Day one of tagging here at Elk creek involves collection of fish by beach seining. Collecting fish is quite labor intensive and beach seining is no exception. So the crew packed up all the gear and headed for the big hole at the mouth of Elk Cr.
This requires two seines. One seine, preferably larger is set at the base of the run. A smaller net is taken upstream and set across the stream. When everyone is in place, the upper seine is pushed to the lower seine using the stream flow for aid. The nets have a lead line sewn in on the bottom, and a cork line sewn in the top. Here we go…
From top to bottom. 1. Setting the catch net. 2. Driving fish down with the driving net. 3. Getting close. 4. Getting the drive lead line over the catch lead line. 5. Everyone together now… 1…2…3…HEAVE and pick both nets up at the same time. We leave a little pocket of water in the center and chase the captured fish to the puddle. Then net them out with a dip net.
This method catches everything in the stream. We caught 160 chinook parr, several steelhead, and a smattering of sculpins, dace, whitefish, tadpoles, dragonfly larva, and suckers. Occasionally we will get cutthroat trout, bull trout, rainbow trout and shiners. On the South Fork of the salmon River we also catch Pacific Giant salamanders. If I’m lucky, I will get you a picture of one of those salamanders in about a month. They are really cool. And strong!
The fish go into a bucket, then into a backpack to be hauled to the station. It was about 1/4 mile from here to the station, so the pack is loaded into a truck and taken to our tagging station.
This hole was not as productive as it was in the past. Over the years, it has been filling with sand and silt, the deeper part has moved upstream about 50 yards. When this hole was originally built (by a road crew) there was a lot of cover along the left bank. This cover is gradually disappearing over the years. 10 years ago we could catch 1000 chinook parr in this one place. Made for a short day of collecting and a long day of tagging.
Now on to tagging. We have been using pittags for over 25 years for smaller salmonids. Up until that time, the technology was too cumbersome for a tiny fish. They are quite small now. There are smaller tags, but they do not have a large read distance. Many would get missed by the detection equipment downstream. Here are two with a dime…
These are a microchip with an antenna, the antenna has 30 feet of fine copper wire. The chip is set with a code, then encapsulated with glass. We use glass as it is quite strong and light. The fish’s body doesn’t reject glass as it does metal or plastic. These tags are loaded into needles and injected into the fish with a specialized “gun”.
First we have to anesthetize the fish, otherwise they are much to rapid to work with. Tagging wide-awake fish is stressful for both fish and tagger. We use a dish pan with a few milliliters of MS222. MS222 is a cold blooded animal anesthetic that is composed of benzocaine (Numzit for teething babies) plus sulphuric acid too make it water soluble and a buffer to neutralize the mixture. It works great on fish, amphibians, and some aquatic insects.
Here I have a salmon parr with a tapeworm looking thing in it’s mouth. No way to look at this while the fish is awake. And yes, the tapeworm was removed.
Tagging is a pretty delicate operation with such a small fish. This one is relatively large. I can safely tag fish down to a size of 55mm.
Pass the fish through the scanner loop to activate and read the tag on to the computer.
Then a quick weight, unless the wind is blowing too hard.
A length…This is a digitizer board, a Calcomp Drawing Board III. We can get a weight with the touch of a “pen” and “punch” or type in other information onto the computer if needed. About the only information we put in regularly in Idaho is a “fin clip for genetics”, the others are there just in case. On 50 fish for each stream, we take a small clip on the tail of chinook and steelhead for genetic marking and tracking. Here I am clipping a steelhead…
with a dishpan of fish in the background. These clips go into a phial of alcohol and are sent to our lab in Seattle.
In it goes. And finally, what the computer display looks like…
The fish shown here was #99, pittag code 3D9.1C2CFF3E45, length of 70 millimeters, weight of 4.6 grams. 3D9 is the manufacturer’s code, I think it is Digital Angel. Yep, those are alphabet characters, the code is in hexadecimal format on the tag reader. This reduces the number of characters in the database. Hexadecimal is base 16, we humans are all used to a base 10 system for numbers. Computers like hexadecimal and programming is simpler when there are a lot of extremely large numbers. A =10, B =11, C = 12, D =13, E =14, F =15. The number “10” = 16. There are over 60 billion possible codes. We’ve got a lot of tagging to do.
The fish are then dropped into a bucket of fresh water for recovery. It takes a few minutes, then they are dumped…
into a live cage in the stream for complete recovery, usually in about 15 minutes. We tagged a little over 1,000 fish in the two days working at Elk creek. Saturday is a day off and then we move to Marsh creek. Tomorrow is a trip to town and viewing the new weir that the Sho-Ban tribe has put in near Fir creek.