The Importance of Oysters in Providing for Healthy Coastal Ecosystems Panelists : Dr. Martin Posey, University of North Carolina Wilmington Dr. Michael Piehler, University of North Carolina at Chapel Hill , I.M.S. and C.S.I Ecosystem Impacts of Oyster reefs: Not Just Food on the Half Shell Martin Posey University of North Carolina Wilmington • With decline of oysters have lost ecological and fishery functions • Roger Mann has estimated ecosystem economic impacts >> fishery impacts • Ecosystem Functions and Human Interest • Filtration and Water Quality • Nutrient Processing • Habitat • Fish, crabs, shrimp • Forage animals • Shoreline Stabilization • Oyster Fishery • Habitat – Habitat for organisms living in reef as well as many other fish, crabs and shrimp. – Nursery habitat for juveniles of fisheries species, forage location for fishery species, habitat for forage species. – How critical are reefs as a habitat? Variety of factors may impact habitat function of restored reefs • Oyster density and size distribution • Reef size • Reef height • Reef complexity • Landscape factors – Spacing, position, proximity • Trophic interactions within the reef system Fundulus Nekton - Summer 20 heteroclitus Lagodon 18 rhomboides 16 Leiostomus 14 xanthurus 12 Mugil cephalus 10 8 U/I larval fish 6 4 Mean abundance per trapper abundance Mean 2 0 uniform small frag large frag mud flat natural 60 Epifauna - Fall Eurypanopeus depressus 50 (g) 2 1.2 Geukensia demissa 40 1 Panopeus her bs tii 30 0.8 Uros alpinx c inerea 20 0.6 0.4 10 0.2 0 0 Total crab abundance . abundance crab Total High Low Neither Mean biomass per 1200 cm uniform small frag large frag mud flat natural • Shoreline stabilization/baffling – may be important in stabilizing marsh edge areas and certain shoreline areas – Receiving increased attention for both ecosystem and management implications Using oysters for shoreline stabilization • Approaches – Shell placement along shoreline – Usually in staked bags • Numerous recent efforts – In U.S.: NC, SC, Fl, Va, Md • Questions: – Under what circumstances can oysters be used in shoreline stabilization? – What are best placement approaches? Ecological and economic benefits of oyster filtraon Michael F Piehler ([email protected]) More nitrogen, less oyster filtraon Percent historical filtraon capacity Corpus Chris Bay Aransas Bay San Antonio Bay Matagorda Bay Galveston Bay West Mississippi Sound Mobile Bay Apalachicola Bay James River +753% York River Tangier and Pocomoke Delaware Bay Hudson River/Raritan -100 -50 0 50 100 Zu Ermgassen et al 2013 Oyster reefs may help resist eutrophicaon Piehler and Smyth 2011, Ecosphere Evaluang estuarine N processing •Rigorous measurements of processes •Net contribuons to N processing •Transferable data $1300 $1600 $800 $200 All values are dollars per hectare per year $1600 Oyster Ecosystem Services Value of oyster services= $10,122 per hectare $656 • Oyster fishery $30 Commercial fish • Fish producon $4,289 Nitrogen removal $4,050 • Provide habitat SAV • Shoreline stabilizaon Shoreline • Water quality stabilizaon • Algae removal • Increase water clarity • Nitrogen removal Grabowski et al. 2012 Value of Nitrogen Removal $28.56 per kg Oysters and nitrogen removal + NH4 + - NH4 NO3 N2 Many thanks .