The 2011 right whale season in Cape Cod Bay had our heads spinning! On several occasions in April, the aerial survey team documented over 100 individual right whales during each flight. This far exceeds our previous record for a single day, which was 70 individuals back in 2010. This year, right whales started piling up in the Bay in mid-April, which is typical, but the size and stability of the aggregations of whales was unlike anything we’ve ever seen. The whales were clustered in the eastern portion of Cape Cod Bay, most of them hugging the shore from Race Point down to Long Point, and even inside Provincetown Harbor on a few days.
Food resources in the eastern portion of the bay were very dense and stable, and the whales were understandably preoccupied with eating – surface and sub-surface feeding on patches of zooplankton, a behavior which makes them vulnerable to vessel collision. The Department of Fish and Game’s Division of Marine Fisheries (DMF) issued an advisory to mariners to post look-outs and go slow (10 knots or less) to avoid colliding with this endangered species. Ship strike is a leading cause of human-induced mortality for right whales.
Although our aerial survey team is still matching whale photographs and tallying the numbers from this past season, they have already confirmed over 300 individual whales seen in Cape Cod Bay and adjacent waters in 2011, and that number could rise! That’s 63 percent of the known population of 473 animals and surpasses our record-breaking count of 199 whales in 2010. It is consistent, however, with the extraordinary number of right whales we’ve been seeing since 2007, despite making no changes to our survey effort.
Why have we been seeing so many right whales around Massachusetts in recent years? The answer is complicated and likely due to a combination of factors, such as recruitment of young animals into the population, use of Cape Cod Bay by individuals not normally seen there, excellent food resources in our area, and poor food resources elsewhere. Further analysis of the data is needed to understand the trend.
But the news hasn’t been all good. Between January and April 2011, four right whales were found dead off the Southeast US coast, including one female seen with a new calf, which was not expected to survive without its mother. During the winter, many right whales migrate down to Florida, Georgia and the Carolinas to give birth and socialize, traversing a very urban ocean in the process.
The exceptional year we’ve had here in Massachusetts further illustrates the importance of Cape Cod Bay to the North Atlantic right whale population. Along with our partners at the Provincetown Center for Coastal Studies, we will continue to monitor and protect this endangered species, with a hopeful eye on the future.