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.
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.