Hi from the Stellwagen Bank National Marine Sanctuary
We received a few reports this week (but nothing yet from Silver Bank -- so I can't tell you whether or not the humpback whales are singing in full voice). However, we do believe that the numbers down there are increasing (not only with migrants but with births of new whales). I hope to have some exciting news for next week's report.
Was anybody able to answer the question about why northern waters are important feeding areas? Humpbacks mate and give birth in the warm tropical waters -- but don't do any eating down there (except for the calves who nurse). But they do a lot of eating up at Stellwagen Bank and the Bay of Fundy in the Gulf of Maine. They feed on small fish, such a sand lance, herring, capelin, and other small creatures like shrimp, krill, and even squid. The answer includes the following key words: nutrients, oxygen, upwelling, mixing, sunlight. More on this next week.
The Virginia Marine Science Museum reports that several humpbacks have been seen over the past few weeks (Jan. 23 - Feb. 6). On daily whale watching expeditions, they have been spotting from 1 to 3 whales a day (but whether they are the same individuals or all different is not yet known (it may never be known). They believe most of these whales are about 30 feet long which would make them juveniles -- not yet sexually mature (so probably not very interested in joining in on the mating rituals down at Silver Bank). Perhaps that's why they're at Virginia Beach for the winter rather than the Caribbean. More on this in another report.
In addition to reports from the east coast -- I'll also have some material for you from two other National Marine Sanctuaries in the Pacific. The Hawaiian Islands Humpack Whale Sanctuary reports that mating and calving are now underway at their location. These whales will leave in the spring for their Journey North to Alaska.
"WHALES HO" by Dr. Peter Craig, Dept. Marine and Wildlife Resources, American Samoa (the following article from the Samoa News, dated September 7, 1993, was sent to me by our Fagatele Bay National Marine Sanctuary in American Samoa in the South Pacific.)
The whales have returned to Samoa. September and October are the peak months when humpback whales (tafola) visit our balmy waters.
It's almost impossible not to get excited when a whale is spotted, and most of us feel inexplicably privileged for a brief glimpse into their mysterious world....Part of our fascination with whales is their huge size, of course. Adult humpbacks grow up to 50 feet long and weigh about 40 metric tons (which equals the combined weight of 200 sump wrestlers).
Humpbacks eat small schooling fishes and krill (small shrimps). They feed by sucking in tons of water in a single mouthful, and then strain the food as they expel the water. The out-going water is filtered through specialized structures called "baleen," which looks (with a little imagination) like a mouthful of coconut fronds.
The appearance of hump backs in Samoa is an important segment of their grand migration up and down the South Pacific Ocean. During the warm months of the southern hemisphere, Samoa's whales feed in the rich waters of Antarctica, located 8,000 miles to the south of us (Samoa). Biologists call this particular group of whales the "Group-5 Antarctic stock."
When the bitter winter sets in down there, the Group-5 whales seek warmer water. They migrate northward, with some going towards Australia and other migrating towards Tonga. Apparantly most of this latter group remain near Tonga, but at least some migrate onward to Samoa.
A few humpbacks might arrive in Samoa as early as July or leave here as late as December, but they are most common here in September and October. They occur in small groups of adults or in mother-calf pairs. Humpbacks have been sighted around all 7 of the islands in the Territory, but we don't know how many are actually here.
[This is Anne now -- Hawaii reports the same findings -- except even greater numbers. But because there are several islands, it is very difficult to count individual whales. American Samoa reports that all of the whales have left for Antarctic waters -- none left. Now -- back to the article]
They migrate here to mate and give birth to their young. And, interestingly, they stop feeding while here -- only when they return to the Antarctic do they resume feeding.
Humpback whales are currently listed as an endangered species because their world-wide populations were decimated by whalers in the 1800s and 1900s. By the time commercial whaling was stopped in 1963, 95% of our stock (Group-5) had been killed.
Recovery of Group-5 has been unexpectedly slow, perhaps because a subsistence harvest of these whales occurred in Tonga as late as 1978. In any event, our whales remain in very low numbers, and in some years hardly any are seen here.
That's all for now. I'll be reporting in again next week.
Anne Smrcina Education Coordinator Stellwagen Bank National Marine Sanctuary