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AGING SARDINE
Reading otoliths
from sardines is the simplest and most reliable method for aging
sardine. Scales and vertebrae can also be used but they are not
as accurate as otoliths. Otoliths are found in pairs in the top
of the head of a sardine just under the skull cap. Determining sardine
age is similar to counting the rings in a tree. Age readers magnify
the otoliths until they can count the rings, or annuli,
and determine the age of the sardine.
The otoliths,
which measure about 1.5-3.0 mm in length, are extracted and sent
to the WDFW laboratory in Olympia, Washington, for age reading.
Catch date, vessel name, sardine length, weight, sex, and maturity
are also recorded and sent along with the otoliths.
Although sardine
can live up to 15 years the majority of commercially harvested sardine
are three to five years old.
Washington Department
of Fish and Wildlife (WDFW) staff coordinate the collection of biological
sampling with Oregon Department of Fish and Wildlife staff to ensure
sample coverage is evenly distributed throughout the Northwest fishery.
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Sardines
compared to a quarter |
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A
pair of sardine otoliths
next to a penny. |
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