Valley Forge has several initiatives that work together to keep the ecosystem at Valley Forge in check. Among these is the Crayfish Corps, an initiative that works to rid Valley Creek of the rusty crayfish, an invasive species of crayfish from the Ohio River Valley Region. The rusty crayfish are larger than native crayfish which means they not only out compete them for space but also for food. Rusty crayfish have harder exoskeletons as well which makes them more difficult for predators to eat and they are also less nutritious than native species.
Sometimes it can be difficult to tell if it is a native or invasive species of crayfish, however usually looking for both the black band and the rusty spots gives a pretty solid indication of species. It is important to correctly identify the crayfish because the rusty crayfish are removed from Valley Creek to be measured and cataloged, while the native species are left to reproduce. The goal of the Crayfish Corps is to maintain a ratio of 1 or fewer rusty crayfish to every 4 native crayfish.
A trip to Valley Creek can also allow for sightings of several other aquatic animals. On my last trip out, for example, we caught a fairly large bass and we saw a water snake sunning itself on a rock. The water snake is nonvenomous and allowed us to take a few pictures before sliding off the rock and heading towards shore. Other animal sightings include chipmunks, deer, waterbugs, other species of fish/snakes, and scuds.