FINAL Gray Whale Migration Update: May 14, 2003
Today's Report Includes:
- Migration Almost Over!
- A Little Baby Boom?
- A Whale of a Season
- How Much Does a Gray Whale Eat Each Day?
- Beast Feast!
- Ice on the Feeding Grounds: Learning Link
- To the Edges of the Ice
- Investigating Issues that Affect Whales: Links to Lessons
- Using Up the Fat Stores: Discussion of Challenge Question #13
- Tails and Flippers: Discussion of Challenge Question #14
- Want to Watch Whales in Baja? Here?s YOUR Chance!
- Year-end Evaluation: Please Share Your Thoughts!
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Gray Whale Migration Route |
The spring gray whale migration is almost over! Stragglers still reward the whale watchers. Mothers and babies have nearly emptied out of the lagoons and are "bringing up the tail" of the northward swim. Here's what our observers reported for our final peek this season. It's been an epic journey--for some whales, the very first. For others, just another of many such journeys during a long lifetime.
The first babies and moms have reached Alaska, while others have just passed Wayne Perryman's census station at Point Piedras Blancas, CA.
Wayne reports the migration is winding its way to a close. "We finished last week with only 22 calves counted. I expect that this week will give us around 15 calves, and the next will be marked by the presence of those long dull days of no calves."
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Copyright by Keith Jones |
How does this year's calf census compare to years past? Wayne says, "This year's total count will be close to last year's. So far we have counted 251 calves, which is higher than the total counts of 1995, 1999, 2000 and 2001, but lower than the big years. We missed a couple of days during the peak of the migration, so I expect our estimate from this year's count will be very close to the estimate of 850 calves from last year's survey. So reproduction for this population is at a good level, certainly high enough to support population growth."
Elsewhere, the migration is also slowing. Read on for observers' reports and some challenges to get you thinking as the whales reach their feeding grounds for a long summer of feasting.
A Whale of a Season
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Mike and Winston send this final report from the ACS/Los Angeles census point: "The Gray whale season is winding down and we had one WHALE of a season. Although our numbers were higher than the past several seasons (while around average during certain times), you must remember that we only see a small percent of the migrating gray whales. Just because we saw higher numbers does not necessarily mean that the Gray whale population is on the rise. It might just be that the whales were migrating closer to shore. Gray whales, like most whales, are still being threatened by humankind's actions, such as the polluting of our oceans and the constant threat of being hunted again. [NOTE: You'll see more on these issues near the end of this report.]
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Channel Islands National Marine Sanctuary near Santa Barbara |
Carol has this question for you: "How many (number, pounds, tons of) copepods does a gray whale eat each day?" Later in this report, Carol gives you the amazing answer. Predict your answers now, and read on!
Leslie Hines says, "We are still seeing Gray Whales regularly in the Kenai Fjords area," so we know many of them reached home. At Kodiak, Alaska, Susan Payne reports a lot of transient orca activity in the harbor: "On May 1, 5 orca transients in the harbor took at least one sea lion under the Near Island bridge. Many people were on the bridge watching the kill when we passed at 1430." A humpback whale passed Lori Mazzuca's house on April 30. That day also brought 12 gray whales off Long Island. And Susan reports this sighting on May 5: "Unknown whale, possibly a single gray whale or fin whale spotted outside Anton Larsen Island where we live. The light was poor and we could not see a blow. One view showed a possible mottled gray back with knobs...could not see a dorsal fin." Based on the clues in the sighting and what you know of gray whale anatomy, what do YOU think they saw?
How Much Does a Gray Whale Eat Each Day? Carol's Question Answered
What answer did you predict for Carol's question? She asked, "How many (number, pounds, tons of) copepods does a gray whale eat each day?" "Gray whales eat about 150,000 kg (340,000 lb.) of food during a 130-to 140-day feeding period. That's a daily average of about 1,089 kg (2,400 lb.). It is estimated to take 300 kg (660 lb.) of food to fill a gray whale's stomach. They feed on benthic amphipods, polychaetes, isopods and tubeworms, and are unusual in their feeding habits as they suck up benthic sediments."
Try This!
- What does "benthic" mean, and how does it apply to a gray whale's food?
- If a gray whale eats 340,000 pounds in 130 days, what's the average number of pounds of food eaten per day?
