Thursday, September 22, 2011

Marking and Coded-Wire tagging at Winthrop NFH

In August I had an opportunity to get out in the field and do some “hands on” work operating an autofish trailer to coded-wire tag Coho for the Yakama Indian Nation (YIN) Mid-Columbia Coho reintroduction program and Winthrop National Fish Hatchery. This facility was opened in 1941 to provide mitigation for the loss of salmon and steelhead habitat that occurred upon the construction of Grand Coulee Dam. The hatchery switched to rearing trout for sport fisheries during the 1960’s and 70’s, but shifted back to helping restore salmon and steelhead runs during the late 70’s and the following decades.

Upon arrival at Winthrop NFH, after an 8 hour drive, Geoff Gribble and I had no time for rest, we immediately got to work preparing for the next day’s early morning adipose fin marking and coded-wire tagging. This wasn’t going to be a small job, as we had three groups of fish of three different species to mark utilizing one of our automated fish marking trailers.

During the process of coded-wire tagging for hatchery salmonids, a metallic tag is inserted into the snout region of the fish before release into the river system. This tag has a six digit identification number etched onto it that is specific for the stock of fish being tagged. To avoid confusion between stocks, this I.D. number will not be used again. When the fish later return as adults, the tags will be recovered and the information present is used for the management of fisheries and the evaluation of fish stocks. The adipose fin marking refers to the removal of the adipose fin from the fish. When a fisherman catches a fish without this fin, he is allowed to keep it. If a fin is present, he must release it as it is a native fish.

Our first task was to unload all of our marking equipment from the trailer. Equipment we had to unload included many things such as a water pump, pipe and hose stands, pump box, cable protectors, air compressor, large tote, electrical cords, buckets, nets, steps, etc. Once everything was unloaded we could begin setting up the automated trailer.

I leveled and adjusted the trailer while Geoff put the pump box and pump into the raceway and connected it to the trailer. Once the pump was setup, we could then pump water into the trailer to rinse the troughs and equipment with fresh water. The trailer is rinsed to remove any residue that may have remained from disinfecting the trailer before it left the previous hatchery. Disinfection is necessary to prevent the transmission of pathogens between hatcheries and groups of fish. So at this hatchery, since we were marking three different species of fish, we had to disinfect the trailer three different times.

After rinsing the trailer out we setup our irrigation pipe (used for distribution of marked fish exiting the trailer) and then cleaned, oiled and lubed all the moving parts of the marking lines and sorter within the automated trailer. At that time we also brought in a few buckets of fish to run through the sorter to sample for length. The sample allowed us to determine what size headmolds and adapter plates we would need to use on the marking lines. The automated trailer is fitted with headmolds and adapter plates that can process specific size ranges of fish. Adapter plates are fitted with foam pads and these plates are what close and hold fish in place at the headmold. The headmold is what the fish slides into headfirst so that it can be tagged and/or clipped.

After we got our sample and setup our marking lines, we were finally ready to call it a day. We left the hatchery knowing we had everything set and ready to go for the next day’s steelhead marking and tagging.

Tuesday morning arrives and it’s time for us to start running the steelhead through the trailer. Although the marking lines have already been set with the appropriate adapter plates, it generally takes a couple of hours to fine tune everything so that the fish are running through with maximum efficiency. When the trailer is running at its full potential, it is capable of marking up to 70,000 fish during an 8 hour work period. This number is largely dependent on the percentage of fish that are sent directly to the marking lines. Any fish that are of a greater or lesser length than the adapter plates on the lines are sent to a stock tank in the back where a couple of hand taggers are present. The hand taggers will process these fish so they do not have to be run through the trailer repeatedly. As there are a greater number of machines that can operate quicker, it stands that as more fish are sent through the marking lines than into the back each day, then more fish will be marked and coded-wire tagged. Steelhead, however, grow at a wider length distribution than do coho or Chinook salmon, so it took us a day and a half to complete almost 64,000 fish. For the rest of that second day, we spent the time disinfecting and moving the trailer so we could run a group of spring Chinook salmon for marking.

Generally spring Chinook are tagged earlier in the marking season. This year, however, we were short a tag group when they were originally supposed to be done. The marking of this group and the following required disinfection only takes a day so we leave that evening ready to start marking the coho the next morning.

The CRFPO marking team has tagged fish for the YIN reintroduction program for a number of years now. The goals of the YIN reintroduction program are to re-establish runs of Coho to the Methow and Wenatchee subbasins and to develop over time locally adapted populations. The program began in the mid-90’s using a stock of Coho from the Lower Columbia River basin and since it’s inception they have achieved a high degree of success restoring Coho runs in the Methow and Wenatchee basins. In fact, they have eliminated reliance on the lower Columbia river stock originally used to re-establish these populations. Brood are now collected from returning adults within the basin.

Coho marking went even better than expected since the fish were of uniform size and the group was tag only. We were happy to wrap up the marking a few days later and go through the disinfection process once again, finally pack up the trailer for transport and call it done. While working on the road can be fun and enjoyable, especially somewhere as beautiful as Winthrop, it’s always nice to get the job done and get back home.

Submitted by Jesse Rivera & Geoff Gribble

1 comment:

  1. Wow, there's more to tagging fish than I thought. Great Job!