Humpback Whale Migration Update: February 26, 1997

Center for Coastal Studies

From: Anne Smrcina, Stellwagen Bank National Marine Sanctuary

Greetings from Plymouth, Mass., headquarters of the Stellwagen Bank National Marine Sanctuary (and home of that famous rock).

I've been able to talk to a naturalist who was recently in the Caribbean about this year's humpback whale migration. Jennifer Shuemaker, a education major at Lesley College on leave of absence, was in the Dominican Republic this past December teaching a course for whale watch guides (the course was sponsored by the Center for Marine Conservation and various Dominican environmental organizations). She reports that the whales were late in arriving at Samana Bay with only a few sightings by early January and no calves reported until the middle of that month. That's not bad or unusual news, however, since most calves are usually seen in February in the Bay.

I also talked to Kim Beddall, a Canadian who moved to the Dominican Republic and is considered one of the originators of whale watching there. Her company, Victoria Marine, is based at Samana Bay. She reports that the whales straggled in on the southward migration, but now seem to be there in strong numbers (perhaps 200-250 in a 120 square kilometer area at the mouth of the Bay). This area, the mouth of Samana Bay, was named a marine sanctuary by Dominican President Balaguer in July 1996.

Kim said that there were no whale watching tours or scientific expeditions that she knew of that were going out to Silver Bank this season, but several wreck divers out on the Bank called in to say that there were incredible numbers of humpbacks out there too.

In Samana Bay, they have seen at least seven mother-calf pairs, the first of which was reported on January 17th. Unfortunately, one of the calves seems to have caught its flipper on some rope with a small styrofoam buoy attached. A disentanglement team was dispatched, according to Kim, but they were unable to pull the rope off (they used a dull, rounded hook with a long pole). On a subsequent trip, the team couldn't find the calf. Kim says they're not too discouraged, because the rope looked to be jute (a natural fiber) rather than monofilament line (plastic) and hopefully will degrade in a short period of time. She said it also looked to be rather loosely wrapped so it shouldn't cause much harm right now.

Whales in Samana Bay may be there in large numbers because of the weather down there. Strong east and northeast winds have produced 7-12 foot seas outside the bay. The mothers and calves may be seeking some shelter (although swells and waves can get to be 4 feet in the bay). Kim reports that she can see whales from her office -- mothers and calves come as close as 100-150 feet from shore in water depths of 15-20 feet.

They saw one big whale in late January logging on the surface and displaying some unusual behavior -- lifting her head and tail stock out of the water at the same time. The whale continued doing this for several hours. Since humpback whales have never been seen giving birth, there was some interest as to whether this was what was happening. But, again, the whale has not been seen again (with or without a calf) and they don't even know if it was a female to begin with.

Kim believes that the whale population will probably peak in late February, which is a little later than in most previous years, and that the northward migration will be underway in March (whale watch tours in Samana Bay usually end in mid-March). They've recently been seeing a lot of surface active groups (as many as 2-4 at the same time), showing competitive behavior (males in competition for females). They've also been seeing some funky juveniles, according to Kim, including one 30-footer "who was hanging out being delinquent." Kim reported that this young whale would do a headstand and hold its tail up, come up for a breath of air, and then do it all over again -- probably just for the fun of it.

Speaking of juveniles, there seems to be a group of them that don't see the need in making the long trek to the Caribbean (since they're not of breeding age). Mark Swingle of the Virginia Marine Science Museum reports that aerial surveys show several humpbacks off of Cape Hatteras, North Carolina and down to South Carolina. In previous years juvenile humpbacks had been seen off Virginia, but this year they are only seeing finbacks. Scientists don't understand this shift in the population -- at first they thought it might be due to water temperature, now they believe it's prey concentration. When the humpbacks are down that way they could be feeding on menhaden and other herring-like fish, or possibly large aggregations of bay anchovies. The winter sightings off the Carolinas have been of whales in the 30-foot range, which would make them all juveniles. Mark reports that they once considered these whales to be about 3-5 years old, although they may possibly be as much as 6-8 years old.

That's all for now on humpbacks. Until next time, this is Anne Smrcina, education coordinator for the Stellwagen Bank National Marine Sanctuary, signing off.

The Next Humpback Whale Migration Update Will be Posted on March 12, 1997