A saw is an essential tool in carpentry. But how can a saw be used for fishing? Sawfish use electro-receptors in their long saw-shaped snout to detect their fish prey living on the bottom of the sea. Then, they trap the fish on the bottom and kill it with their saw, sometimes breaking the fish in half before eating it.
This efficient way of catching fish has allowed sawfish, or “carpenter sharks” as they are widely known, to survive on earth for about 60 million years—surviving the mass extinction that wiped out dinosaurs. But even though sawfish outlived the dinosaurs, the question we must ask today on International Sawfish Day is whether they can survive the fishing activities of man.
With a snout lined with sharp teeth that makes them vulnerable to getting entangled in fishing gear, these unique fish are critically endangered and have vanished from many parts of the ocean.
Sawfish are also vulnerable to extinction because they give birth to litters of only a few live pups and only after they are about fifteen years old. This means that many female sawfish die in fishing nets before they have a chance to reproduce.
To protect the mother, the saw of a newborn sawfish is soft. Indeed, all the “bones” of sawfish are made of soft cartilage like that inside your nose. They are part of class of cartilaginous fish, Chondrichthyes, that includes sharks, rays, and skates.
Newborn sawfish pups have to fend for themselves. Even though they grow slowly, they can reach great lengths in maturity. Two years ago, we documented a sawfish weighing nearly one ton. It was caught in an industrial trawl net and brought to a fish market in Khulna.
This was likely the largest sawfish ever recorded in Bangladesh and among the largest in the world. Local traders informed our colleague G.M. Masum Billah, Marine Program Coordinator for the Wildlife Conservation Society (WCS) Bangladesh, that this giant fish was worth about 1.5 million Taka or US$18,000. The meat was sold for between 1000-2000 Taka or about US$12-24 per kilogram and the fins for 20,000 Taka or US$250.
According to a recent paper written by Alifa Bintha Haque from the University of Dhaka in 2017, two sawfish were landed on average per month, with a maximum of eight recorded in a single month. This alarmingly high mortality rate for a Critically Endangered species is a grave concern, especially due to the long time it takes for females to reach sexual maturity and their small litter size.
If we do not take immediate steps to protect this unique ocean giant, sawfish will be irrevocably lost. Sawfish are protected in Bangladesh under the Wildlife (Conservation and Security) Act of 2012, and international trade in sawfish or their body parts is prohibited under the Convention on International Trade in Endangered Species (CITES).
Why then are they still caught and so highly valued in Bangladesh? According to G.M. Masum Billah, some people, particularly in the Sundarban region, believe that eating sawfish meat will cure cancer and other illnesses. Dried fins are also shipped illegally to other countries where they are considered a delicacy.
This valuable domestic and international trade makes it difficult to convince fishers to release sawfish after they get caught in their gears even though it is a punishable offense.
Like tigers, river dolphins, and pangolins, sawfish will go extinct unless we find ways to save them. WCS uses popular local community radio programs, interactive traveling exhibitions, and informative brochures to debunk myths about their medical value.
We provide instructions for their safe release and promote compliance with fisheries and wildlife regulations. WCS also trains law enforcement officers to improve detection and prosecution of illegal wildlife trade. On International Sawfish Day, these carpenters of the sea need our help to build on those efforts before it is too late.
Writer: Jamia Rahman Khan Tisa is Training and Education Officer with the WCS Bangladesh Program. Elisabeth Fahrni Mansur is Senior Marine Conservation Program Manager with WCS Bangladesh.