Basking shark washes up on shore in Edmunds

by Gail Menzel

    Professor Gayle M. Kraus and 15 of her marine biology students at the University of Maine at Machias had a rare opportunity to dissect something bigger than a frog - a 24-foot basking shark which had washed up on the Edmunds side of the Dennys River just opposite the Dennysville clerk's office. The animal had been sighted in apparent distress on the evening of September 27 off Hinckley Point. The next morning it was found dead on the river bank.
    A large gaping wound on the shark's large conical snout, presumably caused by a propeller collision, apparently disabled its sensory system, causing the fish to lose its bearings, Kraus conjectured. The animal might have suffered a severe infection that, along with severe blood loss, resulted in its death, she added.
   Cetorhinus maximus, as the basking shark is known to biologists, is the world's second largest fish - the largest is the whale shark - and is commonly found near the surface of the water in this region during August and September. In winter, the fish travels to deep water, but little is known of their migration patterns. Kraus noted that a school of about 50 basking sharks was observed this summer off Grand Manan. The animals were breaching, a behavior she suspects was a courtship ritual.
   As plankton feeders, the fish swim with mouths open to filter copepods and other crustaceans, fish eggs and larva through gill rakers. The gentle giants pose no threat to humans; their teeth are numerous but minute.
    The mottled, dark grey individual beached in Edmunds was identified by Kraus and her students as a female, 7.37 meters long (24 feet, 4 inches) and about 4.5 meters in circumference at the widest point. Her dorsal fin was 81 centimeters high and tail 2 meters high. Though she was mature, and the species bear live young, no pups were found in her on autopsy. In addition to the gaping snout wound, she had an old and healed propeller scar on her back. Otherwise the animal appeared to be in good condition.
   The students sampled gills, skin, liver and ovary, and the tissues have been frozen for further analysis as well as for educational use in several courses taught by UMM faculty. If possible, Kraus would like to obtain some or all of the shark's skeleton. Bone testing could help determine the individual's age, and if the complete skeleton could be collected, it would be a prized addition to the university's aquaria exhibit for school children in this area. Kraus was hoping for a volunteer who would haul the animal out on a full tide to a suitable beach where the flesh could decay and the skeleton could be harvested.This story was taken from the Quoddy Tides, October,13, 2000.

Harmless Shark Dies In Dennys River

By Jim Ellingson

    DENNYSVILLE-Last Wednesday, reports of a large fish, disoriented and struggling in the waters of the Dennys River, drew the notice of area residents and wildlife authorities. Thursday, the object of their attention was found dead–a Basking Shark, probable victim of a propeller strike.
    Dr. Gayle Kraus, Professor of Marine Biology at the University of Maine at Machias, said, "The Fish and Wildlife folk got in touch with me [Thursday] to identify what it was ... and , - they wanted -to know what killed it."
   "I'm thinking probably a propeller blade took off its snout ... that would have caused her to be very disoriented. That's where all the sensory-endings are–so they can navigate.
       "I can't think of any animal that would've attacked and not gone back for more–if it were like the great white or the killer whales. They would have finished it off.
    "I think the poor animal died slowly–loss of blood and infection, probably,"
    Basking Sharks (Cetorhinus maximus), are the second-largest living fish in the ocean (after the Whale Shark, which grows to lengths of 50 feet or more) reaching an average length of 22-29 feet (undocumented claims of nearly 40 feet have been reported) and weighing between 4000 - 8000 pounds.
    Unlike its relative, the Great White Shark, the Basking Shark poses little danger to man. Its teeth, nothing like the fleshrippers flashed across the screen in Jaws, are minute and embedded. The shark feeds entirely on plankton, filtering, its food through bristle-like gill rakers.
   Though extensively hunted for its liver, skin, cartilage and fins, many questions remain unanswered about this creature which ranges through most of the world's oceans. It has been the prey of small-scale harpoon fisheries during the 19' and 20th centuries and is currently heavily exploited by harpoon off the coasts of Japan and and China.
    The Basking Shark was declared a protected species in the western North Atlantic by the U.S. National Marine Fisheries Service in 1997.
    Dr. Kraus, and students from her Marine Biology class, took samples and measurements of the huge creature.
   Kraus noted that the shark was a female and that it was carrying no young (pups).
   "We measured her," said Dr. Kraus. "She was 24'4" in length and, at her widest part, about 13' around.
   "She looked in really good health–as best as I could make that (determination]," she said. "If it had been laying on its belly in the water, and you could swing next to it, [the basking shark] would have been 4-5 feet high without the dorsal fin."
    "That sort of girth is just amazing," she exclaimed.
    The information gathered by the marine biology class will be used mainly for educational purposes. Kraus does plan to contact some chemists, at the university, and elsewhere, to see if they are interested in conducting various toxicity-type tests.
    "I am hoping," she said, "that somebody will be a good Samaritan ... and drag [the shark] onto a beach where it could rot out a bit so we can get the skeletal material."
   Kraus would like to put the skeletal material on display where school children and university students could study it.
   The professor noted that the dead basking shark bore a scar across its back–the cause of the old wound was most likely from a prop.
   Basking sharks are believed to feed continuously, slowly following the food source at or near the surface of the water, mouths held wide-open to sieve the plankton from the sea.
   Ordinarily, humans are at no risk from this inoffensive creature. However, the basking shark has been known to flail dangerously if startled by sea kayaks. The immense size and power of basking sharks should invite caution and respect–they have been observed to leap completely from the water. Severe abrasions and lacerations could result from contact with their skin.
   Taken from the Calais Advertiser, October 5,2000.

©WebWise Inc.