Hopefully you’ve watched Kingdom of the Blue Whale by now, and I won’t be spoiling all the fun for you. If you have managed to miss it, then read my original review and tune into National Geographic Channel tomorrow, March 15, at 1pm.
The special brought up a lot of really important conservation issues facing blue whales, as well as other marine mammals.
The single biggest human act that decimated the blue whale population was whaling. The blue whale population had once been estimated at more than 250,000 globally. A ban on the commercial whaling oh blue whales was established in the 1966, but a century of whaling prior to the ban had already decimated the population by 90 percent. Today it is estimated that there are now between 10,000 to 25,000 blue whales worldwide.
The International Whaling Commission (IWC) was set up under the rules of the International Convention for the Regulation of Whaling in 1946. The main duty of the IWC is to review and revise the measures which govern the conduct of whaling around the world, largely guided by the advice from the scientific committee. In 1982, the IWC decided that beginning with the 1986 season, a moratorium would be placed on commercial whaling of all whale stocks. The moratorium allows whaling to be carried out by aboriginal groups if it occurs on a subsistence basis, as is the case in parts of Canada, Russia, Indonesia and the Caribbean. Yet Norway and Iceland still participate in commercial whaling, and Japan has been whaling since 1986 under commercial scientific research permits.
In Kingdom of the Blue Whale, geneticists Scott Baker and Steve Palumbi buy whale meat in order to see if any of it is from illegally killed blue whales. This is a common practice for scientists, and has been used to test caviar to determine sturgeon species, or to test fish or meat in various markets to see if any of it comes from illegally hunted species. Due to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (better known as CITES), which prohibits endangered species and their parts to be traded across international boundaries, the geneticists had to duplicate the DNA in their portable hotel-room genetics lab in order to bring it back to their own lab for testing.
DNA samples were submitted to GenBank, a genetic sequence database, to determine the species of whale meat from the Japanese market. Their findings were frightening: the meat came from a blue/fin whale hybrid. Perhaps due to availability of suitable mates, blue whales are now mating with their cousins, fin whales (the second largest whale species). Because they resemble fin whales from the top, the Icelandic whalers do not realize they are hybrids until after they are killed. So far there have been 11 documented cases of blue/fin whale hybrids. Hybridization threatens the genetic integrity of the species, which can lead to extinction of that species.
Ship strikes are yet another threat to blue whales. In Kingdom of the Blue Whale, we learn that whereas one strike used to happen every few years, four were killed that season alone in California. The scientists used forensics reminiscent of CSI to determine that the dead whale they found was a victim of a ship strike. How did they know that ship strike was the cause of death, and didn’t occur postmortem? Subdermal bruising indicates that the whale was alive when it was struck, something that would not have occurred if the whale had been hit after it was already dead.
Busier oceans means more hazards for blue whales, which feed in dangerous shipping lanes. The increase in ship strike victims indicates that our bigger, faster, more powerful ships are now a greater danger to them. Not only because of the possibility of ship strikes, but because of the increase in anthropogenic noise. It is unknown how anthropogenic noise affects blue whales, but noisier oceans could mean that blue whales perhaps can’t hear each others’ calls. Sonar has been implicated in mass-strandings of other marine mammal species, and examinations have revealed hemorrhages in the ears and brains of the deceased.
Despite the increased threats, it is not all gloom-and-doom. Scientists are studying the life histories of blue whales to learn how to better protect them. Further study of the Costa Rica Dome will also provide us with a better insight to the species. In September 2007, the Center for Biological Diversity, a California conservation group, petitioned the federal government to reduce ship speeds off the U.S. West Coast. The IWC is maintaining a database of ship strikes in order to detect trends over time. Pressure from conservation groups has led to restrictions of underwater noise, and many oil and gas companies have now begun to limit their use of seismic air guns. The Southern Ocean Sanctuary and the Indian Ocean Whale Sanctuary were established. And then there’s you.
Be a scientist: