Relationship of water quality and geochemistry to fish condition factors, isotopic composition and otolith microchemistry within an urbanized watershed: Onondaga Creek (Syracuse, New York)

This study investigates water quality and geochemistry as correlated to fish variables along a rural-urban gradient. Water and four fish species were sampled at fourteen sites along Onondaga Creek (Onondaga County, NY). More rural sites had relatively lower temperatures, conductivities and total suspended solids than urban sites, as well as higher concentrations of dissolved oxygen. Nitrogen and phosphorous concentrations had a negative correlation to distance from the mouth of Onondaga Lake. Urbanized sections of the stream had higher concentrations of calcium, sodium, potassium, strontium and magnesium. Fish condition factors were statistically similar along the gradient, while isotopic composition of delta13C and delta15N was inversely correlated within fish tissue. Fish tissue had higher delta 15N for headwaters and urban sections and lower for agricultural and mouth of Onondaga Creek. Sr:Ca correlation analyses for water geochemistry and otolith microchemistry was positive and significant. Correlation analyses for Na:Ca, K:Ca and Mg:Ca were not significant.