Acknowledgements This work was supported by the NOAA Fisheries Northeast Fisheries Science Center and the NOAA Fisheries Office of Aquaculture. Thanks to Marta Gomez-Chiarri, PG Harris, Mark Luckenbach, and Christine Thompson for sharing data, although these data were not included in the final repository. Background Information The removal of excess nitrogen from eutrophic environments is an ecosystem service provided by shellfish aquaculture that is well described in the literature (Lindahl et al., 2005; Rose et al., 2014; Petersen et al., 2014; Clements and Comeau, 2019). Nitrogen removal associated with shellfish farms can occur via three mechanisms: the assimilation of nitrogen into tissue and shell, which is removed from the waterbody when animals are harvested; the enhancement of sediment denitrification through biodeposit production on farms; and the long-term burial of biodeposits. A robust calculation of the nitrogen removed at shellfish harvest has been previously published using relatively simple metrics: the nitrogen concentration of tissue/shell, the number and mean size of animals harvested, and a conversion of animal size to tissue and shell dry weight (Reichert-Nguyen et al., 2016; Clements and Comeau, 2019). The quantity of nitrogen removed at shellfish harvest has been previously predicted with high confidence, which has led to the integration of oyster and clam aquaculture into nutrient management programs at the local and estuary scale in the United States (Town of Mashpee, 2015; Reichert-Nguyen et al., 2016; Reitsma et al., 2017). The data in this repository were compiled with the intention of expanding the geographic scope of calculation of nitrogen removal associated with harvested eastern oysters (Crassostrea virginica), and to evaluate variation in this ecosystem service across common cultivation practices and ploidy. Data were obtained from sampling locations across the US from the state of North Carolina north to the state of Maine. Data are included for both diploid and triploid oysters, and for three common styles of cultivation: oysters grown on bottom without the use of aquaculture gear, oysters grown in bottom cages, and oysters grown in floating gear at the sea surface. Data curation was undertaken to obtain a dataset that most closely reflects on-farm conditions as possible. The highest priority was to find data collected from working oyster farms, and a second priority was to identify data collected by scientists who employed common cultivation practices in their research studies. In one state within the region (Rhode Island) we were unable to locate data that fit the previous description, and instead have included data from wild oysters from waterbodies that have oyster farms. This data set was used to support the development of the Aquaculture Nutrient Removal Calculator (ANRC,https://connect.fisheries.noaa.gov/ANRC/), a tool designed for use by both shellfish farmers and managers within the aquaculture permit review process. The ANRC is a publicly available, simple online tool that was developed in direct response to feedback from aquaculture resource managers. The ANRC accurately predicts harvest-based nitrogen removal from an eastern oyster farm located within the geographic range of North Carolina to Maine, USA. We have taken an adaptive management approach to tool development, basing our tool on current best available scientific information, with the intention of maintaining and updating this tool when new information and data become available in the future. Data Description This repository contains information on morphometrics and nitrogen concentration of tissue and shell for eastern oysters sampled within the US geographic region spanning the states of North Carolina to Maine. Some of the data in this repository (6 of 10 sources) were previously published as summary statistics in the peer-reviewed literature, but the raw data included here were not archived. Three datasets were not previously published in raw or summary form. One dataset is publicly available in a technical report. The repository is organized with individual oysters as rows and numerical/categorical information associated with those oyster samples as columns. Each sample in the repository contains data on oyster shell height (mm), tissue dry weight (g), data source, ploidy, cultivation practice, and location of sample collection. The repository also contains additional information provided by data sources as available, such as shell dry weight, nitrogen, carbon, sampling date, oyster stock, and other morphometric measurements. References Clements, J.C., Comeau, L.A., 2019. Nitrogen removal potential of shellfish aquaculture harvests in eastern Canada: A comparison of culture methods. Aquaculture Reports 13, 100183. Lindahl, O., Hart, R., Hernroth, B., Kollberg, S., Loo, L.-O., Olrog, L., Rehnstam-Holm, A.-S., Svensson, J., Svensson, S., Syversen, U., 2005. Improving marine water quality by mussel farming - a profitable solution for Swedish society. Ambio 34, 129-136. Petersen, J.K., Hasler, B., Timmermann, K., Nielsen, P., Tørring, D.B., Larsen, M.M., Holmer, M., 2014. Mussels as a tool for mitigation of nutrients in the marine environment. Marine Pollution Bulletin 82, 137-143. Reichert-Nguyen, J., Cornwell, J., Rose, J., Kellogg, L., Luckenbach, M., Bricker, S., Paynter, K., Moore, C., Parker, M., Sanford, L., Wolinski, B., Lacatell, A., Fegley, L., Hudson, K., French, E., Slacum, W., 2016. Panel recommendations on the oyster BMP nutrient and suspended sediment reduction effectiveness determination decision framework and nitrogen and phosphorus assimilation in oyster tissue reduction effectiveness for oyster aquaculture practices, Report to the Chesapeake Bay Program. Available online at https://www.oysterrecovery.org/wp-content/uploads/2017/01/Oyster-BMP-1st-Report_Final_Approved_2016-12-19.pdf. Reitsma, J., Murphy, D.C., Archer, A.F., York, R.H., 2017. Nitrogen extraction potential of wild and cultured bivalves harvested from nearshore waters of Cape Cod, USA. Marine Pollution Bulletin 116, 175-181. Rose, J.M., Bricker, S.B., Tedesco, M.A., Wikfors, G.H., 2014. A Role for Shellfish Aquaculture in Coastal Nitrogen Management. Environmental Science & Technology 48, 2519-2525. Rose J.M.,, Morse, R., and Schillaci, C. 2024. Development and application of an online tool to quantify nitrogen removal associated with harvest of cultivated eastern oysters. PLoS ONE 19(9): e0310062. https://doi.org/10.1371/journal.pone.0310062 Town of Mashpee Sewer Commission, 2015. Comprehensive watershed nitrogen management plan, Town of Mashpee, Available online at http://www.mashpeewaters.com/documents.html.