I'm excited to announce that our segment on WNEP's Pennsylvania Outdoor Life aired today. Don Jacobs and Brian Hollingshead did an incredible job bringing our research into the homes of thousands. It's rare that scientists get offered a platform to present our research to a general audience, and I'm glad to see that it's already generated a lot of interest from viewers.
If you saw this segment and want to know more, please let me know! My contact information can be found in the "Who We Are" section above. If you missed it, the videos are posted below, or can be found here and here.
Post-tagging, the first location collected on a fish is one of the most critical data points. If this location is collected too soon after tagging, we may capture post-surgery stress movements that don’t accurately reflect a fish’s choice to move. If we wait too long, we may miss important movements that could be informative for determining a fish’s behavior. So, before collecting that first point, we typically wait about a week after tagging to start tracking fish.
Why a week? Honestly, that’s timeframe is somewhat arbitrary and probably a better reflection of how long it takes to physically recover from tagging, repair equipment, and get bored in the office (actually, I was bored within a day, but I soldiered on).
One of the only exciting parts of this week was news that we were making a TV debut. On the first day of fall tagging I was joined by staff from WNEP’s Pennsylvania Outdoor Life to document the sampling process and learn a little more about brook trout ecology. It was great being able to share my research with the cameras, and hopefully connect it to a larger audience in central Pennsylvania and beyond.
Footage is starting to surface from WNEP, including a full 30-minute segment on Pennsylvania Outdoor Life that will air in a few days. But, on Wednesday we were included as part of another WNEP program called Power to Save.
Below is video from the Power to Save program. I’d suggest watching the entire segment, but our brook trout research is featured around the 1:50 minute mark. Enjoy, and check back next week for links to the full 30-minute segment.
If you have trouble with the link below, access the original video here.
A few weeks ago the crew of WNEP's Pennsylvania Outdoor Life joined us in the field to shoot some footage of us tagging trout and talking about fish ecology. It was really fun sharing my work with them, and in the next week two television segments from their visit will be airing.
Not in the viewing area? No worries! Check back here for links to all the videos.
In addition to bringing a new tagging season, the end of the summer also shuffled the players behind team "we" that I frequently talk about in my posts. Savannah more than exceeded expectations all summer with keeping both the research and my sanity in check. But, she had to return to her junior year at Susquehanna University. Thanks for all your hard work, Savannah!
Fortunately, her replacement is a familiar face. I've been working with Dan Isenberg for over a year, usually relying on him to collect fish for one project or another. So, his position as a research technician at Penn State just makes his affiliation with the project official.
A little about Dan-He grew up in a rural area in central Pennsylvania next to a large reservoir, which is where his interest in water and what's in it started. He is particularly interest in large fish species, focusing on catfish. He graduated from Susquehanna University, where he was involved in many different fisheries research projects. His experiences range from headwater research with brook trout to river studies on channel catfish.
Dan is currently a full time fisheries researcher at the Freshwater Research Institute at Susquehanna University. He is also searching for a Master's program that focuses on large fish movement in order to pursue his dream of becoming a professor.
The lazy summer days of tracking just got a giant kick start. That’s right; fall telemetry season is upon us. This week we finished tagging 61 brook trout and also collected tissue samples from nearly 150 other fish for genetic analysis.
In an earlier post I walked through the step-by-step process of telemetry tagging. Reading that post now, I feel like it’s a bit of a misrepresentation of the tagging process. The methods are accurate, but it doesn’t do justice to how exhausting the process is. So, what does a tagging day actually look like?
For starters, there are a lot of batteries. And, no matter how good my intentions are to start charging those batteries early the day before sampling, it never happens. Same goes for running odd errands, packing miscellaneous supplies, and making sure everything is labeled. I can start these projects weeks in advance, but it won’t be until the day before that they actually get done. Often this is no fault of my own as I’m waiting for supplies to arrive from collaborators or details to be finalized. Either way, I go to bed far too late. I’m off to a great start.
