NATURALIST NOTEBOOK 16 JUNE TO 22 JUNE
Sun 24 Jun 2007 - Filed under: Main Page — admin
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On June 16th, the Dolphin VII traveled to the middle of Stellwagen Bank National Marine Sanctuary where we found Pepper and her calf.  Pepper was given a name in 1976 when she was observed traveling with another female humpback named Salt.  Pepper is back this year with her ninth calf that we know of.  Because we first started watching Pepper in 1976, we don’t know how old she is, and it’s quite possible that she was giving birth to calves long before we started to recognize her.  Soon, Pepper and her calf were joined by Roswell and her 2007 calf. 

 

 

            Pepper and her calf                                          Roswell and her calf

 

Leaving these two pairs of whales, we traveled north where we witnessed feeding behavior from both humpbacks and Minke whales!  Although both of these species use baleen to filter small schooling fish like sand lance, herring, and mackerel from the surrounding seawater, they use different strategies to do so.  The Minke whales, which are some of the smallest baleen whales that we find in Stellwagen Bank, charge after prey items, taking off in rapid bursts of speed through patches of food.  Meanwhile, the humpback whales in the area were blowing bubble clouds to corral the same sand lance.  Bubbles scare, confuse, and ultimately trap fish so that the humpback whales can maximize the amount of food they engulf with every mouthful. 

 

On June 17th we were treated to three different species of whale during our midday trip.  We started the day with a whale named Echo.  Echo is named for the marking on the left fluke, which resemble a depiction of repeating sound waves.  Meanwhile, not far away, Scylla, another humpback was logging, or resting, nearly motionless, near the surface of the water. 

 

Soon, we noticed the other species in the area, the finback whales and the Minke whales.

Minke, humpback, and finback whales all belong to a group of whales classified as the “rorquals”.  Rorquals refer to the pleats running down the underside, or ventral side of their bodies, all the way to their navels.  As these whales fill their mouths with food and water, these pleats expand.  This is another adaptation that these whales use to obtain adequate amounts of food from their environment.  The rorquals are also referred to as the “gulp feeders”, because they feed by periodically taking in large mouthfuls, straining water, and swallowing large volumes of fish in one mouthful. 

 

 

Ventral pleats or “rorquals” on the underside of Ventisca

 

 

Ventral pleats expand as the whale feeds at the surface

 

It seemed was obvious that these whales were found in the same vicinity because of the massive schools of fish that could be seen near the surface of the water, and Dolphin Fleet passengers were delighted to watch humpback whales blowing bubbles to trap fish, straining water through their baleen with their mouths wide open so all of us could see the baleen hanging down from their upper jaw!

 

On June 18th, humpback whales, including Echo, Thread, Weave, Firefly and her calf, and Cardhu spent the morning feeding.  Bubble nets and bubble clouds surrounded the Dolphin VII, and our humpbacks filled up on thousands of pounds sand lance. 

 

After feeding during in the morning, the same humpbacks had the energy to engage in other behaviors all afternoon.  Passengers on the Dolphin VIII were thrilled as Ventisca approached the boat, rolled over, and slapped its flipper on the water.  Ventisca is the Spanish word for “blizzard”, referring to the whale’s distinct, bright white dorsal fin.  

 

The evening trip took the Dolphin VIII to whale named Rapier and her 2006 calf, who was also rolling on its back and flipper slapping.  We noted how unusual it was to see this young animal stay with its mother for such a long time.  Generally, a humpback will stay with its mother for a year before they go their separate ways, but this particular calf seems to have gotten a late start.  Those of us who remember seeing Rapier’s calf last year noted how much the pattern on the underside of its fluke had become sharpened.  A mature humpback will have a black and white pattern on the underside of its fluke which identifies the whale as an individual.  However, when calves are first born, this pattern is not as distinct, and in fact, has an almost cloudy or hazy appearance. 

 

 

Rapier's 2006 Calf in the summer of 2006

 

On June 19th  as we approached a pair of humpback whales, all of us on the Dolphin VII exchanged excited looks as we noticed the large, rounded dorsal fin on one of them.  Could it be Colt?  Colt is a male humpback, born in 1981 to a whale named Equus.  We always hope for a visit from Colt on our whale watch trips because he is famous for doing what we call a close boat approach.

 

Most humpback whales, while aware of the presence of the whale watching vessel, don’t spend a great deal of time interacting with the boat.  Colt, however, is a different story. As we moved slowly into the area, shut off our engines, and drifted, Colt appeared right off the starboard side of the boat.  As he exhaled, he thrilled whale watch passengers by making a rumbling trumpeting sound as he sent whale breath drifting across the bow of the Dolphin VII! After swimming directly under the boat, Colt appeared on the port side and lifted hisad out of the water.  Although his eye, located further back on the side of his body, didn’t make it out of the water for a true “spy hop”, it was clear that he was trying to take a closer look at us.  Finally, as passengers peered over the railing, Colt seemed to know it, and he blew bubbles beneath the water with enough force such that they boiled to the surface and even sprayed some passengers!  As it neared the time to leave, Colt rolled over, displaying the ventral pleats on the underside of his body and slapping his flipper on the water.  Having had our fill with us, Colt and the humpback whale accompanying Colt, Shards, finally swam away so that we could safely leave for home.  Certainly, any experience with Colt is one that Dolphin Fleet passengers will not soon forget!

