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.