It’s tagging day and the alarm greets me at 4:15am. I think ‘how much do I really want this degree?’ as I roll out of bed. I’m a morning person, but this really pushes my limits. I quickly make coffee and start hauling all of those supplies back to the truck. Thankfully State College grocery stores are open 24 hours, because I still need to get ice for tissue samples (side note: stores may be open that early, but by no means do they expect any customers to be shopping - many looks of insanity are received).
By 6am I’m at campus to meet anyone from Penn State joining me for the day. We throw everyone’s gear in the back and start the two-hour drive to Loyalsock.
We arrive to the site around 8 where we meet a small army of volunteers that have thankfully given up their day to help. Everyone waders up, and we start hauling the entire contents of my truck to the processing station. It takes about 30 minutes to get everything set up and I signal the electrofishing crew to start.
From there my day becomes a juggling act. I’m trying to keep the electrofishing crew moving, but they can’t catch too many fish because I need to collect tissue samples within 30 minutes of capture (after 30 minutes protein levels, the primary thing we are analyzing, in gills and blood change). I’m taking biopsies and tagging fish. But, almost every fish is a judgement call- tag a smaller fish now, or wait until later in the day when we might catch bigger fish but risk running out of stream. We are also trying to recapture fish that were tagged in May, so I’m trying to remember where they are and their tag IDs so the crew can focus effort to a specific place. But, “next to the big tree” isn’t very descriptive to someone that hasn’t been walking the stream all summer.
My job is mentally exhausting, but I barely move from the processing station all day. The electrofishing crew is constantly on the move. One person is wearing a 30-pound electrofishing backpack. The others are carrying heavy 5-gallon buckets of water and fish. Everyone is walking (more like controlled falling) over the equivalent of oiled bowling balls. As soon as they catch a fish, someone has to hike it to the processing station which can be up to half a mile away (recall the 30-minute time window). At the processing station, they set the bucket down, grab an empty one, and hike back to the electrofishing crew. No rest. I have the greatest volunteer crew around, otherwise this would not happen.
We typically finish sampling around 6pm, but the day is far from done. All the fish that we caught are still recovering in nets next to processing and need to be dispersed across the stream. While the new tagged fish are placed somewhat randomly in areas of good habitat, recaptured fish that were tagged in the spring need to be returned to the exact place they were captured. So, everyone grabs a bucket of fish and we start hiking. This week we also added plasma collection to our repertoire (because obviously not enough was going on). To collect plasma, every blood sample needs to be centrifuged for 5 minutes, plasma pipetted off of red blood cells, and then both blood components processed and put on ice. At this point, daylight and patience is growing thin.
We leave the site around 7pm and start the two-hour drive back to State College. I drop everyone off at campus and make a quick detour to my lab where I organize blood samples and place everything in a -110° F freezer. Finally, nearly 16 hours after I left, I make it back home around 9:30pm.
But, remember all of those batteries? That’s right; they all need to be brought back inside to charge. New vials need to be organized and labeled, supplies repacked, and an email sent to the volunteer crew meeting us the next day so they know where to go. Inevitably, something always breaks during the day, so I need to fix or troubleshoot the problems. Finally, around 10:30pm, I’m at least somewhat prepared for the next day. Despite only consuming coffee all day, I really question whether I want to eat dinner or go straight to bed. I opt for food, but only because I can hear my mother in the background scolding me for poor eating habits.
My head hits the pillow around 11pm, and the process starts all over. This time, not only am I waking up to question my desire to graduate, but also wondering just how sore muscles can get.
The other day I was in the middle of the stream and took a rare moment to glance up. Towering above were several large hemlocks playing gatekeeper to the hot sun trying to peak through. In addition to being one of the few trees I can identify, hemlocks are one of the most common species of riparian vegetation in trout streams. But, invasive insects are threatening the health of hemlocks, which could have devastating effects on brook trout populations.
