How Many Places Can A Trout Hide?

Once a fish was recaptured we took tissue samples, checked incisions to ensure healing, and trimmed the tag antenna a little to reduce the risk of it getting caught on rocks.

All of them.  In every single crevice and in every single hole. And just when you think there isn’t one more rock to overturn, nor one more fish left to shock, you throw the probe in as one last Hail Mary. The crew silently pleads “just please be in there.” The shocker lowers their thumb overtop the switch. You take a deep breath.  Electricity flows through the lifeless water.  Nothing is left. 
 
A collective sigh is let out, and if you were any less tired you would have moved on long ago. But you continue shocking, continue pleading.  Then, suddenly, you hear the unmistakable sound of a tail flipping, and you see a white stomach come to the surface. You hold your breath one last time and wait….it has a silver wire hanging from the side.  It’s a tag!  We got it!
 
Now just 99 left to go.
 
Aside from the trip down south, that play-by-play was the entirety of the last week and a half as we tried to recapture all of tagged fish to take tissue samples. In theory this seemed like a fairly easy idea. We had the receiver to locate the tags, we had electricity to pull them out of the water- now go out and get ‘em!
 
Never did I imagine they would burrow themselves under so many layers of rocks. Nor did I think it would take, on average, 45 minutes of electrofishing a 4-ft-long pool before we could pull out a single tag.  But, that’s what it took, and it wouldn’t have been possible without a lot of help and persistence (thanks to Steve, Linda, Tyler, Megan, Savannah, and Dylan!). In addition, there were several tags we finally got to recover that we suspected have been dropped for a long time, but didn’t have the time or muscle to flip large boulders and look for them.

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Two months after surgeries and incisions are completely healed. Most stitches are still in place (like this fish here), but many of those have also been dropped by now.

All in all, it was a pretty successful recapture event.  We managed to take tissue samples from a total of 101 fish, of which about half were tagged fish. The other 50% of tagged fish are either burrowed very deep under a rock or in a large pool, or are completely missing from the study. The tags that are completely missing are likely the victims of predation and, while we try to relocate as many of those as we can, we are also focusing our attention to places a trout might go (i.e., we have steered away from tracking on large hillslopes….likely not a living trout). But, even those fish will provide us with data. They were living in the streams for most of the study and so we do have movement histories, and we may also be able to estimate natural mortality during unusually hot and dry conditions.
 
Looking back, we completed this sampling at about the best timing we could have asked for.  This past weekend the skies opened and Loyalsock finally received over 3 inches of rain. I suspect the fish were reenacting the infamous scene of Andy from Shawshank Redemption, because they were struggling. Hopefully this filled some dry pools and lowered stream temperatures a little, and we’ll go out tomorrow to see if the rains triggered any movement. 

Replace arms with fins, and I think this was the scene in Loyalsock this weekend.

Now all attention turns to watching the forecast and waiting for temperatures to decrease a few degrees.  Our next set of tags arrived yesterday, and I’ve blocked off early September for the next round of surgeries. But, we’ll have to wait until temperatures decrease a few degrees to make sure the fish survive.  Until then, office work, tracking, and resting up for the next round.