Continued work on the Roe-Jan

We continued our efforts on the Roe Jan on Tuesday, but we did not find any additional ammocoetes or any adult lampreys. We attempted to sample where lamprey have been found before but thunderstorms and tides made that impossible. However, we did sample upriver and did not find any more ammocoetes. In addition to ammocoetes we also collect other samples and data. Below is a picture of a kick sample preserved in alcohol.

Kick samples are exactly what they sound like. A sturdy net is placed along the stream bed and then the individual holding the net kicks and stamps materials just upstream of the net. Invertebrates kicked up or disturbed drift into the net and are captured there. Samples like these allow us to determine what invertebrates may be present, which gives us information on habitat quality and habitat types that maybe available. In addition, it helps to build our understanding of the community in which these organisms live. Although the sample looks like a mess of leaves and sand we then pick out the invertebrates and ID them to the lowest level possible (usually genus).

Determining the genus of an insect can take an exceedingly long time as there are many species in the Northeast alone. For instance, in North America there are ~650 dragonfly and damselfly species (~5,500 species worldwide) belonging to 12 genera, often distinguished by microscopic details. This is considered a very small group and relatively easy to differentiate. Other groups, like flies (with ~120,000 species worldwide), are so large keying an individual may take up to an hour or more.

How long will it take to key out the above individuals? Actually not long, both of these appear to be relatively common. The smaller is a badly damaged mayfly (Ephmeroptera) and the larger is likely a common stonefly (maybe Plecoptera:Perlidae:Agnetina) .