Sawfish
Sawfish are primarily found in coastal marine and estuarine brackish waters, but they are euryhaline (can adapt to various salinities) and also found in freshwater. The largetooth sawfish, alternatively called the freshwater sawfish, has the greatest affinity for freshwater. For example, it has been reported as far as up the Amazon River and in Lake Nicaragua, and its young spend the first years of their life in freshwater. In contrast, the smalltooth, green and dwarf sawfish typically avoid pure freshwater, but may occasionally move far up rivers, especially during periods when there is an increased salinity. There are reports of narrow sawfish seen far upriver, but these need confirmation and may involve misidentifications of other species of sawfish.
Largetooth sawfish
The largetooth sawfish can be found worldwide in tropical and subtropical coastal regions, but it also enters freshwater and has been recorded in rivers as far as from the sea. Historically, its East Atlantic range was from Mauritania to Angola. There are old reports (last in the late 1950s or shortly after) from the Mediterranean and these have typically been regarded as vagrants, but a review of records strongly suggests that this sea had a breeding population. Its West Atlantic range was from Uruguay to the Caribbean and the Gulf of Mexico. Although there are claimed reports from several Gulf Coast states in the United States, a review indicates that only those from Texas are genuine. Other specimens, notably several claimed to be from Florida, were likely imported from other countries. Its East Pacific range was from Peru to Mazatlán in Mexico. Historically it was widespread in the Indo-Pacific, ranging from South Africa to the Horn of Africa, India, Southeast Asia and Northern Australia. Its total distribution covered almost , more than any other species of sawfish, but it has disappeared from much of its historical range.