Native SpeciesCrayfish, unidentified

Decapoda (order)
FOUND by graz314
2015-08-10
Readfield
ID Questioned
Quality checked by RP Graziano
Peer reviewed by
Field Notes
The Mill Stream flows from the Dam at the lower end of Torsey Pond. The water is clear with bugs skimming across the surface. The bottom of the stream has clear delineation from rocky bottom to brown,mucky,rotting material bottom. The edges of the stream contain live grasses and the bottom edges have a matted layer of rotting leaves and pine needles. The stream is surrounded on both sides by deciduous and evergreen trees. Use of the kick net produced no sensitive invertebrates (both rocky and mucky areas were tested). A young crayfish was brought up from the sediment in a rocky area. Adult crayfish (type unknown) were seen amongst the rocks and edges of stream. Creek chub (adult and fry) were seen also.The mucky area had a high density of mussels (type unknown).
Supporting Evidence
Photo of my evidence.
In this same 1 square foot area, we actually found four crayfish of approximately equal size. The crayfish moved in and out from under the rocks. Could not determine size.
Photo of my evidence.
Found in the kicknet after kicking up sediment in rocky bottom area. Approximately 2cm in length.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Decapoda (order)
Common name:
Crayfish, unidentified
Count of individuals: 
1-10
Coverage: 
Reproduction: 
How big is it?: 
Is it male or female?: 
Can't tell
Sampling method: 
Net
Photo of our sampling method.
Place Studied
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Map this species
Latitude: 
N 44.393839 °
Longitude: 
W -69.980957 °
Observation Site Information
A photo of our study site.
Habitat: 
Freshwater - In a stream or river
Trip Information
Name:
Mill Stream
Trip date: 
Mon, 2015-08-10 13:30
Town or city: 
Readfield
Type of investigation: 
Species and Habitat Survey
Ecosystem: 
Freshwater
Watershed: 
Lower Kennebec
MIDAS Code: 
5307
Habitat Observations
Species diversity: 
Evidence of vectors: 
Water temperature: 
pH: 
Dissolved oxygen: 

Comments

From the bottom photo I'd guess these were native crayfish, maybe Orconectes limosus - the spiny cheek crayfish. The distinct spines on the "cheek" make them easy to identify (although not visible in the photo). I like the fact that you spent some time watching their behavior. The top photo looks like Orconectes virilis (the northern crayfish) but again, its hard to tell without a specimen.

I'd be interested in a specimen of a male if you saved any.
Karen Wilson, USM

I hadn't set out to find crayfish, so I did not have a trap. My helper tried to catch one by hand, but they are pretty fast. Once I get a trap (either borrow or make), I or one of my students can set out to trap it.

Thanks for the feedback!

I love that you made your own kicknet! So cool.

I usually have luck finding BMIs by pulling up rocks and looking on the tops and undersides. That's another search method you could try.

Did you retain a specimen of the crayfish. I know the species expert is interested in analyzing samples as they are hard to ID to species unless you have the sample. http://vitalsignsme.org/mission-crayfish

Nice photos!!

-Christine

Thanks! I was lucky to have the kicknet materials in my garage! I'm saving that for future use!

I did not retain a specimen. I didn't have a trap, so I will try again once I obtain one.

Interesting... I'm curious if you found one of the invasive or non-native species of crayfish.