Scientists have undertaken a study to find out why endangered Smalltooth sawfish in the United States were still dying, despite changes in fishing practises believed to be responsible.
For many years experts believed the main reason for the decline in Smalltooth sawfish, Pristis pectinata, populations was because the fish were being accidentally caught in fishing nets. However, despite the reduction or elimination of net fisheries in some states, such as Florida where the species is most common, Smalltooth sawfish populations have continued to decline.
According to new research by experts from the Florida Program for Shark Research at Florida Museum of Natural History, which is due to be published this month in the journal Marine Pollution Bulletin, nets are not the only factor responsible in the decline of the species.
Sawfish threatsJason Seitz and Gregg Poulakis obtained data on non-net fishery entanglement, injury, and mortalities by contacting anyone who had contact with the species. The results showed that, besides nets, Smalltooth sawfish were also being damaged by marine pollution in the form of monofilament and braided fishing lines and PVC pipes.
Other sawfish had also been intentionally injured or mutilated by humans who had shot at the fish with spears or arrows or caught the fish and chopped off their saw-like rostra.
Seitz and Poulakis write: "Many people are aware that the smalltooth sawfish is protected by state and federal laws, but some are still not aware of (or willing to accept) this status. The impacts of marine pollution and injuries directly caused by humans on this endangered species can be ameliorated by incorporating fisher education into the conservation and management processes."
Pristis pectinataPristis pectinata is one of six species in the genus Pristis and can reach a size of up to 7.6m/25'. The species has been listed on the IUCN Red List for many years and is currently classified as critically endangered.
Pristis pectinata is found across the world, ranging from the Red Sea to the Philippines and Brazil. It occurs in both marine and estuarine environments and sometimes enters freshwater.
Sawfishes are members of the Pristiformes Order and are closely related to sharks and rays, which are also members of the Class Elasmobranchii.
For more information see the paper: Seitz JC and Poulakis GR (2006) - Anthropogenic effects on the smalltooth sawfish (Pristis pectinata) in the United States. Marine Pollution Bulletin 2006.