How Everglades National Park Unintentionally Saved the Smalltooth Sawfish

Dual Threats Lead to Population Decline

Before intensive nearshore fisheries took off in the United States during the 20th century, smalltooth sawfish ranged throughout the southeastern US from Texas to North Carolina (13). This species is also native to West Africa though it has been eradicated from almost all of this former range. Reports from 1884 indicate that sawfish were “exceedingly abundant” in the marine waters of the Everglades (13). Since the turn of the last century, however, sawfish have disappeared throughout most of their former range and are now only found with any regularity in Southwest Florida (16).

The primary threats to this species are twofold, fishing and habitat loss (17, 19). Due to their namesake saw-like rostrum, sawfish became susceptible to a wide range of fishing gear. The rostral teeth that they use for hunting were easily ensnared in nets. As this fishing gear was important to fishers’ livelihoods and an entangled sawfish was a potentially dangerous animal, captured sawfish were often killed (14). These animals were also prized by recreational fishermen, their saw-like rostrum once again proving to be their Achilles heel (12). These rostrums made for interesting trophies and are still on display in many bars throughout the Florida Keys.

Coastal modification may seem an unlikely culprit in the demise of a marine fish, but it was a very active agent in the loss of the sawfish. While intensive coastal fisheries exploited much of the sawfish's native range, South Florida real estate became a hot commodity (10). While the seemingly inhospitable Everglades kept development at bay for a long while, draining and land reclamation practices turned much of this former wetland into land worthy of development. Waterfront property became a large draw, and much of South Florida’s mangrove forests were cleared and replaced with the sightlier palm trees to “improve the viewshed” (10).

In hindsight, we now realize the importance of mangrove forests for their great water filtering and coastal protection roles. What also went unconsidered during the mid-20th century was the critical role these habitats provide for juvenile sawfish. Juvenile sawfish aka “pups” show a strong fidelity to waters three feet deep or less and adjacent to red mangroves (13). These animals rely on the complex maze of mangrove prop roots to protect them from predators such as bull and lemon sharks, alligators, and crocodiles (8).