The surveys also do not provide the data required to determine the spatial extent of shell on a discrete reef site. Researchers conducted a few surveys to determine the amount of shell on a reef but these do not cover all oyster production areas of the Bay. The first is the number of oysters found in a unit of reef substrate (e.g., bushels) and second is the total volume of reef substrate. These qualitative data are spat per bushel of shell found during sampling cruises.Įstimating the size of a new year-class of oysters on a reef requires two types of data. One weakness in spat production data is that they are qualitative and do not allow accurate calculation of the total number of new oysters in the population. We used data from surveys for computations in this report. We compare power dredging and natural recruitment to rebuild biomass to contemporary aquaculture techniques. This paper evaluates the cost-effectiveness and effects on production of restoration options. To understand the effect of dredging on populations, we analyzed data from scientific studies to predict the likely outcome of these activities. This has created problems for managers who must consider multiple factors in regulating fisheries. Scientific and environmental communities dispute this claim, pointing to differences between bottom renovation and recruitment. Harvesters state that expanding this type of dredging throughout the Bay would lead to increased biomass and public harvest. Many commercial oyster harvesters favor dredging using metal scrapes towed by powered harvest vessels as a beneficial practice.
Disagreements stem from a lack of accurate and defensible data upon which to base decisions.
The Chesapeake Bay oyster resource and fishery have shown wide temporal population fluctuations generating controversy regarding restoration methods. EB-449 | March 2022 Predicting Oyster Production: A Comparison of Natural Recruitment and Aquaculture Abstract