Whales off Cape Cod

Posted byontheroadwithdecPosted inMarine Mammals

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It was mid-June and the ocean water had warmed to about 64 degrees in the inner bays, but it was still in the mid-40s when we arrived off Monomoy (Chatham, Massachusetts) near Crab Ledge and there was a real chill in the air. It may have gotten into the high 70s and low 80s on the mainland on Father’s Day but it was damp and chilly out on the ocean. We were about 18 miles east of the sand spits that make up the Monomoy Islands; an ever-changing collection of sandbars and dunes reaching down to the south of the Cape Cod’s elbow.

The boat trip was arranged by Krill Carson of the New England Coastal Wildlife Alliance (NECWA). She does two of these outing each year, June and September, as fundraisers for NECWA. The fundraising may be modest but the educational value isn’t. We have seen and identified many whales over the years and have added a great many pelagic bird sightings as well. Sharing these opportunities with interested folks is a real treat. This year it was Wayne Petersen, Tom Robben, and me on the microphone; though Krill and her interns were very adept at working the great feeding displays of Humpback Whales that we saw. (We saw the old lady of whale-watching out there – Salt is an animal that was first seen back in the 1970s and is known to have at least 14 offspring!)

Krill does a great deal of work with ocean Sunfish (Mola mola) and her website is well worth visiting. The fall trip will be out of Gloucester, Massachusetts this year, a great time for both sea birds and marine mammals.

Most years there are lots of Humpback Whales along the coast of Massachusetts in the summer. Tourism depends on them as they attract people like magnets attract iron filings. In 2019 they share the spot light with Gray Seals and Great White Sharks; but the whales are much more easily seen than are the sharks. Seal tourism is modest but whale-watching is big business.

Humpback whales are rorqual whales – meaning they have a pleated throat that expands greatly when they take in sea water – hopefully sea water filled with fish or krill. In the image above the whale has its top jaw open and extending upward (fringed with baleen) as the animal rises through the water taking in a gullet-full of water filled with Sand Lance (Launce). The smooth water to the right of the image is the surface water held in the expanded pleats. The whale will swim forward pushing the water up and out of the pleats while the top jaw closes and a filter of baleen allows the water to leave but constrains the food. The water is expelled and the fish remain in the mouth.

Our boat ride was a bit testing for the first hour or so. No one seemed to be ill and that is always a good thing. There is nothing quite as contagious as sea sickness on a smallish boat. We looked around as we traveled and had very little to talk about. There were a few gulls and terns and a Common Loon as well. But when we found whales there was a great deal of activity. We couldn’t decide on a number for the humpbacks (on the way back in to port) but the most conservative number was forty. There could have been sixty whales in our view! It was very impressive.

The best part was that they were bubble feeding in many small groups. Several whales would get together and dive, shallow dives as they were not down for more than a minute or two in most cases, and when under water they would exhale streams of small bubbles as they swam in a circle. This created a rising tube of bubbles that constrained the fish that were enclosed in the “bubble net”. The whales would then turn and rise through the water inside the bubbles, expanding the rorquals and collecting a throat-full of fishy water. When two or three or four or five whales do this at the same time it is very cool.

Here six whales emerge from a complex of bubble nets. They are leading the way upward with the open tip of their top jaw. The baleen is arrayed along the outer edge of the top jaw and will close down over the lower jaw to keep the fish inside as the water is expelled. The gulls are hoping to catch fish as they jump out of the mouths of the whales. It may seem an odd life style for the birds (and perhaps the whales as well) but it seems to work very well.
The bubbles are often dispersed by the wind and surface action of the ocean and are difficult to see. While other times the ocean and wind, and the way the whale releases the air, allows them to be easily seen. There is a similar patch, only of smooth water, that a diving whale can make by flexing its tail as it dives. The circle pictured above is caused by bubbles; the other type (called a “footprint”) is caused by water rising after the whale exerts upward pressure as it dives.
One of the world’s most abundant birds is the small Wilson’s Storm-Petrel. It is pelagic, oceanic; coming ashore to only nest. They nest in the talus rocks of the Antarctic continent and the young are fed until they nearly burst. When they are twice as heavy as the adults and still without real feathers, the adults stop feeding them and head north starting a long migration up to the Gulf of Maine, then over to the European Coast and finally back down along Africa to Antarctica again. The youngster turns his oily fat into muscle and feather and walks to the edge of the rocks and starts north itself – about two weeks after it parents abandonded it. Some years we see hundreds of them other years just a few – it all depends on where the food is.
There is another group of sea birds called shearwaters. Graceful in the air and unafraid of the stormy ocean these birds travel a great migratory circle also. The bird above is a Great Shearwater one of our more common types. We often see Sooty, Manx, and Cory’s Shearwaters as well as the Great. They all have a hook on the tip of the beak to help snag fish and squid.
In addition to the Humpback Whales we had several Fin Whales and Minke Whales. The Fin Whale is a long sleek whale of great size where the Minke Whale is a small whale that rarely fully shows itself and mostly just darts about. We came across a group or two of White-sided Dolphins out there as well. The two animals pictured above were part of a group of 20-25 that hung around with us for a while.

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