June 12th, 2010 by Michael Ricciardi
So-named for it’s elongated, saw-like snout, the largetooth sawfish faces a dire threat to its Florida habitat from the Gulf oil spill.
The spreading oil spill will soon get drawn into the so-called loop current, at which point in will be drawn down into the Gulf Stream which passes right along the Florida Keys on its way up the East Coast of the U.S. This is the sawfish’s principle habitat in this part of the Western Hemisphere.
On May 7, 2010, less than three weeks after the BP/Transocean catastrophe, marine scientists proposed adding the fish to the Federal Endangered Species list, which, if accepted by Congressional vote, would secure them specific legal protections and possibly funding for habitat protection.
The recent Gulf oil spill threatens the habitat of two species of sawfish–the smalltooth and largetooth sawfishes–as it works its way into the loop current and into the Gulf Stream, passing by Florida’s treasured marine habitats.
Once common in Northwestern Gulf waters, the odd -looking creature has not been seen in that region for for several decades. While more common in waters off Central and South America, in the U.S., the largetooth sawfish (Pristis microdon) is found almost exclusively in the shallow waters off Florida’s south coast, the northern most tip of its range. All species of sawfish are listed as critically endangered by the IUCN.
The fish’s cousin species–the smalltooth sawfish (Pristis pectinata)– was officially listed as endangered in 2003. The smalltooth sawfish’s population is restricted to the southern most part of the peninsula, including parts of the everglades (sawfish are also adapted to freshwater) and extending southward to Florida Bay and the Keys–where most if not all of the fish’s “nurseries” are found. This is the habitat that is being threatened by the fast approaching oil slick, posing what might be a deadly blow to the already-threatened creature.
Once depicted as a type of “sea monster” in highly exaggerated, artistic renderings, the bottom-dwelling sawfish uses its’ protruding, tooth-fringed snout (called a rostrum) to stun other fish and for rustling up crustaceans on the sea floor. The nocturnal fish is sometimes called a “carpenter shark” but are most closely related to rays. They are sometimes confused with sawsharks, which are similar in appearance. The largetooth sawfish can grow to lengths up to 23 feet (7+ meters).
The disappearance of a larger predator in any food chain can result in an over-abundance of other species which, if unchecked, can cause irreversible damage to the food web. In this case, however, the oil spill threatens to cause extensive damage up and down the food chain. In this case, the disappearance of the larger predator–the sawfish–would indicate that its food supply has been greatly impacted (smaller fish and crustacean populations may crash) and/or that its mating and nursery habitat has been destroyed or excessively polluted.
Keeping track of sawfish numbers is vital for both Endangered Species Act (ESA) listing and for determining the effectiveness of preservation efforts. If you want to check out the numbers, or, if you are a marine explorer or fisher person and want to contribute, visit the National Sawfish Encounter Database, maintained by Florida Museum of Natural History and the University of Florida.
Read more about this unique marine creature and the threat from the Gulf oil spill here.
For more information, or to learn what you can do to help the sawfish, download and view the power point slideshow here:
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