A First Look at Telemetry Results
Okay, I admit it. I slacked this week on blog post duties. February has already proved chaotic with personal and work-related travel, and the rest of the month will be much of the same. Seems lately I’m treading water just to stay behind. But, that’s the way it goes sometimes.
Thankfully, thought last week’s travel started quite stressful, it ended up being fun. The entire Wagner lab rarely gets together aside from occasional sampling trips to Loyalsock Creek. But, last week we all traveled to California, PA for a joint meeting between the West Virginia and Pennsylvania Chapters of the American Fisheries Society. We represented the lab well with Megan Schall receiving the award for Best Student Presentation and myself receiving the Cooper Award for exemplary fisheries work by a student member. It was also the first conference that Tyler Thompson and Danielle Massie attended, and they did a great job fielding questions about their posters. So, not only did the four of us get a chance to hang out outside of the office, but we did some great science as well.
The stressful part of the week came before we left. I’ve known for over a month that I was going to present results of our telemetry study at this meeting. Yet, even 24 hours before we left town, I still had no real data. I’ve said before that the telemetry dataset is fairly messy and complex, and it wasn’t really clear to me what numbers I wanted to present. All along I assumed I would just describe general trends in the data, but, the more I put together the presentation, the more it become obvious that some visuals were needed.
So, I started measuring fish movement. By hand. And kept measuring fish movement right up until the point we got in the car to leave. Sure, there are programs that will automate this process, and I intend to use them very soon. But, it takes a long time to get those programs to run and I was quite confident I wouldn’t get results within a day. At least by hand I knew I would have presentable data. As an added bonus, as I was measuring the movements I was reminded how cool the dataset is. Sometimes when you’re in the thralls of data collection you forget that your results are actually interesting.
What did I find in my whirlwind analysis? For starters, it confirmed that movement varied drastically across the three populations, and individuals vary considerably in their propensity to move.
Movement data for each of the three major telemetry sties, Pole Bridge (green) Double (black), and Shanerburg (red) runs. You can see that fish rarely moved from their starting location, particularly in Pole Bridge, during summer. However, after spawning, fish in Double and Shanerburg runs made long-distance movements downstream and into the mainstem Loyalsock Creek.
Second, in looking at the genetics, I found that movement is likely effective, meaning that at least some individuals that move into Loyalsock Creek eventually migrate to, and spawn in, tributaries outside of their home stream. This point is important because it indicates that movement into the mainstem is not random. Instead, fish that make long-distance dispersals into the mainstem are maintaining population and genetic connectivity, which we know are critical for long-term population survival.
Results of genetic assignment tests where each pie chart represents the frequency of certain genes in each populations. For example, in Double Run, the majority of fish have genes consistent with Double Run being their home stream, but other fish have genes consistent with an origin in Shanerburg (red). Pole Bridge (green), and areas outside the study (grey). Similarly, Shanerburg Run is comprised of fish from Double, Pole Bridge, Bear, Coal, and sites outside of the study area. Taken together, this indicates that a lot of fish move between these populations.
Pretty cool for a day of analysis, right?
Next week I’m giving the same presentation at the Virginia Chapter of the American Fisheries Society. I attended Virginia AFS for seven years before moving to Pennsylvania, so my motives for going are mostly personal. But, though this crowd is unlikely to care about the current conservation status of Loyalsock Creek, they likely will find the data of considerable interest to the conservation of their own trout populations. I’m just glad I don’t have to analyze the data again for that talk.
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