I know nearly nothing about trees and certainly couldn’t do this topic justice. So, I asked my colleague Erynn Maynard, a PhD student in the Ecology Program at Penn State studying invasive plants, to catch me up to speed on the plight of the hemlocks.
Do you have a favorite hemlock grove? If you spend time outdoors in the northeastern United States and in the southern Appalachian Mountains, you likely can think of a place where this species casts their deep purple shade. Within this region, hemlocks flourish in riparian areas near clear, flowing water, and even thrive in rocky outcroppings and stream-edges. Their roots appear to cling and hug to rocks and squeeze between crevices. They are frequently, although not always, accompanied by the graceful sweeping branches and large leaves of the evergreen shrub, rhododendron (Rhododendron maximum).
While the eastern hemlock (Tsuga canadensis) has tiny needles (1/3 to 2/3 inch in length), they are arranged in a single plane along their many branches to provide dense, evergreen shade (a must-have for trout!). Hemlock seedlings can only grow in a dark, moist litter bed, and so they require the deep shade of a hollow and/or other trees to first pave the way and grow large enough to cast shade on the soil below. Once a hemlock seedling germinates, slowly, over many decades, the hemlock will grow and continue to reach for the canopy. Once it inches above its fellow competitors, all other tree species fail to regenerate and only the occasional beech tree will survive in the shady understory. This is why old hemlock stands are what ecologists call a ‘climax stage,’ meaning that the trees species that make up a forest doesn’t change much once hemlock take over. Well, that is until the hemlock woolly adelgid was introduced.
The hemlock woolly adelgid (Adelges tsugae) is an insect that resembles an aphid and sucks sap from its host trees near the base of the needles. Its native range in East Asia, the woolly adelgid is usually not capable of killing or even severely impacting the health of its host tree. However, in the United States, trees do not have defenses against the pest, and hemlocks typically succumb to adelgid infestation within five to seven years. If you do have a favorite hemlock grove in the southern parts of the hemlock range, you may have noticed it thin out and lose the purple cast shade over the recent years. Sadly, in many areas, the grove may be gone completely.
Why does this matter for brook trout? This thinning of the canopy over coldwater streams allows more sunlight to hit the water causing increased stream temperature in the summer, which brook trout are very sensitive to. In the winter, because air is cold and the ground is warm (comparatively), streams are actually a few degrees warmer when under a dense hemlock canopy and this warmth could facilitate development of brook trout eggs. In some cases, rhododendron shrubs, which have large evergreen leaves, and already existed in the understory can thicken and provide a similar shade and buffering effect. However, in many cases, this shade may also prevent trees from re-establishing at the site, which has many other impacts to the terrestrial and aquatic ecosystems.
Rhododendron is also not an equal replacement for hemlock because they are smaller and are not able to regulate water levels in the same way as the larger, denser hemlock. You can think of each hemlock tree as a storage container for water. When it rains, hemlocks soak up water preventing it from immediately flooding streams. When it’s dry, hemlocks slowly release this water back into the atmosphere. So, loss of each hemlock means an increased risk of flooding and less water available during droughts.
When trees are able to re-colonize after hemlock departs, they tend to be deciduous trees, meaning that they lose their leaves seasonally and are bare in the winter. Unlike the evergreen hemlock, deciduous trees are not actively storing and using as much water during the winter. This results in higher stream flows in the winter when deciduous trees are dormant, but also lower stream flows during the spring and summer as deciduous trees are using a lot of water to grow and maintain their big floppy leaves. In fact, streams with hemlock have a much lower chance of going dry in the summer than streams lined with deciduous trees in the same watershed. This water regulation service provided by hemlock helps keep stream flows consistent for fish, but also invertebrates. An increased chance of seasonally drying is one of many factors that impacts the abundance and diversity of insects and other invertebrate organisms in the stream. Hemlock streams have more of these delicious creepy-crawlies than hardwood streams do, which may be why some studies have found up to three times as many brook trout in hemlock streams as compared to deciduous streams.
