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Marked and Tagged Fish

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Want to report a trout or salmon with a missing adipose fin? It could have a Coded Wire Tag so there are special instructions you should follow! You can find those instructions here: Coded Wire Tags.

Marking programs are implemented for a variety of reasons, including estimating fish growth, mortality, exploitation, and movement. Your cooperation is an essential component of these programs, and successful fish marking programs will result in more abundant and healthier fish for the sport fishery. 

Methods of externally marking fish include branding, tattooing, and optical pattern recognition. Internal tags or marks include both artificial and natural marks. Artificial marks include implanted wire tags, dyes on otoliths ("ear bones") or other hard parts, visible implants, and radio and ultrasonic implants. Natural internal marks include genetic marks, chemical / elemental marks, and biological marks (e.g., unique parasites, others). All of these various methods are used extensively, and each has unique advantages that are dependent on the goals of the marking program.

More types of tags and marks

  • Report Anchor Tags

    Many projects have been conducted using anchor tags. Some anchor tags are plastic and resemble a piece of spaghetti and are often found inserted near the base of a fin. Other types of anchor tags are metal and clip onto a fin or opercle. You might catch a fish bearing an anchor tag with the letters DNR, MDNR, MI DNR or MICH DNR (or other combinations). If you catch a fish with an anchor tag, please report the following information: species, length, weight (if known), tag location (where tag was attached), identification number (the larger of the two sets of numbers), tag return address (for example MICH DNR MM-1), capture date, and capture location by using the tag return form. In the notes box of the form, please list time of capture and sex of fish (if known).

    Upon receiving your information, a letter stating when and where the fish was tagged will be sent to you via US mail.

    If you catch a fish bearing a plastic anchor tag during catch and release season, or if you choose not to keep the fish, please remove the tag and report the tag recovery. However metal anchor tags, such as those found a lake sturgeon, can be very difficult to remove and trying to remove them can cause injury to the fish, so we recommend anchor tags on lake sturgeon should be left attached to the fish.

    Additional Information about Anchor Tags:

    Lake Michigan Yellow Perch Task Group Tagging Project

    Recaptures and recoveries of anchor tags from a lake wide mark-recapture study implemented from 1996-2001 were used to evaluate the stock structure of yellow perch in the southern basin of Lake Michigan and Green Bay.

    Beaver Island Archipelago Tagging Project

    Central Michigan University (CMU) is conducting a smallmouth bass study in and around Beaver Island. The study is designed to determine population estimates and movement patterns. Tagged smallmouth bass may have one or more of the following: jaw, anchor, or sonic tags.

    Lake Sturgeon Distribution and Status in Michigan, 1996-2005.

    Adult lake sturgeon spawning in the Sturgeon River (Houghton and Baraga counties) and other rivers were tagged to monitor movement, characteristics of the spawning stock, and degree of spawning-stream fidelity. In all years, lake sturgeon over 37 cm were tagged with an anchor tag; after 2000, fish over 25 cm were doubled marked with an anchor tag and PIT tag.

  • No Reporting Needed

    Anglers will be able to determine if a fish has been marked with Chemical Markers - OTC. Typically this marking procedure is used to identify hatchery versus naturally-reproduced fish. OTC samples are collected by agency personnel.

    Additional Information about Chemical Markers:

    Analysis of Chinook Salmon Populations of Lakes Huron and Michigan, 1985-2004

    OTC marks were used to determine natural reproduction of chinook salmon in both lakes Huron and Michigan.

    Status of Saginaw Bay Walleye Population and Progress Towards Recovery

    Due to the stocking of OTC-marked fish, it was determined that the strong year classes of the last few years are wild (or naturally reproduced) walleye.

  • All state licensed commercial trap net anglers are required to attach two tags to all trap nets. The tags have a seven digit number and it will be the same number each year. The color of the tag will change each year.
  • Anglers only need to notify agency personnel if the adipose fin (AD) is missing. This is a secondary mark that is used to indicate the fish had a coded-wire tag (CWT) implanted into the snout.

