CWT coded wire tag is magnetized stainless steel wire of adiameter of 0.25 mm, with a few lines of code numberrepresents the particular batch or individual code. By using a special syringe will cut off the line of code, and implantedinto the subcutaneous tissue. Standard length mark is 1.1 mm. For very small animal can use half length (0.5 mm)marker. For the larger specimens or enhanced magnetic field detection, can use 1.5 (1.6 mm) or double length (2.2 mm) marker. CWT label minimum successfully labeled22mm body length of salmon, while CWT markers can also be labeled many crustaceans.

The advantages of CWT system:

 - can be used in a very small animal

 - Minimum biological effects

 - fish sample batch automatic scanning

Limitations of CWT system:

 – in most applications, but to read the decimal codelabel, must be excised animal tissue, usually resulting indeath animal samples.

 – in most applications, but to read the decimal codelabel, must be excised animal tissue, usually resulting indeath animal samples.

 - tags are usually not visible outside.

 - need to buy expensive equipment to apply tag (markingand identification)

 - need to buy expensive equipment to apply tag (markingand identification)

 – need professionals to apply and identification marking

Retrieval and recognition of a large number of manpower need  - mark

Retrieval and recognition of a large number of manpower need  - mark

 - markers in fish body position migration produced easily