Rescuers work round the clock to save dolphins - The Boston Globe
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Saturday, March 13, 2010
Tuesday, March 2, 2010
Shark Attacks Fall in the U.S. in 2009
Shark attacks fell in the U.S. to just 28 in 2009, down from 41 in 2008, and 50 in 2007. There were just 19 attacks in the State of Florida, also down from 2008 & '07 (32 attacks in each of those years). George Burgess (pictured) is an expert who also monitors the International Shark Attack File (Florida Museum of Natural History) and stated for MSNBC.com that worldwide attacks were stable in 2009, and held around 61. Four shark attacks were fatal in South Africa and one fatal attack occurred in New Caledonia in the Pacific. The well-publicized death of a kite surfer in Stuart, Florida led to speculation about new and rising trends in attacks. Stephen H. Schafer, 38, was the first person to die from a shark attack in Florida in five years and only the 14th since 1896. Dr. Burgess investigated the attack and speculated that it was a bull or tiger shark, possibly 8 or 9-feet in lenght.
Dr. Burgess stated that almost 60% of attacks were fatal at the turn of the century, while only 7% of all attacks were fatal betwen the years 2000 and 2010. Many factors are the reason for this but accuracy of reporting, medical care are primary reasons.
More than half of the attacks worldwide involved surfers.
A series of attacks off the New Jesrey coast in 1916 is still being questioned and debated, but most likely a bull shark killed four individuals and injured one more between July 1 and July 12, 1916 on Beach Haven, Spring Lake, and Matawan Creek, N.J. Close To Shore and Twelve Days of Terror were two books written recently and detailed the attacks and investigations. Peter Benchley wrote his novel Jaws (1974) based upon these attacks.
International Shark Attack File
Using similar methods as Ornithologists, Marine biologists have been studying the meaning of humpback whale songs for years, but only in November of 2009 was any significant proof discovered to show that they are used for communication between males when it becomes time for mating. Although both males and females have songs, the male song, that is identified by a series of repeated chirps and wails has far greater intricacy than the stable repeated harmonic of the female song. The more complicated m
ale song suggests that they have a more developed speech pattern than the females. This could be due to the incredible amount of communication needed in the competitive game for a female’s attention when it comes to mating. Humpbacks tend to be solitary animals, and although it is widely believed that humpback whales are monogamous lovers, scientists have found that they actually tend to be widely promiscuous, and only have short “associations,” with females, when they swim together, which can last for either a few hours or to a few days. When a group of male humpbacks approach a female humpback, a competitive pod is created. These pods tend to move very quickly and are very animated as the males will often be violent with each other to the extent that the fights will often result in bloodshed. Their goal may be to obtain the position closest to the female being fought over. Evidence suggests that perhaps the whale in that position will be the one who will eventually mate with the female . However, this suggestion cannot be stated as fact, as scientists are yet to ever see humpbacks mate.To record the whales that led to the discovery that male humpbacks use their songs for communication, Danielle Cholewiak of the Stelwagen Bank National Marine sanctuary, dropped recorders into the waters around the island of Socorro. After about a month, she was able to analyze the recordings made and determine the whale’s position and their songs behavior. It was found that when a male sings alone, their song is more steady and even, as opposed to being more animated and changing when another whale was present. If the two whales stayed together, their songs would be adjusted so that the pair would sing the same theme. Although in the past, the use of sound recordings as variables in experiments have been deemed unuseful, Cholewiak found that when she played simplified recordings of whales own songs in the water, the males listening made their singing more even. With the information gathered in those months, Cholewiak was able to come to the conclusion that when male humpbacks meet each other, their songs change.
Example of a humpback Whale SoundwaveWhales Suspected of Herring Population Shortage
Whales Suspected of Herring Population Shortage
Herring are small oily fish about 9inches in length who can be found in the waters of the North Pacific and North Atlantic Oceans. They play an extremely vital role in the oceanic food chain, serving their role as a major food source for animals like seabirds, dolphins, whales, sharks, sea lions, tuna, and other larger fish. Herring have also been used for food by humans since 3000BC and are still fished today. Needless to say, their absence would put a damper on aquatic life as well as our own on land.
Humpback whales have been suspected of bringing down the herring population in the Prince William Sound, Anchorage. The whales, which usually stop by in the summer, have been stopping by in autumn and feeding on vast amounts of newly born herring. They now thrive in an area that was once poisoned by 11 million gallons of crude oil in 1989. The oil came from the 987 foot Exxon Valdes, a supertanker that sprung a leak and wiped out much of the herring population in the area. In 1980, before the spill, record harvests of herring were recorded compared to 1993 when only 25 percent of the expected ad
ults returned to spawn. Some conservaton organizations have this to say about the herring population “The argument that increasing whale populations are behind declining fish stocks is completely without scientific foundation.”
This picture of a supertanker oil leak depicts the damage that crude oil spills can cause the ocean. Oil spills on top of peculiar humpback whale behavior have led to a scare in the herring world.
North Pacific humpbacks begin their annual migrations from the Gulf of Alaska in early fall. Humpbacks have recently been reported to be skipping their annual mating and birthing trips to places like Hawaii and Mexico. Most humpback whales make mammoth journeys every year between their feeding and breeding sites. ‘Because seasons are reversed either side of the equator, Northern and Southern Hemisphere populations of humpbacks probably never meet; those in the north travel towards their breeding grounds in tropical waters as those in the south are traveling towards the pole to feed, and vice versa.’
A recorded 199 whales were using the sound in Anchorage from September through March with as many as 129 there at one time. So what is the reason for these whales eating and migrating in such obscure ways?
Bibliography:
http://fisherycrisis.com/DFO/bofwhales.htm#3
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x158505
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