Catch turtles by hand or use a long-handle dip net; either way will come with some difficulties -- after all, turtles have been evading terrestrial predators for millions of years. Commercial or custom-built turtle traps are effective, but they may take some time to produce results. Ultimately, the only way to remove all of the turtles from a pond is to drain the water and then collect the turtles by hand.
Always comply with federal, state and local laws. Some areas prohibit the capture of native turtles.
If the turtles are accustomed to your presence, they may allow you to approach within arms’ reach. It is more difficult to capture suspicious specimens, but with practice and adequate stealth, you can capture them with your hands. If the pond is shallow and safe to wade in, you may have better luck trying to sneak up behind turtles, thereby preventing them from escaping to deep water.
A long-handled dip net can make it much easier to catch turtles. You may have to experiment with different handle lengths to determine what length gives you good mobility and suitable reach. If you have access to a canoe or small boat, you can paddle close to emergent logs or rocks and try to net the turtles as they dive into the water.
Turtle traps are usually wire boxes or cylinders that have a funnel-shaped opening. Once it's baited with a chicken leg or wing, you place the trap in the water near the shore. After smelling the bait in the water, the turtles seek out the food and enter the trap. While not technically trapped, as they could swim right back through the funnel, few turtles figure this out.
You will have to set such a trap many times to catch most of the turtles in the pond, and you may not be able to catch every individual by this method. Turtle traps capture turtles without injuring them, but you must be careful to ensure the captured turtles can reach the surface to breathe. Always check turtle traps each morning and remove any that are present.
Draining the Pond
Once you empty the water from a pond, it becomes rather easy to collect a bounty of turtles. However, some may bury themselves in the mud; you will have to dig them out with a shovel. Use care to avoid injuring the turtle.
As the turtles you catch may act defensively, keep your hands away from their mouth and claws. Heavy gloves are appropriate. In most cases, laypersons should avoid interacting with softshell (Apalone spp.), common snapping (Chelydra serpentina) and alligator snapping turtles (Macrochelys temminckii), as these species are often large, aggressive and capable of inflicting serious wounds.