What is being done about this? Well, individual trees can be chemically treated with insecticide (on the trunk or in the soil where it is absorbed into the entire tree) to prevent adelgids from eating them. This is obviously time and cost prohibitive in large and remote areas, and is usually only done in parks and landscaping settings. However, this is not a permanent solution, but merely a hold-over to keep large trees alive until predators are established for the adelgid. While the hemlock woolly adelgid was introduced accidentally on shipped plant material, its insect predators were left behind and nothing in the United States finds the adelgid quite as delicious as its predators from East Asia. Currently, there is a mad scramble to find something from the adelgid’s native range that will eat only the adelgid and that can be reared and released here in the United States. But, this type of biological control agent comes with risks as well. It’s difficult to predict what an introduced insect predator will and won’t eat in the wild in a new range. This means that many people are very opposed to intentionally introducing a new non-native species, however, no tree species native to the U.S. will replace the niche of the eastern hemlock.
Weather permitting, next week we will start the last major round of brook trout telemetry tagging. The end of this project is still several months away, but the close of summer means there is light at the end of the tunnel.
I can also rest easy now knowing that this summer “worked.” It wasn’t always easy, and there were plenty of surprises along the way, but there is a generous dataset sitting on my computer ready for analysis. Since May, I, along with one technician, have amassed 1,497 detections. Every single dot on that map represents a telemetry growth pain, including:
Tagging fish less than 6.5 inches will, without question, result in you spending hours on the side of the mountain trying to recover a tag from a fish that has been predated on. If you’re lucky, the predator will have only carried it to the adjacent hillslope. Often times it will not have spared your soul and you will find yourself hiking miles through a rocky river with snakes.
Lesson learned: only tag big fish. They probably have the most interesting movement data, anyway.
If there’s a section of stream with bad access, the fish will find it. Not only will they find it, but they will love it.
Lesson learned: If your first assessment of a stream is that it’s merely ‘doable,’ immediately delete it from the candidate list. Hiking over rocky outcrops and crawling through downed trees will get old long before the study is over. Relatedly, when tagging, you need to capture every single fish that has ever thought about swimming in the stream. Otherwise, you will have electrofished one mile of stream before running out of tags. Inevitably, those fish will move upstream, making the length of your study area obnoxious.
Telemetry is simultaneously the coolest and one of the most boring methods of data collection I have participated in. I am monitoring the decision-making processes of an iconic fish species. But, after about the third week I had memorized their exact locations and then continued to confirm that I had memorized them about 1,200 more times. And, I’ll keep doing it for the next three months. Fish movement doesn’t break the cycle, either (see above lesson).
Lesson learned: Starbucks might as well be a collaborator. And, sometimes the best skillset for a technician is having a lot of stories to tell.
A tagged fish and a dropped tag can have nearly identical behaviors. Also, tags can drop at any time during the study. As a result, your dataset becomes a series of emotionally charged messages where one day you were excited because the tag surely seemed to be moving. Then, less than 48 hours later, you find it floating on the stream bottom.
Lessons learned: Never get your hopes up with field work. And, invest early in a snorkel. It makes is much easier to recover dropped tags, thus maintaining a high baseline level of frustration.
Fish are incredibly resilient. With light sedation we can collect blood and gill samples and perform a fairly invasive surgery. Minutes later the fish is back in the stream feeding. For humans, this would be the equivalent of taking half a sleeping pill before getting a lung biopsy, having a 30-lb weight stitched into your abdomen, and then being expected to run a marathon.
Lesson learned: Humans are wimps. And, don’t expect your telemetry season will be cut short by sampling mortality.
Finally, and most importantly, brook trout are gorgeous creatures with complex and diverse ecologies. There remain so many unanswered questions.
Lesson learned: I picked the right career.