Summary: A fishing spider is not the most common spider, but you do run into them when water is nearby. That water doesn't have to come from a stream or a lake. Unfortunately, your swimming pool can be a good living environment for fishing spiders, too.
Bill W; West Branch, MI asks: I'm not sure what kind of spider infestation I have. Is there anything I can do or any product I can use to get rid of the spiders in the swimming pool? They even seem to jump on the water.
Dear Bill: So many people ask about different bugs they find and without a picture I can only make an educated guess. The thing that helped me identify this one was your comment that "they even seem to jump on the water."
My educated guess would be that the spiders you are finding in your pool are Fishing spiders. These spiders are common in forests and meadows, especially near streams and creeks where they wait for passing prey on rocks and pebbles at the water's edge. Fishing Spiders will always be found where there
are lots of plants, both in the water and on the shore where they hide from predators and ambush prey. They can even hunt for prey on the water's surface.
Fishing spiders are able to walk on water because of the fine hairs on their tarsi which wrap air and act like small buoys. They are land dwellers and are unable to climb on glass and very smooth surfaces. They normally are not found on vegetation and branches. Their meals are often land insects that have fallen in the water and can't escape, but they eat aquatic insects too. They are not web builders.
People who live close to a wooded habitat may see fishing spiders that wander into their homes from time to time. This can be frightening, especially since the spiders are sometimes very large. Although fishing spiders are big enough to give a painful bite, they are not considered dangerous.
My best suggestion for control would be to cut back nearby vegetation and try applying an insecticide such as
Suspend SC around the perimeter of your property. These spiders are hunting for small prey so try altering any habitat that might attract insects. Night lights directly around the pool, compost piles and stacks of wood should be eliminated.