EFFECTS OF INORGANIC SEDIMENT AND FOOD CONCENTRATIONS ON ENERGETIC PROCESSES OF THE ZEBRA MUSSEL, DREISSENA-POLYMORPHA - IMPLICATIONS FOR GROWTH IN TURBID RIVERS
Sp. Madon et al., EFFECTS OF INORGANIC SEDIMENT AND FOOD CONCENTRATIONS ON ENERGETIC PROCESSES OF THE ZEBRA MUSSEL, DREISSENA-POLYMORPHA - IMPLICATIONS FOR GROWTH IN TURBID RIVERS, Canadian journal of fisheries and aquatic sciences, 55(2), 1998, pp. 401-413
We examined the effects of inorganic suspended sediment (0, 1, 10, and
100 mg.L-1) and food concentrations (0.1, 0.5, and 2.0 mg particulate
organic matter (POM).L-1) on clearance, ingestion, respiration, feces
, and pseudofeces production rates and assimilation efficiencies of ad
ult zebra mussels (Dreissena polymorpha) under laboratory conditions a
t 20 +/- 1 degrees C. Food quality indices (the proportion of inorgani
c to organic material in feeding suspensions = IO ratios) ranged from
0.304 to 63.04. Suspended inorganic sediment above 1 mg.L-1 greatly re
duced clearance rates, ingestion rates, and assimilation efficiencies
of zebra mussels, and ingestion of POM was maintained only at high foo
d concentrations. Pseudofeces were produced copiously by zebra mussels
in the 100 mg.L-1 sediment treatment, and there appeared to be an inc
reased metabolic cost associated with pseudofeces production. Declinin
g food quality caused exponential declines in clearance, ingestion, an
d absorption rates, water processing potential, and assimilation effic
iencies, with the sharpest declines between IO ratios of 0.304 and 5.0
. IO ratios in turbid rivers often exceed 1.71, our experimental thres
hold where scope for growth for zebra mussels was zero. We contend tha
t zebra mussels in turbid rivers may exhibit low growth potential and
may not stabilize at the high population densities seen in their lake
counterparts.