Scientists around the world continue to be concerned about the amount of pollution created by modern industrialization. With emerging nations such as China and India, more people have access to luxuries like cars that produce waste and contribute to climate change. All these factors influence the environment and the affect the animals of the planet. In particular, blue whales are among some of the hardest-hit species at the turn of the century.
Whales have been closely tied to the development of the human race. Before our reliance on fossil fuel and coal, whales were a significant source of oil. In the 19th century, countries had whaling fleets that competed fiercely over whaling grounds. As society moved away from hunting whales as a source of fuel, a threat remained to the sustainability of whale populations. Some nations, despite the efforts of the International Whaling Commission, continue to harvest whales. Although whaling is one of the widely recognized dangers to whale populations, another threat is the death of whales through impacts with ships’ hulls.
Shipping has increased in response to the larger demand of international goods. Many of these ships cross paths with the feeding grounds of whales, resulting in collisions between the ship and the whale. Some of the impacts produce massive trauma to the whale, leading to its death. Though tragic, the solution to accidental killings is simple: Move the shipping lane and reduce speeds of incoming ships.
While the odds are stacked against the survival of whales, there is some encouraging news from a research team at the University of Washington. Led by Trevor Branch, an assistant professor of aquatic and fishery sciences, the researchers discovered that the population of Californian blue whales is rebounding. Although decimated by whaling in the 20th century, the current population hovers around 2,200 whales. This represents a recovery to 97 percent of the historical population around California.
The scientists conclude that the population is relatively healthy compared to other locations around the world. Recently, the population growth of the Californian whales has been declining, which, rather than suggesting a fall in population, signals that the population is stable. When examined with the historical level, researchers conclude that the decline in growth corresponds to the population reaching carrying capacity, or the largest amount of individuals an environment can support. To further examine the population, a research article in Marine Mammal Science utilized a widely accepted model to extrapolate the whale population in California.
However, the research team also highlighted the importance of continuing conservation efforts. By estimate, at least 11 whales are hit by ships on the west coast every year, which is higher than the limits outlined in the U.S. Marine Mammal Protection Act. Though the team stressed that the number of whales killed by ship strikes is not enough to cause a population decline, the report does offer some hope for conservationists. “There is some hope that we can rebuild depleted populations ... the implications [of the study] are that other populations of animals might be expected to rebuild when we stop eliminating their habitat,” Branch said.
To put the optimistic news in perspective, Branch compared the recent study to another done on the Antarctic blue whales. He found that “[Antarctic blue whale populations] declined by 99.85 percent before rebuilding to just one percent of their original levels.” As an emphasis of the difference, 3,400 whales were caught around California in the 20th century while 346,000 were caught near Antarctica at the same time.
