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PIT (passive integrated transponder) tags
Scientists and researchers have been studying sturgeon for many years. Even though much research has been conducted, there is still a lot of information that we do not know. Where exactly are the spawning grounds? Where do they go in the winter? Why do they jump?... and much more. In an attempt to try to answer some of these questions, researchers have been using tagging techniques to track and follow sturgeon throughout their migrations and coastal movements. A few types of tags that researchers have been using are satellite tags, acoustic telemetry tags, and PIT (passive integrated transponder) tags. Each tag aids researchers in getting different information that they are searching for.

PIT tags are tiny little microchips that are placed under the skin of the sturgeon. The tag is inserted with a small needle which pierces the skin and allows the tag to be placed just under the skin. When researchers catch sturgeon through their sampling efforts, they scan then with a PIT tag reader. PIT tag readers are small handheld devices that activate the tag when being scanned and record the unique and individual tag number. They can then take that tag number and find out in what river or where on the coast that fish was originally tagged.

An acoustic telemetry tag being surgically inserted into a sturgeon

Acoustic telemetry tags serve to give a broader picture of the migrations of sturgeon. Acoustic tags are inserted by researchers through a more surgical approach. Using a scalpel, the researcher will make an incision (cut) into the body cavity large enough to fit the tag just under the fatty skin layer. This incision is then closed with stitches. These tags are larger than the typical PIT tag, and are programmed to “ping” or send out signals at specific intervals. Each of these tags has a unique identifying number. When a tagged fish swims near one of the acoustic telemetry receivers, the receiver records the number, date, and time. These acoustic receivers, which are about the size of a 1 liter bottle of soda, and are deployed up and down the coast in coastal waters as well as in rivers and estuaries. Researchers go to their receivers periodically and download all of the data that was collected. Each time a tag is identified by the receiver, it is called a “hit.” The researcher can then see where and when certain fish “hit” the receiver. With this information, and through cooperation with other researchers, they can begin to see exactly where the fish has been traveling.

Satellite tag
Satellite tags are a more in depth and comprehensive collection system. Once the satellite tags are attached to the fish, they begin collecting information immediately. This information is either stored in the tag, or sent directly up to satellites. If the data is being stored, there is usually a designated date where the tag will release from the fish. When the tag releases, it floats up to the surface and begins downloading to satellites all the data that it had collected in its time on the fish. This information is then given to the researcher. More expensive and larger satellite tags are capable of providing “real time” data where the information is constantly being downloaded and updated to the satellites and researchers. This information can show direct paths, and near exact locations of everywhere the fish went while it was tagged.

With all of the data that can be collected from various kinds of tags, they are able to create maps that will helpfully illustrate the travels of Atlantic and shortnose sturgeons.

Summary of Research