Greetings from Stellwagen Bank National Marine Sanctuary:
Yes -- the whales are singing at the Silver Bank in the Dominican Republic. Researchers were going out today to the Silver Bank Sanctuary, but since it's quite a bit offshore (over 80 miles), it's not easy to get out there to do population counts. I'll try to get a report on this overflight for next week's report.
Our contact in the Dominican Republic, Idelissa Bonnelly of the Comision Rectora del Santuario de Ballenas Jorobadas del Banco de la Plata reports that whale watching has been active in a more nearshore area called Samana Bay (with humpbacks from the same group that visits Silver Bank). She says that whales were first sighted on January 8 (3 whales); by January 16 there were about 35. A mother-calf pair was spotted on January 25; and an active group (number unknown) was seen on February 2. Idelissa reports that they have been worried about the potentially harmful effects of an oil spill on January 20 at the mouth of Samana Bay (a ship met up with the coral reef). Although the spill wasn't very big, it was close to where the whales usually congregate. She reports that they were working on this situation.
No humpback whales have been spotted at Stellwagen Bank or around Cape Cod lately, but Dave Wiley, senior scientist from the International Wildlife Coalition, says this is as it should be. The usual scenario is to have some whales around in November and December, a few stragglers in January, and none in February and March. Humpbacks, according to Dave, should start reappearing in New England waters in April.
However, humpbacks have been spotted again off the Virginia coast. The Virginia Marine Science Museum has been running daily whale watch cruises that have been sighting from one to up to four humpbacks per cruise. They believe they have seen at least 20-30 individual humpbacks over the past few weeks. This past weekend they saw six different whales on one cruise (probably four humpbacks, the other two were either humpbacks or fin whales). The fin whales they've been spotting appear to be full size adults (or old juveniles); the humpbacks have been measured at 30-40 feet (making them juveniles and "teen-agers" -- almost adults). The numbers of humpbacks seen in Virginia waters during the winter months seems to be increasing over the past few years. Any ideas why? (For a possible answer, see the technical article at the end of this report.)
Why do whales sing?
The singing of humpbacks at Silver Bank has been documented and studied by behavioral scientists. Here's some information from "Whales Ho" the article by Dr. Peter Craig from American Samoa that was excerpted in last week's report....
"While an occasional spout of whale-breath can be seen in our local waters [Samoa], you can hear the whales too, if you stick your head in the water. Humpbacks are famous for their unique "songs." Yes, whales sing! During mating season, male humpbacks sing to either attract females or defend their territory from other male whales, much like birds do with their own songs.
The whale's song is haunting and complex. It sounds like an eerie series of chirps, squeaks, whistles and grunts. I know that "grunts" don't seem like they could make much of a song, but you just have to take my word for it. It is unlike anything you have ever heard.
Scuba divers can hear the singing if they hold their breath and pay attention. Snorklers can also hear the songs, but they have to dive at least 10 feet deep to get below the noisy surface layer of water. (Landlubbers can listen to the humpback's song in the video "Star Trek - 4").
The song lasts about 10-20 minutes, it has a beginning, middle and end, and all males of the same stock sing the same song. Thus, biologists can identify where a whale comes from by listening to its song. For example, Hawaiian humpbacks sing a different song because they belong to a different stock of whales that migrates between Hawaii and Alaska [and Silver Bank whales sing their own brand of songs].
The whales' song is one of the world's wonders of nature and it's at your doorstep [in Samoa or Hawaii or the Caribbean -- for those of you not so lucky to hear the songs in person, there are audiotapes available in some nature and record stores, as well as the Star Trek video].
That's all for now. What follows is an excerpt from a technical report "Appearance of Juvenile Humpback Whales Feeding in the Nearshore Waters of Virginia" which appeared in Marine Mammal Science in July 1993; copyright 1993 by the Society of Marine Mammalogy; 9(3):309-315.
In the western North Atlantic, humpback whales (Megaptera novaeangliae) migrate from summer feeding grounds off the coasts of the northeastern U.S.,Canada, Greenland, and Iceland to winter breeding grounds in the Greater and Lesser Antilles. The end points of the breeding migrations are well documented; however, exact routes are not known. It is believed that these humpback whales migrate well offshore in deep ocean waters. It has also been suggested that during the breeding migration and residency on the breeding grounds, humpback whales engage in little, if any, feeding activity.
Previous research has indicated that the geographic and temporal distribution of juveniles (sexually immature) in the western North Atlantic is similar to that of other humpback whales. Most adult and newborn North Atlantic humpback whales are on breeding grounds between January and April; however, there are reported sightings in high latitude waters in these months. Little information, though, exists on the activities of juveniles during this time. Known juveniles have been reported on the outskirts of primarily adult "surface active groups" in breeding areas. Segregation by age and reproductive class has been reported for migrating humpback whales in other geographically distinct areas. This segregation has not previously been documented for North Atlantic humpback whales during winter migrations.
We offer the first report of humpback whales in nearshore waters off the coast of Virginia during the months of January through March 1991 and 1992. We observed juvenile humpback whales feeding near the mouth of Chesapeake Bay, within 4 km of shore. The appearance of the whales was correlated with large aggregations of feeding birds and the presence of large schools of fishes.
Our observations support the hypothesis that some juvenile humpback whales do not migrate to breeding grounds but, instead, migrate to mid-Atlantic nearshore waters apparently to feed.
The appearance of increasing numbers of juvenile humpback whales in Virginia coastal waters has been quite dramatic. Anecdotal evidence supports the hypothesis that this phenomenon is recent. Commercial and recreational fishermen as well as long-term coastal residents confirm our belief that the seasonal abundance of humpback whales in Virginia has greatly increased.
Unfortunately, the apparently expanding presence of these whales in mid-Atlantic coastal habitats increases the potential for adverse interactions with commercial and recreational vessels and/or fishing gear. In Virginia, juvenile humpback whales are found in and around some of the busiest military and commercial shipping lanes in the U.S. and are present during a winter/spring gillnet fishery. Our stranding records include two confirmed vessel strikes and two entanglements since 1990.
Although no individual [whale] was observed long enough to preclude the possibility that it migrated to the Antilles, our data are consistent with the hypothesis that juvenile humpback whales seen nearshore along the mid-Atlantic coast during the winter do not visit the breeding grounds that year. In addition, observed feeding behaviors in areas of concentrated sources of food indicate that winter foraging may cause this distribution.
The presence of juveniles in Virginia broadens currently accepted theories of winter distribution. Juvenile humpback whales in Virginia waters may be a natural result of an expanding North Atlantic population. Further study is needed to fully document the extent to which juvenile humpbacks are utilizing nearshore waters of U.S. mid-Atlantic states. The results may prove to be vital new information for the continued recovery of this endangered species."