Swim tunnel test

This year's research is about the behavioural abilities of fish larvae and how it interacts with their physical environment. We will study both their swimming speed and their ability to orient in the open ocean. Today, we received the swim tunnel, ordered from Loligo systems which will allow us to measure the ability of fish larvae to swim against a flow. Check out the video on the product page to understand how the tunnel works. While the principle of the recirculation of water within the double layered tunnel can seem complex, it was quite easy to set up; in particular because Matthew Foretich, a PhD student from RSMAS, was here to help us. Matt spent a week to study Loligo's products as part of class at RSMAS. He was able to give us small tips and highlight details which will help use the tunnel successfully in the future. Here are Robin and Matt setting the tunnel up.

Loligo 1

But, today, as kids receiving a present on Christmas, we couldn't wait to try it. So we set everything up as fast as we could, popped a weeks-old juvenile fish into the tunnel, and turned the turbine on. Here is a video of the result. We start with a slow speed, then crank the speed up and the small Mullidae keeps up with it very well, and we finally come back to a reasonable speed before letting the fish out, back to its quiet and comfortable aquarium. We then examine the flow inside the tunnel by injecting dye in the water. We leave it to you to guess the nature of this dye. Remember this is a french-american cultural exchange program ;)