    "The advantages of external physical marks are that they can be seen without dissection... Marking...can be accomplished by clipping or punching fins or other body parts with scissors, nail clippers, side cutters or other tools. Because (fin clipping) is a simple and quick process, it has been a popular marking method employed on many different types of organisms...it is often used in conjunction with other marking methods to alert the person recovering the organism to look for internal tags." - Nielson, L. A. and Johnson, D. L., 1983. Fisheries Techniques.

    Additional Information about Fin Clips:

    Great Lakes Fish Stocking Database

    Information on fin-clipped fish can be obtained from agency personnel or by visiting the "Great Lakes Fish Stocking Database". This database was developed by Great Lakes fisheries agencies for fishery managers, scientists and other interested parties desiring access to a centralized, comprehensive database of all fish stocked into the Great Lakes. Interested parties may search a particular species and clip to determine stocking origin.

    Lake Michigan Steelhead Fin Clips 1995-2009

  • Report Jaw Tags

    Many projects have been conducted using jaw tags. You might catch a fish bearing an external tag with the letters DNR, MDNR, MI DNR or MICH DNR (or other combinations). If you catch a fish with a jaw tag, please report the following information: species, length, weight (if known), tag location (where tag was attached), identification number (the larger of the two sets of numbers), tag return address (for example MICH DNR MM-1), capture date, and capture location by using the tag return form. In the notes box of the form, please list time of capture and sex of fish (if known).

    Upon receiving your information, a letter stating when and where the fish was tagged will be sent to you via US mail.

    If you catch a tagged fish during catch and release season, or if you choose not to keep the fish, please record the tag information to properly report upon release.

    Additional Information about Jaw Tags:

    Inland Waterway Survey

    The DNR is conducting a three-year tag-and-recapture study on the walleye population in the inland waterway in Northern Michigan. The tag-and-recapture study consists of jaw tagging walleye to determine movement and seasonal distribution of the species in the inland waterway - instructions for returning jaw tags. In addition to the tag-and-recapture study, Michigan State University is also evaluating larval walleye distribution, the forage community of the waterway and walleye diets - instructions for returning walleye stomachs.

    Lake Huron / Erie Tagging Project

    These projects are used to determine movement, set harvest limits and determine mortality rates. Walleye tagging programs are ongoing in both Lake Erie and Lake Huron. Lake Huron tagging started in 1981. Lake Erie tagging started in 1978.

    Green Bay Tagging Project

    Jaw tagging is used to assess movement patterns and annual rates of exploitation and survival of walleye in Michigan waters of Green Bay. Tagging started in 1988 and is ongoing.

    Beaver Island Archipelago Tagging Project

    Central Michigan University (CMU) is conducting a smallmouth bass study in and around Beaver Island. The study is designed to determine population estimates and movement patterns. Tagged smallmouth bass may have one or more of the following: jaw, anchor, or sonic tags.

    Corey Lake and Pleasant Lake

    The Michigan Department of Natural Resources will be conducting a fish survey on Corey and Pleasant Lakes during the spring and summer of 2008. The study is being conducted to collect information on indices of abundance and estimates of annual harvest and fishing effort for largemouth bass. A second objective of the study is to collect sufficient growth and mortality statistics to be able to evaluate effects of fishing on largemouth bass. Special fishing regulations have been established on these lakes to improve these valuable fisheries.

  • NO REPORTING NEEDED

    Internal / PIT tags are an implanted tag that is used when an individual fish needs to be identified. The tag contains a series of numbers and letters that can be obtained by passing a "PIT Tag reader" over the implanted tag.

    Additional information about PIT Tags: 

    Lake Sturgeon Distribution and Status in Michigan, 1996-2005

    In Lake Michigan after 2000 lake sturgeon over 25 cm were doubled marked with a PIT tag and anchor tag.

    Great Lakes Lake Sturgeon Tag Identification Database

    The Great Lakes lake sturgeon tag identification database was developed to facilitate communication between individuals who tag and recapture lake sturgeon in the Great Lakes.

