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Anadromous fish live much or most of their lives in
ocean waters but return to streams to spawn; other
species-- semi-anadromous-- live in estuarine waters
but also return to fresh water to spawn. Waters where
anadromous fish spawning occurs are particularly
important to the State's fishery resources, and the
success of spawning is critical far beyond the
immediate area where reproduction occurs.
To develop this indicator, five species of anadromous
fish--American Shad,
Alewife,
Blueback Herring,
Hickory Shad,
and Striped Bass
-- and two semi-anadromous species --
White Perch
and Yellow Perch --
were examined for all river systems sampled under the
Index of Biotic Integrity sampling program. An index
was developed based on the mean catch per unit effort
(CPUE) of anadromous and semi-anadromous species
combined. The CPUE was calculated for every site on a
yearly basis and then ranked into five groupings. The
mean rank for each river was calculated and multiplied
by two to adjust it to a scale ranging from 1 to 10.
This index can serve as a fair measure of the value of
juvenile anadromous/semi-anadromous fish habitat for
each river system.
For Maryland's Clean Water Action Plan
Unified Watershed Assessment, watersheds were placed in
Category I (needs restoration) if they were in the
lower 25% of scores for the applicable watersheds for
the Anadromous and Semi-anadromous Fish Index.
Indicator Use
Watersheds with streams where anadromous and semi-
anadromous spawn are particularly vulnerable to
landscape disturbances that could result in physical,
chemical or biological degradation. This suggests
that extra care be taken in clearing and grading in
the vicinity of the streams. These watersheds may
also contain important opportunities for conservation
activities of both governmental and private-sector
organizations.
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