Finding Aquatic Invertebrates In Eastern Ontario

Hey Folks!

I have just made my triumphant return from the very first BIObus trip of the season! While this trip was a bit shorter than former excursions, we still covered a lot of ground and sampled all kinds of water bodies!

In the past, BIO has been more focused on collecting terrestrial invertebrates. This summer however, we have started a standardized protocol for sampling aquatic invertebrates! I am going to briefly go over some of the techniques we used. Each differs depending on the type of water body in order to maximize the efficiency of the sampling.

The first method I would like to talk about is the “Jab and Sweep” method.  This is usually used in a wetland area where there is a large amount of muck substrate on the bottom. You jab the sweep net into the muck, pull it out, and then sweep the water above the substrate you just disturbed. After you pull your sample up out of the water, you walk back to shore and wash the contents into a holding bucket.

This is Graham demonstrating the “jab and sweep” in an opening to the water in a heavily vegetated wetland in Thousand Islands National Park
This is Graham demonstrating the “jab and sweep” in an opening to the water in a heavily vegetated wetland in Thousand Islands National Park

Then there is the “Dancing” method.  This is usually used in lakes and streams where there is a smaller amount of substrate on the bottom. It works best when there are small rocks and boulders in the stream so there are lots of invertebrates holding on to them! Then you go out as far as you can into the lake or the stream (usually up to a meter deep). You take a measurement of how far you are from shore, and then you take your depth measurement.  Now, if you are in a stream, you face downstream and “dance” to kick up the substrate as you move sideways towards the shore with the D-net in front of you. If you are in a lake then you face away from the shore and “dance” to kick up the substrate as you move backwards towards shore with the D-net in front of you. After you make it to shore you was the contents of your D-net into a holding bucket.

This is Priscila in Charleston Lake Provincial Park doing the “Dance” method to collect specimens
This is Priscila in Charleston Lake Provincial Park doing the “Dance” method to collect specimens

There are also two methods we used to collect plankton samples.  Both these methods call for the use a motorboat! The first method is plankton towing. You run the boat slowly with a net system towing behind to collect the plankton near the top of the water surface. The second method is the Schindler-Patalas plankton trap. This method is used more often to take the plankton samples deeper in the water body. It takes in the water at the depth you pull it up from and then it closes it off until you pull it back up to empty out the contents.

This is Graham and I about to measure the distance he samples in a beautiful stream in Frontenac Provincial Park
This is Graham and I about to measure the distance he samples in a beautiful stream in Frontenac Provincial Park

That’s it for this blog. There is a lot of field work going on in the next couple months so keep checking back for new blog posts from everyone on their adventures in the field!

Thanks for reading,

Dan

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