Aquatic Invertebrates- 10/3/13

In this lab, the Hester- Dendy sampler’s that were placed in Chagrin river at Chagrin Reservations Metropark on September 19, 2013 were collected and brought back to the lab to identify the organisms that were trapped on the samplers.

Hester- Dendy sampler’s are used to collect invertebrates in lotic bodies of water over a period of time. They consist of several 3 square inch wooden blocks held together by a bolt and separated by spacers so that invertebrates can colonize in between the blocks. They are anchored by a brick and placed in areas of water where they will remain submerged and exposed to water flow.

Hester- Dendy just removed from water

To collect the traps, they first had to be located in the river by finding the flagging tape on the riverbank. Once the flagging tape was found, the search began! We looked for the bricks placed in the water that the Hester-Dendy’s were anchored to. Once the bricks were located, the Hester- Dendy’s were carefully removed from the water, as not to disturb it too much and scatter the settled organisms, and placed in a plastic bag to keep everything together. Once all of the Hester- Dendy’s were collected, they were all put into a garbage bag for easy transport back to the lab.

While at Chagrin River, we also attempted to collect additional invertebrates by kick- seining. This was done by finding a riffle in the river (as riffles are the best place to find invertebrates because of the increased oxygen) and placing a one square meter seine net perpendicular to it. Two to three people stood up stream of the net and lifted up rocks and disturbed the benthos as

Kick Seining in Chagrin River

much as possible to funnel what may be at the bottom or under the rocks into the net. The net was then carefully lifted from the bottom out of the water, and samples were collected in vials filled with 70% ethanol.

D- Net

After visiting Chagrin River, we drove west to the West Woods in Novelty, OH. Here, we went to a lake to collect lentic invertebrates. Lake invertebrates are usually found in the littoral zone benthos or attached to plants growing along the edges of the pond. There is typically less diversity in lentic systems then there are in lotic systems, such as the Chagrin River. We used triangle nets for collection because that was all that was available, but D- nets are the proper net that should be used when collecting lake invertebrates. D- nets are stronger and allow for scraping stream bottoms, collecting benthos organism, and sweeping in thick vegetation. Collection was done by wading into the shallows and stirring up the bottom to collect any disturbed organism. Once an organism was caught, it was transferred into a vial containing 70% ethanol.

West Woods Lake

 Sampling at West Woods Lake

After we finished collecting at the West Woods, we returned to the lab to identify what we had found. To collect and identify the invertebrates on the Hester-Dendy’s, the samplers had to be removed from the plastic bags and placed into containers. Then, the nuts at the top of the sampler were unscrewed and the wooden plates were removed one by one. Organisms were picked off of the plate with forceps and placed in a petri dish of 70% ethanol.  The organisms were identified and keyed-out to family using the “Guide to aquatic macroinvertebrates of the upper Midwest” found at this website: http://www.dep.wv.gov/WWE/getinvolved/sos/Pages/UMW.aspx.  A list of what was

Picking inverts of samplers

found follows:

·      

   

Order Ephemeroptera (Mayflies)

o   Family Baetidae (small minnow mayfly)

o   Family Heptageniidae (stream or flat-headed mayfly)

·      Order Diptera (True Flies)

o   F. Simuliidae (Black fly)

·      Order Trichoptera (Caddisfly)

Philopotamidae

o   F. Hydropsychiodae (Net-spinning caddisfly)- very common throughout streams and construct nets at the open ends of their dwellings

o   F. Philopotamidae (Finger net caddisfly)- This family is very pollution intolerant, which is good news for Chagrin river, because it indicates the water is very good quality 

·      Order Odonata (dragonfly and damsal fly)

o   F. Anisoptera (dragonfly)

·      Order Coleoptera (beetles)

o   F. Elmidae larvae (Riffle beetle)

Elmidae larvae (from Bugnet.com)

We did not get to key out the invertebrates from the West Woods lake due to time constraints. Though from observations, Order Heimptera, and Odonata, were definitely found. This was a great lab, and cool to see our efforts from 2 weeks prior pay off.