Humpback Whale (Megaptera novaeangliae)

Humpback whale breaching off Bermuda

Humpback whale breaching off Bermuda

Humpback Whales are found in all oceans of the world. The species was first described from the east coast of the US, hence the species Latin name referring to New England (novaeangliae). The genus name ‘Megaptera’ (big winged) refers to the ‘mega’ size of the humpbacks pectoral fins which can grow to 4.5 m (15 ft), about one third the length of its body. These characteristic fins are pure white.  The body colour of a Humpback is dark, usually black on the back and head lightening to grey or white underneath.

Humpbacks grow up to 18 m (60 feet) long, and their body shape is stocky compared to other baleen whales. The head has a number of tubercles; a series of rounded sensory knobs which contain a single stiff hair. The knobs are located on the upper and lower jaw and the top of the snout.

Humpbacks have a relatively small dorsal fin. The name humpback comes from the shape of this dorsal fin which has a fleshy hump at its base. The name could also apply to the bumpy appearance of the spine between the dorsal fin and the tail (the fluke). These are the vertebrae, and can be seen in many individuals when the whale is about to raise its tail before a deep dive.

Not all whale species raise their tail out of the water when diving deep (called a sounding dive) but Humpbacks do. This allows observers to see the underside of the Humpbacks tail fluke. The fluke of the Humpback Whale has a jagged trailing edge and fleshy rounded tips. The top is dark while the underside is marked with white and dark markings that can vary from almost completely dark to almost completely white and everything in between. The markings under the fluke are unique to each whale and allow researchers to compare photos of whale’s tails to identify individuals and follow their movements. (See http://www.whalesbermuda.com/fluke-ids for more information on tracking Bermuda’s whales from fluke photos).  Many whales also have distinctive marks and scars from fighting with each other, from attacks by sharks and Orcas, from entanglements with fishing gear or from attached parasites (like barnacles).

Humpbacks belong to the whale group Mysticeti, meaning they have plates of baleen instead of teeth. The baleen hangs from the roof of the mouth and is used to filter food out of the water. They also have up to 20 wide grooves on their throat. These grooves are like pleats and allow the throat to expand to an enormous size to accommodate a gulp of water. The whale pushes the water out through the baleen and uses its massive tongue to clean trapped food from the plates.  Humpbacks eat small schooling fish, like capelin, and crustaceans, like krill.

The double-nostril blowhole of a Humpback Whale. Note tubercles on the snout

The double-nostril blowhole of a Humpback Whale. Note tubercles on the snout

Baleen whales like Humpbacks also have a two-part blowhole that resembles the nostrils of a human nose (unlike the Sperm Whale which has teeth and a single blowhole). When the Humpback exhales through its blowhole it produces a bushy spout about 3 m (10 ft) high. Looking for this cloud of exhaled breath is usually the first clue to whale watchers that they have found a whale.

Humpback Whales in all oceans migrate from breeding and calving grounds in warm tropical waters to feeding grounds in cooler temperate waters. In the western north Atlantic, Humpbacks move from calving grounds in the Caribbean to summer feeding areas off New England, Eastern Canada and Greenland. This migration brings them past Bermuda in the spring and fall.

The best time of year to see Humpbacks in Bermuda is from Mid-February to April. Whales can be seen from South Shore cliff tops such as St. David’s Head, Cooper’s Island, Portuguese Rock at Spittal Pond, and South Shore Road between Warwick Long Bay and Church Bay. There are also numerous boat trips available seasonally.

The global trend for the Humpback population is a slow increase thanks to the end of industrial whaling and other protective measures. All whales are threatened by many human activities in the sea where the effects are mostly unknown. These activities include the increase in human-caused marine noise, military exercises, oil, gas and mineral exploration, offshore energy projects, entanglement in fishing gear and collisions with ships. Humpbacks in some areas are still threatened by illegal whaling. According to Reilly et al. the global population of humpback whales is estimated to be around 60,000 – slightly less than the population of Bermuda.

All species of whales, dolphins and porpoises are protected in Bermuda’s 200 mile exclusive economic zone under the Fisheries Act. The Humpback and Sperm Whales in particular are listed under the Bermuda Protected Species Act [Protected Species Amendment Order 2011].  The Humpback Whale is listed under Appendix I of both the Convention on the International Trade in Endangered Species (CITES) and the Convention on Migratory Species (CMS). Both of these Conventions were signed by the UK and have been extended to Bermuda.

Reference:

Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell Jr., R.L., Butterworth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán, J. & Zerbini, A.N. 2008. Megaptera novaeangliae. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. http://www.iucnredlist.org/apps/redlist/details/13006/0

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