The Future for 80% of Trout Habitat
Thanksgiving came and went. The Christmas decorations are up and making the house annoyingly festive. Now it’s time to take a deep breath and prepare for the chaos that comes before the next long holiday. Not sure why, but it always seems like early December has the most deadlines.
First up- The Troutlook might be expanding. Penn State offers a pretty lucrative deal where undergraduates can apply for a semester-long research fellowship. It starts with a small research proposal - background information, proposed methods, significance of results, etc.- that offers a nice introduction to what the “professionals” have to do when trying to convince a granting agency to give us money. If funded, the student gets paid about $1,700 and gets three academic credits to conduct research during the semester. It’s a really great gig.
This semester I’ve had several undergraduates approach me about opportunities to volunteer in the field or help analyze data (lesson one: volunteering with a grad student is a great way to get experience and put your foot in the door). Penn State has a fairly small fisheries program, and so one goal I have anytime a student joins me is to give them career advice and answer questions they have about jobs and grad school (lesson two: volunteer for everything, you’ll always learn something). I had two students in particular that stuck with me despite me ignoring their many, many attempts to volunteer (lesson three: persistence- One of my favorite quotes that summarizes grad school is “I have no special skills, I am only unreasonably persistent”). I started working with them around the same time I heard about Penn State’s fellowship program, and it made perfect sense for both of them to submit a fellowship proposal. Those are due this week, and I’m optimistic that we may be adding some undergraduates to the team. Fingers crossed!
I spent some time this week editing the first draft of their proposals. Of course both proposals are for research related to brook trout and climate change, and the proposal guidelines have tight word restrictions. When pressed with word limits, a great strategy is to floor the reader with a quick statistic that paints a harrowing picture about your subject at hand. No fancy numbers, no long descriptions, no background of fish required. I found it in a paper that Seth Wenger and his colleagues wrote in 2011:
Nearly 80% of brook trout habitat will be lost to climate change.
Why so high? Yes, stream temperatures are rising above brook trout thermal tolerance. We all knew that. But, that’s not the only aspect of climate change that will affect brook trout. We spend so much time focusing on temperature that we often forget about other aspects of climate. For example, more rain and less snow will lead to increased winter stream flows. For fall-spawning brook trout, higher flows during winter will results in decreased egg survival and accelerate population loss. The negative effects of increased stream temperatures and higher winter flows may also be accelerated were there are multiple trout species, such and brook and brown, that are competing for the same resource, or increased watershed development that may degrade habitat or fragment populations.
But, 80%. Wow.
These results represent a model for brook trout populations out west where they are nonnative. So, perhaps they aren’t directly transferable to native brook trout populations of the east coast. But, in the west streams are generally colder and brook trout populations larger and more robust. So, I can only guess what a similar model for east coast populations would look, but I feel fairly confident in saying the numbers wouldn’t be pretty.
Also disheartening is that these projections are for 2080. Perhaps I was just being naïve, but I used to think that climate projections were so far in the distance that we didn’t have to worry. Surely we would fix these problems by then. And, 60 years may still seem fairly distant. But, it suddenly seems like the clock is ticking. Our time to fix this problem is running out. Every generation of trout counts. Every year that we don’t make progress is another year closer to extinction.
This is why I do the research I do. At times it seems like my ideas are grasping at straws with more oddball ideas. And, maybe they are. But, if we are to save trout, we need to do more than model their numbers, stock more fish, and plant more trees. Those are all worthwhile endeavors, but we need more. We need something different, something new. Something that very soon can start tipping the odds in favor of brook trout.
And, it all starts with an oddball idea….
To the Day I Never Thought Would Come
I made it- 168 days after I released the first tagged trout back to Loyalsock, I am hanging my waders up to dry. Telemetry season 2016 is over. And, it a good one.
Here are a few quick numbers to describe the last 6 months.
What’s on the docket now? First off, a lot of sleep. Then, a lot of unanswered emails. “I’m in the field” has been a great way of avoiding a lot of requests and obligations. Thankfully most people emailing me understand the chaos of field season, but I can no longer play that card.
After that, it’s time to start thinking about how to analyze all the data. In addition to the telemetry study I have about three other projects that are in need of attention. The data for all of them are collected, the results fairly clear and predictable, but it’s time to start making them more official and getting them ready to publish. For example, I can tell you a lot of great information from what I saw in the field. But, rather than saying “the fish moved,” I need to relate movement patterns to things like stream flow, fish size, and hopefully genetics. To do that, I also first have to clean all the data- fix bad GPS points, download temperature data, make sure everything is recorded correctly, etc. A lot of mind numbing days are ahead. But, sneak peek- the fish moved. And the most surprising thing, at least to me, is how many fish moved to Loyalsock after spawning. We thought it might happen, but I was thinking it would be a smaller percentage than what we found. During November sampling we really struggled to find adult brook trout, while in September they were plentiful.
