|
The St. Lawrence River is situated in the Eastern part of Canada and is connected to the largest group of lakes in the world, the Great Lakes.
The area around the Great Lakes is very industrialised. Big cities like Chicago and Detroit are situated on the Great Lakes and there are also big aluminium smelters in the area. The aluminium smelters pollute the water with PAHs (Polycyclic Aromatic Hydrocarbons), which many regard as the main reason for the relatively high rate of cancer among the beluga whales in St. Lawrence. To that add immense agriculture in the St. Lawrence valley. Pollutants from different sources all end up in the St. Lawrence River, adjacent to which a local population of beluga whales lives all year round. This population constitutes the southern boundary of the distribution of beluga whales.
At the beginning of last century 5000 beluga whales lived in this area, while in 1997 the number of belugas in the St. Lawrence River was estimated as 1221. Today there are only about 650 individuals. The main causes of death among this local population of beluga whales are parasites, viruses, bacteria and cancer.
The contaminants in the beluga whales mainly come from their prey species. American eels and other prey species of the beluga whale live in very industrialised areas near the Great Lakes and Upper St. Lawrence before they migrate downstream and get eaten by beluga whales. The contaminants in the prey species accumulate in the beluga whales and therefore reach such high levels. The male belugas in the St. Lawrence region have up to 100 times higher levels of PCB, DDT and mirex (a pesticide and fire retardant) than the male belugas in the Arctic population.
Apart from human-caused threats to the population of beluga whales in the St. Lawrence River, there are also other factors that constitute a challenge to this population, such as the low level of genetic variation because of their isolation from the Arctic population and their tendency to breed near river mouths and estuaries which are usually heavily polluted. Usually beluga whales return to the same place to breed year after year. Because of the toxins and heavy metals that gather in the body fat of the belugas, their general health and thus the reproduction rate is lowered. Even if pollution came to a complete halt today, the problems would remain for a long time since toxins are transferred from mother to calf.
The beluga whales in the St. Lawrence River earned the status of an endangered population from the governmental Committee on the Status of Endangered Wildlife in Canada (COSEWIC), both in 1983 and 1997. The Canadian federal Department of Fisheries and Oceans (DFO) has the responsibility for the conservation, management and research on the beluga whale. These activities follow the Marine Mammal Regulations, which also prohibit any hunting of beluga whales in the St. Lawrence region.
A recovery plan for the beluga in the St. Lawrence region was formulated in 1995 under the leadership of DFO and the World Wildlife Fund Canada (WWF Canada). Many organisations are involved with the implementation of this recovery plan, which involves everything from reducing pollution to monitoring the health of the population. If you want to know more about the recovery plan, please visit whales-online on this subject. Here you can also order a copy of the recovery plan.
| 
