Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

Planet Earth

How to Follow a Fish

The tools researchers use to track their scaly subjects.

By Lacy SchleyApril 10, 2017 5:00 AM
school of fish shutterstock_110080493.jpg
(Credit: Peter Leahy/Shutterstock)

Newsletter

Sign up for our email newsletter for the latest science news

1. Jaw tags: Researchers use these external tags, about the size of a quarter, to identify whether a fish has an internal tracker implanted in it. It’s usually fit onto a fish’s lower mandible.

2. Pop-up satellite archival tag: This external tag collects detailed data on fish vitals, location and environmental information, such as light levels.

3. Acoustic transmitter: Internal or external tag that’s ideal for tracking fish in deeper water. These transmitters produce a unique set of pings that get assigned to an individual fish. To collect data, researchers either go out in a vessel to pick up signals or download the information from receivers stationed in the fish’s environment.

Fish catching gear
(Credit: William Zuback/Discover)

4. Cinch tags: This type of external tag indicates the fish bearing it is part of a study and lists contact information for the agency monitoring it. If recreational fishers reel in a catch with a cinch tag, they should report it to the agency listed on the tag.

5. Large-scale model of coded wire: Unlike the model shown here, these internal tags have a true diameter similar to that of mechanical pencil lead. The wire comes on a spool and is lined with imprinted numbers. When a biologist cuts off a piece to make a tag, a unique serial number will be paired with a fish. To read this number, researchers need magnification equipment.

6. T-bar tags: External tags that come in a variety of colors. Similar to cinch tags, T-bars flag the fish as part of a study.

7. Radio telemetry tag: Internal tag for tracking fish in shallower waters. Researchers use an antenna, either handheld or secured beneath a plane or boat, to pick up the tag’s radio signal.

8. Visual Implant (VI) tags: Internal tags mixed with brightly colored biocompatible substances that researchers implant into translucent sections of a fish. While it’s possible to spot them with the naked eye, researchers typically need fluorescent light or magnification to see VI tags. Different colors can indicate details such as the year a fish was tagged for study.

9. Hydrostatic tags: Much like cinch tags, these external tags flag the fish as being part of a study.

10. Passive integrated transponder (PIT) tags: An internal tag that biologists must scan to activate. PITs relay data on fish growth rates and movement patterns to a receiver.


[This article originally appeared in print as "Tag, They're It."]

2 Free Articles Left

Want it all? Get unlimited access when you subscribe.

Subscribe

Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 70%

Subscribe

Already a subscriber? Register or Log In