Bay of Islands Wildlife Guide
The Bay of Islands is a absolute haven for wildlife.
With a resident dolphins population estimated to be 500 strong, the Bay of Islands is one of the best places in New Zealand view wild dolphin and migratory whales. The sub tropical climate and pristine waters make it the perfect place to visit any time of the year.
Within this page you’ll find information on some of the resident mammals within our region, as well as some of the whales that we often encounter on their migration north. The marine mammal guide below provides an indication of some of the species likely to be seen during our cruises and is based on data collected by our crews over the past 7 years.
Little Penguin (Eudyptula minor)
Size and Weight: Little Penguin typically grow to between 30-33cm tall and usually weigh 1.5 kilogram on average
The world's smallest penguin, little penguin or "kororā" in Maori stand just over 25 cm and weigh around 1 kg. The plumage is slate-blue with a bright white belly. They are found on most of New Zealand's coastline and in southern Australia.
They spend much of their time at sea hunting small fish, crustaceans and squid. Like all penguins they cannot fly, but their paddle-like flippers are excellent for 'flying' through the water. They can reach speeds of up to 6 kph underwater.
Little penguins forage for food up to 25 km offshore and 70 km from the colony and you will often see a solitary little Penguin bobbing up and down on one of our cruises.
Little penguins only come ashore under the cover of darkness and live underground in burrows, natural holes, or under human structures or buildings.
Bottlenose Dolphin (Tursiops truncatus)
Size and Weight: The average length of an Adult is 1.9-3.9m
Bottlenose dolphin have a relatively short beak and a high, hooked and prominent dorsal fin. Colour is dark or light grey on the back grading to white on the undersides. There are estimated to be around 500 individuals that live in the Bay of Islands area.
Those living close to the shore feed primarily on a variety of inshore bottom-dwelling fish and invertebrate species. Their dives rarely last longer than 3-4 minutes inshore, but may be longer offshore.
Females breed every 3-5 years and calves suckle for around 2-3 years. Calving peaks are known to occur for most populations between spring and summer/autumn. Female bottlenose dolphins can live up to more than 50 years of age, and males can reach as old as 40-45 years.
Common Dolphin (Delphinus delphis)
Size and Weight:
Common dolphins may form enormous schools of several thousand individuals. They are also known to associate with schools of pilot whales and other dolphin species such as dusky dolphins. This species is abundant but precise population estimates are largely unknown.
Common dolphins feed on a variety of prey, including surface schooling fish species and small mid-water fish and squids. They are known to dive to depths of 280 metres in search of prey and hunt cooperatively within schools. Dives can last up to 8 minutes but are usually between 10 seconds and 2 minutes.
Age at sexual maturity is estimated to vary with region but for the Pacific is thought to range from 7-12 years for males and 6-7 years for females. Maximum age is estimated to be 22 years.
Orca Whale (Orcinus orca)
Size and Weight: Newborn 2.1 - 2.5m , 180kg. Adult 5.5 - 9.8m, 2.6 - 9 tons
The Orca whale is the most widely distributed mammal on earth with the exception of humans. There are estimated to be 150-200 Orca that inhabit New Zealand waters. Orca are typically encountered in family groups or pods, varying from less than 5 to about 30 individuals. Pods are usually formed for life and can result in the development of unique dialects. A pod usually consists of males, females, and calves of varying ages. Several smaller pods may join occasionally to form larger groups of 50 or more individuals called herds or aggregations.
Orca whales are very sophisticated and effective predators. They have an extremely diverse diet and are the only known cetaceans that regularly prey upon other marine mammals. When they arrive in the Bay the dolphins usually skip town for the day! Attacks or kills have been documented on more than 35 species, including blue whales. Fish species are also important in their diet (e.g.: salmon, tuna, herring, cod, sharks and rays). Squid, octopus, sea birds and sea turtles are also eaten. Orca whales hunt cooperatively and are even known to intentionally strand themselves on beaches temporarily, in order to catch seals. Adult killer whales eat approximately 3% to 4% of their body weight in food per day
Females give birth to their first calf between 11 and 16 years of age and tend to do so every five years for their 25-year reproductive life span. The gestation period is 15-18 months and calves are nursed for at least one year. Females are known to live up to 80 or 90 years. Males reach physical maturity at about 21 years of age and live for a maximum of 50-60 years.
New Zealand Fur seal (Arctocephalus forsteri)
Size Weight: Adult females: maximum length 1.5m, weight 30-50kg. Adult males: maximum length 2.5m, weight 90-150kg.
The New Zealand fur seal or ‘Kekeno” in Maori are the most common seals in New Zealand waters and are members of the Otariidae family of pinnipeds, fin-footed carnivorous marine mammals. They are found throughout the country and in western and southern Australia and are distinguished by visible external ears and hind flippers which rotate forward.
Their coat is dark grey-brown on the back, and lighter below; when wet look almost black. There are estimated to be some 50 - 60,000, Kekeno in New Zealand.
Kekeno are excellent swimmers and weaned pups have been known to turn up almost anywhere around New Zealand. They feed mainly on squid and small mid-water fish, but also take larger species such as conger eels, barracuda, jack mackerel and hoki.
The New Zealand fur seal dives deeper and longer than any other fur seal with female fur seals on the West Coast known to occasionally dive deeper than 238 m, and for as long as 11 minutes.
Females reach sexual maturity between 4 -6 years and will give birth to a single pup more or less every year until their death at on average 14 - 17 years. Females mate 6-8 days alter the birth of their pup, and then have delayed implantation; the egg is fertilised, but it does not implant in the uterine wall for another 3 months. Gestation is therefore about 9 months, even though the female is mated 360 days before she gives birth.
