Fishing without a line should be great, no lines to untangle, or get snagged in the rocks and trees. If you have a fish hook or could improvise one from a piece of wire and you want to make a fishing line that is possible. All sleeping bags, tents, parkas, coveralls and seat covers are sewn together with strong nylon thread. Taking seams apart carefully will yield a workable fishing line, tie it to a stick. A piece of wire from a vehicle might also be used with a hook.
State wildlife agencies send a strong electric shock into the water to raise fish temporarily for tagging. Explosives and poison are used to rid small lakes of unwanted fish.
There are numerous opportunities available for taking fish without a hook and line or bait. Many people in northern states never use a hook and line. They get their fish by spearing them. Most build a dark house to sit in out on the frozen lake. The dark inside makes it easier to see what is below. They cut a hole in the ice and spear the fish as they swim below the shack. A fish decoy is positioned below the shack but some times there are hours between each passing fish. The states all have different spearing regulations and ban spearing in open water during spring spawning season. Most states allow spearing rough fish like carp and suckers the year-round. Archery hunters go after big carp with their bows and arrows but use a line to retrieve the arrow.
Most states have rivers with small spillways to regulate the depth of the water every few miles. When these spillways are running you can stand in the water downstream next to the spillway. Hold your arms and hands in the water near the bottom. As the temperature of your hands nears the water temperature the fish will swim between your hands and you can pick them up.
San Diego, California has the grunion run from March through September. This sounds easy enough for anyone, just bring your buckets down to the beach. Pick the grunion up off the sand between incoming and outgoing waves and put them in your bucket.
'Missouri legalizes bare-hand fishing.' For the very adventurous there is catfish noodling. These brave people get right in the water and hunt for big catfish under logs and in caves in the river banks. Anyone getting their bare hands on a 50 pound catfish and dragging it out of the river will certainly have a fish story to talk about. Some states made catfish noodling illegal because they claimed it took the large spawning fish instead of smaller ones. Catfish noodlers must also have a few snake and snapping turtle tales to tell. Large snapping turtles might take a notion to haul a catfish noodler to the bottom of the river. There are catfish noodling pictures at this link.
Duluth Minnesota has the annual smelt run. The smelt run has been in decline for many years but the smelt still come out of the big lake every spring. There was a time in the fifties and sixties when the smelt were so thick you could harvest a garbage can full with a small dip net in minutes. Some smelters lost their lives wading in the river. They slipped and fell, then got washed out into Lake superior never to be found.
There is a large variety of nets for taking fish, some states allow hoop nets and casting nets. Strong arms are needed to throw a casting net and catch fish. Gill nets were very popular back in the pioneer days, almost every family had one. That net might have meant survival for a lot of them. Fishing laws soon made gill nets illegal, to protect the fish population. That was a debatable subject for decades, as all the fish would die in the lakes from winter kill periodically anyhow. Gill nets are still used today by a few outlaws and commercial fishing companies. The nets have a larger mesh so the small fish swim through, only the large ones get caught. Commercial fishing is also done by dragging a mile of seine under the ice in the northern lakes. The fish are herded to a large hole near the shore where they are harvested.
Fishing without a line has many possibilities you might pick up easy fish in tidal pools, or fish trapped by receding flood waters. Possession limits and licenses will be enforced no matter how you take fish. Boaters on rivers connecting to the Mississippi have fish jumping right into their boats. The Asian Carp are moving north following all the rivers they get into, nothing seems to be stopping them. They jump high in the air to avoid boat motors and land right in some boats.