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Right Whale Migration Update: April 29, 1998
Today's Report Includes:
- Latest Migration Data
- Precious Cargo in Shipping Lanes
- President Clinton Sides With the Whales
- Right Whale Express: Answer to Challenge Questions #4
To: Journey North
From: Anne Smrcina
Greetings from the Stellwagen Bank National Marine Sanctuary.
It looks like the right whales are on the move -- it's just
that we don't quite understand why they're moving the way they are. As they have in past years, most of the whales
have left Cape Cod Bay (although #2158, a young male born in 1991, still seems to be hanging out there, and there
may be some other stragglers too). Over the past few weeks whales have been spotted at various locations.
We know that historically whales were found all along the Northeast coast. Long Island and Cape Cod had profitable whaling stations in Colonial days. It may be that the whales have always gone in regions where they've recently been sighted, but we are only now keeping an eye out for them. Perhaps their numbers were so low in past decades that they just didn't have enough individuals to get to these places regularly.
Precious Cargo in the Shipping Lanes
While it's interesting to hear about all of these new sightings, there is some concern about the positioning of these whales. Very often they are found directly in--or quite near--today's active shipping lanes. And collisions with ships is the greatest known cause of right whale deaths.
Why do the whales use the Great South Channel area when there are so many boats there? Ships use the channel because it has deeper water than the areas just to the east (Georges Bank) and west (Nantucket Shoals).
The whales also use it because of the area's wealth of food, due to its geology and physical oceanography.
Take a look at a map of the Atlantic off the Northeast coast. The last two sightings I have from April 22 are:
- 41 30N 69 21W
- 41 10N 69 13W
Both of these positions are near the 50 fathom contour line (a fathom is 6 feet). If you look at the bathymetry
of the area you can see that there is a big "V" shaped section of deeper water between Nantucket/Cape
Cod and Georges Bank in the Gulf of Maine. Scientists call this "V" a "frontal boundary zone."
These fronts can have active transport of water -- with upwelling and
downwelling taking place. It's an area where masses of zooplankton can get concentrated by the meeting of two
types of water. Here, the deeper waters of the Gulf of Maine (the open part of the "V") get stratified
-- with warmer water staying at the top and colder water staying below with little mixing. The shallower waters
south of the point of the "V" are more easily mixed and are generally colder. Where these warmer northern
surface waters and colder southern waters meet is where the whales are often found -- skim feeding on the collected
copepods. The Great South Channel leads right up into the point of this V-shaped" frontal zone.
Whales have used these waters for eons -- long before man put boats in the water. These animals are not adapted
for flight from large "predators" since they have no real enemies. Therefore, it is up to us to look
out for them, and avoid situations that could lead to collisions.
President Clinton Sides With the Whales
President Clinton has recently backed environmentalists in that regard. On April 23rd he approved a plan (opposed by the Navy) that would require large commercial vessels entering Cape Cod Bay and the Great South Channel to signal ahead to the Coast Guard and announce their entry into these critical whale habitats. It also applies to the southern critical habitat off Georgia and Florida. The proposal has been sent to London for approval by the International Maritime Organization. This reporting system would allow the ships to receive updated information on the known positions of whales, and hopefully prevent future collisions.
"We believe this reporting system is essential if we are to ensure the survival of these majestic creatures," said President Clinton. If approved by the IMO, the mandatory reporting system will begin next year.
Right Whale Express
Answer to Challenge Questions #4
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Migration Route of North Atlantic Right Whales |
If you used the distance calculator on the WWW you'll find that the mileage as the crow flies is 1,109 miles or 964 nautical miles (a nautical mile is 1.15 miles). The answer would be 38.5 days.
Until my next report, this is Anne Smrcina, education coordinator of the Stellwagen Bank National Marine Sanctuary signing off.
The Next Right Whale Update will Be Posted on May 13, 1998.