This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
All species of sawfish around the world could soon gain full protection under the U.S. Endangered Species Act, a move that comes just in time for the iconic but critically endangered creatures. Sawfish populations have dropped 90 to 99 percent over the past few decades, mostly because of coastal development in sawfish habitat and peoples' willingness to pay top dollar for the animal's striking toothed snouts. Those "saws" (technically called rostrum) also put sawfish at risk from fishing nets, which can easily become entangled on the teeth. Experts fear that all sawfish species face extinction if these threats remain unaddressed.
"Sawfishes have an affinity for the same coastal habitats and river estuaries that humans desire for development," explains Dr. Nick Dulvy, co-chair of the Shark Specialist Group of the International Union for Conservation of Nature (IUCN). (Sawfish, sometimes known as carpenter sharks, are actually rays, which are closely related to sharks.) "Encroachment and mega-delta cities, particularly in southeast Asia, combined with the rise of monofilament gill nets, have almost eliminated sawfishes from all but two places in the world: Florida and Northern Australia." That's quite a change from a few decades ago, when sawfish could be found in the coastal waters of 80 nations.
As if the dramatic decline weren't bad enough, conservation efforts to date have been somewhat hampered by what the IUCN calls the "chaotic" taxonomy of sawfishes. Scientists traditionally recognized seven sawfish species, but recent studies suggest that number should be reduced to five. That new information hasn't made its way into the law books yet, leaving some confusion as to which species live in which waters and which sawfish are protected.
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Earlier this year the Convention on International Trade in Endangered Species (CITES) took the first steps to correct some of the confusion and patch the holes in sawfish protections. Although CITES still recognizes seven sawfish species, all seven now appear under its Appendix I, which prohibits all cross-border trade in listed species. CITES had previously listed one of the seven sawfish species under its Appendix II, which provides a lower level of protection. Dulvey says putting all sawfish under Appendix I makes it easier to protect all sawfish, regardless of how many species actually exist. "Having one species in a different CITES appendix always leaves the wriggle room and uncertainty that can be accidentally or intentionally exploited by traders," he says. "This change solves the uncertainty and ambiguity that would have resulted from the recent taxonomic change in sawfish names without exposing international diplomats, law enforcement and customs officials to the arcane rules of fish taxonomy."
The U.S. is now taking a similar action. Last month the National Oceanic and Atmospheric Administration (NOAA) proposed protecting all sawfishes under new rules which would both enhance and supersede two earlier Endangered Species Act (ESA) listings. NOAA also took the opportunity to update its list of sawfish species to reflect the new taxonomy. Under the proposed new rules, the following five species will now be recognized and could receive ESA protection: narrow sawfish (Anoxypristis cuspidata), dwarf sawfish (Pristis clavata), largetooth sawfish (P. pristis), green sawfish (P. zijsron) and smalltooth sawfish (P. pectinata). Some of these, including the sawfish off the coast of Florida, were already protected under the ESA but under previous species names. NOAA's new proposal includes not just the previously protected sawfishes but all those around the world—a move that would make it illegal to import sawfish or their saws into the country and therefore protect the animals from American consumers.
With new protections either in place or pending, Dulvy says the next challenge is to figure out where sawfishes still exist in sufficient numbers so targeted conservation efforts can be established. Populations in the Amazon and Congo rivers have not been surveyed recently and may have already disappeared. Other populations face pending disasters: massive freshwater dams planned in Myanmar could threaten sawfish populations in that region, and the recently proposed Inter-Oceanic Nicaragua Canal would go through two important habitats for freshwater sawfish in the San Juan River and Lake Nicaragua. "We urgently need to find these last remaining sawfishes populations and protect them fast," he says.
NOAA is accepting public comments on its new proposal to protect all sawfish through August 5. Meanwhile, the IUCN Shark Specialist Group is developing a sawfish conservation strategy and also seeks information on sawfish information from the public.
Photo: A sawfish photographed by Lorenzo Blangiardi at Genova Aquarium. A sawfish rostrum collected "a long time" ago in a Nicaraguan lake, photographed by Mike Simpson. Both used under Creative Commons license