It is that time of year when we start to see Humpback whales migrating past Akaroa Harbour. The first sighting last year was on 8th June 2016 but this year our first sighting was on 15th May 2017. We never know how many times a season we will spot them but last year we saw the whales on 9 different days within the month of June.
“We’ve had the most amazing experience of sighting so many migrating humpback whales this season and wondered why this was the case when in the past we are lucky to spot them on less frequent occasions. Apparently, the reason for this is that the humpbacks we are seeing are from the East Coast of Australia due to their population growth, and our waters being around 3 degrees warmer than normal at this time of year. They are expanding their migration path in search of new lands, or seas, as the case may be”, says Rebecca Cooper, Marketing Manager of Akaroa Dolphins
An article on the 15th of May 2017 in the Otago Daily Times said, “A survey of the coast off Dunedin showed it was home to a surprisingly large population of whales”. This is really exciting for us as over the last few years we have seen an increase in whales over the winter months. They migrate north to the warmer waters for the winter months and generally follow the continental shelf, which is located 12 nautical miles off the coast of Banks Peninsula.
Humpback whales are the main type of whale we see but on occasion, over the years there have been sightings of the Southern Right whale and Sperm whale outside Akaroa Heads.
Here are some fun facts about the Humpback whales:
How to identify
Humpback whales are well known for their spectacular breaching and beautiful whale songs.
They have a small dorsal fin with a distinctive hump at the front, knobbly protuberances on the head, the tip of the lower jaw and leading edge of extremely long flippers.
Their tail flukes have a unique black and white colour pattern which is broad. This helps scientists to identify individuals. They are generally black with white on the underside and on their flippers.
Humpback whales are not the biggest whales. That honour goes to the blue whale. Humpbacks can grow to 18 metres long, about the size of a school bus.and they can weigh a whopping 40 tonnes. Like most whales, females are larger than males. Newborn start their life at around 4-5 metres.
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.
Teeth mark and scars are often seen on humpbacks which could suggest that killer whales commonly attack. However, it is only known that young calves and sick animals suffer fatal blows.
Due to their coastal distribution, humpback whales were heavily exploited by the whaling industry. It is estimated that over 90% of some populations were killed but most populations now appear to be recovering. These whales are known to die from entanglement in fishing gear and collisions with ships.
This large marine mammal is part of the baleen whale suborder and is known to consume a number of different small prey such as squid, krill, herring, pollock, haddock, mackerel, capelin, salmon and various other fish.
In late autumn the Humpback whales start their annual migratory route. They head up to the warmer tropical waters of the Pacific to begin their winter breeding and calving and then return south in spring. The whales migrate around 5000km on average, which is one of the longest migratory journeys of any mammal on the planet.
Humpbacks have a wide geographic range and are found in all the world’s oceans. Most humpback whales make mammoth journeys every year between their feeding and breeding sites because seasons are reversed either side of the equator, Northern and Southern Hemisphere populations of humpbacks probably never meet. Those in the north travel towards their breeding grounds in tropical waters as those in the south are travelling towards the pole to feed, and vice versa.
Humpbacks are only capable of travelling at 8kms/hr but during their long journey they average only 1 km/hr, resting and socialising along the way. Not all members of a particular population will travel together. The humpbacks that pass the eastern shores of Australia, on their way to summer feeding grounds in Antarctica each year stop off in the warm waters of Harvey Bay. The first to arrive are groups of older juveniles, followed by mature males and then by mothers and calves.