This past week has been “Shark Week” on the Discovery Channel. Ever since I was a kid, I’ve been fascinated by marine biology and in particular, the group of elasmobranchs—rays, sawfish, skates and sharks. Growing up on the Maine coast, I never encountered a shark while swimming but read Peter Benchley novels like Jaws,The Deep and The Girl by the Sea of Cortez with a voracious appetite. In 1995, I eloped to Kaua’i with my mother (who got married to my step-dad there) where I saw dorsal fins and had some melodramatic desire to swim with them. But they left and I swam with a sea turtle instead. Then in summer of ’99, I was in the Bay of Fundy with classmates from College of the Atlantic, and a 30 foot basking shark surfaced near our research vessel. After that experience, I read everything I could find on shark and ray conservation. The shark-like smalltooth sawfish (Pristis pectinata), for example, which can go into freshwater, as well as shallow waters of bays and estuaries in the southeastern U.S. and Caribbean, is technically a ray. Listed as an endangered species, the smalltooth sawfish has become extirpated because of changes to coastal environments—namely losses of wetlands, such as the Everglades. According to the Mote Marine Laboratory in Florida, “even if effective conservation plans can be implemented it will take sawfish populations decades, or possibly even centuries, to recover to post-decline levels.” http://www.seaweb.org/resources/briefings/sawfish.phpand see http://www.mote.org/index.php?src=gendocs&ref=sawfish-home&category=Shark%20Research
Meanwhile there is one shark, the bull shark, that regularly visits freshwater wetlands and waterways, and it is considered the most dangerous shark in the world. Bull sharks hang around coastal waters and islands (like Virgin Gorda, where I just went snorkeling in March) but also travel up rivers, such as the Mississippi River, and some rivers in New Jersey, to give birth to their pups. While the pups live in freshwater for a year or so, the mother may stick around and encounter people. Fully grown, they reach about 8 feet. Yikes!http://news.nationalgeographic.com/news/2005/07/0719_050719_bullsharks.html and see http://www.conservationinstitute.org/ocean_change/predation/bullshark.htm
The all-seeing lemon shark begins its life in mangrove swamps. The only shark to have eyelids and able to see in color, the females go into lagoons every April and give live birth to babies, which are attached by an umbilical cord. The young lemon sharks hang out in the mangroves for the first year before leading very independent lives. Lemons are very dangerous; known as the sprinters of the shark world, they can go from 0-20mph in 2 seconds. Fully grown, they reach about 8 feet, too. http://www.elasmo-research.org/education/ecology/estuaries-lemon.htm and seehttp://www.sharktrust.org/content.asp?did=26543
Because several shark species use coastal estuaries as nursery areas, researchers have looked at conservation strategies to help protect wetland habitat for the sharks. According to the latest IUCN Red List of Threatened Species, published by the UK-based International Union for the Conservation of Nature, at least 17% of the 1,045 shark and ray species, over 12% of groupers and six of the seven marine turtle species are threatened with extinction. Over-fishing, climate change, invasive species, coastal development and pollution are believed to be the chief causes.http://www.iucnredlist.org/ In Florida, citizens in Delray Beach just voted to approve a ban on shark fishing at a city beach. (July 21, 2009) http://www.sun-sentinel.com/news/palm-beach/delray-beach/sfl-delray-shark-ordinance-p072209,0,3967811.story
Initiatives for Shark Conservation at the Federal and State Level (2008 info)
Update: Cape Cod National Seashore has reported (May 2011) a recolonizing of marine life along the sandbar, including seals, which have attracted Great White Sharks.
Funny quiz: What type of shark are you? Go to: http://dsc.discovery.com/sharks/what-kind-of-shark-are-you-quiz.html According to that quiz, I am a goofy hammerhead. Ha! Leave a comment if you take the quiz to let us know what type of shark you are. If you think the quiz is fishy, feel free to say so. (I think I’m more like a ray anyway.)
Update: (August 2011) Largetooth sawfish to become second elasmobranch to receive Endangered Species Act protections. http://www.southernfriedscience.com/?p=10818