Humpback Whale Migration Update: March 12, 1997

Center for Coastal Studies

Hello from the Stellwagen Bank National Marine Sanctuary --

No word yet on humpback movements up northward -- it's still a bit early for that. In fact, Oceanic Society Expeditions is sponsoring a cruise to Silver Bank (Dominican Republic) next week to watch whales in those warm, southern waters. They are expecting to see large numbers of adult whales as well as many females with calves from their live-aboard vessel. I'm hoping to have a report from them for my next humpback whale report on March 26th.

I do have word from Newfoundland about some humpbacks that have decided to forego the winter migration. This seems to be a regular event -- in which some humpbacks decide to spend their winters feeding on arctic cod and herring along the northeast coast of Newfoundland. These "Christmas" whales, as they call them in Canada, herd the small fish into coastal bays. Jon Lien, a whale researcher from Memorial University, reports that it is not uncommon to see whales feasting on small fish that they pin along the town wharves. The bays where most of this activity is happening are: White Bay, Notre Dame Bay, and Bonavista Bay in Newfoundland.

Thanks to all the students who sent in answers to Challenge Question # 2 about upwelling "What is "upwelling" and how does upwelling affect the ocean food chains?"

• Click Here to See Students' Answers to This Question.

Students at Iselin Middle School in New Jersey (ims@gorgon.com) explained it this way:

"Upwelling is the movement of deep cold ocean water to the surface. It brings nutrient rich waters to surface. It effects food chains by bringing more food to the surface so organisms in that area have more food. Plants using these nutrients will grow, the herbivore has food, and the small and large carnivores also will eat."

Upwelling is extremely important to the marine food chain. Let me provide some background. In the ocean, animals live and die. Their waste products and bodies (after they die) sink to the ocean floor, where they are decomposed by bacteria and transformed into basic nutrients, such as phosphates and nitrates. These materials are needed by photosynthetic organisms (plants, protists and some bacteria) for growth. In turn, small floating animals called zooplankton eat the phytoplankton. Zooplankton are eaten by small fish, jellyfish, filter-feeding crustaceans and mollusks and many other creatures (including some whales like the right whale), these small animals are eaten by larger animals (including some whales like humpbacks), and large fish are eaten by sharks and orcas. But how do the nutrients get from the ocean floor to the surface in the first place?

The answer is upwelling -- a movement of deep, nutrient rich water to the surface. In a global picture, most upwelling takes place along the western edge of continents. Winds cause surface waters to move offshore, allowing deep water to flow upwards to take its place.

Other forces can also cause upwellings. In the book "From Cape Cod to the Bay of Fundy: An Environmental Atlas of the Gulf of Maine" it is reported: "Upwellings can also occur in inshore areas with strong tidal surges, as well as where currents force deep water over shallow offshore banks." Stellwagen Bank is one such example. When underwater currents encounter an obstruction, the water has to flow somewhere (it cannot be compressed). The only place for this mass of water to go is up. As the rich water settles on top of the bank it provides the nutrients needed by the base of the food chain. Upwelling areas around the world are rich in marine life -- and are usually important feeding grounds for whales.

Here's a Challenge Question for next time.

Challenge Question # 3
"Humpbacks are known as the acrobats of the ocean, often seen breaching (jumping out of the water), and flipper and tail slapping. For what purpose are these actions?"

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

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

1. Address an e-mail message to: jn-challenge-hwhale@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:

Challenge Question # 3
"Humpbacks are known as the acrobats of the ocean, often seen breaching (jumping out of the water), and flipper and tail slapping. For what purpose are these actions?"

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 reports. She will provide updates on alternate weeks. They will be posted on the following WEDNESDAYS: 2/5, 2/12, 2/26, 3/12, 3/26, 4/9, 4/23, 5/7, and 5/21.

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