I spent the past few weeks in Sarasota, Florida, visiting Mom so I could help her with odd jobs around the house... and teach her how to use her very first real computer. It is somewhat difficult to believe that Mom now has a laptop more powerful than anything I own. Finally she can actually receive my Dive Dry columns, see the pictures of her kids and grandkids, and surf the Internet on her own.
Now Sarasota is a beautiful city located on the west coast of Florida south of Tampa. It offers a full calendar of cultural events which Mom and her many friends enjoy. One thing it doesn't offer much of is good diving. The Gulf of Mexico is very shallow and dive boats have to travel many miles out from shore to reach good dive sites. Before flying out, I had warned my 80,000 diving colleagues on ScubaBoard.com that I would be visiting the region. Not long after I arrived, I received an invitation from Colin (CBulla) of the Florida Conch Divers (the local equivalent of our own California Kelp Divers on the board) to join their annual Thanksgiving turkey fry and shark tooth dive at Venice Beach, just 10 miles to the south.
Now I was well aware that Venice Beach was one of the finest shark tooth diving sites in the world, but I had heard that divers had to swim upstream in a river to find them. Upon arriving at the site, I discovered that the diving actually occurred right off a nice sandy beach. When I got there the turkeys were deep frying and there was a great spread set out for all to partake of. Despite my love of "munching," I was too busy meeting the ScubaBoard folks from Florida to eat any of the yummies. Good thing Mom and I still had plenty of leftovers in the fridge to satisfy that desire.
As soon as I walked towards the table, ScubaBoard's owner Pete Murray greeted me with a big hug. Pete had been out to dive with us on the King Neptune earlier this year, and gave me my very first dry suit after our dive. Although I have yet to try it out, winter is rapidly approaching and once I master it I'll be warm and dry when I dive despite rain, sleet or snow (oops, this is southern California... none of those happen here). Pete, or NetDoc as he is known on the Board, introduced me (known unimaginatively as DrBill) to the divers from this other "west coast."
Now I'd heard of Venice Beach as the place to find fossil Megalodon shark teeth. If great white sharks scare you, this ancient shark was the Barry Bonds of the family looking like a great white on massive steroids. Fortunately for divers world-wide, it is known only from the Miocene and Pliocene, a few (2-20 million) years before yours truly started diving. I should warn you that there are some scientists who believe this shark may still be alive today as a relict species. Although it is in the same shark family (the Lamnidae) as the great white and mako, there is some scientific dispute as to whether they really are close relatives of Jaws. Their maximum size is also disputed. Early scientists believed they might reach 100 feet in length, but recent size estimates based on fossilized teeth suggest a maximum size of about half that. Now a shark only 50-60 feet long would be enough to soil my wetsuit!
Megalodon is known scientifically as Carcharodon megalodon, a name given it in 1843 by Louis Agassiz, perhaps America's first world-class scientist. Agassiz was a professor at Harvard and in 1859 founded the University's Museum of Comparative Zoology where I spent much of my undergraduate years. This species is believed to have reached a body weight of nearly 50 tons or more. Now I'm a mere 1/400th that size but Mom can tell you I used to eat copious amounts of food in my growing years. And Avalon's own Chuck Liddell can confirm I did break a record for munching on prime rib (13 pounds) that had been set by one of the Los Angeles Lakers back in the 1970's. However, I'd lose any eating contest to this toothsome giant which, at maximum size, would have to eat a ton of food each day. Since its diet is believed to have consisted of whales and other large marine mammals, I can't picture myself going head-to-head with it in an all-you-can-eat competition. I like my red meat lean, not full of blubber.
This Shark-on-Steroids (SOS) is believed to have frequented ancient shallow seas where plankton-feeding baleen whales similar to our gray whales would have been found. Millions of years ago Florida was largely submerged, and may have been a nursery for this and other shark species. Hmmm, I wonder if the predicted rise in sea level due to global warming might re-create these habitats and allow any relict Megalodons to exhibit a population bloom in their former turf? Gulp! Other areas where megalodon fossil teeth have been found include Bakersfield, La Jolla and the Sahara Desert! Of course I only dive one of those three locations.
Shark tooth diving off Venice is not limited to these not-so-gentle giants. Pete brought back 345 fossil shark teeth on his first dive, and 328 on his second. There were a number of different shark species represented in his finds. Why does the ocean off Venice offer such richness? Millions of years ago when Florida was inundated, sharks lost teeth all over the State in a natural process of tooth replacement. It has been estimated that a single shark living some 25 years may shed as many as 20,000 teeth over its lifetime. A much larger "Gulf of Mexico" existed back then until central Florida emerged from this ancient sea, providing plenty of habitat for these top predators.
Two processes are responsible for the concentration of teeth here. An ancient river cutting through the center of the State eroded inland rock formations and carried dislodged fossil shark teeth with it to the river's mouth near present-day Venice. Coastal processes are eroding the beaches there, aided by hurricane storm events, thus exposing the teeth deposited many years ago. So each Thanksgiving, ScubaBoard's Conch Divers hold their turkey fry here and gather up teeth by the thousands. Venice even holds a shark tooth festival of its own each year in April.
On a person note, my trip to Florida involved another tooth incident... but one that I wish I could have avoided. Mom took my sister Judy and I out to dinner. As I bit down on my first French fry, I felt a crunch between my front teeth. After I swallowed, I noticed something seemed to be stuck between my two front teeth ("all I want for Christmas..."). Upon inspection in a mirror, I discovered that the pebble or whatever was in the French fry had broken off part of one tooth! A few days later I was off to Mom's dentist for what ended up as a large epoxy filling... and an unexpectedly large bill for nearly $300. So much for that new dive computer I planned to buy myself for Christmas. Now why can't I be more like sharks... replacing lost teeth with ease, and without such expense?
© 2007 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles," "Gentle Giants: Giant Sea Bass" or "Common Fish and Invertebrates of the Sea of Cortez" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!
Dr. Bill and Pete Murray in front of the ScubaBoard banner, some of the 673 shark teeth Pete found on his dives;
a diver with a small fossil megalodon tooth and a megalodon tooth from my personal collection.
This document maintained by
Dr. Bill Bushing.
Material and images © 2007 Star Thrower Educational Multimedia