Search

Benthic invertebrate community composition was surveyed across the salinity gradient of the Pensacola Bay Estuary in Florida during summer 2016. Macrofauna densities ranged from 1000 to 9300 individuals m−2, with highest densities occurring at the upper estuary and the lowest in the mid‐ and lower estuary. Taxonomic richness and Shannon diversity were lowest in the upper estuary and increased along the salinity gradient. Small‐bodied, near‐surface infaunal polychaete species (e.g., Mediomastus ambiseta and Paraprionospio alata) dominated the macrofaunal community in fine sediment areas. We calculated the Gulf of Mexico Benthic Index of Biological Integrity for each site and compared the index scores with those from Environmental Monitoring and Assessment Program ‐ Estuaries, an earlier benthic assessment model. Condition evaluations by the different models did not match across all sites in this study; however, scores consistently indicated that most sites were at or near degraded levels, implying that Pensacola Bay represents a marginal habitat for a "healthy" benthic macrofauna community. This study provided new information about the benthic communities and sediments in the Pensacola Bay estuary. Integr Environ Assess Manag 2020;16:245–256. Published 2019. This article is a US Government work and is in the public domain in the USA. KEY POINTS: Study describes benthic communities in the Pensacola Bay system, in the Gulf of Mexico (GOM), and evaluates habitat condition using 2 benthic index approaches, i.e., GOM Benthic Index of Biological Integrity (B‐IBI) and Environmental Monitoring and Assessment Program ‐ Estuaries (EMAP‐E).Results of this study suggest that more systematic testing and reference site assessments are needed to make the GOM B‐IBI more useful for environmental management applications, particularly for high‐salinity regions of northern Florida estuaries with muddy sediments.Until the GOM B‐IBI can be refined to include panhandle‐specific metrics, the EMAP‐E index may be the most appropriate model for assessing the benthic habitat condition in this region. [ABSTRACT FROM AUTHOR]

Efforts to restore the Eastern oyster ( Crassostrea virginica) reef habitats in Chesapeake Bay typically begin with the placement of hard substrata to form three-dimensional mounds on the seabed to serve as a base for oyster recruitment and growth. A shortage of oyster shell for creating large-scale reefs has led to widespread use of other materials such as Surf clamshell ( Spisula solidissima), as a substitute for oyster shell. Oyster recruitment, survival, and growth were monitored on intertidal reefs constructed from oyster and Surf clamshell near Fisherman’s Island, Virginia, U.S.A. and on a subtidal Surf clamshell reef in York River, Virginia, U.S.A. At the intertidal reefs, oyster larvae settlement occurred at similar levels on both substrate types throughout the monitoring period but higher levels of post-settlement mortality occurred on clamshell reefs. The oyster shell reef supported greater oyster growth and survival and offered the highest degree of structural complexity. On the subtidal clamshell reef, the quality of the substrate varied with reef elevation. Large shell fragments and intact valves were scattered around the reef base, whereas small, tightly packed shell fragments paved the crest and flank of the reef mound. Oysters were more abundant and larger at the base of this reef and less abundant and smaller on the reef crest. The availability of interstitial space and appropriate settlement surfaces is hypothesized to account for the observed differences in oyster abundance across the reef systems. Patterns observed emphasize the importance of appropriate substrate selection for restoration activities to enhance natural recovery where an underlying habitat structure is destroyed. [ABSTRACT FROM AUTHOR]