Last week I was sure the number of dropped tags would slow down. Boy was I wrong. This week we found nearly triple the number from last week. This was frustrating to say the least, but we went on a warpath trying to physically see every tag to confirm that it was on a fish.
The lower flows have been great for seeing into some pools, but the stream bottom still remained difficult to see in the deeper pools and riffles. So, despite my facetious remarks when I started this project, this week I donned a diving mask and snorkel and sought to touch every tag in the stream. I couldn’t get to many tags that were deep and under rocks, but I did get a “fish eye view” of most. Some were indeed drops, but more often than not I would see an antenna poking through the rocks and when I attempted to gently tug on it a brook trout would lunge at my face. So, I can confirm that many of the tags are still alive and well.
It’s hard to say why these tags are dropping. We know for sure that some are predation events. We found one tag about 15 feet from the stream buried several inches in tree roots and with little bite marks all over the tag and a frayed antenna. There was another tag that migrated several miles downstream in 48 hours and was located on a hillside (birds are likely suspects for that one). Tags could also be dropping because, as flows decrease, fish are spending more time swimming between rocks and into tight spaces where the antenna may be getting snagged in tight crevices. Finally, tags could have dropped a long time ago and we are just now finding them. All three of these explanations are likely equally responsible for the drops we found this week.
But, for the tags that are still in fish I can tell you a few things. First, they continue to move. Nowhere too far or unusual yet, but some movements have required the fish to traverse some rather rough terrain (as my knees can attest).
Second, anglers are catching them and by in large putting them back. I’m fortunate that this project is taking place in a watershed that not only supports the research, but is genuinely interested in helping achieve the results. This project not be possible without the field and logistical support, but also the backing from anglers who not only are not releasing tagged fish but are also genuinely interested in the study and stop to ask me questions when they see me on the water. It also makes the project a lot more rewarding to know that there is so much local interest in the study.