Unusually Large Numbers Gather East Of Chatham
It's not unusual to see whales in the waters east of Chatham. For the past several weeks, however, there has been an unusual number of whales off the town's coast, dozens of them feeding on a heavy concentration of their favorite meal, sand lance.
“Probably the biggest whale show on earth is east of Chatham,” said pilot Norman St. Pierre, who sees the whales while spotting tuna for local fishermen. One some days he's seen as many as 100 whales feeding, and often sees large groups floating on the surface “just sleeping” after gorging themselves.
“I think they all came here because it was a real feed,” he said.
His instincts are correct, say researchers, who have been spending time off Chatham observing and tagging the humpback, fin and minke whales.
“It's attracting a lot of animals,” Jooke Robbins, senior scientist and director of the humpback whale research program at the Center for Coastal Studies in Provincetown said of the proliferation of sand lance. The whales follow the prey, and can be quite close to the coast at times or as far east as the shipping lanes or even the edge of Georges Bank. In the past week they moved as far north as the area off Highland Light in Truro and then back south again. “There's quite a lot of shifting,” she said.
Researchers from the CCS have been monitoring the whales on a weekly basis as weather allows, and for the last two weeks in June worked with scientists from the Gerry E. Studds Stellwagon Bank National Marine Sanctuary and other agencies to investigate the underwater behavior of the whales. Last week those researchers spotted a humpback entangled in fishing gear among the group off Chatham; a team from the CCS was able to free the animal.
According to David Wiley, the sanctuary's research coordinator, the program has been operating at this time of year off Chatham for the past several years. Its goal is to learn about whales' vulnerability to entanglement in fishing gear and collisions with ships—the major cause of injury and death among large cetaceans—along with basic behavioral ecology. Using long poles, researchers attach suction cup tags that collect data on whale movement, including pitch, heading and depth; some record sounds or even high-definition video. The tags remain in place one to two days, he said in an email.
Working on the sanctuary's 50-foot research vessel The Auk, which was stationed in Stage Harbor, scientists tagged 29 humpback and two fin whales, Wiley said. Other partners in the program include Moss Landing Marine Laboratories, National Marine Fisheries Service, the Ocean Alliance, the University of California Santa Cruz, the University of Michigan, Stanford University, Syracuse University and the Woods Hole Oceanographic Institution.
Researchers from the Center for Coastal Studies have been studying the whale population in the Gulf of Maine since the 1970s, using the unique pattern on the underside of the animals' tail to identify individuals. “We know pretty much most of these whales,” Robbins said. Observing the whales off Chatham helps ascertain the status of each animal in the population, and collect data as needed.
There is no way to assess the amount and location of the sand lance populations that the whales follow, Robbins said, but it's clear that the resources has been farther south than usual. Whales are usually seen in higher numbers on Stellwagon Bank, but the waters east of Chatham have attracted more than the usual number this year.
“It's not every year,” she said. “Some years we don't have that many whales off Chatham. This seems like a larger aggregation for sure.”