Two, humpbacked whales took a wrong turn in the ocean and swam inland towards California’s capital, San Francisco. Unaware of the mistake, they swam 90 miles up the Sacramento River till they reached the man-made, fresh water channel used by ocean-going ships.
Marine biologists rushed to the waters to make an examination of the animals. They noticed that the 45-foot, mother and her 20-feet calf were both wounded. The biologists inferred that the injuries must have been caused by a propeller of a ship, either in the open ocean or shortly after their entering the bay. Though the wounds were not rated as life threatening, the veterinarians were concerned that prolonged stay in fresh water would affect the skin of the marine animals. Another point of concern was that, in the absence of its natural food, the mother was not eating and seemed anxious to locate the return route.
Rescue workers embarked on a plan to coax the rare whales (named Delta and Dawn by the Governor!) back to the ocean. The strategy adopted was to make unpleasant, underwater vibrations through a series of unpleasant, blasting noise from a boat on the upstream side thus prodding the whales to reverse direction. In Addition, they played the recordings of feeding humpbacks in the front, to lure the whales back into the sea. Initially it seemed like the whales were turning a deaf ear to the sounds. But, six days after getting lost, the wayward whales started to move on their own, in the direction that would eventually take them to the ocean. But the agency is still watching as the whales still have hurdles to cross, before they reach the open sea.
The clock is ticking...
Humpback Whales can easily be identified by their stocky bodies with obvious humps and black dorsal colouring. Once considered a common species, the humpback whale is now currently listed as threatened. There is a global population of approximately 10,000 humpback whales. About 2000 humpback whales inhabit the North Pacific.
Most North Pacific humpback whales begin their annual, southern migrations from the Gulf of Alaska, in early September. One group travels to the coast of Baja in Mexico. Another migrates to a group of islands south east of Japan. But the largest population makes it to the Hawaiian Islands. This migration takes the humpback approximately 4 to 8 weeks to complete. They breed in the warm waters off Mexico and Hawaii.
Around March, the adults and the newly born calves, begin the return migration, back to colder water of Alaska to feed and rebuild their blubber supply. April-May is the when they pass by the Californian coast.
Why did the two whales in news, veer from their path?
Though each year, the National Marine Fisheries Service rescues at least one off-course whale, dolphin or porpoise, little is known on why certain animals go off path. Researchers say that they could investigate the wayward behaviour completely only if the animals died and their bodies were recovered.
But the animals generally survive as their built in compass guides them back to the sea.