Note: Please read the updates below, because the validity of the reported bull shark attack, via the Global Shark Attack File, is questionable, and I believe it’s merely myth. First, there seems to be no press record or mention of the 1955 attack. Furthermore, Lake Michigan is mostly too cold to sustain bull sharks, which are a tropical/subtropical species that will “migrate north along the coast of the U.S. during summer, swimming as far north as Massachusetts, and then return[ing] to tropical climates when the coastal waters cool.” Even in August, Lake Michigan surface temperatures are barely warm. One study found that young bull sharks left a “lagoon during winter months . . . when water temperatures dipped below 68 degrees.” Additionally, an electric dispersal barrier was constructed to prevent nuisance species from entering Lake Michigan from the Mississippi River Basin and vice versa; although Asian carp may have breached the barrier. Most likely, the Lake Michigan bull shark attack is myth, and may have resulted from more credible sightings of bull sharks in the Mississippi River.
ORIGINAL POST (15 July 08): According to the Global Shark Attack File, in 1955 George Lawson had his right leg bitten by a bull shark (Carcharhinus leucas) while swimming in Lake Michigan near Chicago. Apparently, the attack was unprovoked and by surprise. The incident log does not mention any other attacks from Lake Michigan, so it appears the incident was an aberration. However, freshwater shark attacks, although rare, are possible.
Bull sharks have been recorded in the Mississippi River, but it has been claimed that a series of dams and locks known as the Illinois Waterway, which connects the Mississippi River with Lake Michigan, should prevent bull sharks from entering Lake Michigan. Furthermore, Lake Michigan bathers shouldn’t be too concerned, because bull sharks prefer warmer waters. From In-Fisherman:
According to the Illinois Department of Conservation, two commercial fishermen from Alton, Herbert Cope and Dudge Collins, caught a bull shark in 1937. They found something troubling their wood and mesh traps late that summer. Concluding that it was a fish, they built a strong wire trap and baited it with chicken guts.
The next morning, they caught a 5-foot 84-pound shark, which they displayed in the Calhoun Fish Market where it attracted crowds for days. Although some folks suspected a hoax, the catch was considered authentic. Biologists later concluded from photos that it was a bull shark. Recently, Clint Smith of Alton supplied an old photo of the catch, with the present-day ADM flourmill in the background.
Bull sharks can live a long time in freshwater. In 1972, one was caught 2,500 miles up the Amazon. The journey from New Orleans to Alton is about 1,750 miles. Dams now prevent sharks from entering Illinois.
More from Wikipedia (with cited sources):
After Hurricane Katrina hit in 2005, a large number of bull sharks were sighted in Lake Ponchartrain. Bull sharks have occasionally been seen in the Mississippi River as far north as St. Louis. Even more rare, due to cooler waters, bull sharks have made their way up the Illinois River and into Lake Michigan such as an encounter off the coast of Chicago, Illinois. In that incident the shark was verified by U. of Illinois biologists as being a female 6 feet 9 inches and weighing over 300 lbs.
UPDATE 1 (10 Aug. 09): Bull sharks are not restricted to saltwater. Due to its physiology, the bull shark is highly adaptable to freshwater conditions, so they can tolerate a wide range of salinity. Furthermore, Bull sharks can travel far rather quickly. Consequently, bull sharks have been recorded far into both the Amazon and Mississippi Rivers. However, the Lake Michigan record is questionable.
Although the Global Shark Attack File cites a Lake Michigan bull shark attack, I believe the Lake Michigan record is highly unlikely, since there doesn’t appear to be any news sources, such as the Chicago Tribune, documenting the attack during the 1950s. Apparently, the Global Shark Attack File cites its authority via a book called Man-eating sharks: a terrifying compilation of shark-attacks, shark-facts and shark-legend by Felix Dennis, published in 1976.
As a reader of this blog, if you have further information, then please email me or provide it in the comments. I’ve provided some clippings from the Chicago Tribune that suggest the attack probably didn’t occur. Furthermore, a bull shark was reportedly caught from Lake Michigan at one time, but this was revealed to be a hoax.
UPDATE 2 (15 Aug. 09): A librarian from South Campus Library at Macomb Community College, in Michigan, very kindly pulled the book that supposedly mentions the Lake Michigan shark attack (emphasis added):
Yes, there is a mention of a shark attack in Lake Michigan in the book you cited, [Man-eating sharks, a terrifying compilation of shark-attacks, shark-facts and shark-legend! Edited by Felix Dennis, published in 1976]. However, the book has no in text or parenthetical citations, nor does it have a bibliography. So, no authority for the information is mentioned. Here is the passage in which the attack is discussed:
One of the most astonishing shark attacks on record took place in 1955 when George Lawson a Chicago boy was attacked while taking a swim in Lake Michigan!
Rescuer John Adler who hauled the boy, minus most of his right leg, into a boat, said ‘I just couldn’t believe it, but I had to believe what I saw happening right before my eyes!’ When doctors found the dreadful injuries on Lawson they had no hesitation in proclaiming that it was indeed a shark bite. Others who had witnessed the attack saw the fish heading away back into the deep parts of the lake, its passage marked by…a tell tale dorsal fin.
What kind of shark would travel thousands of miles necessary through fresh water rivers and lakes to get to Lake Michigan?
Well there is one species well known for its aggressiveness and also for its liking of fresh and brackish waters, the infamous Carcharhinus Leucas, (now often called Carcharhinus Springer).
South Campus Library
Macomb Community College
Wikipedia mentions the attack too, but suggests that the shark was caught and identified. Given what’s in the book, there definitely seems to be conflicting information regarding the bull shark attack from Lake Michigan. From Wikipedia (emphasis added):
Bull sharks have occasionally been seen in the Mississippi River as far north as St. Louis. Even more rare, due to cooler waters, bull sharks have made their way up the Illinois River and into Lake Michigan such as an encounter off the coast of Chicago, Illinois. In that incident the shark was verified by U. of Illinois biologists as being a female 6 feet 9 inches and weighing over 300 lbs.
The mystery continues, because Wikipedia doesn’t provide a reference for this sentence, “In that incident the shark was verified by U. of Illinois biologists as being a female 6 feet 9 inches and weighing over 300 lbs.” For the sentence before, it cites the Global Shark Attack File. I’ll keep updating this blog post as more information is discovered.
UPDATE 3 (15 Sept. 09): Wikipedia “deleted the discredited ‘shark of L. Michigan’ story . . ..” The Global Shark Attack File still reports the attack as:
Shark related news & information on the net:
- Global Shark Attack File
- International Shark Attack File
- Shark Attacks in Perspective
- How, When, & Where Sharks Attack
- The Relative Risk of Shark Attacks to Humans: Compared to Other Risks
- Bull shark information via FishBase.org
- NOAA FISHERIES FACT SHEET: Bull Shark
- The Bull Shark: It lurks in the shallows, even in fresh water. And it loves to kill.
- Rare sighting: Bull shark spotted on Alabama River
- Bull sharks take to Louisiana swamp
- Freshwater Sharks and Rays
- ‘Virgin Birth’ By Shark Confirmed: Second Case Ever