Today was a beautiful, calm day, albeit overcast, on Jeffreys Ledge. We headed up to where the whales had been over the weekend, with great spotting conditions. And despite scouring the area, we saw not a single right whales! We did see over 25 humpback whales (including some we hadn't seen in years), over 100 harbor porpoises, Atlantic white-sided dolphins, and fin whales – but no right whales. Our plankton tows showed that there is still a plankton resource there, but the dominant whale species has totally shifted from right whales (whales that eat plankton) to humpbacks (whales that eat fish).

So where have our right whales gone? We know that just yesterday, a National Marine Fisheries Service aerial survey of Cashes Ledge, an offshore bank far east of Jeffreys, saw almost 50 right whales, many more than they had seen in previous flights. We look forward to comparing our identification photographs with theirs to see if some of the whales we had been seeing show up far to the east.

This kind of sudden departure is well known in right whale habitats. In Cape Cod Bay, where they feed in numbers during the spring (sometimes almost 100 whales in the Bay), work at The Center for Coastal Studies (CCS) they often depart with no warning within several days of the end of April. CCS studies show that they will leave even if the food resource is still good, because it may be better elsewhere (they usually head out to the Great South Channel, on Georges Bank, in early May).

Will the whales return to Jeffreys Ledge, or are we done for the year? We don't know. We did not survey the east side of the Ledge at all today – that will be covered on our next survey, and there may well be right whales there. On the other hand, in one of our previous seasons (2004) we had a large aggregation of surface feeding right whales that built through November, then suddenly departed near November 20, and we barely saw another right whale for the year. We know so little about the Jeffreys Ledge habitat that each year's data adds an important piece to the puzzle. Stay tuned as we learn more through the next several weeks.