The numbers of California blue whales that are alive today has approached the historic numbers of whales that lived during the most recent era of whaling by man. Cole Monnahan, a doctoral student in quantitative ecology and resource management, and colleagues from the University of Washington reported the development in the Sept. 5, 2014, edition of the journal Marine Mammal Science. The development is considered a conservation victory.
The California blue whale is the first whale species to grow in numbers that approach historical populations. The researchers found 2,200 California blue whales using sonar to detect individual’s acoustic calls. The researchers suggest that this population is about as large as the present environment can sustain.
An exact census required a known number of whales killed by whaling. Yulia Ivashchenko of Southern Cross University in Australia is credited with searching the previously unobtainable records of Japanese and Russian whaling kills from 1905 through 1971. The number of California blue whales killed during that period of time was 3,400.
The research also established that the known range of the California blue whale extends from the equator to the Gulf of Alaska. Previously the range of the California blue whale was thought to be a small area that is 20 to 30 miles west of the California coast. The number of California blue whales killed by ships is more than three times the limit allowed by the U. S. Marine Mammal Protection Act. The researchers claim that an 11-fold increase in shipping would not harm the California blue whale population as it presently exists.
The largest animal in the world is not considered to be safe as a result of increase in numbers alone. The California blue whale will remain an endangered species. Growing numbers is a positive sign for the future of all whales.