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Gray Whale Migration Update:
Today's Report Includes:
- Latest Migration News From the North: Challenge Question #20
- Ice on the Feeding Grounds?
- Try This! Spot a Match With Whale Photo ID Lesson
- Great Whale Watching in Channel Islands Marine Sanctuary
- The Ice and Calf Connection
- Baby Boom: Good News About Cows and Calves
- Counting Whales: Challenge Question #21
- What Direction? Discussion of Challenge Question #16
- Q and A With Lisa Munger: Discussion of Challenge Question #17
- Sea Ice Not Always Nice: Discussion of Challenge Questions #18 and #19
- Year-End Evaluation: Please Share Your Thoughts!
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Gray Whale Migration Route |
What a busy time for whale watching! Peak numbers of cows and calves have passed census sites in California since our last report. At the other end of the whale trail, whales are passing by Seward, Alaska while making their way along the coast, and sightings from Kodiak have included plenty of orcas as well as gray whales. Read complete Alaks reports from Capt. Leslie Hines in Seward and Susan Payne in Kodiak:
Also in Alaska, an aerial survey of the Togiak District was flown April 26, covering the coastline between the upper Nushagak Peninsula and mid Hagemeister Island. Pull out a detailed map and see if you can locate this region of Alaska. James Browning of the Alaska Department of Fish and Game surveys for herring, but said approximately 250 gray whales, 8 sea lions and several seals were counted on the survey. He also noted, "We are getting actual water temps from the P/V BERING STAR twice a day; it was 1.5 degrees C. for April 26." Can you answer this?
Challenge Question #20:
"What is the Fahrenheit reading for sea water that's 1.5 degrees C.?"
(To respond to this question, please follow
the instructions below.)
Ice on the Feeding Grounds?
The whales haven't eaten much for months, mostly fasting until their arctic feeding grounds are once again ice-free. What's the situation? Kate Wynne from the University of Alaska in Fairbanks reports, "Grays are still filing by Kodiak. I have no idea what the ice cover is doing, but it has been exceptionally warm and dry here in the Gulf of Alaska so I wouldn't be surprised if the ice was well on its way north!" You know from the Challenge Question above that the water is cold, but how can we tell where the ice is? Keep your map out as you go to the web site below and see how far north the whales can go before they run into ice:
Try This! Spot a Match With Whale Photo ID Lesson
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Dr. William Megill of CERF |
Great Whale Watching in Channel Islands Marine Sanctuary
Gray whales continue their journey north up the coast. Thanks to the volunteers from NOAA's Channel Islands Marine Sanctuary, who have some great whale sightings to help us feel like we're in the field with them:
The DOUBLE DOLPHIN's reports include seven mother & calf pairs as well as five single whales. Most sightings during this period were made very close to shore. A dramatic display occurred on April 14, when a mother & calf pair were surrounded by feeding Bottlenose Dolphins and a flock of active Loons. This event was so close to shore that surfers and beachwalkers were able to enjoy the sighting with the boats.
The CONDOR EXPRESS reported eight mother & calf pairs. In addition there were two separate sightings of a single Humpback Whale. The Humpback seen on April 24 was entangled in fishing gear, with one or more ropes around its midsection. The whale circled for a long time in the same area, staying near the surface. No deep dives were observed. This same whale was observed by the DOUBLE DOLPHIN, and land-based observers. Both vessels reported the entanglement to the Santa Barbara Marine Mammal Rescue.
The SUNSET KIDD's sightings occurred near-shore. The Gray Whales sighted were all following the coastline along their northbound migration. The Gray Whale pair sighted on April 14, approached and stayed alongside this quiet sailboat for several minutes. Sometimes the whale's misty blow lands on a passenger. Most people describe whale blow as having a fishy smell. Why do you suppose that is?
The RACHEL G reported six mother & calf pairs as well as three single whales. One mother Gray Whale was particularly large, estimated at 45 feet in length. April 14 was a particularly good day on the RACHEL G. First, a single Gray Whale approached within 30 feet of the vessel and the excited passengers. Later that day, a mother & calf pair were spotted in kelp beds only 10 feet from shore, surrounded by energetic Bottlenose Dolphins. This vessel also had a notable sighting on April 21, about 2/10 mile off-shore, when a very active calf spyhopped twice and rolled around showing his pectoral fin; then the calf and nearby mother continued steadily travelling along the migration route."
But watchers didn't have to be on a boat to see whales up close. During the mother & calf migration, shore-based sightings are common. "One notable mother-calf sighting occurred on April 17 when the pair rolled around in a near-shore kelp bed, displaying their pectoral fins, flukes, heads, and bodies. They continued this behavior for over 30 minutes. Sometimes Gray Whales use kelp to hide from predators, but no predators were reported in the area. Mother & calf pairs also use kelp as a place to nurse. We cannot say with certainty why this pair was in the kelp," said the volunteers. "What do you think?"
The Ice and Calf Connection
In this season's reports, we've been exploring the ice and calf connection by studying the work of Wayne Perryman. To summarize, the summers of 1998 and 1999 were the key feeding years for the 1999 and 2000 migrations. In both 1998 and 1999, the spring ice was late departing from key areas of the Bering Strait. This might have had a dramatic impact on the whales by shortening their feeding season and launching them on their migration in a much weaker condition.
