How Many Right Whales Do We Miss?

North Atlantic right whale at the end of a feeding bout in Cape Cod Bay, Massachusetts. Marine Mammal Photographs were taken under NOAA research permit #19315. (Photograph by Center for Coastal Studies)

Considered the “right” whale to hunt during whaling times, North Atlantic right whales are endangered with a population of about 500 individuals.  Every spring, right whales come back to Cape Cod Bay, Massachusetts. Some years it seems like they’re in droves, their goal: to feed on dense patches of microscopic zooplankton.

Cape Cod Bay is the ideal place to study right whales. Since 1998, the Right Whale Ecology Program at the Center for Coastal Studies in Provincetown, Massachusetts, has conducted aerial surveys every winter and spring to identify individual right whales using the Bay. Every good weather day, a team of observers takes flight in a tiny, twin engine, plane (affectionately called “Skymaster”), counting and photographing the creatures below.

I spent countless hours in that little tin can of a plane, going back and forth, back and forth, over Cape Cod Bay, thinking about how many whales I had seen, but also wondering about how many whales I had missed. Right whales are elite breath-holders, diving for sometimes up to an hour. Skymaster flies at about 100 miles per hour, so a whale could easily be missed if it were on a dive when we passed through the area. The whales we missed would lead us to underestimate the number of animals using the Bay on any given day.

I want to predict how many right whales will use Cape Cod Bay in the future based on information we know about their food, and the environment on a local, regional, and global level. But, to make these predictions, I also need a key piece of information, how many whales are using the bay, including the whales that are missed by Skymaster.

The dive time data team hard at work on the F/V Resolve. Photographs were taken under NOAA research permit #19315.
The dive time data team hard at work on the F/V Resolve. Photographs were taken under NOAA research permit #19315. (Photograph by Center for Coastal Studies Right Whale Ecology Program)

It is for this reason, that I was perched on the roof of F/V Resolve, on a cold, January day, taking freezing, salty, spray over the bow, looking for right whales. Dive time data are what we were after, but finding whales at this time of year is not for the faint of heart. Hours were ticking by, and we had seen nothing, the ocean felt like a big lonely expanse, devoid of life.

Finally, I heard the crackle of a friendly voice on the radio, Skymaster had found whales and we weren’t far from them. We copied the coordinates, and then crisscrossed that area for the next two hours, still coming up empty.

Right whales are exceptionally cryptic animals, especially when subsurface feeding, revealing incredibly little of themselves at the surface. As the sun began to fall in the sky, so did morale on the boat. I should have picked a species that inhabits the tropics, I thought. But the setting sun was also a cue for zooplankton to migrate to the surface, and, luckily for us, right whales followed in pursuit of their tiny prey.

Finally, the whales, which had been there all along, began to skim-feed, swimming at the surface with their mouths wide open, allowing us to collect some of the necessary data to determine how many right whales are missed by surveys.




Meet the Author
Laura Ganley is a PhD student in Environmental Biology at the University of Massachusetts, Boston. She has been working with whales in a variety of capacities all over North America for the last ten years including humpback whales in the Gulf of Maine, right whales in Cape Cod Bay and the Southeastern United States, and bowhead whales in the Alaskan Arctic.