Scientists and volunteers conducting surveys of North Atlantic right whales off the Florida coast have seen a significant decline in right whale numbers this winter. They have seen only four adults and three calves so far. With a whale population of over 500, these sightings are the lowest since surveys began. A meeting in Massachusetts later this month will discuss the possible reasons for the lack of sightings. Climate change and a lack of food are likely causes leading to dwindling numbers of right whales.
The North Atlantic right whale has a long history of human exploitation. Current threats include entanglement in fishing gear and collisions with ships. This species of whale had a population of just 50 individuals until the National Oceanic and Atmospheric Administration passed rules to protect them. The population has grown to over 500 in recent years.
Annual surveys of the right whale population provide population size estimates. Photo identifications of individuals are also used tell ships where whales are located to prevent collisions. A network of committed volunteers and organizations, including the Marineland Right Whale Project, Florida Fish & Wildlife Conservation Commission and the Georgia Department of Natural Resources, conduct both aerial and shore-based surveys each season. This consistent and large-scale effort resulted in sightings of up to 200 whales off the coast of Georgia and northeastern Florida in winter of 2011.
Jim Hain, program director of the Marineland Right Whale Project, confirmed that the low number of whales during the 2017 season has occurred despite good weather and survey conditions. While the winter season has not yet ended, surveyors do not expect an increase in whale numbers.
Migrating Right Whales
These sightings are part of an annual right whale migration. Found off the coast of New England and Nova Scotia in the summer, pregnant females, juveniles and some males migrate to the southeast Atlantic coast in winter. The whales may not have not migrated as far south in 2017. But surveys carried out further north at Cape Hatteras have also confirmed an absence of whales.
Philip Hamilton, a research scientist at Anderson Cabot Center for Ocean Life at New England Aquarium, confirmed a significant decline in the distribution of right whales in other habitats, such as their summer feeding grounds in the Bay of Fundy and the Great South Channel. Cape Cod is the only place where more whales are present at their feeding habitat.
Scientists are unsure what’s causing the decline, but it may be due to climate change and warmer ocean temperatures. Hamilton’s concern is that female whales are not getting enough food and so are experiencing a longer calving interval. Calving usually occurs every three or four years, and the females lose one third of their body weight while pregnant and nursing. A lack of food sources may result in a longer recovery time for the females. This may in turn delay calving to every six to seven years.
