Humpback Whale Migration Update: April 25, 2001 Today's Report Includes: Greetings From Stellwagen Bank National Marine Sanctuary Sad News About Boston's Popular "Inland" Humpback Humpbacks in Cape Cod Bay Gannets Signal Schools of Food: Challenge Question #17 Stellwagen's Most Important Bait Fish Magnificent Marine Mammal Vocalizations News Flash - Athens, Greece: Challenge Question #18 How Many Calves Born to Mural? Discussion of Challenge Question #15 Knobby Heads: Discussion of Challenge Question #16 Greetings from the Stellwagen Bank National Marine Sanctuary. Courtesy of Thomas L. Conlin. Humpbacks are here in great numbers! Food supplies are plentiful this time of year and we have sighted numerous mother-calf pairs both in the Cape Cod Bay and further out in the Great South Channel. The big news last week was the death of Inland, a juvenile humpback that was sighted often this past fall and winter in the waters near the shore of the Bay. Sad News About Boston's Popular "Inland" Humpback Throughout the Fall of 2000, The Whale Center of New England reported on a young humpback whale, ultimately named Inland, that had been making its way in and out of harbors between Boston and Gloucester. Journey North also reported Inland's sightings this season. Now we hear sad news about this popular and often sighted whale. Inland was found dead off the Virginia coastline in April, apparently the victim of an entanglement in fishing gear. The animal was found floating 500 yards from the shore of Virginia Beach with pieces of gill net wrapped around its head and tail. She was one of at least three humpback whales to die off the east coast during April, 2001, the other two whales also had serious entanglement scars. Migration Route of Atlantic Humpback Whales Map courtesy of MacalesterCollege New whale-friendly gear regulations approved for New England fishermen earlier this year might have saved this young humpback whale. Earlier this year, on advice from the team, the fisheries service required New England fishermen using gill nets and lobster trawls to modify their gear by installing weak links in their float lines. The links, or thinner pieces of rope that are placed every 50 feet in a line, allow the whales to break free if they become tangled in the gear. But the fisheries service did not pass the same rules for mid-Atlantic fishermen despite the fact that young humpbacks are known to spend the winter months feeding off the coast of Virginia and the Carolinas. Inland was one of these young humpbacks, probably about a year old, that stayed in the northern feeding grounds this past winter. The 30-foot animal was dragged to the shore near Virginia Beach, examined and then buried in sand to hasten decomposition. Read the news-breaking article for yourself by visiting: The Gloucester Daily Times Because the right whale is an endangered species there are many governmental regulations involved with custody of a dead body. National Marine Fisheries Service is in charge of the endangered species act and is responsible for the dead whales. The New England Whale Center applied to the NMFS for the skeletal remains, and was given this whale and was granted permission for its display. The Whale Center will dig up the huge carcass and find a new place in Massachusetts to decompose the body. The body is left to decompose by natural decomposers, either under the earth or in an enclosed sieve in the ocean. This process usually takes about a year. The skeleton will eventually be displayed by the Whale Center. Humpbacks in Cape Cod Bay There are many more sightings now as the humpbacks return to their summer feeding grounds. The Center for Coastal Studies keeps a list of humpbacks they have sighted this season. To see who has shown up, take a look at the list of names spotted in 2001. Do you recognize any of these names? Visit the CCS to learn who has been spotted in and around Cape Cod Bay this season Recently, scientists from the Center for Coastal Studies boarded the research vessel Gannet and headed out to sea. On April 11th,the aerial survey team sighted some humpbacks on the ocean side the Cape Cod Bay. With this information, and a relatively calm day, the CCS team headed out of the bay and found Jumanji (the 1999 calf of Dyad), Flounder (the 1997 calf of Vulture) and Nucleus traveling together searching and lunging for food. Circling high above as a telltale sign that fish were in the area, the researchers spotted a group of northern gannets scouting out some prey. Gannets Signal Schools of Food Gannet Photo Courtesy of the Center for Coastal Studies. Gannets are the largest seabird in the area with a wingspan of over 170 centimeters (6 feet). Classified in the Pelican family, these birds share characteristics of the family: flexible throat flap for holding quantities of fish, and webbing between all four toes of the feet. These large birds cover great distances. Soaring high, these sharp sighted birds look for fish. With eyes located near the front of their heads, their keen eyesight allows them to find schools of fish from high above the ocean surface. Their long pointed design gives them speed and superb diving ability. When they spot fish they tuck back their long wings and dive straight down into the water for their prey. Air pockets in their skull and necks cushion the impact when they hit the water at great speeds. Once under water they grab at the