While I’m looking forward to spending more time at the office and having some resemblance of a normal schedule back, it won’t take long for me to miss Loyalsock. While the bulk of field work for my degree is now complete, we have discussed the possibility of sampling more in the spring and summer. So, hopefully it won’t be too long before I’m back.
For now, Happy Thanksgiving! And if you’re fishing Loyalsock, keep an eye out for my antennas. My babies are on their own until spring.
The Little Trout That Could
In 2014 it was a hunch.
In 2015 it seemed like a long shot.
In August it was wishful thinking.
In September it seemed possible.
But today it is without a doubt confirmed. Brook trout use Loyalsock Creek as overwintering habitat.
In my post last week I hinted that this was probably the case. There were a few tags that suddenly appeared in the mainstem shortly after what I had guessed was peak spawning season. But, we couldn’t be sure. There’s always a question of whether a dropped tag floated downstream. And, even with some tags entering the mainstem and going upstream, it’s always possible that they were gobbled up by a bird.
But, there’s no question about it now. This week we’ve been doing the final round of 2016 tissue collections and finished a little early on Thursday. On a wing and prayer, with daylight dwindling, I sent the crew to an area on the mainstem Loyalsock that had a few tags and was shallow enough to wade through. I was hoping to maybe move the tags around, which would confirm that it was in a fish, and with any luck actually capture a brook trout. But, even if a trout was there, the probability of catching it was small. Backpack shockers are intended for small streams where you can push fish into habitats they can’t escape. In larger waters, the fish feel a little tingle and start running. And, walking in Loyalsock is like sliding around on greased bowling balls. But, I had to try.
So, Dan and I hoisted on the backpacks and started shocking. Chubs, madtoms, smallmouth bass. All signs of a cool water fishery and not what you want to see in trout waters. We shocked past where the receiver said the tag was, but it didn’t move. It started to seem likely that it was a drop. We fine-tuned the signal to a large rock and Dan started shocking all around it. I stood on the side anxiously awaiting the outcome and prepared for disappointment. Standing there, I see a white mass come out from under the rock and held my breath in excitement waiting for Dan to identify his catch. Sure enough, not only was it a brook trout, but it was tagged fish 38.16. Success! And, after searching for more tags, we ended up catching a much smaller, untagged brook trout. They are there, and they are fairly abundant.
That fish was originally tagged in East Branch in September. In the early weeks of fall tracking we saw it swimming in a shallow pool several times, likely preparing to spawn. And then it disappeared. Based on my experiences this summer, that usually meant that something had eaten the fish and taken the tag far away. But, in the days that followed I noticed tags go “missing” at a much faster pace than I ever saw over the summer. Looking to rule out possible downstream movements, I tracked Loyalsock one day. Sure enough, there they were.
Now that we are nearly at the end, I can confidently say over 1/3 of fish tagged in September moved into the mainstem Loyalsock (and that proportion might be much higher once I determine how many tags were dropped in the stream. And, I’m sure more are on their way. There are a few fish that have been moving downstream in the past week and are probably on their way to Loyalsock now.
Tributary to mainstem trout movements are not as uncommon as you might think. And, though only a handful of studies have documented this movement pattern, it makes a lot of ecological sense. Coming off of a stressful summer and increased activity with spawning, adult trout are literally starving. And, they know that they need to prepare for a long, cold winter ahead. In the winter fewer insects are emerging and the once bountiful streams lack significant sources of food for trout. But, mainstem rivers have many small fish that are not only plentiful, but have a higher caloric value than small insects. In fact, during sampling the last two days we found several trout with small trout tails hanging out of their mouths. Diets once made almost entirely of insects have quickly shifted to fish-dominated.
The mainstem also offers some thermal buffer relative to the smaller tributaries. As stream temperatures continue to drop, trout will enter into periods of dormancy known as torpor. Trout don’t actively choose to go into torpor; it’s a physiological response to cold water because, unlike humans and other endotherms, fish cannot maintain their body temperature. Their body temperature is the same as the water they are swimming in, and when they are cold their muscles don’t function as quickly as when they are warmer.
Torpor is likely, at least in part, an evolutionary response to a lack of food. While in torpor, fish metabolism is very low and they require very little energy to remain alive. However, while torpor may allow fish to survive cold winters, it also decreases their ability to continuing growing and reduces the amount of energy they can put towards producing offspring. But, by staying a little warmer during winter, fish occupying mainstem rivers will spend less time in torpor, more time feeding, and they can put more energy into growth and reproduction.
So, in short, trout migrating to the mainstem have more food sources, grow larger, and maybe even produce more and healthier offspring. More interesting, though, is that only a subset of the population seems to engage in the behavior. Some seem hardwired to do these movements, and others content staying in the small streams. What causes this? Great question, but I have no idea. At least not yet. I still have over a year to figure it out.
