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002489 and continue to decrease, reaching a low in January. In contrast, biomass of Chara contrana and Potamogeton pectinatum tends to be highest in winter (Ayers and Mckinny 1996a, McKinney et al1996, 1997). Algal growth and discharge patterns indicate that steady flows favor recovery from disturbance compared to fluctuating flows. Rapid recolonization in the Lees Ferry reach is attributed in part to subsequent high steady high flows that may have promoted zoosporogenesis that occurred in the splash zone following the BHBF (Shannon et al1996). The BHBF had an significant immediate negative affect on the filamentous green algae: reducing biomass to 15% of the total representation, but one month later had increase to 65% of the ash free dry mass. Recovery time for both phytobenthos and macroinvertebrates occurred within one months time for some monitoring sites. Variables affecting recovery time were light intensity (i.e., clear water with no tributary inputs), and discharges that were steady flows (McKinney et al 1996a, 1997; Shannon et al1996). Macroinvertebrates that use the algal community as a substrate follow a similar pattern of productivity. There is a lag time associates with this interaction. 1995-96 data indicate that macroinvertebrate biomass was lowest in February and showed an increase through September (Ayers and McKinney 1996a, McKinney et al1996; Shannon et al1996). Phytobenthic and zooplankton conposition has changed since the implementation of interm flows. Zooplankton densities in the river were consistent throughout Grand Canyon prior to Interim Flows (Haury 1988). Currently patterns show a negative correlation between zooplankton density and biomas with distance from GCD (Ayers and McKinney 1996b; Shannon et al1996). Variables associated with this charge are potentiallimnological changes in Lake Powell and changes in the discharge pattern from 1980-86 and present. Native Fish Flannelmouth suckers Flannelmouth sucker spawn in the spring in warm water tributaries (Paria, Little Colorado River, Havasu Creek, Kanab Creek). Greatest CPUE for adult flannelmouths has occurred in the Lees Ferry Reach caught most often in eddy return channel with sandy substrates and vegetation present. Adults were also caught in runs with highest CPUE reported for the Lees Ferry Reach and the LCR-Bright Angel Reach (Maddux et al1987). Lowest CPUE was associated with boulder substrates. Sub-adults were caught most frequently in eddies and runs over sand with higher CPUE when vegetation was present. Larval FMS were found inhabiting mainstem backwaters and nearshore areas (tributaries) with sand/silt bottoms along with larval bluehead suckers. Larval suckers drift from spawning grounds to nursery areas and larvae may drift down to lower reaches to utilize those habitats as nursery and rearing areas (Thieme and McIvor 1996). Overall capture oflarval FMS (ca 18 mmTL) in Grand Canyon is low. Spawning in the Lees Ferry reach was documented by McKinney and Rogers (1996), but recruitment in the reach has not been documented and successful recruitment is probably low due to cold water temperatures. Main spawning sites are considered to be the Paria River (Theirme and McIvor 1996), LCR, Kanab Creek and Havasu Creek (AGFD 1996). Return channels below National Canyon and Bright Angel Creek may be important habitats for this life stage. Other critical areas include RM