 

 

Colt peers up at Dolphin VII whale watch passengers

 

On June 20th, was gray, rainy, and foggy, and as we left Provincetown Harbor, we knew that we would have to work hard in order to find whales.  As luck would have it, we came across three humpbacks, including Giraffe and Falcon, only an hour into the trip.  As we watched these whales, the fog closed in and we had to listen for the rumbling exhalation of the humpbacks to figure out where they were surfacing. 

 

 

A rain squall over Stellwagen Bank

 

Luckily, the skies cleared enough that we were able to see more spouts in the distance.  As we approached the spouts of what appeared to be humpback whales, we also noticed smaller disturbances near the slick in the water where the humpbacks appeared to be feeding.  As we got closer, our suspicions were confirmed.  Leaping among the feeding humpbacks were Atlantic white-sided dolphins!  Atlantic white-sided dolphins are among the several types of odontocetes which visit Stellwagen Bank during the summer, meaning that unlike the humpbacks, finbacks, and Minkes, these whales have teeth which they use to capture their prey. 

 

 

Atlantic white sided dolphin mother and calf

 

Reaching maximum lengths of only about 8 feet, the size contrast between the dolphins and the surrounding humpbacks, who can reach lengths of over 50 feet, was striking!

 

By June 21st, the fog and clouds had lifted, and bright, clear skies abounded.  Our first stop was by Nile and her calf.  Nile and her calf appeared to have a destination in mind and were traveling in a straight, linear direction.  Although Nile did not show us her flukes by diving, we could easily recognize her by her distinct, hook-shaped dorsal fin. 

 

Leaving Nile and her calf behind, we headed east where we found another group of humpbacks, Anvil, Tear, and Grommet.  Nearby, Cygnus and Sloop were lunging through the schools of sand lance that they had just concentrated by blowing rings of bubbles.  Sloop is named for the marking on his right fluke which resembles a single-masted sailing vessel, or sloop.

 

 

Sloop

 

Later in the trip, we came across Habeñero, a humpback whale born in 2001 to a whale named Pepper.  Having seen Pepper and her brand new calf early in the week, we were excited to recognize the fact that multiple generations of humpbacks can be found around Stellwagen Bank at any given time during the bountiful summer feeding season.

 

On June 22nd, we witnessed the most feeding that we had seen on any other trip that week!  Passengers peering over the railings of the Dolphin VII could see enormous schools of sand lance moments away from being swallowed whole by one of the many humpbacks, including Sloop, Cygnus, Ventisca, and Cardhu, congregating in the area. 

 

One of the benefits of recognizing individual whales is that it has helped us learn that humpbacks favor different feeding styles.  For example, Sloop, a male humpback, has a particularly energetic way of corralling fish, as he uses his chin to slap the surface of the water, possibly for the purpose of stunning the fish.  Then, he will dive through the bubble cloud and lunge through the school of fish, engulfing an enormous mouthful as he resurface to strain the seawater out through his baleen plates.  Meanwhile, Cygnus, Cardhu, and Ventisca blew bubble clouds to trap fish. 

 

Meanwhile, the whales weren’t the only ones enjoying the wealth of food in the area.  Sooty shearwaters, a frequent visitor to Stellwagen Bank, flew low over the surface of the water, causing the fish to leap out of the water in alarm, causing a distinct disturbance visible from the deck of the boat.  Sooty shearwaters, like humpback whales, take advantage of the plentiful fish in the North Atlantic during the summer.  However, the shearwater never experiences a true winter.  The shearwater will cross the equator to nest and breed on the rocky islands off the coast of Argentina during our winter, which is the only time that these birds will spend on land. 

 

 

A sooty shearwater prepares for take off!

 

 

 

 

 


Rapier's calf 2007.jpg
Sun 24 Jun 2007 - Filed under: Naturalist Log Photos — admin
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Naturalist Notebook 9 June to 15 June
Thu 21 Jun 2007 - Filed under: Main Page — admin
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June 9th was a gray day on Stellwagen Bank, it gave forth to an excellent day of whale watching.  On the morning trip we came across Pepper, one of the humpbacks that we’ve been watching since 1976, alongside her ninth calf.  Although Pepper is a grandmother, she is still returning with new calves every few years.  One of the questions we hope to eventually answer by our recognition of individuals is how many calves a humpback whale might have in her lifetime.  Some of our humpbacks have had over ten calves during the time that we’ve been watching them, and it’s quite possible that they’re capable of giving birth to even more! 

