April 24, 2017 — North Atlantic right whales need a lot of food each day — the caloric equivalent of 3,000 Big Macs — and right now there’s plenty of it in Cape Cod Bay, in the form of a tiny crustacean.
“The food resource is the thickest we have seen in 32 years,” Charles “Stormy” Mayo, head of the right whale ecology program at the Center for Coastal Studies, said of the zooplankton that whales consume.
In years past, the center’s water sampling in the bay has shown total zooplankton densities usually less than 5,000 organisms per cubic meter. While the individual zooplankton are measured in millimeters, the whales that eat them are among the largest animals on earth, reaching lengths of more than 50 feet and weighing up to 79 tons.
But on April 14, for example, the densities reached well over 40,000 organisms per cubic meter across most of the bay, according to Christy Hudak, the center’s associate scientist. Some areas west of Great Island in Wellfleet reached 72,000 organisms per cubic meter.
On that same day, more than 40 percent of the total population of right whales left in the world, 217 out of 524, were spotted in the bay.
“It might be that the food resource is particularly strong this year, and if it continues that will bode well for right whales,” biologist Mark Baumgartner of the Woods Hole Oceanographic Institution said. “Alternatively, food in other habitats at other times of the year may be poor, leading to right whales concentrating in fewer places and fewer times, such as Cape Cod Bay in early spring.”
Scientists are looking at possible connections between the high concentration of right whales in the early spring in Cape Cod Bay and low calving rates.