Humpback whales

Humpback whales are easy to identify and are well known for their spectacular breaching and beautiful, complex songs. Humpbacks have wide-ranging but distinctly seasonal distributions.

Southern Ocean humpbacks migrate thousands of kilometres between high-latitude summer feeding grounds and low-latitude winter breeding and calving grounds.

Humpback whale flukes.
Humpback whale flukes as seen during the Cook Strait whale survey

Facts

Humpback whales (Megaptera novaeangliae) have a small dorsal fin with a distinctive hump at the front, knobbly protuberances on the head, tip of lower jaw and leading edge of extremely long flippers.

Their flukes are broad and have a unique black and white colour pattern, which allow individuals to be identified. They have a variable colour but are generally black with white patches on the flippers.

  • Newborn: length 4-5 m
  • Adult: length 11.5-15 m

Humpback whale underwater.
Humpback whales have a small dorsal fin with a distinctive hump at the front, knobbly protuberances on the head, tip of lower jaw and leading edge of extremely long flippers

History

In the Southern hemisphere, commercial whaling in the 20th century brought humpbacks close to extinction.  NZ ceased whaling in 1964, with the closure of the Perano whaling station in Tory channel.  The stocks had diminished such that humpbacks were no longer migrating through Cook Strait and commercial whaling was no longer viable.  Since then NZ has become a vocal advocate for whale protection and conservation.

Population

Humpback whale seen during the Cook Strait whale survey. Photo: Simon Childerhouse.
Humpback whale seen during the Cook Strait whale survey

In the Southern Hemisphere there are six humpback whale stocks, as defined by their Antarctic summer feeding areas. They are frequent visitors to the coastal waters of New Zealand when they undertake seasonal long distance migrations (710,000 km/yr) between summer feeding grounds in high latitudes (Antarctica) and winter calving and breeding grounds in tropical or near tropical waters.  They travel mainly along the east-coast and Cook Strait during winter and return along the west-coast during spring.

The Oceania population of humpback whales has recently been classified as 'endangered' by the International Union for Conservation of Nature (IUCN).  

Diet and foraging

These whales are baleen feeders with a generalised diet, including krill and small schooling fish (e.g. mackerel and herring). They show the most diverse feeding techniques of all baleen whales including lunging through patches of prey, stunning prey with their flippers and forming "bubble-nets".

Life history

Breeding and calving both occur in winter, as gestation lasts around 11 months. Nursing seems to continue until calves are one year old. Both females and males are sexually mature at around 5 years old and females typically give birth every two to three years.

Threats

Killer whales.
Killer whales 

Predators

Teeth mark scars suggest that killer whales commonly attack humpbacks. It is likely however, that only young calves suffer fatal attacks.

Human impact

Due to their coastal distribution, humpback whales were heavily exploited by the whaling industry, and it is estimated that over 90% of some populations were killed. Most populations now appear to be recovering. These whales are known to die from entanglement in fishing gear and collisions with ships. As these animals are only visitors to New Zealand, whale watching is opportunistic and is unlikely to affect their behaviour.

DOC's work

Cook Strait whale survey

The Department of Conservation has been undertaking whale surveys in Cook Strait annually since 2004 to determine the present status and level of recovery of humpback whales in New Zealand waters. It also sheds light on the migratory pathways and destinations of these whales. This information will be used for management of these whales and further their protection in the Southern hemisphere. This is the only project of its kind in New Zealand waters.

Read about the 14th annual Cook Strait Whale Survey - media release 10 June 2014

In 2008, OMV New Zealand Ltd signed up to a partnership with DOC to support the Cook Strait whale project. This will ensure that the project will continue for another three years and provide an opportunity for DOC and OMV to work together. The project is also supported by Transact Management Ltd, a commercial transaction company and Picton-based Dolphin Watch Ecotours.

Nadine Bott setting up a theodolite at the lookout during the Cook Strait whale survey. Photo: Simon Childerhouse.
Nadine Bott setting up a theodolite
at the lookout during the Cook Strait
whale survey

South Pacific research and management

DOC contributes to humpback research and management programmes in the South Pacific. One aspect of this includes collecting photographs of whales photographed on the Cook Strait whale survey and those taken by the public on an opportunistic basis and collating them into a New Zealand catalogue.

 Then comparing to other similar catalogues throughout the South Pacific through a collaborative group, the South Pacific Whale Research Consortium.

Such catalogues allow us to identify individuals and estimate population sizes and movements. Genetic sampling is also undertaken on the Cook Strait whale survey to determine the relationship between individuals seen in New Zealand and other populations. 

Strandings

DOC is also responsible for managing stranding events.

Boat rescuing a humpback whale that got caught up in bouys and rope from crayfish pots in Kaikoura. Photo: Ann McCaw.
Boat rescuing a humpback whale that got caught up in bouys and rope from crayfish pots in Kaikoura

You can help

Ex-whalers looking for whales as part of the Cook Strait whale survey. Photo: Simon Childerhouse.
Ex-whalers looking for whales as
part of a survey

Approaching whales

When boating in the vicinity of whales, common sense rules apply and regulations exist so as disturbance and danger are minimised. General rules are outlined below:

  • If a whale approaches your boat, slow down and stop
  • Ensure that you travel no faster than idle or 'no wake' speed within 300 metres of any marine mammal
  • Approach whales from behind and to the side
  • Manoeuvre your boat sensitively near whales. Do not obstruct their path, cut through a group or separate mothers from calves
  • Keep at least 50 metres from whales (or 200 metres from any large whale mother and calf or calves)
  • No more than 3 vessels within 200 metres of whales
  • Swimming with whales is not permitted
  • Avoid sudden noises that could startle the animals
  • Co-operate with others so all may see the whales without putting them at risk

Aircraft should also maintain a safe horizontal distance of at least 150 metres from whales and should avoid flying or imposing a shadow directly over a marine mammal either at sea or on shore.

Keep their environment clean by carefully disposing of any rubbish in appropriate receptacle, plastic waste can be particularly hazardous when discarded near waterways or beaches.

If you see set nets being used within closed areas then contact the Ministry of Fisheries on 0800 4 POACHER (0800 4 76224).

If you accidentally catch or harm a whale you have a legal obligation to report it as soon as possible, but within 48 hours, to DOC or MFish.

Report sightings

Sightings of whales can be reported to the 0800 DOC HOTline (0800 362 468). These are always of interest and help increase our knowledge of cetacean distribution and movements around New Zealand

Photograph the whales if you can. Photos can be used to identify individual whales. The most useful photos are of:

  • the left side of the head;
  • the full length of the body, particularly showing any identifying marks.

Also record and give DOC staff the following information:

  • the date, time and location of the sighting (GPS coordinates if possible);
  • the number of whales and whether any are calves;
  • the direction they were travelling; and
  • your contact details.  

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Contacts

DOC 24 hour emergency hotline:
0800 DOC HOT (0800 362 468)

Phone to report:

Seals severely injured, entangled, or being harassed by people or dogs
Whale or dolphin strandings
Sick or injured wildlife

For other enquiries, contact your nearest DOC office