Orcas at Risk
Some cetaceans are now facing an uncertain future because their populations have declined to the point that there are only few of them left in the world. Killer whales are not in the list of endangered species, but they are vulnerable to a number of threats of natural and anthropogenic origin.
The Red List of the International Union for Conservation of Nature (IUCN) classifies Killer whales in the “Data Deficient” group (DD), but the reality is that some specific populations are already threatened.
Threats.
Cetacean observation and whaling have existed since the early years of mankind. They are one of the most important threats to orcas, but over time the human population has increased, cities have grown, the needs have diversified, and the pursuit and achievement of individual goals have become one of the cardinal points human civilization.
The threats killer whales face could be classified in two groups, natural dangers in their habitat, and those originated by human activities. The first are those that any wild animal frequently experiences, but they usually do not represent great danger to their population unless it is an epidemic. For example, orcas suffer from fungal or bacterial infections or they can get parasites that can undermine their quality of their life, especially if they are already sick or weak. It has also been found that some orcas get sick with Hodgkin’s disease, tumors, stomach ulcers and skin diseases. Other large animals are not a problem for the orcas, because if they are full-grown healthy adults, they have no predators.
The list of threats that branch from the human activities is comprehensive, and it includes:
- Commercial-Hunting. Unlike baleen whales, killer whales have not been massively and systematically hunted, but sometimes they were killed for their fat, skin, flesh and internal organs. In modern times, some native tribes of the Arctic still capture orcas to survive. However, in specific regions hunting to market their bodies has been more common than initially believed. This practice has decreased, there is still hunting in Japan, Greenland, Indonesia and some parts of the Caribbean.
- Capture for Entertainment. Orca intelligence makes them attractive to humans, as they are capable of learning to perform aerobatics. Therefore, live catches of killer whales are sometimes made for displaying them in aquariums.
- Habitat Pollution. Water pollution directly affects their health. For example, in the coastal waters of British Columbia (Canada), the presence of polychlorinated biphenyl (PCB) is so high that it is a risk for three populations of orcas visiting areas. In addition, oil spills are very dangerous accidents that directly affect their body or indirectly through decreased prey.
- Excessive Noise. Killer whales are very sensitive to noise since they use echolocation, so military and industrial activities that generate excessive noise tend to disturb them.
- Decreased prey. Habitat pollution or any other disturbance to it, as well as overfishing, reduces the number of prey available to orcas.
- Collisions with boats. The crash with any vessel can cause orcas mild to severe wounds that have the potential to get infected and cause their death.
- Problems with fishermen. Many of them see the orcas as a threat because they have learned to steal the fish from them. For example, fishermen in Brazil say that killer whales are able to consume 50 percent or more of the swordfish catch. Although some choose to implement inoffensive actions to deter killer whales, others with less patience can shoot them.
- Climate-change. It is an increase in the temperature or in the water level of the oceans affecting their composition, which can also alter the availability of its usual prey.
Survival Expectations.
Until 1981, the whalers of Norway, Japan and the Soviet Union had captured about 6,000 whales. The populations of the Strait of Gibraltar, southern British Columbia and Washington are the most affected by pollution and declining prey. Some people think they are wild animals that attack humans at the first opportunity. Its common name, Killer whale, does not seem to help the change in that perspective. It is not a killer whale.
It is important to recognize all the threats to these beautiful animals to take actions that make them prevail in the world for much longer. The Red List does not classify them as Endangered (EN) still. We can avoid it!
http://www.iucnredlist.org/details/15421/0
http://seaworld.org/en/animal-info/animal-infobooks/killer-whale/conservation-and-research/
http://en.wikipedia.org/wiki/Killer_whale # Whaling
http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/killerwhale.htm
http://us.whales.org/species-guide/orca-killer-whale
