Greenside Darter - Etheostoma blennioides
In 1996, we
conducted research to illustrate some positive effects
that dams may have on fish. We focused specifically on
the greenside darter (Etheostoma blennioides),
which was observed in abundance downstream from the
Mannheim Weir on the Grand River, Ontario.

Bunt,
C.M., S.J. Cooke and R.S. McKinley. 1998. Creation and
maintenance of habitat downstream from a weir for the
greenside darter (Etheostoma blennioides) - a
rare fish in Canada. Environmental Biology of Fishes. 51:
297 - 308.
Abstract - The
biology, microhabitat use and migratory behaviour of
greenside darters (Etheostoma blennioides) was
studied at the Mannheim Weir on the Grand River, Ontario
during the summer of 1995 and 1996. Officially threatened
in Canada, greenside darters reached maturity at age 1 and
lived for up to 4 years. They were found in riffle
habitats that consisted of cobble and loose boulders, with
large mats of Cladophora. This type of unembedded
substrate is uncommon in the Grand River watershed.
However, local abundance of greenside darters downstream
from the Mannheim weir was likely due to high water
velocities from weir discharge, freshets and ice scour
that help maintain unembedded riffle areas. Trap data
indicated that greenside darters temporally partition this
habitat with the stonecat (Noturus flavus). Other
darter species were not commonly found in areas used by
greenside darters. Predators and morphology influenced
depth selection and habitat choices of the greenside
darter. Denil fishways at the Mannheim weir were rarely
used by greenside darters due to prohibitively high water
velocities and exclusion by larger fish.
 
We also
conducted experiments to demonstrate the effectiveness of
various capture techniques for benthic stream fishes:
Cooke, S.J., C.M. Bunt and R.S. McKinley. 1998. Injury and
short-term mortality of benthic stream fishes - a
comparison of collection techniques. Hydrobiologia. 379:
207-211.
Abstract
-Small benthic fish such as darters are frequently
collected for stream inventory purposes or to document
habitat use, with the intent of releasing the fish
unharmed following enumeration. The purpose of this study
was to examine the injury and short term mortality (8 d)
of greenside darters captured by live wire pot trapping
and electrofishing, using two different settings (80Hz,
6ms and 60Hz, 6ms). Two different electrofishing
techniques were used, spot electrofishing and sweep
electrofishing. Short term mortality was highest for fish
collected in live pot traps. Abrasion from the wire traps
appeared to remove scales and irritate the skin. By the
conclusion of the study, 74% of the fish caught in live
pot traps were dead from fungal lesions. Greenside
darters captured by all electrofishing methods exhibited
low short term mortality (<10%). The only initial
mortality, hemorrhaging and spinal damage, occurred for
fish collected using 80Hz, 6ms sweep technique, although
the short term mortality was still far less than that
observed among trapped fish. The spot electrofishing
technique resulted in no injury, with either of the
settings. Live trapping produces little initial mortality,
and thus may be wrongly viewed as a safe alternative for
the collection of threatened benthic stream fishes,
compared to electrofishing. We suggest that researchers
studying small fish in warmwater systems use caution when
collecting and handling fish for subsequent release.
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