  • Obtaining information about the behavior of animals in their natural environment is difficult. Telemetry tags allow researchers to identify the location of a fish by detection of a signal from a transmitter that has been implanted in the fish. Two types of signals / transmitters are typically utilized by fisheries researchers; radio and sonic (acoustic). Radio transmitters are utilized to monitor fish locations and habitat use in shallow, fresh-water environments. In situations where radio telemetry is not practical or appropriate (e.g., in deep or highly conductive water), researchers can use acoustic transmitters and receivers to track fish.

    In general, telemetry tags will only be discovered if a fish is cleaned (filleted, gutted) for human consumption. Most fish carrying telemetry tags will also carry information (address, phone number, email) concerning tag reporting, either on the telemetry tag or on an associated tag (e.g., anchor tag, jaw tag). Telemetry tags are costly, but can be re-used by fisheries managers if returned.

    If you find a telemetry tag, refer to the information on the tag (or associated external tag) for further instructions. If you have problems reading the tag, please contact the Lake St. Clair Fisheries Research Station at 586-465-4771.

    Additional Information on Sonic Tags:

    Evaluation of Lake Sturgeon (Acipenser fluvescens) Populations in the St. Clair River and Lake St. Clair

    Sixteen adult lake sturgeon were tagged with sonic tags in the St. Clair river system and have been found to spend parts of the summer and fall months in Lake St. Clair.

    Beaver Island Archipelago Tagging Project

    Central Michigan University (CMU) is conducting a smallmouth bass study in and around Beaver Island. The study is designed to determine population estimates and movement patterns. Tagged smallmouth bass may have one or more of the following: jaw, anchor, or sonic tags.

  • Obtaining information about the behavior of animals in their natural environment is difficult. Temperature / Depth-Recording tags allow researchers to collect information about the habitat occupied by fish over relatively long time periods. The tags contain sensors that record temperature and depth (or pressure) at locations occupied by a fish, at time intervals ranging from seconds to days. These data are stored on a computer chip in the tag, and can be downloaded to a computer once the fish is captured and the tag recovered.

    In general temperature / depth-recording tags will only be discovered if a fish is cleaned (filleted, gutted) for human consumption. Most fish carrying temperature-recording tags will also carry information (address, phone number, email) concerning tag reporting, either on the temperature-recording tag or on an associated tag (e.g., anchor tag, jaw tag). Temperature / depth-recording tags are costly, and data can only be recorded if tags are returned to fisheries managers for computer download.

    If you find a temperature / depth-recording tag, refer to the information on the tag (or associated external tag) for further instructions. If you have problems reading the tag, please contact the Lake St. Clair Fisheries Research Station at 586-465-4771.

    Additional Information:

    Bergstedt et al. 2003. In situ Determination of the Annual Thermal Habitat Use by Lake Trout (Salvelinus namaycush) in Lake Huron

    Records of the temperatures occupied by 33 lake trout (Salvelinus namaycush) at large in Lake Huron were obtained for up to 14 months per fish, at 75-minute intervals, from surgically implanted archival temperature tags. The objectives of the tagging were to obtain temperature data to refine bioenergetics models of sea lamprey (Petromyzon marinus) predation on lake trout, and to compare the temperatures occupied by strains of lake trout stocked in Lake Huron.

  • Anglers often notice distinct yellow marks that are circular in shape and are often found on the belly near the pelvic fins. Because fisheries professionals use artificial dyes or ink to mark fish, these circular-yellow marks found on Great Lakes Chinook salmon are often misidentified as an artificial mark. However, these marks are not artificial marks used by fisheries professional to track salmon in the Great Lakes, but instead they are naturally occurring in Great Lakes Chinook salmon. These circular-yellow marks are usually noticed in late July through early September as a salmon undergoes the process of maturating and preparing to spawn. In general, there is a good deal of variation in Chinook salmon coloration especially as they start this metamorphosis and are staging prior to running the rivers. What is really unique about these marks as the fish starts to turn from a silvery-white to a yellowish-brown in color is that the areas beginning the change can appear as a perfect yellow spot or circle about the size of a quarter. Again, these spots are naturally occurring pigmentation and not an artificial dye or mark used by fisheries professionals.