AsianScientist (Mar. 7, 2012) – Researchers have recently made a startling discovery – a sawfish’s saw can actually sense electric fields to locate and attack prey. This is contrary to previous assumptions that sawfish are purely bottom feeders that use their saw to rake the sandy bottom.
The sawfish shares a common ancestry with the shovelnose ray, and it is believed that their powerful saw-like rostrum with teeth on the outside evolved to extend their niche in the underwater world. They feed on catfish, mullet, and freshwater prawns.
Once common in tropical and subtropical regions, sawfish spend their young life in freshwater river systems until they reach adulthood – and are about age ten and at least three meters long when they move into the ocean.
The discovery, led by University of Western Australia (UWA) School of Animal Biology researcher Barbara Wueringer, provides evidence that the sawfish also feed closer to the surface.
This knowledge may help save the sawfish from extinction by providing crucial information for captive breeding programs and strategies to save them from falling victim to commercial fishing nets, say the researchers.
“Despite their worldwide decline, there is an indication the population in Australia is still in good condition,” Wueringer said.
Four species, which are protected in Australia, are found in the northern half of the country. The sawfish has never officially been targeted and are hence caught only as by-catch.
Unfortunately, their impressive saws are often taken as trophies by both commercial and recreational fishermen. Their fins are also popular in the shark fin trade.
“The more we know about them the better we can protect them. The first step might be to develop by-catch diversion strategies. And for captive sawfish, we can make sure they get the right stimuli to survive and reproduce,” said Wueringer.
The article can be found at: Wueringer BE et al. (2012) The function of the sawfish’s saw.
Source: University of Western Australia; Photo: www.elasmodiver.com.
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