Humpback Whale Migration Update: May 24, 2000
Greetings from the Stellwagen Bank National Marine Sanctuary
My apologies for not sending a report last time, but I've been caught up in a number of projects including building the new web site for the sanctuary. Our home page will be at (http://www.sbnms.nos.noaa.gov) starting in June! The past month has seen a major change in the whale population locally, with many sightings, not just of humpbacks, but other large baleen whales and large pods of Atlantic white-sided dolphins.
Yippee!! Mother-Calf Pairs Arriving in Cape Cod Area
Researchers from the Center for Coastal Studies in Provincetown, Mass. report that since the start of the month they have seen the first of the mother-calf pairs. The first whales appearing with calves are: Salt, Pepper, Trident, Rapier, Midnight and Sickle. Salt and Pepper were two of the very first whales to get names (rather than just catalog numbers) several decades ago. Salt has returned over the years with eight known calves (her last one was in '98 named Tabasco). Dayle Taylor of the New England Aquarium reported seeing her first calf of the season on Sunday, April 30, and noted that the animal was very small, still light in color with some of the fold marks still apparent on the skin. The mother did not fluke when she made her dive, so the naturalists were not able to identify that whale at that time (she may have been one of the other six, or she may be a seventh humpback mother in the sanctuary).
Fantastic Whale Watching
The Stellwagen Bank National Marine Sanctuary is sponsoring a series of research cruises by the Center on the bank to better understand the population of whales that come to this area every year.
The first of these cruises was scheduled for May 9th. The day started with promising results. According to Jooke Robbins of the Center, they spotted and photographed 5 humpback whales, feeding fairly wide spread over the central and eastern portion of the bank. Three were juveniles, including Bric-A-Brac (first seen in 1998, so this whale is at least three years old) and one mother-calf pair (Trident & calf). Also in the area were 5 fin whales and 2 minke whales.
Despite the best laid plans, the cruise changed just after 10am, becoming a rescue mission. The Center is on call as the region's disentanglement team for endangered whales. Just as they reached the southern end of the bank, where whale abundance was at its highest (20-30 whales), the research vessel was diverted to respond to an entangled right whale in Wilkinson Basin, an area east of the sanctuary. Notes Jooke, "Although they couldn't photograph and take skin samples of the whales in that area, they did recognize Kilter (a mature male), and Salt and her calf, Mars (a mature female). Skin samples help the scientists understand family trees, genetic diversity, sex of the animal, and possible effects of pollution.
'Sickle' Seen with Another Calf!
Jooke also noted that Sickle, one of this year's new mothers, has an interesting history. The average birth rate for humpbacks is 2-3 years, but Sickle had a calf last year too. She has been quite the producer, with calves in 1994 (Jigger), 1995 (North), 1997 (Chalet), 1999 (Estuary) and 2000. Consecutive year calves are unusual, due to the demands of gestation and nursing. Usually whales rest a year to build up body reserves to tide them through these demanding periods. In addition to the mothers and calves, the majority of the whales sighted thus far have been females and juveniles, however there are mature males around as well.
Get Out Your Bird Identification Guides
A Whale-Sized Thank You
Good luck with all of your studies and I'm looking forward to working with all of you again next year.
This is Anne Smrcina, education coordinator of the Stellwagen Bank
National Marine Sanctuary, signing off for this year's Journey North
Making Sense Out of Weather Maps- Discussion of Challenge Question #11
Looking at weather maps can teach us many things about the world around us. Whale watching in late-April was difficult in the Cape Cod area due to rough seas and stormy weather. Looking at the weather maps we provided for April 19 and 23 we see there was a large low pressure system just off shore at that time. Pressure systems cause the winds
that make the sea rough. In general air moves from high pressure to low pressure. Strong winds resulted from the low pressure centers off the coast making it difficult for the research vessels out at sea.
Discussion of Challenge Question #12
Last update we reported that the northern portion of Stellwagen Bank had recently been the feeding ground for some of the early arriving whales. Several adult females with juveniles were seen earlier and more recently he was able to confirm a sighting of an adult male. But to date, there have been no confirmed sightings of any mother-calf pairs. We asked this question, "Is there any reason why the researchers have seen the whales (or expect further arrivals) in the above-mentioned order: adult females and juveniles, adult males and finally mother-calf pairs?"
Scientists believe that the mother-calf pairs will stay in the calving grounds as late as possible to give the
calves the best chance of gaining strength before making the long commute north. The adult females who are not
pregnant go to the breeding grounds searching for a mate. If they become pregnant, there is no further reason
to stick around, so they may be the earliest arrivals to the feeding grounds. The pregnant whales probably want
to build up as much of a reserve of blubber to support themselves and their fetuses during the year-long pregnancy
as well as provide reserves for the nursing period. Researchers also believe that males may stick around the breeding
rounds for longer periods to mate with as many females as possible. Juveniles may or may not make the trip down
south. Those that do go may accompany their mothers and keep the same schedule. Those that don't make the southern
migration may be staying in more northern waters where the trip back to the feeding grounds is quicker (juvenile
humpbacks have traditionally been seen off the Virginia and North Carolina coasts during the winter months).
This is the FINAL Humpback Whale Migration Update for 2000. We hope you have enjoyed learning about our whale
relatives and realize we are all involved in each others lives, even our friends under the sea!
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