Marine mammal officials are warning kayakers, boaters and surfers to avoid a group of gray whales spotted less than a mile off the coast of Pacifica.
People have been unintentionally hassling the giant sea creatures this week, leading to concern that the three adult whales and two calves may become separated or abandon their natural feeding ground, according to Gulf of the Farallones National Marine Sanctuary spokeswoman Mary Jane Schramm.
Several days ago, a surfer paddled directly over where a whale was about to surface for air. On Wednesday, five kayaks "converged very closely" on a whale to "have a closer look," according to Schramm.
"It doesn't look like intentional harassment with malice, but they are crowding the whales," she said.
Coming into such close range of a gray whale can be extremely dangerous to both the person and the whale, she said.
"People approaching these whales may think they don't have any real impact on them if they just do it once or a couple times," Schramm said.
"But there could be a cumulative impact of a number of people doing this, which might cause the animals to abandon this particular little feeding ground," she added.
Gray whales are not on the endangered species list, but in 1999 and 2000 the gray whale population -- then about 26,600 whales -- dropped by about a third likely due to malnutrition, according to Schramm.
Schramm said if people want to watch the whales, they should take a designated whale-watching trip or watch with binoculars from a high point along the coast.
It is illegal, she said, for a person to come within 300 feet of a gray whale under federal law. The Marine Mammal Protection Act also states anyone who harasses or disturbs a gray whale could face civil or criminal charges.
"We feel people do not mean to harm them, but they may inadvertently do so," Schramm said. "These animals need our protection and our respect. We need to learn how to share the road with the whales."