Rusty crayfish (Orconectes rusticus) are native to waters in the Ohio, Kentucky and Tennessee region. Although they are indigenous to parts of the Ohio River basin, they are not considered native to the Commonwealth. Rusty crayfish were first found in the Commonwealth in 1976. Recent survey work funded by the Commission to assess native crayfish distribution and abundance has documented additional rusty crayfish populations, mainly in southcentral Pennsylvania.

There is little known about what ecological impact the expanded presence of rusty crayfish has had in the state. Potentially, rusty crayfish can reproduce in large numbers and reduce lake and stream vegetation, depriving native fish and their prey of cover and food. Their size and aggressive nature keeps many fish species from feeding on them. Rusty crayfish may also reduce native crayfish populations by out-competing them for food and habitat.

As a non-native species, the introduction of rusty crayfish into Pennsylvania waters has long been illegal. Likewise, rusty crayfish are not on the list of species legal to propagate for sale as fish bait by licensed bait dealers. The new action to make them illegal for possession, sale, barter or transportation is an additional preventive measure to further reduce the chances that rusty crayfish could be inadvertently spread to new areas by anglers acquiring them as fish bait.

"There is no direct evidence that anglers have spread rusty crayfish beyond their normal range. Crayfish are a popular fish bait, however, and it is very difficult to distinguish rusty crayfish from other species commonly found in Pennsylvania. So to help stop the potential spread of rusty crayfish, we are asking anglers who collect crayfish for bait to not transport any crayfish from one water to another,” Austen said.

Adult rusty crayfish are characteristically 3-5 inches long (nose to tail) with large claws that exhibit black-banded tips. The best identifier of the rusty crayfish is a set of dark, rusty spots on the midsection. These spots are found on each side, appearing as if it were picked up by someone with paint on their thumb and forefinger.

The rusty crayfish now joins a list of other exotic species banned in the Commonwealth that includes zebra mussel, bighead carp, silver carp, snakeheads, black carp, quagga mussel, round goby, tubenose goby and European rudd.

• Aquatic Invasive Species

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