SS1.09 Fisheries Population Linkage Spatial and Temporal Variation in Zooplankton
Date: Wednesday, June 12, 2002
Time: 4:00:00 PM
Location: Carson C
 
HarrisonJP, Darrin Fresh Water Institute, Biology Department, Rensselaer Polytechnic Institute, Troy, New York, USA, harrij6@rpi.edu
Boylen, C, W, Darrin Fresh Water Institute, Biology Department, Rensselaer Polytechnic Institute, Troy, New York, USA, boylec@rpi.edu
 
EVALUATION OF FISH SIGHTING PATTERNS, ANNUAL CHANGES IN ZOOPLANKTON, ABIOTIC FACTERS, AND ENCROACHMENT OF ANOXIC PELAGIC WATERS IN A SMALL ADIRONDACK LAKE
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The completion of an annual hydroacoustic sightings profile, in conjunction with DO and temperature assessments accrued across a three-year study, revealed significant changes in diurnal and monthly fish distribution patterns. Three factors-anoxic water encroachment, thermal and chemical stratification, and zooplankton dynamics-show relevant influence in connection to these changes. Detailed assessment of DO has revealed an annual anoxic water expansion from the benthic interface in spring, to epilimnetic waters by the fall. Ongoing gill nettings, subsequent gut analysis, and enumeration of the zooplankton composition suggest a shift in food availability exists. The variations in sighting patterns reveal strong changes to diurnal patterns with respect to pelagic species, alterations in littoral zone dispersions due to thermal declines in the fall, and potential correlations to the food web dynamics with respect to zooplankton composition and changes in the vertical migratory habits of Chaoborus species. The dynamics suggest that these factors, and the influences they impart, necessitate anoxic water incursions by pelagic fish species.