It is one of the most successful rebounds of whale population numbers since the ending of whaling in 1966. The latest estimates of Humpback whales in the North Pacific has been put at over 21,000. The new estimates were put together by a team of marine researchers from NOAA Fisheries Service.
The latest figure produced by a re-assessment of a census by marine scientists shows a substantial increase in numbers from the low point of 1400 that remained of the North Pacific humpbacks when commercial whaling finally came to an end. The new estimates of population means that the humpbacks are more abundant now than some pre-whaling population estimates. [pullquote]These improved numbers are encouraging, especially after we have reduced most of the biases inherent in any statistical model.[/pullquote]
A new looks at humpback whale numbers estimated in SPLASH.
The new study took a new look at a 2008 census called Structure of Populations, Levels of Abundance and Status of Humpbacks, or SPLASH. Using new statistical analysis of the 18,000 photo id’s of tail – or flukes taken between 2004 and 2008. The new method of analysis enable a much more accurate estimate to be made. It saw the original estimate of under 20,000 individuals being boosted to over 21,000.
“These improved numbers are encouraging, especially after we have reduced most of the biases inherent in any statistical model,” said Jay Barlow, NOAAs Fisheries Service marine mammal biologist at the Southwest Fisheries Science Center in La Jolla, Calif. “We feel the numbers may even be larger since there have been across-the-board increases in known population areas and unknown areas have probably seen the same increases.”
John Calambokidis, senior research biologist and co-founder of Cascadia Research said, “This latest revision to the study provides an accurate estimate for humpback whales in an entire ocean that could not have been possible without researchers working together to pool data. While populations of some other whale species remain very low this shows that humpback whales are among those that have recovered strongly from whaling.”
400 researchers from 10 countries researched humpback whales for SPLASH.
The original SPLASH study involved hundreds of international scientists in an attempt to estimate for the first time the numbers of humpback whales in the North Pacific. The aim was to discover the overall population levels, genetic make up and population structure. Scientis from as far afield as the US, Japan, Russia, Mexico, Canada, the Philippines, Costa Rica, Panama, Nicaragua and Guatemala all took part and submitted data for the study.
Trying to estimate the numbers of humpback whales has particular challenges for marine scientists. One of the most challenging aspects is that the species has one of the longest migrations of any mammal as they move between summer feeding grounds and winter breeding areas. The original survey in 2008 suggested that there are still to be discovered breeding grounds for the humpback whales particularly for the population whose summer feeding grounds are in the Bering Sea.
The song of the humpback whale.
The song of the humpback whale is probably one of the more well known and popular marine sounds. The songs are produced by the male humpback and can take place at the winter feeding grounds and also while the whale is on the migration route. Occasionally the males may start to sing at the summer feeding grounds shortly before leaving for migration or for a short time after arriving there after the migration. Male humpbacks generally only sing when they are alone and will stop singing when joined by another whale.