In 2000 and again 2001, the ice retreated earlier, perhaps offering better feeding opportunities. Will 2002's spring counts bring any answers? As the cow/calf counts keep coming, we're about to find out!
Baby Boom: Good News About Cows and Calves
Wayne Perryman reports: "Based on the distribution of ice last summer, we predicted that this year would show a recovery in calf production after three consecutive very low years. Looks like we hit it right on the head. Last week we counted as many calves (87) as we counted in all of 2001. Calves and cows look good and robust. We are probably just past the peak of the migration and things should start slowing down a bit. Expect that this year's final count will end up right near the middle of the 9 surveys." Do you think Wayne Perryman's study will count twice as many calves as last season? Stay tuned!
The migration of cow/calf pairs has been in full swing with, according to ACS/LA Census Director Alisa Schulman-Janiger. "Our cow/calf counts are going great! At 37 northbound pairs (including 6 today, April 19), we have spotted more cow/calf pairs to date than 13 out of the past 18 years; we have already passed the northbound calf SEASON TOTALS for 7 of those years! Our cow/calf migration generally peaks around 22 April (very different from last season's late migration)!" Is 2002 shaping up to be a good recovery year after three low seasonal counts? Or is this an early cow/calf migration? Alisa says, "We will know the answer soon, if the wind and the fog stay away!"
Counting Whales
The biggest day at the Piedras Blancas census was on 16 April (15 calves). How does that compare with the biggest days for the ACS/LA census at Long Point? Take a look at the data from the official census of the American Cetacean Society near Los Angeles:
Then come back and answer:
Challenge Question #21:
"What was so unusual about the sightings from ACS/LA census on Earth Day, April 22? What were the two biggest days for cows/calves going north?"
(To respond to this question, please follow
the instructions below.)
What Direction? Discussion of Challenge Question #16
Last time Kate Wynne reported at least a dozen grays passing Long Island (near city of Kodiak) on April 10, mostly groups of 2-3. Some were very near shore, taking their time but heading 'north' (actually south, down the east side of Kodiak Island). We asked: "Why would northbound whales change direction and head south down the east side of Kodiak Island?"
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Susan Payne describes exactly what happens to explain changes in direction. You'll get the picture better if you look at a good map as you follow her description:
"Gray whales follow the coastline closely during their northbound migration along California, Oregon, Washington, and Vancouver Island in British Columbia. In some areas they are often seen just outside the kelp line. The majority of gray whales tend to cross from cape to cape across large bays like Monterey Bay and, here in Kodiak, across Chiniak Bay from Afognak Island to Cape Chiniak. The main gray whale corridor in front of Sitka is 20 miles offshore. Whales swim along the Kenai Peninsula, passing by Rugged Island and Cape Resurrection. This is where they are often seen by our contacts in Seward. Then, when they cross from the Kenai Peninsula to Afognak Island over open water, they change their generally northerly migration route to a westerly direction across the Kenai Peninsula and to the southwest along Kodiak Island. Some gray whales may swim down the Shelikof Strait instead of on the east side of Kodiak Island. They more or less continue this southwestly direction until they swing northerly through Unimak Pass or through False Pass. The gray whales then actually head east along the north side of the Alaska Peninsula past Nelson Lagoon before they swing north again across Bristol Bay."
Q and A With Lisa Munger: Discussion of Challenge Question #17
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Lisa Munger at Nelson Lagoon School Photo John Concilus |
Iselin Middle School 7th Graders Nina, Hannah and Sara, who read Lisa's interview very closely. They answered: "The two surprising things that Lisa has learned are both about strange occurrences. The first thing is the gray whales [Correction: check again. Lisa said the RIGHT whales] are up in Alaska at least until October, which is later than previously thought. The second thing is that the humpback whales sing in the winter and not just during the breeding season in the summer."
Sea Ice Not Always Nice: Discussion of Challenge Questions #18, #19
Challenge Question #18 asked: "Why is summer feeding better at higher latitudes?"
The answer has to do with photoperiod. Summer feeding is better at higher latitudes because the long days produce lots of phytoplankton (small marine plants), which are eaten by zooplankton (small marine animals). Together, these are the basic food for all ocean life. A lot of plankton stimulates the growth of the marine food web including bottom dwelling amphipods, the primary prey of gray whales.
Challenge Question #19 came from Wayne Perryman, who asked: "Can you name a polar mammal that, unlike the gray whale, feeds more successfully when sea ice is present?"
Correct answers came from Georgia and also from Iselin Middle School 7th graders Nina, Diana, Hannah, and Sara were correct when they answered: "One polar mammal that feeds more successfully when sea ice is present is the polar bear. Polar bears live where it is cold all year long so they would know how to hunt when sea ice is present. They mostly hunt large animals like seals and fish. The only thing is, that the sea ice has to be partially melted in order to catch the fish."
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.
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 #20 (OR #21).
3. In the body of EACH message, give your answer to ONE of the questions above.
The FINAL Gray Whale Migration Update Will Be Posted on May 15, 2002.
Copyright 2002 Journey North. All Rights Reserved.
Please send all questions, comments, and suggestions to our feedback form
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