Abstract
Naples, Florida is built around the subtropical Naples Bay estuary. Crassostrea virginica oyster reefs once thrived in Naples Bay but have declined 80% from historical levels due to a combination of dredging, shoreline hardening, altered hydrology, and water quality impairment. Efforts are underway to restore oysters in the bay through projects involving artificial reef construction and hydrology management changes. To gauge restoration successes, we monitored oyster reef characteristics and water quality at natural and constructed reefs throughout the estuary. Multiple indicators of oyster reef health were monitored, including the density of oysters, spat recruitment, and oyster tissue copper concentrations. Avian habitat use was also monitored as an indicator of the benefits of the reefs for wildlife. Assessments were conducted monthly for a year at locations which included three reef restoration sites, a control site with good water quality, and an urbanized site with poor water quality. Recruitment to artificial substrates was good, with oyster abundance on created reefs higher than in pre-restoration and control strata and similar to natural reefs after two years. The abundance and diversity of bird species at post-restoration sites indicated the value of restored reefs as foraging habitat. Oyster abundance and recruitment was highest at mid to high salinity sites, though these sites had few large, old oysters, indicating high mortality. Lower salinity sites had fewer but larger oysters, more non-oyster fouling organisms, and higher water column and oyster tissue copper concentrations. High mortality, substrate limitation, and boat wake disturbance are likely impairing oyster reef recovery in unrestored areas of the lower estuary. In the upper estuary, the impairments are more likely to be recruitment limitation, freshwater stress, and copper pollution effects on larvae. Helpful management actions would be to add more breakwaters and living shoreline structures in the middle to lower estuary, reduce the copper pollution, and complete hydrologic restoration projects to reduce extreme freshwater flows.