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Gray Whale Migration Update: April 4, 2001
Today's Report Includes:
- Exciting News from the Migration Trail
- Gray Whale Enemy Number One
- Tales told by Tails: Challenge Question #10
- Try This! Whale Journey Literature Link
- Teacher Tip: Friends of Gray Whales
- Watching Whales on the Net
- Whales in San Francisco Bay: Discussion of Challenge Question #6
- Putting It All Together: Discussion of Challenge Question #7
- Heavy! Discussion of Challenge Question 8
- Heaviness Helps: Challenge Question #11
- Cows and Calves: Discussion of Challenge Question #9
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Gray Whale Migration Route |
This week brings exciting news all along the migration trail! The American Cetacean Society reports the season's first sighting of a cow/calf pair on March 29, and Leslie Hines reports the first arriving gray whales seen at Resurrection Bay and Seward, Alaska on April first. Down in the Baja lagoons, Keith Jones reports, "There are still hundreds of whales in Laguna Ojo de Liebre. Of course the babies are all really large and very active. They are looking more like miniature adult whales instead of the cute pug-nosed baby whales." And here is the news about the whales beyond the lagoons on their journey north!
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Alisa Schulman-Janiger of the ACS census says that northbound sightings are still well below past numbers. The ACS is still not sure whether the peak of the migration has passed. Alisa says it's a very odd year, with definite pulses of migrants rather than an obvious increase and then decrease. Many offshore grays in large pods have been reported by fishing boats. The same is true farther north at Monterey Bay Whale Watch (36.67N, -122.00W), where Nancy Black reports seeing about 10-15 adult and juvenile grays in their three-hour trip but no cow/calf pairs yet.
Here's the ACS sighting summary since our last update. How many southbound and how many northbound whales have been reported? What was the top day for sightings in this period?
| Date |
Southbound |
Northbound |
Total Whales |
Calves South |
Calves North |
| 20-Mar |
0 |
1 |
1 |
0 |
0 |
| 21-Mar |
0 |
14 |
14 |
0 |
0 |
| 22-Mar |
0 |
10 |
10 |
0 |
0 |
| 23-Mar |
0 |
9 |
9 |
0 |
0 |
| 24-Mar |
0 |
17 |
17 |
0 |
0 |
| 25-Mar |
0 |
17 |
17 |
0 |
0 |
| 26-Mar |
0 |
24 |
24 |
0 |
0 |
| 27-Mar |
0 |
28 |
28 |
0 |
0 |
| 28-Mar |
0 |
26 |
26 |
0 |
0 |
| 29-Mar |
2 |
30 |
32 |
0 |
1 |
| 30-Mar |
0 |
10 |
10 |
0 |
0 |
| 31-Mar |
0 |
11 |
11 |
0 |
0 |
| 1-Apr |
0 |
18 |
18 |
0 |
0 |
| 2-Apr |
0 |
14 |
14 |
0 |
0 |
|
Season to Date* |
428 |
516 |
944 |
11 |
1 |
Mike and Winston sent some photos to show us what they saw on March 26:
"The morning crew of the ACS/LA census was treated to a total of 17 breaches. Breaching is a strange behavior where the whale will suddenly and without warning leap up out of the water. Breaching may be a courtship behavior or some form of communication. Whales may also breach to get rid of parasites, or maybe it's just for fun!"
Take a look!
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Mike also said, "April 1 was no April Fools Day joke for 3 jet skiers as
a gray whale surfaced only a few feet away from them as they were sitting and talking.
The Census had their own little surprise when a pod of 20-30 Orcas (killer whales)
came by and stayed in the area for about two hours. Orcas are a rare sighting off
the coast here in southern California." (You'll read more about orcas later
in this report.)
Continuing northward, Geoff Grillo reported this from his area off the coast of Washington
state: "The whales have been going by sporadically. Some days there have been
many sightings and other days not so many. The few whales that seem to stay in the
bay all year must be out visiting their northbound friends because we haven't seen
them for a couple weeks." Geoff expects to have more news next report.
