New peril for gray whale survival? Predatory orcas spotted in Baja calving lagoon
As gray whales migrate through the Baja California peninsula, they have an undeniable vulnerability to killer whales. The predators sometimes chase and harass the marine mammals as they try to cross the narrowest point along the peninsula, known as the Baja California Peninsula Bridge.
For their part, killer whales, or orcas, have a variety of threats. Like harp seals, they’re prone to illness. They also may feed on baby whales or harass pregnant females to ensure that their calves reach maturity. They may also injure or kill marine mammals for fun. The fact that it takes as much as a week for a newborn to fully wean from its mother’s milk means for both parties a great deal of work.
There’s also a much more dire threat: orcas are known to prey on young whales (that’s just what they’ll do if they want to eat), and that’s why there’s much concern about the gray whale population over the long term. If there’s a threat to the whales from orcas, there’s a good chance there’s a threat to the orcas from the whales.
It’s not clear if this relationship holds true in the far southern Baja California Peninsula. It’s hard to tell whether killer whales are targeting the gray whales. The only way to find out is to have a look-see in the lagoon waters of the Baja Peninsula.
The Baja California population of gray whales
Between 1994 and 2014 there was no evidence of gray whales at the location of the Baja population. So what happened to the gray whales?
It seems likely that the whales simply got sick and the population went down. A study of gray whale numbers in 2005 found that the population fell from over 100 in 1995 to 70 in 2001 to 16 in 2007.
But in the Baja Peninsula there’s evidence of a recovery in the population after 2011. This year a survey in the lagoon identified a gray whale population of more than 30.
The same study found that the gray whales are more common on San Nicolas Island than they are on the mainland. There are a number of