Sawfish populations halved as nations fail to enforce conservation laws

February 10, 2021
Sawfish are being cut to the point of extinction worldwide. (Pixabay/Public Domain)

Sawfish are being cut to the point of extinction worldwide. (Pixabay/Public Domain)

 

Sawfish have lost 59% of their historical distribution and are heading toward complete extinction due to overfishing, a new study says, posing a threat to ocean biodiversity and indicating that policies worldwide to protect the world's largest ray are not being enforced.

Published Wednesday in Science Advances, the report found that the already dwindling populations have disappeared from nine more nations than scientists had previously confirmed, meaning they are now extinct in 55 of the 90 countries that were once their home.

​This has coincided with countries around the world failing to rigorously enforce their own marine protection obligations, including to regulate overfishing, the researchers note.

Their study utilized an in-depth review of all sawfish-related literature published between 2014 and 2019 to form geographic models of the fish’s prevalence around the world.

Sawfish are members of the ray family that can exceed 20 feet long and are characterized by their long, flattened nose-like extensions, or rostrums, lined with sharp teeth. They tend to be solitary creatures, residing in murkier water and camouflaging themselves at the bottom of the ocean. They are also especially susceptible to overfishing. 

Overfishing occurs when too many fish are caught at once and a particular population is depleted faster than it can reproduce. Like other sharks and rays, sawfish often reproduce only once every few years.

“When compared to other marine fish, sharks and rays are generally much more vulnerable to overfishing, and once populations are depleted, they can take a very long time to come back,” Sonja Fordham, an author on the paper and president of The Ocean Foundation’s Shark Advocates International in Washington, D.C., told The Academic Times. “They’re just not equipped to replenish their population at pace with fishing.”

In fact, another recent paper, to which Fordham contributed, explains that the population of oceanic sharks and rays as a whole fell by 71% in 50 years, largely due to overfishing as well.

On top of this, Fordham explains, the spiky rostrum that sawfish have makes it very difficult for them to avoid getting tangled in fishing nets, which can also be a cause for death — even when accidental — because it's even harder for them to be released from the net.

“You might have a country that has said, 'You can't fish [sawfish] on purpose,' but it's important to say, 'You can't keep them, either,' to make sure the incentive is to avoid them in the first place," Fordham added. “There is no question that overfishing is the main driver for sawfish risk of extinction.”

Citing The Convention on International Trade and Endangered Species, Fordham relayed that there is essentially a global ban on trade, but many countries are not properly enforcing restrictions, leading to black-market trafficking of sawfish fins and other parts.

“People might be surprised by how many countries around the world have obligations under various wildlife treaties to strictly protect sawfish, and they haven't produced the actual regulations yet,” Fordham said. "It’s really concerning.”

The study also highlights the recent commercialization of areas worldwide containing the specific habitat that sawfish need, which has often resulted in buildings inundating mangrove environments. The researchers believe this is likely driving sawfish out of their own grounds.

In the U.S., at a time when the conservation of marine fish is vital due to rising extinction rates, advocates worry policymakers are moving in the wrong direction. 

Of particular concern is recent changes to the Endangered Species Act, a rare occurrence. The Trump Administration finalized an "extinction plan" as part of the law in 2019, tightening the criteria for what qualifies as an endangered species. This policy delays the implementation of a recovery plan to save animals at risk until it is too late, advocates argue.

“The U.S. has been a leader, but it hasn't been great the last few years,” Fordham said. "Reestablishing that role of sawfish leader on the international stage would be really important at the time when sawfish need all the champions they can get."

However, Fordham emphasized that over the years, the U.S. has taken strides toward protecting sawfish, beginning with adding them to the list of endangered species in 2003, the result of a petition Fordham helped spearhead in 1999.

“Predators are important for ocean balance," she said, "keeping prey populations in check. People benefit from healthy oceans in a variety of ways, from fishing, to ecotourism, to quality of environment."

For those concerned about the animal’s protection, Fordham says that by writing to policymakers in support of sawfish, particularly in Florida where they tend to congregate, a little can go a long way. She also notes that there is power in tourism: Tourists can spread information about the importance of conserving sawfish to different countries’ officials, if the opportunity arises.

“There are a lot of strikes against this particular group of animals," Fordham concluded, “and they need all the help they can get.”

The paper, “Overfishing and habitat loss drive range contraction of iconic marine fishes to near extinction,” published Jan. 10 in Science Advances, was authored by Helen F. Yan, Lindsay N.K. Davidson, Danielle H. Derrick and Nicholas K. Dulvy, Simon Fraser University; Peter M. Kyne, Charles Darwin University; Rima W. Jabado, Elasmo Project; Ruth H. Leeney, University of British Columbia; Brittany Finucci, National Institute of Water and Atmospheric Research; Robert P. Freckleton, University of Sheffield; and Sonja V. Fordham, Shark Advocates International. The lead author was Helen F. Yan.

Saving
We use cookies to improve your experience on our site and to show you relevant advertising.