Marking and tagging for releasing
activity
Masatoshi FUTAGAWA
August 27, 2017
Markers and tags
The marking or
tagging is essential activity in order to identify the released fish in the field.
According to identification, we evaluate the activity such as growth, survival,
migration of the fish at field and evaluate economic effect. Thus, it is
necessary to announce to public that request to inform catch data about tag
code, location and size of fish.
·
Nasal septum defect: Some hatchery made
fish shows nasal septum defect, nose holes are connected. The data have to
revising by the defect rate of the released fish batch.
·
Plucking fins /
spines: Pluck ventral, pectoral fin or spine at dorsal fin.
The method does not harm any survival and growth according to the paper. Even so, the mark
recover within few years.
·
Anchor / darts
tag: The
tag has some number and letters, used commonly for fish. The tag removes
sometime.
·
Alizarin
complexone (ALC) / tetracycline (TC) staining:
Otoliths scale and bones are stained by ALC or TC, larvae and juvenile
immerse in the solutions or feed solution
mixed in diet. Advantages of the method are applicable
for small samples with large number at once. It not harms growth and survival
and keeps years. Disadvantage is not able to identify from outward appearance.
Hence, the marker combines with physical markers such as plucking.
·
Visible
implanting elastomer (VIE): The material made of fluorescent silicon and it is
injected at transparent or white tissue of fish. The marker identifies easily
but removes sometime.
·
Coded wire tag
(CWT): The tag made of
stainless steel wire 0.25 mm with numbers which read by magnifier. The tag is implanted by injector at length of
0.5, 1.1, 1.6 and 2.2 mm.
· Passive
integrated transponder (PIT) tag: The tag function by
radio identification, 70 years lifetime. However, the tag cost is around 60 USD
in each tag. It use for salmon migration in a stream or identification individual
broodstock. Recently the tag applies to pet, dogs and cats.
·
Acoustic
transponder (Pinger); The transponder used for tracking fish and water
temperature and depth simultaneously. It function long distance and long term
(1 year). The transponder is inserted in abdomen surgically in 23 cm is the
minimum fish size, accepting 2 % of body weight based on uses.
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