Day 6 in Thonon

Today was a super fun day. I had to talk at the lab and my French hosts listened politely as I talked about some of my research on the Great Lakes. I then heard a very interesting talk about how otoliths microchemistry can be used to descriminate trout raised in different hatcheries from wild fish in rivers. Think of this. A fish is born and raised in water with chemical properties and those properties become part of the fish in their bones. By looking at the chemistry of the bones that were built early in life, one can seemingly understand from which water source the fish originated from. Of course, you need to know what it is you're doing to make the method work.

After lunch we tested the larval fish trawls. I say trawls because we fish two at the same time; one port side & one starboard. We wanted to be sure we could fish when the platform was on the boat. Here is a picture of a trawl in the water. Special thanks to Orlane Anneville for taking today's photos!

We wanted the trawl to fish so that the top was right at the surface, so to make this happen we had to pull in some line. JC is doing most of the work here.

We fished the trawls for about ten minutes and brought them in to see what we caught. Each net caught one larval coregonid for two in total. The fish were small so we think they were newly hatched. Here is Jean-Christophe unscrewing the cod end bucket to empty the catch into a pail. 

We put the two baby fish back in the lake alive!