How to prevent non-target species from entering traps?

Selecting the Right Materials

When constructing fish traps and weirs, it’s essential to use materials with specific mesh sizes that allow target species to enter while keeping non-target species out. For example, a mesh size of 1-2 inches (2.5-5 cm) can be effective for catching small fish like trout, while larger mesh sizes may be necessary for larger species. Additionally, using materials with a smooth surface, such as wooden or plastic slats, can help prevent non-target species from becoming stuck or getting caught.

Trap Design and Placement

To prevent non-target species from entering traps, it’s crucial to set traps in areas with limited escape routes. This can be achieved by placing traps in areas with a strong current or by using a funnel trap design that narrows the entry point. For example, a rock weir can be designed to direct water flow towards the trap, while a basket trap can be placed in a location where the target species is most likely to congregate. By carefully selecting the trap design and placement, you can minimize the number of non-target species caught.

Baiting and Attracting Target Species

Proper baiting is essential for attracting target species while minimizing non-target catches. When using bait, it’s best to use small amounts and place them in areas where the target species is most likely to find them. For example, in a fish trap, bait can be placed near the entry point or in a bait chamber that allows target species to enter without attracting non-target species. By carefully selecting the bait and placement, you can increase the chances of catching target species while minimizing non-target catches.