Why on earth would you try to “brew” anything using parasitic fish that slurp the blood and guts out of other fish?
Kandace Griffin: It's like we're making coffee. You're passing a hot liquid over a solid and making lamprey coffee. We have a flask of solvent, and as that heats up, it's going to evaporate. And then we'll condense over the extractor body, which has our whole body sea lamprey, and then it will go back down onto the sea lamprey. That's how the alarm cue is extracted from the body.
Griffin: We collect it, and then that's what we can use in our experiments. An alarm cue is a substance that warns other animals, typically of the same species, that a predator is around or attack has occurred. So for sea lamprey, when their skin is abraided, they will release this cue into the water and other migrating sea lamprey you can smell it.
Griffin: And they know that an attack was either close in space or time. So we're working to create some alternative control methods for controlling the sea lamprey. TFM is put in by the what the river discharges. Doesn't matter how many lamprey are in there. You still have to put the same amount to match the river discharge, whether you kill one or a million.
Griffin: So if we are able to have other alternative control methods such as manipulating their behavior and driving them into a trap on areas where maybe the TFM is not economically viable or on tribal and First Nations lands that putting a chemical pesticide in the water is unfavorable. The tags in the lamprey are emitting a signal that the receivers in the river can hear. And so each lamprey has a tag with a unique code.
Griffin: And when it's heard on at least three receivers at the same time, then we can find that 3D position. With the technology that we have, we will be able to tell are they changing their ground speed or are they changing their sinuosity? Are they taking a straighter path? How are they mitigating this risky area? Maybe we can push them towards a trap or push them towards an area of the river that is unsuitable for their spawning grounds, so maybe their eggs don't survive.
Griffin: So then there's fewer of them. They're trying to make it up to their spawning grounds with enough energy to put into their spawning. So now we know if you put on an alarm cue right here, how are they going to manage this risk while also managing their energy expenditure? Because these animals have a limited energy budget. They've stopped feeding and they want to be as energy efficient as possible.
Griffin: And so what might have been the most energy efficient route now is now the risky route. And so how are they going to manage this tradeoff in their movement decisions?