Right Whale Migration Update: March 12, 1997

Center for Coastal Studies

Hello from the Stellwagen Bank National Marine Sanctuary in Plymouth, Mass.

I've got some interesting information for you this week. It seems researchers from the Center for Coastal Studies in Provincetown, Mass. have spotted the first mother-calf pair of the season in Cape Cod Bay. The whales were seen on March 5th -- this is 10 whole days earlier than the first sighting last year, and 20 days earlier than the next earliest sighting in previous years.

Researchers are not sure why this mother (identified by Marilyn Marx as Staccato) and her calf have come in so early this year. Marilyn is considered one of the experts in right whale identification, and she is now studying many of the photographs of whales taken during aerial surveys in the calving grounds off the Florida and Georgia coastlines. As far as she can tell, Staccato wasn't one of the 16 mothers seen down there. If so -- this is another calf to add to the total.

Other right whales (males, females and juveniles) have been seen over the past few weeks in Cape Cod Bay feeding and socializing. We've had some rather bad weather lately, so there haven't been too many reports from the field. The maximum number of whales seen on any one day in Cape Cod Bay was about 10.

My first challenge question to you was about the difficulty of right whale spotting. As students at George Seitz Elementary School on Kwajalein Island in the South Pacific said, "Sometimes the water conditions are just so dark it is impossible to see whales." (gses@tcsn.net)

Even for the most experienced cetacean scientist, finding a right whale is not an easy task. First of all, conditions at sea are quite variable, and often very rough. During the winter and spring, winds put a chop on the sea that hides the splashes of surfacing whales. The right whale does not have a dorsal fin and has a broad, flat back, making it hard to see as it rests at the surface. Feeding whales can dive for periods of up to 15-20 minutes, putting them under water and out of sight for much of the day. Whales migrating may spend only about 10 percent of their time at the surface, taking a breath or two before submerging again. The easiest spotting is during a fair weather day in the calving grounds when the mothers and calves can be seen at or near the surface playing, nuzzling and nursing. Two factors that aid in right whale sightings are the whale's distinctive v-shaped blow and the showing of its tail (flukes) as it dives.

The latest report of right whales in Cape Cod Bay is that of a group of three whales on March 8th at:

42  02N  70 13W
41  58N  70 13W
41  58N  70 08W
42  02N  70 08W

Down south, the mothers and calves seem to have moved on out. Chris Slay and Lisa Conger of the New England Aquarium's right whale research group reported on March 7th that:

"Another calving season is coming to a close. There'll be stragglers but it looks like most of our moms slipped out of the area under the cover of fog and wind at the end of last month. This is no great surprise. Most right whale cows decide to take their calves home in late February, often covering 20-30 nautical miles a day until they reach Cape Cod. The last couple of sightings from this update are of a mom trying to decide it she's really ready to go.

"When the water temperature climbs towards 60 degrees F. the whales get restless for cooler water and other species begin to move inshore, particularly sea turtles. It's really quite striking how pivotal that 60 degree mark seems to be. We hit that mark during the middle of the week (2/27-3/5) and our sightings on 3/4 and 3/5 reflect the transition from winter to spring. On those two days we saw 754 turtles, mostly loggerheads; 863 bottlenose dolphins; and 520 cownose rays (Rhinoptera bonasus, surely one of the coolest Latin names in the animal kingdom). We also recorded over 20,000 sharks....just in time for spring break!"

His last reported mother-calf sighting on March 5th was: 30 32.5N 81 07.3W

And now for Challenge Question # 3:
"If the right whales travel 20-30 nautical miles a day, and its about 1,200 miles from the calving grounds to Cape Cod Bay, how long would it take for a mother-calf pair to swim that distance (provided they don't stop to sightsee along the way)?"

To respond to this Challenge Question please follow the instructions at the end of this report.

Chris Slay also gave me the answer to Challenge Question #2: "What might be the favorable type of bathymetry, temperature and sea conditions down south that would attract the right whales?

Water temperature in the calving grounds is about 10-15 degrees centigrade (50-60 degrees F), approximately the temperature of the water in the summer feeding grounds. It seems to be the temperature the whales like the best. Any hotter, and they start to move on (as Chris noted in his report). The shallow bathymetry may provide some security for the mothers and calves from large pelagic predators such as sharks and orcas. And the westernmost part of the Georgia Bight (an important part of the calving ground) is somewhat sheltered from the rougher conditions of the open Atlantic Ocean.

Chris reports that the total of 17 possible calves for this season is very exciting, and leads them to be a bit more optimistic for the future of the species. But there are still many factors that can affect the survival of the right whale.

My second Challenge Question for you today is about this issue of survival.

Challenge Question # 4
"What do you think are some major threats to the survival of the calves during their first migration and subsequent travels?"

To respond to this Challenge Question please follow the instructions at the end of this report.

Until March 26th, this is Anne Smrcina signing off.

Note About Latitude and Longitude Figures
Journey North customarily reports latitude and longitude data in "decimal degrees". Mr. Shapiro's students in Largo, Florida were confused by this format, so we asked Ann to explain.

"These figures show degrees, minutes and tenths of minutes. That's how they report the data from the southern calving grounds and the northern feeding areas. Hope we didn't confuse too many teachers and students. If they're used to the decimal degree format, here's how to convert:

Example:
31 13.6N (Latitude of a Right Whale Mother-Calf Pair on Feb. 18 )

"The whales are 13.6 minutes north of 31 N. There are 60 minutes in a full degree. Since the whales are 13.6 minutes north, that's 13.6/60=.2266 of a full degree. Here's the answer: 31 13.6 N = 31.2266 N

How to Respond to Today's Challenge Questions:
Please do not answer both questions in one message!

How to Respond to Journey North Right Whale Challenge Question # 3

1. Address an e-mail message to: jn-challenge-rwhale@learner.org
2. In the Subject Line of your message write: Challenge Question # 3
3. In the body of the message, give your answer to this question:

And now for a Challenge Question # 3:
"If the right whales travel 20-30 nautical miles a day, and its about 1,200 miles from the calving grounds to Cape Cod Bay, how long would it take for a mother-calf pair to swim that distance (provided they don't stop to sightsee along the way)?"

How to Respond to Journey North Right Whale Challenge Question # 4

1. Address an e-mail message to: jn-challenge-rwhale@learner.org
2. In the Subject Line of your message write: Challenge Question # 4
3. In the body of the message, give your answer to this question:

Challenge Question # 4
"What do you think are some major threats to the survival of the calves during their first migration and subsequent travels?"

Don't Forget!
Please include the name of your school and your location so we can credit you properly for your answers.

Please Note:
Anne has adjusted the schedule for her regular Humpback Whale migration reports. She will provide updates on alternate weeks. Re will be posted on the following WEDNESDAYS:

2/12, 2/26, 3/12, 3/26, 4/9, 4/23, 5/7, 5/21

The Next Right Whale Migration Update Will be Posted on March 26, 1997.