To: Journey North
From: Anne Smrcina
Stellwagen Bank National Marine
Sanctuary
Plymouth, Massachusetts
Greetings from Stellwagen Bank --
Word from Florida is that there has been only one sighting over the past week -- again its Aprodite and her calf, this time off Flagler Beach on March 25.
The U.S. Navy has funded an extension of the survey season to allow coverage through April 14. According to Chris Slay, "This should provide more information to support our belief that most, if not all, right whales have departed the calving ground by April." Some of the flights will be conducted over offshore waters in conjunction with Navy exercises, allowing the research team to cover areas that have rarely been surveyed.
The Center for Coastal Studies continues its work in Cape Cod Bay, sending teams out almost every day (depending on weather). A summary of the season-to-date indicates that at least 40 different whales have been seen, but only one mother-calf pair so far. The researchers usually see about 20 whales per trip. They have also sighted a few harbor porpoises.
The whales, when sighted, are often involved in social behavior or feeding. That gets us to last week's challenge question about whale feeding behaviors.
Whales seen here in Cape Cod Bay are usually feeding on copepods (small crustaceans that look like tiny shrimp with large antennae). The largest of the copepods (but still very small), Calanus finmarchicus or Cal fin, is the right whale's favorite food, although they also eat other types of copepods including Pseudocalanus.
These copepods do not stay in one place in the water column, however. Unlike phytoplankton which stay close to the surface, the copepods migrate -- down during the day and up towards the surface in the late afternoon and evening.
Cape Cod Bay is very shallow (deepest depths are in the 200 foot range, and most areas are much less). Therefore, copepods may reach the surface late in the day where surface feeding or skim feeding may occur. During mid-day, the whales usually have to dive for their food. When the whales move on up to the Bay of Fundy later in the summer, depths are greater (600-800 feet), the copepods usually don't make it to the surface, and skim feeding is rarely seen.
And here's today's CHALLENGE QUESTION. We've been discussing whale activities, but how do these recharge their batteries?
Challenge Question # 66:
"Do whales sleep? And if they do, how do they sleep in the ocean without drowning? "
Until next week, this is Anne Smrcina signing off.
How to Respond to Challenge Questions #66:
1. Send an e-mail message to jn-challenge@learner.org
2. In the Subject line, write: Challenge Question #66
3. In the Body of your message, answer the question.
The Next Right Whale Migration Update Will be Posted on April 10, 1996.
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