Every spring, right whales are observed feeding in and around Cape Cod Bay. This year, the Cape has seen fluctuating numbers of right whales thanks, in part, to the weather. Weather conditions play a role in how plankton—right whales’ primary food source—sets up in the water column. Strong winds and currents can decrease the ability of the plankton to aggregate in large patches. When this happens, right whale numbers tend to be low because feeding on scattered “crumbs” is less efficient than feeding on the complete “slice.”
This spring’s weather has been inconsistent for strong plankton patch formation. We have this big picture view thanks to the hard work by our colleagues at the Center for Coastal Studies, who study plankton in the Bay and conduct aerial surveys for right whales.
This is the third spring in a row our team has collaborated with NOAA’s Northeast Fisheries Science Center to collect biopsy samples from individual right whales for which we have no genetic information. To biopsy a whale, an arrow with a specialized tip that collects a small plug of blubber and skin is shot at the whale’s body using a crossbow. Even though it sounds rough, the vast majority of whales display little or no reaction to this, and the spot heals over quickly. The scientific gains from this endeavor, however, are enormous.
From one sample, we are able to confirm who the mother is, discover who the father is, and determine the sex. The newly darted individual gets added to this database, which will help determine any offspring he/she has in the future, as well help match it to a dead animal through a skin or bone sample collected from a carcass. Genetics has also helped scientists estimate the original size of the population before commercial hunting and even tell us how few calving females there were at the population’s lowest point. So far, about 70 percent of the population has been sampled.
We focus our efforts on the Cape Cod habitat because in recent years it has harbored some of the largest aggregations of right whales. Last year, there were more than 200 individuals photographed on a single day! Thus our chances of finding targets are so much greater there than in other habitats.
The team has sampled three individuals in Cape Cod Bay so far this year: Catalog #3295, #3823, and #4042. Catalog #3295 was first seen in 2002, but since he wasn’t observed as a calf, we don’t know who his mother is. Once the geneticists at Trent University create his profile, we should learn about his mother, and possibly about his father and his own offspring!
We’re keeping our fingers crossed for better weather and more opportunities in the coming weeks to cross a few more individuals off our list.