Product Information


The first three systems described below all involve implanting tags into tissue beneath the skin so that, following healing of the initial wound, the tags become encased in healthy tissue. This requires that the tags are (1) small, (2) bio-compatible, and (3) nothing remains penetrating the skin. These three characteristics are the primary differences between NMT tags and others which tend to be much larger, and have an external code-bearing component that is anchored internally through a permanently raw lesion. Problems with the latter typically include unqualifiable levels of tag shedding, reduced growth and poor survival. The advantages of NMT's coded wire tagging system over external tagging was demonstrated in Atlantic salmon (Ísaksson and Bergman 1978) and Arctic char (Berg and Berg 1990). Roberts, et al. (1973) has described the histopathology of the external tag lesion in detail. Mourning, et al. (1994) found that rainbow trout tagged with small implants grew significantly faster and suffered far less tagging injury than externally tagged fish.

The Archival Tag is a device which is attached to or implanted in a large highly migratory pelagic fish, such as a tuna or billfish, to keep a record of its travels over a time period which may span seven years. In terms of size and function, it is very different from the other NMT tagging systems.

Excellent descriptions of fish tagging techniques and their application are provided by Parker, et al. (1990) and Nielson (1992). Both volumes are available from the American Fisheries Society.

NMT's tagging/marking systems are:


Northwest Marine Technology, Inc
P.O. Box 427, Ben Nevis Loop Road, Shaw Island, Washington 98286
Telephone (360) 468-3375 Fax (360) 468-3844