The breeding season is from mid-November to Mid-January. Pups are suckled for about 300 days, though some will continue to suckle into their second year.
Bryde's Whale (Balaenoptera brydei)
Size and Weight: Adult male measure 12.2 to 15.2m and weigh about 13-22 tons. Females are slightly larger than males.
Bryde’s whales (pronounced "broodus") feed on pelagic schooling fish, such as anchovy and herring. In general, Bryde's Whales have a bluish-gray body with white on the underside. They have very broad and short head with relatively large eyes.
The Bryde’s whale has twin blowholes with a low splashguard to the front. It’s blow is narrow can reach blow up to 4m high It also has no teeth but has two rows of baleen plates which are similar to bristles and filter animals
Found singly, in pairs or in small pods of up to 7, Bryde’s Whales may gather in pods of up to 30 in prosperous feeding grounds. When undisturbed, dives of 1-8 minutes are often followed by 4-7 blows of up to 4m in height.
Bryde’s whales are believed to breed year round and their gestation period is estimated to be 12 months. Calves are about 4 m long at birth and weigh 1,000 kg.
Migrating Whales
Long-finned Pilot Whale (Globicephala melas)
Size and Weight: Birth weight approx 100 kg. Adult males can reach up to 7.6m and weigh up to 3.8 tons. Adult females measure up to 4.9m and weigh up to 1.5 tons.
The pilot whale, like the killer whale, is a member of the dolphin family, and is second only to the killer whale in size. Pilot Whales have a distinctive rounded head with a slight beak and up curved mouthline. They are largely dark grey, black or brown in colour. They often have a “saddle patch” behind the dorsal fin. The dorsal fin is set forward on the back and sweeps back. The newborn whale's dorsal fin is flexible at birth so as to facilitate the birthing process. The body is elongated but stocky and narrows abruptly toward the tail fin.
Pilot whales are primarily squid eaters, but will feed on fish as well. It has only 40 to 48 teeth, compared to 120 in many other dolphin species and may represent an evolutionary trend towards fewer teeth as a squid eater. Life span is about 45 years in males and 60 years in females for both species.
Pilot whales are very social and are often found in groups of10 to 30 in number on average but some groups may be 100 or more. They are quite active and will frequently approach boats.
Males reach sexual maturity at about 4.5 m or 12 years of age. Females reach sexual maturity at about 3.7 m or 6 to 7 years of age. Gestation lasts approximately 12 to15 months and calving occurs once every 3 to 5 years. Most calves are born in the summer, though some calving occurs throughout the year.
Blue Whale (Balaenoptera musculus)
Size and Weight: Blue whales in the Southern Hemisphere reach lengths of 30m and can weigh over 100 tons. Females are larger than males of the same age, the largest perhaps weighing as much as 150 tons.
The blue whale is the largest mammal, possibly the largest animal, to ever inhabit the earth.It has a long tapering body that appears stretched in comparison with the stockier build of other whales. The head is flat and U-shaped and has a prominent ridge running from the blowhole to the top of the upper lip. The dorsal fin is small, visible only briefly during the dive sequence. Located around three-quarters of the way along the length of the body it varies in shape from one individual to another; some only have a barely perceptible lump, but others may have prominent and falcate dorsals.
When breathing, the whale emits a spectacular vertical single column blow (up to 12m, typically 9m) that can be seen from a great distance on a calm day. Its lung capacity is 5,000 litres. Blue whales have twin blowholes, shielded by a large splashguard.
The flippers of a Blue Whales are 3-4 metres long and can reach speeds of 50 km/h over short bursts, usually when interacting with other whales, but 20 km/h is a more typical travelling speed. When feeding they slow down to 5 km/h and can eat up to 40 million krill a day.
Blue Whales most commonly live alone or with one other individual. It is not known whether those that travel in pairs stay together over long periods or form more loose relationships. In locations where there is a high concentration of food, as many as 50 Blue Whales have been seen scattered over a small area. However, they do not form the large close-knit groups seen in other baleen species.
Blue whales reach sexual maturity between the ages of 6-10 years, or when males average about 23 m and females are about 24 m. During the first 7 months of its life, a Blue Whale calf drinks approximately 400 litres of milk every day. Blue Whale calves gain weight quickly, as much as 90 kg every 24 hours. Even at birth, they weigh up to 2,700kg– the same as a fully-grown hippopotamus.
Because of their enormous size Blue Whales where not hunted until after 1900 when the technique of inflating dead whales with air was invented so they wouldn't sink after being harpooned. A single 30m blue whale could yield up to 120 barrels of oil, and the blues were killed by the thousands. The slaughter peaked in 1931 when over 29,000 were killed in one season. Pre-whaling population estimates were over 350,000 blue whales, but up to 99% of blue whales were killed during whaling efforts. Presently, there are an estimated 5-10,000 blue whales in the Southern Hemisphere,
Humpback Whale (Megaptera novaeangliae)
Size and Weight: Adults measure 11.5 - 16m and weigh 25 - 40 tons. Newborns measure 3 – 4.5m and weigh up to 1 ton.
Humpback whales have a knobbly head and extremely long flippers. Their flukes are broad and have irregular knobbly edges and unique colour patterns, which allow individuals to be identified. Their dorsal fin is low and stubby, with a distinct hump at the front. Their body and flippers are coloured blue-black to dark grey with partially white undersides. Adult: length 11.5-16 m
There appear to be at least 10 geographically distinct populations worldwide. Between migrations these animals spend much of their time fairly close to the shore. They are frequent visitors to the coastal waters of New Zealand when travelling on migration routes running between the Balleny Islands (Antarctica) feeding grounds and the breeding area north of New Zealand. They travel mainly along the east-coast during autumn and return along the west-coast during spring, occasionally passing through Cook Strait.
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”.
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 years.
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