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Feeding is the main activity of hungry whales returning north. During its five- or six-month feast on the arctic feeding grounds, an adult gray whale will swallow tons of food. Whales have a lot of weight to gain back after months of living off fat reserves in the calving and mating lagoons and along the migration trail! Susan Payne fills us in with some scientific information on the feasting of gray whales. When you read it, you'll find out why scientists think gray whales turn on their side while feeding, and what feeding tracks are:
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The whales haven't eaten much for months, but as you just learned, that will soon change when their arctic feeding grounds are once again ice-free. Do you ever wonder: What is sea ice, and what does it look like? Could you eat sea ice, or is it too salty? Why are scientists interested in measuring sea ice? Find answers here:
To the Edges of the Ice
You may remember that gray whales don't have dorsal fins, but instead have 6 to 12 knuckles or bumps along the dorsal ridge. When you think about their migration route, do you think this feature of their anatomy is an adaptation? How far north is the sea ice-free?
Check out this sea ice site for the daily ice maps showing Alaska's open waters and see where the ice stops each day:
Investigating Issues that Affect Whales: Links to Lessons
We celebrate that gray whales had a better season than in SOME recent years. These magnificent, intelligent marine mammals share our planet, but troubles they encounter are most likely caused by human actions rather than anything the whales themselves do. Protecting the planet and living things ends up being the mission of caring people who speak out on issues that can and do cause troubles for creatures and habitats, and ultimately for every living thing. A world better for whales is a world better for ALL of us. If you'd like to find out about some of the issues facing whales, we've created a page with some links. Use the information to choose an issue, find the facts, and educate others. More people caring about whales means more people caring about the planet we all share.
For lessons in developing informed opinions, or debating values and viewpoints, please see:
Using Up the Fat Stores: Discussion of Challenge Question #13
"Rice and Wolman (1971) calculated that gray whales burn 19 kilocalories per kilogram of body weight per day. What is the conversion for tons to kilograms? How many kilocalories does a 40-ton whale burn per day?"
To find my answer, first I needed to know how many kilograms go into a ton. The answer to that is 1,000. Then I took 1,000 and multiplied it by 40 tons (the whale's weight) to get 40,000 kg. Then since they burn 19 kilocalories a kilogram you take that number and multiply it by 19 to get the final answer which is 760,000, said Michael from Challenger Middle School.
"WOW," dds Samantha, a seventh grader at Challenger Middle School. We agree! Michael and Samantha were among many of you who sent the correct answer. Thanks to all these students for working on this Challenge Question!
* Courtney, Olivia, Luke, Johnathan from Pymatuning Valley in Andover, Ohio
* Mai Huynh, N.V., Jack Nguyen, Van Nguyen, Michael Rafanan and Samantha from Challenger Middle School.
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Photo Mike & Winston |
"How is a whale?s flippers similar to and different from your hands?"
We heard from MANY of you on this answer--with a flood of students from San Diego's Challenger Middle School and Iselin New Jersey's Iselin Middle School! Thanks to all of you! You stated that the skeleton of a gray whale flipper has four long finger-like digits and looks similar to a human hand. The digits in the flippers cannot be moved individually like our fingers can, but whales use the entire flipper. For example, a whale mother can use her flippers to hold her baby close while it nurses. Others added further creative thoughts:
Sarah, from Challenger Middle School (San Diego) wrote, "Whales cannot move individual "fingers" like we can. But then again, if grey whales needed to use their "fingers" individually, they'd be able to. That's how adaptation works." Exactly!
Nick points out that both whales and humans propel ourselves through water with help from flippers and hands, and both species also use flipers/hands for weapons when necessary.
Jack mentions how humans can rotate our hands and steer things such as cars, just as whales rotate their flippers to steer their bodies through water.
Want to Watch Whales in Baja? Here?s YOUR Chance!
Keith Jones reminds us, "Next year we want to provide the funding for a group of between 9 and 14 high school seniors/juniors and their chaperones to experience the Baja Jones Adventure to the gray whales." Is your school interested? If so, contact Keith Jones: keith@greywhale.com with a letter of interest by June 15th. (An email query is acceptable to begin.)
Year-end Evaluation: Please Share Your Thoughts
Please take a few minutes to share your suggestions and comments in our Year-End Evaluation Form below. The information you provide at the end of each year is the single most important tool used to guide our planning.
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Journey North |
This is the FINAL Whale Migration Update for Spring 2003. Have a wonderful summer as you keep your eyes open for news of gray whales. We hope you'll be back with us for the journey north in 2004!
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