Exciting news came April 1 from closer to the far end of the migration trail: "Great
news! The gray whales are here! (This is no April fools joke!) It's about time! They
might have been here earlier; the weather hasn't been very favorable for viewing
the last week or so. Both Kenai Fjords Tours and Renown Tours saw whales today. Renown
spotted two gray whales close to shore on the SW corner of Rugged Island in Resurrection
Bay. Kenai Fjords Tours had their first gray whale sightings today, two miles SW
of Rugged Island. We saw two or possibly three whales and one actually showed its
tail for us. Awesome day! It is very likely that the sightings were of different
whales, so two groups sighted so far."
Rich, Leslie, Vicky and Terry - Your Alaskan Explorer Crew
Gray Whale Enemy Number One
Each spring, grays leave their warm lagoons in an orderly way to swim north to their feeding grounds. The first group travels from February to June. These are the adult bulls, young whales from the previous year, and the newly pregnant cows. New mothers and their calves stay longer in the lagoons. They travel from March to July. Before the long swim north, cows gradually lead their calves into the main channel of the lagoon for "spring training." Calves face into the strong tidal currents and swim, going nowhere but gaining strength. Finally they are ready to leave the tranquil lagoons and face the arduous passage north. What is life like on their journey north? Killer whales are one of the dangers, and this week's reports brought severa; killer whale sightings.
Caitlyn Toropova is a Marine Biologist. She is also a Natural History Filmmaker currently affiliated with Natural Wonder Films in San Francisco. Caitlyn founded this company to make natural history documentary films. She writes to us from England, where she is involved in filming a documentary on killer whales. Here's what Caitlyn told Journey North about the connection between gray whales and killer whales:
"Although killer whales can and do eat gray whales occasionally, there is a lot more to it than that. Killer whales are the gray whales' main predator. Killer whales are amazingly good and adaptable hunters. That means they can eat many different kinds of food using many different techniques. (Not many animals can do that!). When killer whales do attack a gray whale, several things happen:
- It's almost always a calf. This means they usually have to separate the calf from its mother, which takes coordination, skill, and communication among many killer whales. (This can take up to 6 hours.)
- After the calf is separated, the KW's attack in very deliberate ways, often teaching the young of the killer whale pack how to make the kill.
- Usually, just the tongue and lower jaw are eaten. This is a bit of a mystery, considering there is a lot more meat on the whale and the kill took extraordinary amounts of energy.
- When attacks on gray whales do happen, the entire process is rarely seen from start to finish. Killer whales are like wolves in that a pack works together with strategy to make a kill. In this case, it's on a gray whale, and only when little other food is available."
Listen to live recordings of killer whales off British Columbia.
Tales told by Tails
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Challenge Question #10
"What do you think happened to this whale's tail?"
(To respond
to this question, please follow the instructions below.)
Try This! Whale Journey Literature Link
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Teacher Tip: Friends of Gray Whales
Mike & Winston sent us this announcement, and interested students may wish to follow up: On March 28, Australians for Animals (AFA) and The Fund for Animals filed a petition with the U.S. government asking it to list the eastern north Pacific or "California" gray whale population as a threatened or endangered species under the Endangered Species Act (ESA). They feel the listing is essential to protect gray whales and their habitat from increasing threats including aboriginal whaling, global warming, El-Nino events, benthic or bottom trawling, and offshore oil and gas development. The 44-page petition provides scientific evidence of these and other threats and their impact on gray whales and their habitat. A full copy of the petition and executive summary can be obtained at www.fund.org or from sarnold@byronit.com
Keith Jones also urges friends of gray whales to "speak out and write a letter or send an email to some politician. Tell them what you think of Japan and Norway gearing up to begin killing serious numbers of these wonderful creatures."
We have one more announcement in our "Friends of Whales" category. Canadian born David McTaggart was the founder of Greenpeace International, which grew from about a dozen original Canadian members with a small sailing vessel to an international activist group with operations around the world. Called the "shadow warrior" by some, McTaggart was a driving force behind Greenpeace campaigns to save the whales, to stop the dumping of nuclear waste in the ocean, to block the production of toxic wastes, to end nuclear testing, and to protect the Antarctic from exploitation. The whales lost a friend when David died in March, 2001 in a car crash. He was 68.
Watching Whales on the Net
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Whales in San Francisco Bay: Discussion of
Challenge Question #6
Last time Mike and Winston told us about grays seen near San Francisco Bay. A close
eye was being kept on these whales to make sure they find their way out into the
ocean again. We asked, "What reasons are there for concern when gray whales
are seen in San Francisco Bay?"
