Largetooth sawfish
Adults are primarily found in estuaries and marine waters to a depth of , but mostly less than . Nevertheless, the species does appear to have a greater affinity for freshwater habitats than the smalltooth sawfish ("P. pectinata"), green sawfish ("P. zijsron"), and dwarf sawfish ("P. clavata"). Largetooth sawfish from the population in Lake Nicaragua appear to spend most, if not all, of their life in freshwater, but tagging surveys indicate that at least some do move between this lake and the sea. Captive studies show that this euryhaline species can thrive long-term in both salt and freshwater, regardless of its age, and that an acclimation from salt to freshwater is faster than the opposite. In captivity they are known to be agile (even swimming backwards), have an unusual ability to "climb" with the use of the pectoral fins and they can jump far out of the water; a individual jumped to a height of . It has been suggested that this may be adaptions for traversing medium-sized waterfalls and rapids when moving upriver. They are generally found in areas with a bottom consisting of sand, mud or silt. The preferred water temperature is between , and or colder is lethal.
Sawfish
Sawfish fishing goes back several thousand years, but until relatively recently it typically involved traditional low-intensity methods such as simple hook-and-line or spearing. In most regions the major population decline in sawfish started in the 1960s–1980s. This coincided with a major growth in demand of fins for shark fin soup, the expansion of the international shark finning fishing fleet, and a proliferation of modern nylon fishing nets. The exception is the dwarf sawfish which was relatively widespread in the Indo-Pacific, but by the early 1900s it had already disappeared from most of its range, only surviving for certain in Australia (there is a single recent possible record from the Arabian region). The saw has been described as sawfish's Achilles' heel, as it easily becomes entangled in fishing nets. Sawfish can also be difficult or dangerous to release from nets, meaning that some fishers will kill them even before bringing them aboard the boat, or cut off the saw to keep it/release the fish. Because it is their main hunting device, the long-term survival of saw-less sawfish is highly questionable. In Australia where sawfish have to be released if caught, the narrow sawfish has the highest mortality rate, but it is still almost 50% for dwarf sawfish caught in gill nets. In an attempt of lowering this, a guide to sawfish release has been published.