Jk. Tucker et al., SENSITIVITY TO AERIAL EXPOSURE - POTENTIAL OF SYSTEMWIDE DRAWDOWNS TOMANAGE ZEBRA MUSSELS IN THE MISSISSIPPI RIVER, Regulated rivers, 13(6), 1997, pp. 479-487
We report the results of five experiments performed during periods of
lowered river water level in Pool 26 of the Mississippi River. Four ex
periments compared survivorship of zebra mussels (Dreissena polymorpha
) and unionid mussels (Unionidae). Under mild spring conditions (March
), survivorship of zebra mussels was similar to that of unionid mussel
s, but during summer (July) survivorship of zebra mussels was lower th
an that of unionid mussels. Survivorship of zebra mussels was greatest
when attached to native unionids, compared with detached zebra mussel
s and zebra mussels attached rocks. A fifth experiment compared surviv
orship of 10 species of unionid mussels after 24 hours of aerial expos
ure. In general, survivorship of thick-shelled species, such as Amblem
a plicata, was greater than survivorship of thin-shelled species, such
as Potamilus ohiensis. The experiments conducted suggest that drawdow
ns during warm summer conditions could have a profound, negative influ
ence on zebra mussel demography and distribution. In contrast, unionid
mussel survival was unaffected by aerial exposure of up to 24 hours d
uring a midsummer drawdown. (C) 1997 John Wiley & Sons, Ltd.