Mass Marking and Tagging at National Fish Hatcheries

Howard in the autofish trailer

When people ask me what I do for a living, I tell them that I’m in charge of running a manual mass marking and tagging trailer, as well as an autofish trailer. Then I get the “uh-huh” nod and the “that’s nice” comment. So let me explain in more detail what I do for the U.S. Fish and Wildlife Service (USFWS). 

Our office supports Quilcene, Quinault, and Makah National Fish Hatcheries. My work includes operating a 44’ trailer to mass mark all of the fish at each of these hatcheries. Mass marking helps us determine whether a fish was raised in a hatchery or is a wild fish.  Mass marking is done by clipping the adipose fin from each hatchery fish by hand with scissors. A percentage of the fish are also tagged with a coded-wire tag. A coded-wire tag is 2.2mm long by 4 hair widths wide and has a six-digit code imprinted on it. This code lets us determine where the fish originated---a USFWS hatchery, a Washington State hatchery, or a tribal hatchery.

        Marking a young salmon (left) and manually tagging a young salmon (right)        

By law, all salmon and steelhead released from Federal hatcheries have to be massed marked unless the fish are being used in a study. So each year I work with many others to mark a lot of fish! Makah National Fish Hatchery raises 2.4 million fall Chinook salmon, 240,000 coho salmon, and 180,000 winter steelhead; Quinault National Fish Hatchery raises 600,000 coho salmon and 200,000 winter steelhead; and Quilcene National Fish Hatchery raises 600,000 coho salmon. 

The manual mass marking and tagging trailer that I operate needs one operator and 12 crew members to make the trailer run. When we are only mass marking the fish, we can mark about 60,000 to 80,000 fish per day in an 8-hour shift with a full crew. When we are tagging the fish, we can tag about 30,000 to 45,000 fish in an 8-hour shift.



Inside the autofish trailer

The autofish trailer that I operate needs one operator and two crew members to make the trailer run. This trailer has six automated stations and one station in the back of the trailer for the two crew members. It can mark and tag about 60,000-100,000 fish in an 8-hour period. The trailer measures the length of each fish and then sends the fish to one of the six stations. For example, the operator can tell the computer to send all fish that are 100mm to 120mm long to Station 1; send the fish that are 121mm to 130mm long to Station 2, and so on. All of the fish that are outside of the programmed size ranges are sent to the back of the trailer to be marked and/or tagged manually.

So, in a nutshell, I’m responsible for the supervision of the clipping/tagging crew, monitoring the health of the fish during marking and tagging, and coordinating with my peers at the hatcheries, fish health center, tribes, and other agencies. If you stop by any of the USFWS hatcheries on the Olympic Peninsula and see our trailer, please knock on the door and ask for a tour. I’ll be happy to show you how it all works!


-- Howard Gearns, Biological Science Technician/Mass Marking and Tagging Trailer Supervisor

 

Determining the Age of Salmon Produced at Federal Hatcheries

the USFWS Lacey office collects biological information from a portion of each returning salmon run at Makah, Quilcene, and Quinault National Fish Hatcheries on the Olympic Peninsula. We record sex, length and species for each fish. We also collect scales from the side of the fish behind the dorsal fin to determine the age of the fish. These scales are placed on an adhesive strip on a card and returned to the office for analysis.  Back at the office, each scale card is imprinted onto an acetate sheet using heat and pressure. The acetate sheets are then magnified with a microfiche reader so that the scales can be easily seen.

Rings (called circuli) form on each scale just like rings on tree trunks. The circuli are visible in the lighter area of the scale. The darker banded areas are called annuli--they are formed during the winter months when the fish grow more slowly. We can estimate the age of each fish by examining these rings. 

The age data we gather is then used to estimate the age and survival rate of the returning salmon. 

Here are some videos demonstrating the scale collection/analysis process: