To: Journey North
From: Anne Smrcina Stellwagen
Bank National Marine Sanctuary
The humpbacks are still down south in the Caribbean. Idelisa Bonnelly de Calventi of the Comision Rectora Santuario de LaPlata (Silver Bank Sanctuary) of the Dominican Republic sends her regards to all Journey North participants.
She reports that the Sanctuary has instituted a special mooring area for whalewatching boats this year, due to the increased popularity of this ecotourism location, which is quite a distance off shore from the Dominican Republic's mainland. The Silver Bank Sanctuary has also designated an agent to observe the whalewatching activities.
In Samana Bay, an in-shore whalewatching spot, Idelisa reports that 20 different whales have been spotted along with 5 newborn calves. In addition, some competitive groups have been seen, and according to Idelisa "this means that we may have more whales for the next year", because competitive groupings usually indicate mating activities.
CHALLENGE QUESTION #19: Why would humpback whales go to the Caribbean to have their calves?
In answer to last week's question about water temperatures off the Virginia coast , I received the following responses from students:
Students from Mrs. Schaum's class t2busy@aol.com said "We think that the average water temperature off the Virginia Coast is 39.2 degrees Fahrenheit. Mrs. Sorrentino's fifth grade class at Holy Trinity Episcopal Day School sharons@umd5.umd.edu in Bowie, Maryland also sent us a response, and they think "that the average temperature of the water off the coast of Virginia is about 60 degrees Fahrenheit. 4 degrees Centrigrade is about 39 degrees Fahrenheit"
For the full information on the water temperature question, I spoke to Sean Bourgeois of the Virginia Marine Science Museum. Sean reports that winter water temperatures have been significantly lower in 1996 and 1994 than other years and both these years have also had very low whale sightings.
Although water temperatures along the Virginia Beach coast can vary a lot because of influences from the Chesapeake River, there are still very significant differences that can be seen year to year. Sean gives us the following readings based on temperature data from the Virginia Institute of Marine Science's Juvenile Finfish/Blue Crab Assessment Program:
1992 5.32 degrees C
1993 4.85 C
1994 2.28 C
1995 4.45 C
1996 probably at or below 2 C
Now -- how do you convert from Celcius to Farentheit. There's a simple equation that goes: F-32 = 9/5 C.
So -- if Celcius is 4 degrees, F = (9/5 x 4) +32 or approximately 39 degrees F.
Sean reports that water temperatures have been as low as 35 degrees F. What would that make them in degrees C? 4 degrees C seems to be the dividing line for seeing or not seeing whales -- and the deciding factor seems to be prey. The fish the whales feed on move off to where water temperatures are warmer. Sean notes, however, that bottlenose dolphins have been seen lately, which is unusual because these animals aren't known to frequent cold water areas.
It's been a winter with many unusual weather and wildlife phenomena. Let's see what's in store during our journey through spring.
This is Anne Smrcina signing off for this week.
The Next Humpback Whale Migration Update Will be Posted on: March 6, 1996
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