 

 

Pepper and her 9th Calf

 

In the afternoon, we came across another mother and calf pair, Perseid and her calf.  Perseid’s calf surprised us all by leaping out of the water right next to the Dolphin VIII.  While we still are unsure of why whales breach, in the case of Perseid’s calf, it may very well have been some sort of play behavior.  It’s typical for mammals to play by practicing behaviors that they will later use as adults, and as Perseid’s calf breached repeatedly, we were given an excellent opportunity to puzzle over why an adult whale might use this behavior.

                                               

 

 

Perseid's calf breaches

 

 

Perseid and her calf approach the boat

 

On June 10th  we were delighted to see a humpback whale named Regulus back in Stellwagen Bank, particularly as Regulus was an object of major concern several years ago, having been entangled spotted entangled in fishing gear.  Regulus has since shed the gear, but he serves as a reminder of many of the perils that our whales face, even in national marine sanctuaries like Stellwagen Bank.  It’s estimated that over fifty percent of humpback whales have had some sort of encounter with fishing gear, whether or not it has resulted in a long term entanglement.  Entanglements can impair a whale’s ability to feed and breathe, and the presence of lines on a whale’s body can cause infection and injury if it remains on the body.  We are always sure to carefully photograph whales that we know have been entangled in the past to make sure that they are recovering from their entanglement experience. 

 

 

 

Regulus' dorsal fin

 

June 11th  brought us to a number of humpbacks, including a whale named Tongs, who treated us to very close looks, even fluking right off the bowsprit.  At this point, the passengers were able to grasp the expansive width of the fluke, which sometimes reaches a fifteen foot span! 

 

Another highlight, particularly for the birdwatchers on board, was the return of one of our most common winged visitors to Stellwagen Bank—the Wilson’s storm petrel.  We often marvel at the length of the humpback whale’s migration, but the petrel has an arguable more impressive winter jaunt, traveling to islands off the coast of South America to nest and breed.  This is the only time that these birds spend on land.  The petrels are also notable for their diet.  While most birds in Stellwagen Bank are feeding on the same small schooling fish that our humpbacks eat, the diet of the petrel is more comparable to that of the North Atlantic right whale.  Both of these animals, one weighing a mere few ounces, the other weighing sixty tons, acquire their nutrients from tiny pieces of zooplankton in the form of copepods, which are shrimp-like crustaceans the size of a flea.  To many people, the return of the petrels to the North Atlantic signal the fact that summer is really here. 

 

On June 12th, our first sighting was a Minke whale.  Minke whales are small for baleen whales.  They can reach lengths of thirty feet, but in Stellwagen Bank, many of them are significantly smaller.  In fact, most of the Minke whales in the Gulf of Maine are thought to be juveniles.  Minke whales can be easily overlooked by whalewatchers because they are very fast and elusive, and don’t tend to spend the same amount of time engaging in surface behaviors as humpbacks, for example, do.  However, this particular Minke whale proved us wrong and shocked everyone on the boat by breaching!

 

 

Breaching Minke whale

 

Rougher seas and windy weather seem to elicit more breaching from Minke whales.  While humpback whales can be observed breaching in most any kind of weather, Minke’s are rarely seen in this type of behavior.  This leads many researchers to believe that maybe breaching is a way for these whales to make sure that they get themselves far enough out of the water to breathe on windy days.  Perhaps it helps them to move through stormy seas more efficiently also.  Either way, those passengers who witnessed the breach will not soon forget the sight of the torpedo-shaped whale launching itself through the waves.

 

June 13th was too stormy for whale watching, but by June 14th, Dolphin Fleet passengers were ready to brave the seas, and our passengers were treated to two species of baleen whales on our noontime trip.  Our first sighting consisted of one or two finback whales, which are the second largest animal on the planet.  After grabbing a few looks at the finbacks, we came across Lace, a humpback whale, who was fluking and displaying the lace-like pattern on the underside of her fluke. 

 

The afternoon trip brought us to many more humpbacks, including Photon and her calf. 

We also came across a humpback whale named Tofu.  Tofu was named for the almost all-white pattern on its fluke.  Tofu is two years old and was born to a female named Isthmus.  In the rough seas, Tofu appeared to be fighting against the surf at the surface of the water. 

 

 

Tofu in rough seas

 

By June 15th the wind had died down a bit but the seas were still churning.  Luckily, we were able to find active humpbacks in their usual stomping grounds.  Perseid and her calf started off the day by breaching several times, much to the delight of Dolphin VIII passengers.  Later, Milkweed and Falcon were observed traveling together.  Finally, we came across a humpback tail breaching.  When a whale tail breaches, it throws its tail out of the water and slams it back onto the surface of the water.  While we were able to identify most of the other whales in the area that day, including Dash Dot, Garland, and Thread, there were others whose identities remained a mystery.  If these whales remain unidentified and they continue to return to Stellwagen Bank in subsequent years, they will most likely receive names.  Until then, we will add them to our growing list of individual humpbacks who are using the vast productivity of Stellwagen Bank to feed.