Three Decades of Change in Demersal Fish and Water Quality in a Long Island Sound Embayment
Estuaries are impacted by multiple anthropogenic stressors from eutrophication to climate change. Long-term observational datasets allow the determination of trends in estuarine indicators and the prediction of future conditions. Here, a dataset of water quality and demersal fish community composition in a Long Island Sound embayment (Norwalk Harbor, Connecticut) from 1987 to 2016 was examined. Mean water column water temperature increased, dissolved oxygen decreased, and salinity increased over the study period, with simultaneous changes in the demersal fish community. Fish abundance declined overall, with declines in CPUE observed across multiple species including the commercially important winter flounder (Pseudopleuronectes americanus). As fish can serve as effective indicators of estuarine health, these changes suggest a negative shift in the health of this Long Island Sound embayment. Climate change presents an increasing threat to estuaries and the ecosystem services they provide, especially when coupled with other anthropogenic stressors. Management actions are needed at multiple spatial scales, from local to global, to combat these threats to estuarine health.
KeywordsEstuaries Demersal fish Climate change Winter flounder Long Island Sound
The authors wish to thank Penny Howell, Norm Bloom, Sue Steadham, the Wilton High School Marine Biology Club, and the dozens of student and adult volunteers who participated in the collection and analysis of the fish and water quality data over the study period.
Funding was provided by Copps Island Oysters, Jeniam Foundation, Social Venture Partners of Connecticut, Hillard Bloom Shellfish, King Industries, Norwalk River Watershed Association, Newman’s Own Foundation, NRG—Devon, Soundsurfer Foundation, Trout Unlimited—Mianus Chapter, Long Island Sound Futures Fund, Elizabeth Raymond Ambler Trust Foundation, Adolph and Ruth Schnurmacher Foundation, Daphne Seybolt Culpeper Foundation, Fairfield County’s Community Foundation, New Canaan Community Foundation, Coastwise Boatworks, 11th Hour Racing Foundation, and Horizon Foundation, and the generosity of individual donors.
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