"Scientists are concerned for the whales in the bay. They are concerned because
they are not sure if the whales will have enough room to get out of the bay and into
the ocean," said Rayne and Kelly from Iselin Middle School team 7B.
Marine biologist Caitlyn Toropova has been involved in research about grays in San
Francisco Bay, where she was the Oceanic Society Gray Whale Project Coordinator.
Caitlyn told Journey North some additional important reasons why finding gray whales
in SF Bay is of such concern to scientists:
"Gray whales have been seen feeding in SF Bay, which is heavily contaminated
with toxins, heavy metals and PCBs. If the whales are ingesting these toxins as well
as food there is concern it could harm them. Gray whales have not historically been
found in SF Bay. This makes us ask, 'Why, then, would they be coming in here now?'
This leads to thinking that there may now be so many gray whales (around 25,000)
that there may not be enough food for all of them in the Arctic feeding grounds,
so some will have to find food elsewhere. Perhaps the whales in SF Bay are finding
the first suitable place to feed on their way North from the breeding lagoons of
Baja. Alternatively, maybe whales are disoriented and accidentally swim into the
bay. It's too soon to tell what the answer is because it takes a long time to find
out patterns of behavior with a large whale."
Putting It All Together: Discussion of Challenge Question #7
"What are some possible explanations why whale census data (dates and counts) change from year to year?"
Casey and Janet (5L from Travell) had this to say: "Baby whales are born and older whales die. Also the babies might take longer to become trained. And whales have brains so they might decide to leave earlier or later."
You were thinking! There's much more to say about this complicated question, with natural and human-caused environmental changes all playing a part. We hope you'll also read the discussions for Challenge Questions #6 and #9 in this report. Stay tuned!
Heavy! Discussion of Challenge Question #8
"What makes it possible for animals as heavy as gray whales to easily float and move in water?"
Even though a whale is big and heavy, it is not as heavy as the water it pushes away, so it floats. Saltwater is denser than fresh water, and everything floats more easily in denser water. We challenge you to research further. What adaptations of huge sea mammals enable them to be more buoyant? Water buoyancy has allowed whales to attain their enormous sizes, but why is this important?
Heaviness Helps:
Challenge Question #11
"What advantages does their huge size provide to whales?"
(To respond
to this question, please follow the instructions below.)
Cows and Calves: Discussion of Challenge Question #9
Last time we showed the a summary of Cow/Calf surveys between 1994 and year 2000 from Piedras Blancas, California and asked: "How would you describe the trend in numbers of cows and calves since gray whales were removed from the Endangered Species List in 1994? What reasons might account for the trends?"
"We think it might have gone up because the gray whales were removed from the endangered species list," wrote Alicia and Laura from Iselin Middle School. "We also think in a couple of months the number of calves would go up because the numbers keep on going up, down, up, down. We think it will go up."
We hope you're right and the numbers go up! Experts offer several possible reasons for the downward trend of the past two years. Some think the low number of calves over the last two years is due to poor feeding seasons for the gray whales during summer in the Bering Sea. Longer periods of ice covering the whales' feeding areas have prevented females from feeding throughout the season and building up enough reserves to carry out successful breeding. (The ice is due to colder ocean temperatures associated with La Nina, the cold water period after an El Nino weather event.) An overall decline in the productivity of the Bering Sea could may also be a factor. The amphipods that are a major food source for gray whales are normally extremely abundant, but the ecology of the Bering sea may be changing. Lower food production could be a result. Over the last two years, a number of gray whales have washed up along the beaches on the northbound migration, perhaps a result of not feeding well enough the previous summer. Another idea is that the gray whale population may have reached carrying capacity and there may not be enough feeding areas to support such a large number of whales. If that's the case, whales would die off or not reproduce as well and the population would decrease. Experts are also studying the predator/prey relationship between the increasing gray whale population and their predators, the killer whales.
How to Respond to Today's Challenge Questions:
IMPORTANT: Answer only ONE question in each e-mail message.
1. Address an e-mail message to: jn-challenge-gwhale@learner.org
2. In the Subject Line of your message write: Challenge Question #10 (OR #11).
3. In the body of EACH message, give your answer to ONE of the questions above.
The Next Gray Whale Migration Update Will Be Posted on April 18,
2001.
Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form
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