Fish Communities as Indicators of Environmental Quality in the West River Watershed

The West River bordering New Haven and West Haven, Connecticut, is under evaluation for potential restoration of a former salt marsh. As part of a larger survey of biota associated with this river, the fish fauna was examined in the estuary and adjacent freshwaters. The results provide baseline data for monitoring restoration efforts and indicate the environmental health of the river. The fish communities lacked intolerant species, included significant numbers of individuals of non-native fishes, and showed low abundance and diversity of the native species, all indicating that this stretch of the river represents poor fish habitat with significant ecological disturbances. Some sites contained individuals with excessive parasites, tumors, ulcers, and fin erosion, which suggests physiological stress and potential human health hazards. These problems are localized in the vicinity of combined sewage outflows and/or storm sewer runoff from streets. They are exacerbated by periodic low flow or stagnant waters caused by the tide gates. Salt marsh restoration with tide-gate modification could improve habitat for species with commercial and recreational value and improve movement of diadromous fishes. The West River, a coastal watershed system on the New HavenWest Haven border in Connecticut, once included a thriving salt marsh in the area of the present day West River Memorial Park. In 1919, installation of tide gates restricted the flow of marine water upstream (Kenny 1995). The tide gates were installed in order to limit tidal flow for agricultural, flood control, and mosquito control projects (MacBroom 1995). The ensuing degradation of the salt marsh upstream from the gates brought many ecological changes to the area. High tide levels of the original marsh were reduced, and the salinity concentration generally became lower, although it still remained brackish (Kenny 1995). These physical factors caused a change in the vegetation of the park, allowing common reed (Phragmites australis) to thrive. Lower water levels also caused an increase in wildfires due to the frequent dryness of the environment (MacBroom 1995). With restricted water movement, soil settlement became common, changing the chemistry of the river water and bottom. These environmental changes continue to affect the aquatic and terrestrial life of the watershed ecosystem. Moreover, the tide gates restrict the passage of diadromous fishes, physically preventing some of them from entering the estuarine and freshwater areas upstream.