Saltwater fishing nets, while common enough on the coasts, are rare when you go inland.
Saltwater fishing nets are stronger and made of more durable materials than other fishing nets mainly due to what saltwater fish are being caught by the nets.
While crabs are not fish,
saltwater fishing nets are also used to catch crab.
Saltwater fishing nets are made strong because they are used to hold larger and stronger fish while still alive, such as a large swordfish.