ABOUT MARINE LIFE- Dolphins and Whales

There are over 75 known species of whales and dolphins in the order Cetacea. They can be further split into Toothed or Baleen Whales. Toothed whales (Odontoceti) have peg-like teeth which they use to catch fish, squid, and marine mammals. They have one blowhole (nostril) and hunt in groups using echolocation. There are about 66 species of toothed whales worldwide. Dolphins have conical teeth and belong to the family Delphinidae.

Baleen whales (Mysticeti) sieve tiny crustaceans, small fish, and other tiny organisms from the water with baleen structures in their mouths. Baleen is a comb-like structure that filters food from the water. Baleen whales are larger than the toothed whales and have 2 blowholes (nostrils). There are 10 species of baleen whales worldwide.

 

 


Hawai'i is home to 11 species of oceanic dolphins, 3 Sperm Whales, 2 Beaked Whales, and 1-3 Baleen Whales. The actual number of whales and dolphins in Hawai'i fluctuate because they are either permanently living in Hawaiian waters or seasonally migrating. Here in Hawai'i whales and dolphins are a regular sight and can often be seen from the shoreline.



Click here for a list of Hawaiian Whales and Dolphins.


Whales and dolphins are mammals and breathe air just like humans. Both have hair, milk young, possess a four chambered heart, maintain a high body temperature relative to the outside temperature, and ultimately have a shared ancestry. Cetaceans give birth to single young via a birth canal and calves will suckle milk from their mothers.

The most common dolphins seen in Hawaiian waters are the Spinner dolphins, Spotted dolphins, Bottlenose dolphins and Rough-toothed dolphins.

 







Spinner dolphins are known for their high flying acrobatic manoeuvres and aerial spins. They can jump into the air and make as many as seven spins and can be seen doing head slaps, tail slaps and playing with objects in the water. Spinner dolphins are more active at night when they move into the open ocean to feed on a range of fish, shrimp, and squid that rise close to the surface. They hunt in packs using choreographed formations and acoustics to corral their prey.



During the day when we see dolphins close to shore they come to the shallows to rest, care for their young, avoid predators and engage in reproductive activities. Although they appear to be moving up to the surface and down to the bottom, they are actually in an important period of rest. Human activity can interrupt this because they are highly social animals and are curious about movements of boats and people around them. Female spinners reach sexual maturity at 5-12 years of age and on average give birth to a calf every second or third year.

A common Baleen whale that can be seen from September to May in Hawaiian waters is the Humpback whale. Hawaiian waters can contain upwards of 10,000 humpbacks during whale season and you can clearly see them spouting and splashing from the shore. These whales migrate long distances (over 3000 miles) from their feeding grounds in Alaskan waters to mate, give birth, and nurse their young. Humpbacks cannot feed here because the nutrient poor warm waters do not support their huge appetites. Also if they do eat their metabolism will rise and they could overheat! Since there is no food for them here they must migrate back north to build up their fat storage for next year’s migration.

 

 

Humpback whales reach sexual maturity around 5-9 years of age. Mature females typically calve every
2-3 years and have a gestation period of 10-12 months. It is believed they live to 40-60 years old.

 





Humpback whales have a number of distinct behaviors that can be identified when watching them from the shore or boats, including:

Male Humpbacks will sing long complex songs lasting 10-20 minutes, repeated continuously for hours at a time. This is though to be part of their mating behaviour. For sound recordings of the Humpbacks see the Jupiter Foundation.

Whales and dolphins are threatened by marine debris, pollution and vessel collisions. Whales and dolphins can become entangled in marine debris and fishing gear, causing injuries and immobility. Whales’ habitat can be greatly impacted by human activities resulting in poor water quality, such as urban run-off and shoreline development. See Homeowners Guide for how you can help minimize your impact on local water quality. Vessel-whale collisions can cause injuries to humpback whales- if you have a vessel stay outside the legal limit of 100 yards from any whales. See Guidelines for how to operate your vessel around whales.

The Hawaiian Islands Humpback Whale National Marine Sanctuary (HIHWNMS) was established in 1992 to ensure the continued protection of humpback whales and their habitats. The sanctuary's goal is to promote comprehensive and coordinated management, research, education and long-term monitoring for the endangered humpback whale and its habitat. The Sanctuary lies within the shallow warm waters surrounding the main Hawaiian Islands. Given the geographic isolation of the islands and the amount of migratory whales that visit (nearly two-thirds of the Northern Pacific population), scientists estimate that the Sanctuary constitutes one of the world’s most important habitats for the endangered whale where they breed, calf and nurse their young. NOTE…it would be useful to include a map of the sanctuary.

All Cetaceans are protected under the Marine Mammal Protection Act. Thirteen species of whales and dolphins worldwide are considered endangered according to the Endangered Species Act. For more information go to the Office of Protected Resources (NOAA).

Three of the species of whales we see in Hawai'i are listed as Endangered under the Endangered Species Act: the Sperm Whale, Humpback Whale, and Fin whale.

See Guidelines for how to make sure you are minimizing your impact on whales and dolphins in Puako.


Photographs: Robert Shallenberger and Andrew Walsh.

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