upwelling. Humpback whales feed on plankton and small schooling fish. They swallow large amounts of water and fish, filter out fish by pushing them up against baleen, and expel water through their mouths. These baleen plates are made up of a protein called keratin, which is the same protein that makes up hair and fingernails. Once the weather here gets colder, these whales migrate back to the Caribbean to mate, socialize, and give birth to calves.
Before the commercial whaling moratorium in 1985, the species was threatened to the point that only 5% of all humpback whales in the world had survived. Now, there are several acts set to protect humpback whales and other marine mammals. Of the fourteen distinct populations worldwide, four are endangered and one is threatened. The conservation status of the population we see in New England is now listed as least concern, but humpback whales around the world still face threats like whaling in some countries, vessel strikes, harassment, underwater noise, habitat disruption, and entanglement in fishing nets and gear.
For a video of these dolphins in Cape Cod Bay, check out our Facebook post!