It’s been awhile since I’ve posted a true research update. That’s because there’s not a lot going on. I mean, yes, I am working. And, I’m making good progress. But, not every day, or even week or month, leads to interesting results. But, I’m inching forward and I’ll reach the finish line eventually. Until then, I’m sparing you the details of how much pipetting and data entry I do on the average day. Trust me, it’s for your benefit.
This week I was able to get out of the lab and into the field to do my monthly tissue collections. While it’s great to get into the field, this work is always a little anti-climactic. The objective of this study is to determine how fish respond to temperature stress at a cellular level. So, we go out and collect tissue samples, hoping to capture increases and decreases in gene expression, the measure of stress, as stream temperature rises and falls. Seems like I would have a carefully designed, clear sampling plan, right?
Ha. My sampling dates are always a moving target. I try to predict stream temperature by looking at the five-day forecast. But, I’ve found that even obsessively checking all forecasting websites rarely gives a great prediction of air temperature or perception. Even if it did, air temperature doesn’t always predict stream temperature. But, it’s all I got. I then look at my calendar, try to scrounge up technicians and, voilà, I land on a date where it may or may not be the temperature I hoped for, but at least I have some help.
Once I’m in the stream, I have no idea what the temperature actually is. I have loggers recording stream temperature every 30 minutes. But, I don’t download the data until the end of the day so that I know what temperature was while sampling. Doesn’t really matter, though. After a two-hour drive I would sample regardless of the stream temperature.
So, we collect 20 or so fish. Sometimes it’s an easy 4-5 hours, other times it’s a 10-hour fight battling high flows and small fish sizes. When I return back to campus, the samples go in a deep freeze and sit. Sometimes for a few days, sometimes for a few months. Once they are delivered to our collaborator in West Virginia who actually measures gene expression, the samples sit again. Most samples from 2016 have been process at this point, so I have some idea of what the data show. But, it’s still a guess, and I just cross my fingers we’re doing it right.
So, I can’t tell you much about the data we are collecting. But, I can tell you, at least anecdotally, a little about how the populations are looking. Last summer was rough for trout. It was hot, it was dry, and our telemetry data showed that trout were getting picked out of the streams by birds and other animals left and right. There were then high rains in fall that washed away eggs, followed by a pretty mild winter. All in all, there was lot of concern in Pennsylvania about how the populations, particularly the young-of-years, were going to look this spring/summer.
Turns out, they are doing just fine. At least in the handful of streams we are sampling right now. Unfortunately, the one-year-old fish are still a little too small for us to sample just yet, but they are huge. And, come November, these fish will be recruited into our study. More impressive, the young-of-year and little floating footballs. I’m not sure I’ve ever sampled a trout stream with fish that were consistently so large. (You also notice I’m not telling you where we’re sampling. It’s a public stream, but I’d like to keep all the fish to myself, thank you).
Does that mean all the fish in Pennsylvania are doing well after the rough conditions over the last year? Absolutely not. The streams we sample are forested, have minimal fishing pressure, and at least one seems to have an exceptional forage base. In the weeks to come, a more extensive survey of Loyalsock streams will be undertaken by Susquehanna University. Until then, we won’t have a great picture on how Loyalsock populations faired over the last year.