Population Status: How many humpback whales are there in the North Pacific?
Although humpback whales are still listed as an endangered species by the U.S. Endangered Species Act (1972), many populations of humpback whales appear to be recovering from years of intensive and destructive whaling practices that decimated this and other species of whales.
In the twentieth century, some 200,000 humpback whales were killed in the Southern Hemisphere alone. With an estimated 95% of the population wiped out, humpback whales finally gained protection from whaling in the North Pacific in 1966.
From 2004-2007, over 50 research groups and more than 400 researchers (including researchers from Whale Trust) from ten different countries worked together to photo-identify humpback whales throughout the North Pacific Ocean to determine current population estimates. This project, called SPLASH, which stands for Structure of Populations, Levels of Abundance, and Status of Humpback Whales, indicates that the North Pacific Population has rebounded since the cessation of whaling to include approximately 18,000 individuals. The results show that roughly 50% of this population winters in the Hawaiian breeding and calving grounds. Download Executive Summary Report here.
Threats to Humpback Whales
Despite growing populations, humpback whales are still threatened by a variety of different factors, mostly anthropogenic (or human induced) factors. Entanglement in fishing gear, declining fish stocks and human competition for limited food resources, climate change, underwater noise pollution, environmental toxins (e.g., PCBs and DDT), as well as threats of resumed whaling practices continue to present threats to recovering populations of humpback whales.
With increasing populations of humpbacks whales and bigger and faster boats, whale collisions and ship-strikes are a growing concern for nearshore whale populations. During the 2005-2006 and 2006-2007 seasons, there were a total of 12 confirmed ship-strikes (six in each season) on humpback whales in Hawaiian waters. Of course, these numbers reflect only the number of confirmed reports; that is, the one’s that were both reported and verified or confirmed.
Entanglement in fishing gear is also a global concern for many species of whales. During 2006 and 2007, there were seven confirmed reports of entangled humpback whales in Hawaii, and scar analysis on humpback whales in Hawaii suggests that 33% have recently been entangled.2 Similar trends exist on feeding grounds. From 1997-2004, 52 humpback whales were reported as entangled in fishing gear in Alaska.3
Although these numbers appear to be growing, it is unclear whether or not this reflects a real trend in an increasing number of ship-strikes and entanglement or whether there is more awareness and therefore an increase in the number of collisions or entanglements reported each year.
What You Can Do: Avoiding Collisions with Whales
Humpback whales are protected in Hawaiian waters. Unless operating under a federal research permit, approaching humpback whales within 100 yards or within 1,000 feet from aircraft is prohibited by federal regulations.
Slow Down! Although there are no regulations for speed limits in Hawaii, research shows that severe injuries (to whales and people) are less frequent and severe when boats are traveling at 13 knots or less.
Keep a sharp lookout for whales and keep your hands at the helm and near the throttle at all times. Newborn calves are often hard to see and surface more frequently than adults.
Warn other vessels in the area using the VHF radio about the presence and/or location of whales if appropriate.
For more information on the permitting process or laws protecting marine mammals, please visit the following websites:
Natural predators for humpback whales, as well as most other species of cetaceans, include transient killer whales (that is, killer whales that feed primarily on other marine mammals) and aggressive species of sharks such as tiger or great white sharks. However, these predators usually prey on sick, vulnerable or young whales, such as calves or yearlings.
Reporting Incidents with Marine Mammals
Report stranded, entangled, or injured whales, vessel collisions and other marine mammal incidents by calling the NOAA hotline at 888-256-9840 or download a marine mammal entanglement information sheet.
Fore more information:
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