A deadly new threat could be looming on the horizon for gray whales, a species that is already suffering from a mysterious population decline.
For the first time in recorded history, killer whales have been observed in the Mexican refuge of the greys: the warm, shallow lagoons of the Baja Peninsula, where these 40-foot-plus leviathans give birth, nurse and feed. mate in peace. Until now, conservationists have viewed the area as a haven from shipping, fishing gear and killer whales – the ocean’s apex predator.
According to reports from researchers and local fishermen, Laguna San Ignacio has been visited twice this year by killer whales.
A group appeared in January and was filmed as orcas fatally attacked two resident bottlenose dolphins. They may have also killed a gray whale calf, although no bodies have been found to confirm this.
Cindy Hansen, educator and advocacy coordinator for Orca Network, a nonprofit organization based in Freeland, Wash., said a piece of skin and fat was found, “but no genetics were done to be able to obtain a positive identification”.
Then, last week, another group of killer whales swam into the lagoon. This time there were no gray whales – most were either in the Arctic where they traditionally spend their summers gorging on small shrimp-like crustaceans they pick up from the ocean floor, or just beginning their southward migration along the North American coast. Gray whales usually inhabit the lagoon from late January and leave in mid-March or April.
It is not clear if the two groups of orcas were made up of the same individuals. While researchers were able to photograph and identify each of the killer whales in January, a research team was not present to photograph the intrusion last week, said Laguna San Ignacio Ecosystem Science Project principal investigator Steven Swartz.
“Orcas are normal wildlife there,” said Swartz, who is based in Maryland when not studying whales in Baja. “They are off the coast of Baja and in the Gulf of California, so they are no strangers to the area. What was odd was that we never had authentic, real-time verified sightings inside the gray whale breeding lagoons.
He said that while no killer whales had ever been documented in the lagoon before – going back to whaling records from the mid-1800s, when San Francisco-based whaler Charles Melville Scammon slaughtered thousands of gray whales with its crew – it was not. surprising that these social and intelligent animals find it.
“It’s the second time we know, although they may have come more frequently, but we’ve never seen them,” he said. “Perhaps they arrived at night. We do not know. Now, if these guys are just coming to have a look and they’ll leave or come back later, we don’t know.
Earlier this month, the National Oceanic and Atmospheric Administration reported that the number of gray whales living along the eastern North Pacific has declined nearly 40% from its 2016 peak. calves born last year was the lowest they’ve seen since they started taking records.
“You know, every calf matters,” Swartz said. “As the population tries to recover … and the number of calves is down and the reproduction rates are down, this could be a concern. If the orcas arrive during whale season and target the gray calves, yes, that’s one more blow against the recovery of the population.
In 2019, the National Oceanic and Atmospheric Administration declared an “unusual mortality event” after alarming numbers of gray whales began washing up along the shore from Mexico to Alaska. Then and now, the cause of the mass mortality remains elusive, but it appears that something has dramatically altered the food web of these large bottom-feeding cetaceans.
Every year, gray whales migrate from the warm, protected lagoons of the Baja Peninsula in Mexico to the cold waters of the Arctic and subarctic. Then they return to Mexico, where they mate, give birth, and nurse their young.
It’s a 12,000 mile round trip migration that takes whales past the busy coasts of North America – through shipping lanes, around fishing boats, near tourist crowded and intrusive and sometimes in the mouths of hungry orcas.
“Killer whales also have to make a living,” Swartz said. “There are obviously concerns for the gray whales as they are the charismatic regional megafauna with people coming from all points to see the gray whale. But we also care about other wildlife.
As to why they suddenly show up, neither Swartz nor Hansen seemed to have an answer; “Chance” seemed like the most likely driver, Swartz said.
However, Swartz noted that the behavior of the gray whales and the shallow depth of the lagoon may prevent orcas from doing too much damage to the gray whales, if they return while the giants are around.
“Gray whales can be extremely defensive, aggressive, especially if it’s a female and her calf is threatened,” he said, noting that killer whales hunt in packs, like wolves. “Except in their world, they are three-dimensional, so they need relatively deep water to tackle large prey.
Gerardo Freer, a caretaker with Antonio’s EcoTours at Laguna San Ignacio, heard of the sighting and said he believed the killer whales were targeting a colony of sea lions that live on an island at the bottom of the lagoon.
“We’ll see if the pod of orcas come back when the grays are here,” he said.
Los Angeles Times