The Hawaiian humpback whale population, like many of our great whale populations, is a conservation success story. In the early seventies the numbers of whales visiting Hawaii each year was less than 500, placing them in imminent danger of extinction. However, today numbers are on the rise, due primarily to the outlawing of commercial whaling. It is estimated that 4 - 6,000 whales may visit Maui waters each winter, 10-12,000 may pass through Hawaii over the season and this represents some 60- 75% of the Central North Pacific stock. As these numbers suggest, humpback whales, once designated as endangered, are on the road to recovery and may soon be down-listed, becoming one of the very few species to actually make it successfully off the endangered species lists through resurgence, not extinction.
The survival and recruitment of each new generation is essential to this recovery. Current research data suggests that at least 1 in 5 humpback whale calves do not survive the natal migration from low latitude wintering grounds, such as Hawaii, to the high latitude regions, where food awaits, and our research clearly indicates that the development of calves on the nursery grounds is all about preparing for this perilous journey. Follow these links for more on Hawaii’s calf population and the results of our research, chronicling the changes in behavior and development of calves in nursery waters.
Once they arrive on the feeding grounds new challenges await the young calves. Predation by killer whales may be an issue, and for the new calf learning to feed is the next developmental step. Humpback whales feed primarily on krill, and also on small schooling fish; calves must learn to make extended dives and use complex methods to coral and capture food. Luckily for the calves, most mothers will generally continue to nurse through their first feeding season, as they develop these skills. Once full size, as adults they will need to take over 1000lbs of food per day, they store the excess energy in blubber and use this as their food supply each during their winter migrations. In years to come climate change could well impact the availability of food and even today, pressures of existing fish stocks are mounting. Development of proficient diving and fishing skills is key to the survival and the successful recruitment of these young calves into the adult breeding population.