Sunday, June 26, 2016

"A Whole Lotta #Cray in a Small Area" - Ranger Pat

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.
Native Crayfish
Rusty Crayfish
The rust crayfish are easily identifiable (for the most part) by a couple of signature features. Both the native and the rusty crayfish have orange bands on the tips of their claws, however the rusty crayfish also have a black band around the tips of their claws. The rusty crayfish are also named as such for a reason - they have rusty colored spots on the sides of their carapaces.

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.

The Crayfish Corps goes out every Saturday with nets and waders for approximately 2 hours to catch crayfish. You position your net directly downstream of a rock you think crayfish are under and when you turn the rock over the current carries the crayfish straight into your net. Recently, Ranger Pat devised a new method of crayfishing where you stretch a drag net across the stream and turn over rocks for about 5-10 feet ahead of the net. The current carries everything down into the net and then we sort through everything in the net to find crayfish. This is a more effective method of crayfishing and can net several dozen per try. On average, about 15 people can find 100 crayfish an hour in Valley Creek.

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.

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