Wednesday, July 21, 2010

Day Two – Part Two – Lemon Shark


These little fellas are adorable!! Check 'em out.

Statistics

• Mature length – 7-9 feet
• Mature weight – 200 lbs
• Lifespan is approximately 20 years
• Found in subtropical, shallow water


It’s called Lemon Shark for its pale yellow-brown color. This shark is found in Atlantic waters, and the Gulf of Mexico and the Caribbean. It can be aggressive if provoked, but is generally thought to be of little threat to humans. According to the International Shark Attack Files, there have been 10 recorded bites on humans by lemon sharks. Statistically speaking, you are more likely to drown when going to the beach than to be bitten by a shark - any shark. On United States beaches in the year 2000, there were 132 beach fatalities. Seventy-four of the fatalities were caused by drowning. There were twenty-three shark bites, total. Not all of them were fatal. The chances of drowning while at the beach are 1 in 3.5 million. The chances of being bitten by a shark: 1 in 11.5 million. Just food for thought.

According to the Florida Museum of Natural History, there is some evidence that two separate populations of lemon shark exist within the western Atlantic Ocean; one in the Caribbean and one in the Gulf of Mexico.

The lemon shark is found typically in shallow inland waters, in depths of 300 feet. They like to hang out in coral reefs and enclosed bays.

Reproduction

Lemon sharks give birth to live, free-swimming pups. Their gestation period is 9-12 months, and result in litters of 4-17 pups. When they are born, lemon sharks are only 24-26 inches long. I think they are of the prettier shark species. Watch this video of a lemon shark giving birth!


Tonic Immobility

Tonic Immobility was first discovered by Dr. Sam Gruber, accidently, during research on shark eyesight. He found that he could induce tonic on some sharks by turning them upside down, and gently touching the sensory area located on their nose and the front of their face. From what I’ve seen, lemon sharks seem to be susceptible to a much deeper state of Tonic Immobility. Being smaller than a lot of other sharks, they can sometimes be flipped on their back, resulting in a deep state of tonic. I saw a video where a baby lemon shark was flipped onto its back, causing it to go into tonic, then a minor surgery was performed to insert a tracking transmitter into the shark. There was no anesthesia involved, and the shark didn’t even flinch. It was amazing how deep the “trance” was. I looked for the video online to share, but I couldn’t find it.

I hope you enjoyed this blog on the Lemon Shark!

Sources

http://marinebio.org/species.asp?id=490
http://www.flmnh.ufl.edu/fish/sharks/statistics/beachattacks.htm
http://www.wavescape.co.za/sharks/sharkman.html

2 comments:

  1. These guys live for 20 years? Wow. Surprised about the deep tonic state, as well. Very cool.

    ReplyDelete