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 filtra on
Michael F Piehler ([email protected]) More nitrogen, less oyster filtra on
Percent historical filtra on 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 eutrophica on Piehler and Smyth 2011, Ecosphere Evalua ng estuarine N processing
•Rigorous measurements of processes
•Net contribu ons 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 produc on $4,289 Nitrogen removal $4,050 • Provide habitat SAV • Shoreline stabiliza on Shoreline • Water quality stabiliza on • 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