fish and bring them to the surface to eat them and rest between dives. Challenge Question #17: "The northern gannet is only one bird in the Pelican family. What are some other birds found in this family?" (To respond to this question, please follow the instructions below.) Stellwagen's Most Important Bait Fish Sand Lance Photo Courtesy Anne Smrcina,SNMS Sand Lance (Ammodytes americanus) may be the most important bait fish on Stellwagen Bank. Averaging 15 centimeters, or about 6 inches long, their skinny bodies and sharply pointed jaws allow them to dive into the sand at the bottom of the bay to hide from predators. This habit gives them their nickname, "sand eel." Their long, skinny bodies allow them to wiggle up or down easily so they can follow their favorite food, copepods, as they migrate up and down in water columns throughout the day. Thousands of these fish make up a school which moves in the water in search of food. They can often be seen swarming at the surface, their keen vision allowing them to snap up tiny copepods with their sharp jaws. Very few marine mammals will pass up on the opportunity to feed on a school of sand lance when they are found at the surface. Humpbacks will happily munch on large mouthfuls when given the opportunity. Magnificent Marine Mammal Vocalizations We have so much to learn from this magnificent marine mammal. Although their marine habitat creates some challenges for study, humpback vocalizations have been recorded and studied extensively. And it is fascinating to learn about what has been discovered! The humpback whales' song is probably the most complex vocalization in the animal kingdom. The song, which is made up of repeated themes, can last for up to 30 minutes and some humpbacks sing for hours at a time! The songs are composed of low and high frequency sound waves. Some are so low that they can not be detected with the human ear. Did you know that whale songs travel really far underwater? Would you believe a humpback's song can travel up to 10,000 miles? Learn more about this magnificent creature's songs. Link to Singing Humpbacks News Flash - Athens, Greece International news report published April 19th in the St. Paul Pioneer Press, documented a rare sighting of a young humpback frolicking in the sea off southern Greece! The report cites, "whale experts scrambling to document the visit of the wayward wanderer." There have only been a few reports of humpbacks passing through the Strait of Gibraltar to enter the Mediterranean. "The humpback, measuring about 35 feet, is estimated to be about 4 or 5 years old and appeared to be in good health," said marine biologist Emilia Drouga, who heads Delphis, the Greek Society for the Study and Protection of Dolphins and Whales. Pull out your atlases and find the western opening to the Mediterranean Sea. It would seem that the odds are rather small that a whale could find its way into the Strait of Gibraltar. What can you find out about that narrow opening? Challenge Question #18: "The Strait of Gibraltar is a rather narrow opening into the Mediterranean. How wide is the opening and what is its greatest depth?" (To respond to this question, please follow the instructions below.) How Many Calves Born to Mural? Discussion of Challenge Question #15 "What is a possible calving history for Mural that incorporates the known sighting history (Hint: on average humpbacks calve every 2-3 years.)?" Thanks to Jenny Fleming who estimated that Mural may have given birth to up to 7 calves in her 22 years. Here is what Anne Smrcina shared with us: "Mural may have a calf every three years (on average humpbacks calve every 2-3 years) and may bring her newborn to Stellwagen Bank very early in the season (as she did this year). By the time traditional whalewatching starts in mid-to-late April, she may have already departed with her calf to other feeding grounds (we'll see if she sticks around this year). In the years she doesn't have a calf, she seems to stick around later into the summer. So, she could have had quite a few calves over the past 22 years - if she started having babies at 5 or 6, she could be up to as many as 5 or more calves by now." Knobby Heads: Discussion of Challenge Question #16 "What are the knobby structures called 'stove bolts' by Yankee whalers, and what is their purpose?" The knobs on the humpback's head were once called 'stove bolts' by the Yankee whalers. Scientists call these tubercles (two'-bur-kuls) or sensory nodules. Each are about the size of a golf ball. The tubercles are distributed on the humpback's upper and lower jaws and along the lips in about the same area that facial hair is found on humans. The number of tubercles varies from whale to whale, with each possessing a unique tubercle pattern. Each tubercle contains a hair follicle, sometimes with a single light gray vibrrissa about 0.5 to 1.05 inches long. There is some suggestion that the tubercle acts as a sensory organ, but their exact function is unknown. How to Respond to Today's Challenge Question: IMPORTANT: Answer only ONE question in each e-mail message. 1. Address an e-mail message to: jn-challenge-hwhale@learner.org 2. In the Subject Line of your message write: Challenge Question #17 (or #18). 3. In the body of your message, answer the question above. The Next Humpback Whale Migration Update will Be Posted on May 9, 2001. Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form