Rapid video assessment detects qualitative differences in oyster reef habitat

A combination of anthropogenic stressors and overharvesting has led to a loss of oyster reefs and the important ecosystem services they provide. Addressing these losses through restoration is now a focus of coastal and estuarine conservation efforts. The present study tested a low-cost, qualitative rapid assessment approach for monitoring habitat characteristics of subtidal oyster reefs differing in restoration activity. The study was conducted in 4 tributaries of the Choptank River complex, Maryland, USA, which included harvest areas and no-take reserves (sanctuaries). At each site, a categorical score ranging from 0 to 3 was compared with percent cover of oyster shell and of fouling organisms. Restored reefs in oyster sanctuaries had higher scores (2 to 3) and percent cover of oyster shell and fouling organisms than unrestored sanctuary reefs or reefs open to harvest; higher scores were also associated with greater percent cover of hard substrate and fouling organisms. The Harris Creek sanctuary reef system had the highest percentage of scores of 3 (40%), followed by tributaries with partially restored reef systems (14% in Little Choptank, 6% in Tred Avon) and harvest areas (2% in Broad Creek). Although validation with metrics of live oysters is needed, rapid video assessment appears to be an effective, low-cost tool for qualitative monitoring of subtidal oyster reefs in areas with adequate visibility.