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Sharing the Waterways with Whales
The approximately 43 foot long adult female gray whale was bleeding heavily from its blowhole and mouth, and it had several shallow propeller scars on its back. Members of the NOAA Marine Mammal Stranding Network from The Marine Mammal Center attempted to perform a necropsy, or post-mortem, on the whale, but the tide washed the animal away. A live whale of similar description had been seen in the area earlier in the week. It is hoped that the dead female did not leave a calf behind as the calf could not survive alone.
Springtime is the season of greatest vulnerability of gray whales to vessel impacts in the busy San Francisco Bay Area. Gray whales live exclusively in the Pacific Ocean with current estimates putting the population at 22,000. The largest group lives off the Pacific Coast of North America. In Baja California, where this group breeds, friendly whales swim up to whale watchers and allow themselves to be touched. There are even tales of mother whales lifting their calves to be pet by tourists in small boats in Baja!
Unfortunately, very young calves sometimes have not developed the natural wariness they should exhibit around vessels. Gray whales are one of eleven species known to be struck by ships. Typically, large vessels are the principal source of injury to whales, and the faster the vessel travels, the more likely it is to hit a whale and the more severe the strike. For whales with endangered populations, such as right whales near Florida, the overall effect of ship collisions is more significant than to the East Pacific gray whale population.
Spring is the time for boaters to be especially aware of “sharing the road” with whales, especially gray whales, because they travel so close to shore. That they sometimes enter into the bay means boaters should exhibit extra caution. Very little of the whale is visible from the surface, so boaters should watch for what looks like a puff of smoke about 10 feet high, which indicates it has surfaced to breath. It may do this several times before a prolonged dive, with several minutes intervening. Boaters should not approach a whale within 300 feet (the length of a football field), or cut across a whale’s path, make sudden speed or directional changes, and especially should not get between a whale cow and her calf.
Off San Francisco, mother gray whales, traveling north with their new calves, run an obstacle course of large vessels in Gulf of the Farallones sanctuary’s busy shipping lanes; thousands of large ships pass through the gate each year. Gray whales are the most coastal in habit among all large whale species, hugging the shoreline on their migration. They move slowly, only 3-6 miles per hour, and mother and calf pairs are more vulnerable to ship collisions as they stop and rest frequently close to shore. Even small craft collisions with whale can have disastrous results for both whale and vessel. Gray whales have been seen in San Francisco Bay almost every spring, with whales entering the Bay for short periods of time on their migration.
Join the Farallones Marine Sanctuary Association on its next Whale Watching Trip! Click here for more information.
Read more about gray whales here.
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