Crayfish Inventory Project

Crayfish Inventory Project

– Victoria Chicatun and Lise Coquilleau

Crayfish play important roles in freshwater systems, including those of ecosystem engineers and bio-indicators of water quality and habitat. Crayfish are also a keystone species in the trophic web of lakes and streams due to their large size, mobility, behaviour, omnivory, and as an important prey item for birds, mammals, turtles and fish. Additionally, protected crayfish may act as an umbrella species for the conservation of communities. Currently 8 species are found in Quebec, two of which are highly invasive: the Rusty crayfish and Spinycheek crayfish. These non-indigenous species are known to displace native crayfish, decrease the abundance and diversity of aquatic plants and invertebrates, and reduce some fish populations. The goals of this project were to 1) create a baseline inventory of the crayfish species at Kenauk, and 2) study the effect of predatory pressure on crayfish abundance and diversity. To do this lakes were categorized based on the present fish species, bass and pike, rainbow trout or no predatory fish, to represent different types of predatory pressure (bass and pike being avid consumers of crayfish). Crayfish were sampled at each lake using two methods: overnight traps baited with canned catfood and 45 min of active sampling at dusk, using flashlights and nets.

So far two species of crayfish have been found, both being native in this range: Orconectes propinquus (Northwestern clearwater crayfish), and Orconectes virilis (Virile crayfish). No non-indigenous species have been found.