Gray Whale Migration Update: March 5, 1997

Will Hagan, Macalester College

Greetings from the Channel Islands National Marine Sanctuary!

First, before that baby gray whale gains any more weight let's answer last week's Challenge Question!

"Gaining at a rate of about 1.2 pounds per hour, how much total weight has the calf gained since her arrival at Sea World on January 11?"

Let's calculate the estimated weight gained by February 19th (the date of the last report). That's 40 days at 24 hours per day and weight gain of 1.2 pounds per hour = 40x24x1.2 =1,152 pounds. If she continued at that rate until today she would have gained a total of 54 days x 24 hours per day x 1.2 pounds per hour = 1,555 pounds!

Our thanks to all the classrooms who submitted answers to this question:

• Mrs. Berger's 5th Grade "Whale Team" from East Hills School in Roslyn, NY
• St. John the Baptist School in Oregon
• Ms. Nosworthy's class in Washinton State
• Mrs. Davis' 6th grade class in Lorenzo, Texas
• Ms. Heilman's ,5th Period, 7th Grade in Pennsylvania
• Ms DeWit's Challenge Class of third graders from Katherine Curren Elementary in Hopkins, MN.
• The 5th period class from Oak Hall School in Florida
• Ferrisburgh Central School, Ferrisburgh, VT
• Mrs. Amy Driscoll's second grade class at Timothy Dwight School in Fairfield, CT.

The classrooms each counted a different number of days than I did since the calf arrived at Sea World on January 11, so everyone came up with slightly different final answers based on the number of days they counted. Using the different number of days though, just about all the answers were correct, and just about everyone showed us that they knew the correct formula to calculate the calf's weight gain. For instance, Claire Modica of the Whale Team from East Hills School in Roslyn, LI. showed the correct formula in this answer: "At 24 hrs. per day, I multiplied 24 x 1.2 and got 28.8." She then multiplied 28.8 x the number of days since the calf's arrival at Sea World to reach the number of pounds gained by the calf.

• Click Here to View all Students' Answers to Challenge Question # 1

Will Hagan, Macalester College

While the pregnant females appear to head for the warm Baja lagoons to give birth, many calves are born during the migration from central California southward. In fact, Island Packers a group that provides whale watching excursions out of Ventura, California has spotted about 20 southbound mother/ calf pairs so far this year.

The Santa Barbara Museum of Natural History sponsored a trip to Magdalena Bay (in southern Baja) earlier this month. Gary Robinson, Manager of the Sea Center in Santa Barbara was fortunate to serve as a naturalist on this special trip to see Gray Whales. Gary kept a journal of his adventures in Baja and we are very lucky that he is willing to share some of his encounters and photos with us.

Gary and his crew of passengers stayed on an 80 ft boat called the Don Jose in Magdalena Bay and took daily trips in "pangas" (small skiffs) to see the whales.

Here are some excerpts from his journal...

February 4th
"Before breakfast, a gray whale was seen spouting some 400 yards distant as well as 3 or 4 bottlenose dolphins. Morning- boarded pangas at 8:30 am and headed for shallows. Were greeted by a whale spyhopping. Observed several cow calf pairs. One calf was observed not more than 10 ft from our panga. We also moved to the "boca" or mouth of the bay and observed many spouts and whale flukes...most seemed to dive after taking only one breath at the surface. (After lunch) Observed several more cow-calf pairs as well as one pair of adults rolling on sides (pre-mating behavior)."

February 5
"Morning- Spectacular sunrise over an absolutely placid bay. Boarded pangas and headed for the entrance of Magdalena Bay. As we approached many spouts could be seen on the horizon. It seemed at times that 20 or 30 whales were blowing at once. We all thought we would be thick with whales all around. But this was not the case. Magdalena by is very large and groups of whales were traveling and diving all around but at some distance from us...we moved to shallow waters and encountered several large groups of whales of 6-8 animals each. There was much spyhopping, rolling and circling about. Occasionally a whale or whales would let out a mass of air below the surface which would bubble up in the center of these circling whales. Two simultaneously spyhopping whales were observed.

February 7
"Morning - boarded pangas for travel to the bay's entrance. Conditions were calm and we had several very close approaches by whales pursuing other whales. One ( I assume a male) approached the boat very closely from behind, dove beneath us and lay there before raising its rostrum out of the water not more than 3 ft from us. After 2 hours of this, we moved to shallower waters where we again observed two cow-calf pairs and several mating groups in the shallows. In places the water was less than 15 ft deep and we could see the whales skirting the bottom. Spyhopping behavior was observed and one whale breached 5 consecutive times."

Here's today's Challenge Question #2:

"It has been reported that less than 6 percent of all gray whale calves are born in Magdalena Bay each year. How many calves would that be?"

Hints:
* Assume a total population of 23,000 gray whales and 15,000 mature adults.
* Assume a 1:1 ratio of males to females.
* Assume that half of the females will bear young in a given year.

To respond to this question, please follow the instructions at the end of this report.

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Laura Gorodezky
Education Coordinator
Visit Channel Islands National Marine Sanctuary

How to Respond to Today's Challenge Question #2:

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

"It has been reported that less than 6 percent of all gray whale calves are born in Magdalena Bay each year. How many calves would that be?"

Hints:
* Assume a total population of 23,000 gray whales and 15,000 mature adults.
* Assume a 1:1 ratio of males to females.
* Assume that half of the females will bear young in a given year.

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

The Next Gray Whale Migration Update Will be Posted on March 19, 1997.