Though they generally resemble sharks in body type, the sawfishes are actually more closely related to the skates and rays. They are large, coastal fishes that are easily characterized by the long, tooth-covered rostrum (or snout) that protrudes off of the front of the head. Unfortunately, overfishing and habitat loss have combined to drive several species of sawfishes to very low numbers.
The smalltooth sawfish is one of the largest species of sawfish, reaching lengths of up to 25 feet (7.6 m; including the rostrum). It lives in coastal seas and estuaries and relies on mangrove forests for critical habitat during its juvenile years. Smalltooth sawfish reproduce via internal fertilization and give birth to well-developed, live young. After birth, the young receive no further parental care and are immediately self sufficient with respect to feeding and avoiding predation.
Smalltooth sawfish use their long rostrums for the dual purposes of locating prey and immobilizing it. The rostrum is covered with special organs that help these fish locate prey in the low visibility of coastal waters by sensing the electric field created by other fishes and invertebrates. After locating small fish prey, smalltooth sawfish shake their heads from side to side, injuring or stunning fish and making them easier to capture. This behavior is analogous to that used by swordfish and thresher sharks. Smalltooth sawfish also use their electric sense and their rostrums to dig for buried invertebrates in soft sediments on the sea floor. Using these methods, smalltooth sawfish eat a variety of prey.
Though the rostrum is a vital component of smalltooth sawfish biology and ecology, it is also a large part of the cause of its overwhelming depletion. The rostrum is easily entangled in fishing nets. Coastal net fisheries targeting this or other species drove down the numbers dramatically. There are no longer any legal targeted fisheries for this species, but it is still accidentally captured in fisheries targeting other species. Loss of mangrove forests risks important nursery areas for this species, threatening attempts at recovery. Finally, though it has been given legal protection throughout its range, poaching still occurs in some places because its fins are valued in the shark-fin trade. Scientists now consider the smalltooth sawfish to be critically endangered (very highly vulnerable to extinction). Without careful management of the activities that threaten smalltooth sawfish and other sawfishes, this unique group of fishes could be lost.