Human beings have an innate desire to control their environment. If I want a pond in the backyard, I make one. If we want dry land, as in the Netherlands, we build dikes and make dry land. Yet with the advent of a steadily warming climate, mankind finds itself stymied. We want to ensure that certain things we value, like endangered polar bears and right whales, continue to exist. But what if the very environment we have altered stacks the deck against them?
The National Marine Fisheries Service (NMSF) is facing a problem. Between 2016 and early 2018, 18 North Atlantic right whales died. The majority of those deaths occurred in the Gulf of St. Lawrence. Yet under U.S. laws — the Endangered Species Act (ESA) and the Marine Mammal Protection Act (MMPA) — the federal government is required to maintain the species’ existence. To do that NMFS must ensure that the impact of lobstering and other activities on the right whales is reevaluated on a timely basis. Lobster fishing is one of those federally-permitted activities. Several environmental organizations have sued NMFS to ensure that they reevaluate the impact that lobstering and other fisheries have on the right whales.
But what if the deaths and recent population decline among right whales has little to do with lobster fishing? What if it is instead an unintended consequence of a warming Gulf of Maine?
Erin L. Meyer-Gutbrod, a quantitative ecologist at the Marine Science Institute at the University of California, published a paper last fall which found that changes in the temperature of the Gulf of Maine have altered the distribution of right whales, leading them further north in search of food. That, in turn, has led the whales into Canadian waters, where the stringent laws protecting them in the U.S. do not apply.
Right whales build up bulk by eating a species of fat-rich copepod called Calanus finmarchicus. Migrating from their southern winter grounds, they return to Massachusetts Bay around February to gulp down dense patches of the copepods, which overwinter in the region and rebound as the sun grows stronger. Meyer-Gutbrod and colleagues examined right whale birth records against C. finmarchicus abundance in the 1990s and 2000s to see if there was a correlation. They drew on data compiled by the Continuous Plankton Recorder survey, which NOAA has conducted since 1961 between Boston and Cape Sable, Nova Scotia.
Meyer-Gutbrod constructed a computer model to project what might happen to the North Atlantic right whale population during the next century under various scenarios of food availability and human-induced mortality. Based on whether C. finmarchicus abundance was high or low, and how many whale deaths occurred due to human activities, the model indicated that, “Contrary to previous predictions, the right whale population is projected to recover in the future as long as prey availability and mortality rates remain within the ranges observed during 1980-2012.”
The author cautions that, “The population projections under conditions of increased anthropogenic mortality rates demonstrate that the North Atlantic right whale population may decline to extinction if an additional six adult females (or 13 total individuals taken from demographic states at random [male or female]) are killed each year, assuming prey conditions remain similar to those observed from 1980 to 2012.”
Meyer-Gutbrod also pointed out that, regardless of human activities, Gulf of Maine temperatures have forced the right whales to migrate further in their search for C. finmarchicus, thus expending more energy than in the past. “Given the known effects of nutritional limitations on calving intervals, the increased time and energy used to extend the winter calving migration may have a detrimental impact on the population’s recovery rate,” the paper states.
How can NMFS protect the right whales if they are heading north in search of food into the heavily fished and unregulated waters of Canada? That is a question that neither the ESA nor the MMPA can address.