Graduate students do a lot of reading. And, sometimes, you stumble on a research article that is so obvious you wonder why you never thought about it before.
For me, one such article was, “Landscapes to Riverscapes: Bridging the Gap between Research and Conservation of Stream Fishes” coauthored by Kurt Fausch and his colleagues in 2002. I first read this article as an undergraduate, and it’s probably been assigned reading in no fewer than five other classes along my academic journey. Every time I read it I think two things. First, “duh”. Second, “why are we (still) ignoring these concepts in our management of fisheries?”
The take away message is that fish ecology is often not reflected in our design of research projects and management of fish populations. Seems like a major oversight, right?
In everyone’s defense, it’s really difficult, perhaps impossible, to cover all aspects of a species’ ecology when designing a research project. For example, we’re lucky if we can scrape together enough funding to run a project for 2-5 years. But, many fish species live much longer than that and are affected by processes that occur much less frequently (e.g., disease, rare weather events) or over very long time scales (e.g., climate change, evolution). So, we end up with a series of studies with important results, but results that many not be entirely appropriate for the species of interest. For example, a short-term study on the effects of floods on fish populations might conclude that they are catastrophic. But, if you look 10-50 years later, you might find that they are beneficial.
Likewise, scientific crews are often small, overworked, and under paid. We can only cover but so much area, and so we decide to sample a few hundred feet, maybe yards, of habitat. Or, we might use aerial maps to visualize entire watersheds. But, with these two approaches we’ve missed the spatial scale that is likely most important. Fish don’t stay put in one pool, or even a small stream segment. And, very often, they don’t move around the entire watershed. The scale that is probably most important, at least for trout, is measured in miles. But, sample crews can’t measure fish and habitat across miles of stream, and we certainly can’t use maps to document the fine-scale habitat features that are found in these stream segments.
The scary thing is that our data often lie to us, and we don’t know that we’ve collected information at the wrong temporal or spatial scale needed to answer the research question of interest. We could study the same population of fish for decades and never see movement. But then, suddenly, a slight increase in temperature or a little bit more rain, and you may see long-distance dispersal (this happens in populations of Arkansas darters, which seem to make long-distance movements, but only every 5-10 years after heavy rains). Or, we might study a species only during summer (which is common) and miss seasonal behaviors or changes in habitat use that correspond to different stages in the individual’s life cycle. And, if we do that, we may (and often do) falsely conclude that fish don’t move or make some other inaccurate statement about a species’ ecology.
Even more scary, these rare events and small-scale habitat features that we very often miss in our studies are some of the most important for fish populations. It’s the rare, long-distant movements that recolonize streams and connect populations. And, it’s the seasonal use of tiny areas of ground water upwelling or short-term occupancy of unique habitat features that fish use to spawn or survive thermal stress.
Though scientists are starting to realize the inadequacies of our studies (not to say we are fixing them, our hands are often tied), management hasn’t always kept up. For starters, managers’ hands are also tied. They can only work with the information they have and, as I’ve said, the information is often inaccurate or missing. But, sometimes, the protocols in place for protecting fish species need updating to better reflect improved information on species ecology- information that highlights the importance of considering different temporal and spatial scales in management plans.
Take for example Pennsylvania. In Pennsylvania waterways are given a designated use classification based on the aquatic species present. The streams I’m currently researching have different designated uses depending on the exact location, but include “Exceptional Value,” “High Quality Cold Water Fishes,” and “Migratory Fishes,” largely due to the presence of healthy trout populations. But, Loyalsock Creek itself has a designated use for ‘Cold Water Fishes’ indicating the river is used to propagate or maintain cold water species, including trout.
What’s the problem? This designation system emphasizes population size, which is a very reasonable approach when considering the data in hand and average conditions. Shanerburg Run is a high quality system because there are far more trout there than in Loyalsock Creek and, unlike Loyalsock Creek where summer temperatures far exceed trout thermal tolerance, Shanerburg Run can support trout all year. Further, evidence of wild trout in Loyalsock Creek has been limited because most sampling occurs in summer (when Loyalsock is too hot) and the system, which is a combination of deep pools, shallow riffles, and large boulders, is test for all fisheries sampling gear.
However, as we are learning from our telemetry study (and perhaps the anglers of Loyalsock already knew), Loyalsock Creek may be critical over-wintering habitat for a sub-set of brook trout. They don’t stay there all year, and it’s certainly only a small proportion of fish, but these nomadic individuals may be critical for sustaining brook trout population connectivity. As I talked about in my post last week, connectivity greatly improves population health by increasing genetic diversity and lowering the probability of population extirpation. So, protecting these fish may be disproportionately more important when considering conservation strategies.
Given this, are main stem rivers getting enough protection in brook trout watersheds? It’s hard to say. This is one case on one small scale with results that are still unfolding. But, it does highlight the need to think beyond “average” and consider how fish habitat use may change depending on the time and space scale you are considering.