A Year Later

Exactly one year ago, fueled by coffee and angst, I tagged my first telemetry brook trout and started what would be an 11-month study on movement and gene expression of four brook trout populations. I had no idea what I was getting myself into (for starters, it was supposed to only last six months). And, as I continue to analyze the data, I’m not entirely sure what I got myself into. But, what I do know is that one year later, a combination of good fortune and effort led to some pretty cool data. 

So, what did I learn in the last year?

• Collecting telemetry data isn’t THAT hard.  When I started my Ph.D., I never imagined I’d do a telemetry study. And, honestly, I had no desire. The combination of electronics, lingo, and uncertainty really dissuaded me from wanting to purse this costly endeavor. But, I knew it was a great skill set, and I was assured by many colleagues that I’d catch on fast. I was reluctant to believe them (I think I even called many of them liars to their face), but they were right. The first few days were exhausting and confusing, but I caught on. In the end, everything I was worried about didn’t really matter.  What mattered was knowing which rocks absorb tag signals and needed to be tracked carefully, developing expert skills in “I Spy the Antenna” when trying to confirm dropped tags, knowing the appropriate defrost settings to use in the truck when drying out a receiver that took a belly flop into the stream, and finding a way to silence the phantom chirping noises from the receiver that you hear in your sleep (that thing really haunts you at night). 

In case you're wondering, 30 minutes on medium heat can dry out the inside of a receiver box, but I would not recommend.

• Analyzing telemetry data is THAT hard. It seems easy. There are points on a graph, and you just need to measure the distance between the points to see how far a fish has moved.  But, I have nearly 3,000 points, and the distance between points needs to be measured with as little error as possible. That’s tough because GPS points collected in remote locations (like Loyalsock State Forest) are inherently inaccurate because satellite reception is limited. So, there’s a lot of work done back in the office to get the points as close to the right location as possible. Then, I have to make judgement calls about whether the movement data truly represent a fish, or whether I think it’s actually a dropped tag. Tags that never move can’t always be trusted, but neither can tags that only move downstream. So, I look at the GPS points and all the notes and make a decision for every individual tag, 180 in total. Only then can I start measuring movement distances. Thankfully there are software programs that can automate this process so I don’t have to individually measure the distances by hand. But, it requires coding data into the computer and double checking that it’s working correctly. I still haven’t finished all of this, but I’m close.  Then I can finally start actual data analysis. I know many of you are interested in hearing about fish movement and our results, but the road to the information is not as smooth as it may seem. 

A little snapshot of what it looks like to measure fish movement distances.

• But, it’s all worth it because the telemetry data are really interesting. Without it, we wouldn’t have figured out that brook trout move into Loyalsock Creek after spawning, and that these movements are the basis for a metapopulation (metapopulation is just a fancy word for several smaller populations that are separated, but sometimes share individuals among them). It’s a fairly rare discovery. While a lot of anglers and biologists assume that this type of movement pattern exists in brook trout, it doesn’t happen everywhere and its hard to document. But, it’s extremely important to find these metapopulations so we know how to properly conserve brook trout. Now we know without doubt that Loyalsock Creek is important brook trout habitat, and that we need to preserve connectivity between tributaries and the mainstem in order to conserve brook trout in that region. Or, more simply, brook trout conservation- which includes anything from habitat restoration to considerations about fish stocking- can’t ignore mid-reach waterways if we want to preserve the genetic integrity and health of native populations. 

The little fished that proved metapopulation dynamics in Loyalsock Creek.

• Speaking of genetics, somewhere along the way I picked up several projects that focus on genetic and molecular ecology.  My hatred for these topics wanes a little with each day, but I never envisioned I would be where I am today.  It started innocently with population genetics. Though this level of genetic study was (and still is, actually) far beyond my level of understanding, I knew the tools needed to complete it were readily obtained from textbooks and conversations with friends working in that field. Now that the data are largely in hand and results are rolling in, I can’t believe I tried to get out of studying genetics. Without the genetic data, we wouldn’t be able to tell that movement into Loyalsock Creek is effective- meaning fish that move into Loyalsock Creek go on in future years to spawn outside of their home tributaries. This just proves to us that the movement we saw with the telemetry data isn’t random or unintentional.  There are fish out there are that ‘hardwired’ to move back and forth between tributaries and larger mainstems, and they are the ones keeping the metapopulation connected. 

With a simple clip of the fin, we can get a whole lot of data on genetic diversity and population connectivity.

To monitor gene expression, we not only have to sample fish in hot temperatures, but also cold. That's okay..eventually you don't feel your fingers, anyway!

• And then, to this day, I don’t know how this happened.  Maybe it was one of those “no means yes” deals, or just a reckless decision made before the coffee kicked in, but I found myself leading a study of gene expression and microRNA. Unlike population genetics, those aren’t terms you can readily Google. And, I don’t really know anyone that studies gene expression that I can run to with insanely stupid questions (so, sorry to Luke, our collaborator on this project). But, I’m learning as I go.  I’m learning that brook trout can survive just fine without a few gill filaments, that drawing fish blood isn’t all that hard, and that you will get awkward stares when you set up a mobile centrifuging station in the parking lot of a gas station. I’m also learning gene expression data can be really interesting. It turns out, brook trout turn on the machinery (i.e., genes) to express heat shock proteins very early in the year, around mid-April. These proteins help keep cells alive when it’s hot, but “hot” to a trout appears to start around 50°F. It’s important to know when fish start expressing these proteins because, as we’re learning, there is a limit to how long the genes can stay on and how much heat shock protein can be produced.  By the time it’s actually hot in July, the genes are no long actively cranking out heat shock proteins and fish have to use whatever is left to protect their cells. If the genes turn off too soon, then fish could be left without heat shock proteins to keep their cells alive. This result has implications for future climate change, as we’re projecting stream temperatures to warm earlier in the year and reach higher maximum temperatures. So, the question is, will fish have the molecular capacity to keep up with these temperature rises?

 
Having spent much of the last year working outside, I have to admit that it feels a little weird to not be frantically packing and preparing for field work right now. But, as much as I would rather be out in the streams, it’s time to hang up my waders and get to analysis. After all, I need to graduate eventually! 

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