Assessing oyster population Assessing oyster population recovery in Chesapeake Bay: recovery in Chesapeake Bay: Management from a food-web Management from a food-web perspective. perspective. Richard S. Fulford Richard S. Fulford Denise Breitburg Denise Breitburg Roger Roger Newell Newell Mike Kemp Mike Kemp Mark Luckenbach Mark Luckenbach Place holder for GCRL Place holder for VIMS
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Assessing oyster population recovery in Chesapeake Bay: Management from a food-web perspective.
Assessing oyster population recovery in Chesapeake Bay: Management from a food-web perspective. Richard S. Fulford Denise BreitburgRoger Newell Mike KempMark Luckenbach. Place holder for GCRL. Place holder for VIMS. TroSim-CASM Modeling approach. - PowerPoint PPT Presentation
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Assessing oyster population recovery Assessing oyster population recovery in Chesapeake Bay: Management from in Chesapeake Bay: Management from
a food-web perspective.a food-web perspective.
Richard S. FulfordRichard S. Fulford
Denise BreitburgDenise Breitburg Roger NewellRoger Newell
Chesapeake Bay Trophic Simulation Model Chesapeake Bay Trophic Simulation Model (TroSim) (TroSim)
Multi-species bioenergetic modelMulti-species bioenergetic modelBased on CASM Model frameworkBased on CASM Model frameworkDynamic network modelDynamic network modelDaily time-stepDaily time-step
Model single years to view seasonal patterns Model single years to view seasonal patterns
ijiiiijij
jj i
jjijii
i PRpUMtempRwBBBawtempfC
Bt
B,,
,, )(****)(max*
*
Modeling ConsumptionModeling Consumption
CCmaxmax – Maximum Consumption Rate (g/g/d) – Maximum Consumption Rate (g/g/d)
wwi,ji,j – Preference of consumer i for prey j – Preference of consumer i for prey j
aai,j i,j – assimilation efficiency of consumer i – assimilation efficiency of consumer i
eating prey jeating prey j
ff(t) – temperature adjustment of consumption(t) – temperature adjustment of consumption
Consumption follows seasonal patterns in Consumption follows seasonal patterns in both composition and rateboth composition and rate
Modeling Energetic Costs and Modeling Energetic Costs and MortalityMortality
RRmaxmax – maximum respiratory costs (g/g/d) – maximum respiratory costs (g/g/d)
U – Excretory lossesU – Excretory losses
SDA – Costs of consumptionSDA – Costs of consumption
ff(t) – Temperature adjustment of respiration(t) – Temperature adjustment of respiration
rsp(i,t) – Consumer and season specific rsp(i,t) – Consumer and season specific costs of egg productioncosts of egg production
m(i) – Consumer specific natural mortalitym(i) – Consumer specific natural mortality
Model GroupsModel Groups6 producer groups (phytoplankton by size)6 producer groups (phytoplankton by size)
14 Consumer groups in seven categories14 Consumer groups in seven categorieszooplankton, gelatinous zooplankton, pelagic bacteria, zooplankton, gelatinous zooplankton, pelagic bacteria,
Reef associated fish Rogers, Healey Breitburg, Abbe
Non-reef associated fish Fishbase, Moser and Hettler Jung and Houde 2000 rel. to anchovy
Benthic bacteria S. Bartell C. GilmourC. Gilmour
Project ObjectivesProject Objectives
Main bay Model – Mesohaline Baywide Main bay Model – Mesohaline Baywide average average
Tributary Model – Patuxent and Choptank Tributary Model – Patuxent and Choptank RiversRivers
< 2 microns
2-4 microns
4-10 microns
10-50 mic
50-100 mic
> 100 microns
Phytoplankton
Bay Anchovy
Oysters
Acartia tonsa
Microzoopnktn
Sea Nettles
Ctenophores
POC
Pelagic Prey Fish
Benthic
Zooplankton
On-reef inverts
Off-reef inverts
DOCN P Si
Benthic Bacteria
HNAN
Pelagic Bacteria
Detrital Pools
Atlantic Menhaden
Oyster Larvae
Anchovy Larvae
Ctenophore Larvae
Larval Pools
Gelatinous Zooplankton
Non reef fish
Reef-assoc. fish
< 2 microns
2-4 microns
4-10 microns
10-50 mic
50-100 mic
> 100 microns
Phytoplankton
Bay Anchovy
Atlantic menhaden
Oysters
Acartia tonsa
Microzoopnktn
Sea Nettles
Ctenophores
Detrital Pools
Pelagic Prey Fish
Gelatinous Zooplankton
Benthic Planktivores
Zooplankton“Lost”
Model Linkage DynamicsModel Linkage DynamicsDaily N, P, Si and inorganic TSS concentrationsDaily N, P, Si and inorganic TSS concentrations
Light, temperature and nutrient limitation of primary productivityLight, temperature and nutrient limitation of primary productivity
DO dynamics and water column stratificationDO dynamics and water column stratification
Benthic-pelagic coupling and sediment resuspension dynamicsBenthic-pelagic coupling and sediment resuspension dynamics
Daily removals by top piscivoresDaily removals by top piscivores
Water Quality Models
TroSim-CASM Fishery Production Models
Decision Support System - NOAA Coastal Ocean Program Funding
Data suggest oyster recoveryData suggest oyster recoverywill …will …
reduce phytoplankton biomass and reduce phytoplankton biomass and particulate matter in water columnparticulate matter in water column
increase water clarityincrease water clarity
decrease production of other planktivoresdecrease production of other planktivores
possibly decrease production of higher possibly decrease production of higher level consumers via bottom-up effectslevel consumers via bottom-up effects
Have similar effects as nutrient reductionHave similar effects as nutrient reduction
Modeling Oyster RecoveryModeling Oyster Recovery
Modeled 10X, 25X, and 50X scenariosModeled 10X, 25X, and 50X scenarios
Assume threshold relationship between oysters Assume threshold relationship between oysters and sea nettlesand sea nettles
Assume linear relationship between oyster Assume linear relationship between oyster density, reef-associated fish, and on-reef density, reef-associated fish, and on-reef invertebratesinvertebrates
Assume no relationship between oyster density Assume no relationship between oyster density and off-reef invertebratesand off-reef invertebrates
Model results suggest oyster Model results suggest oyster recovery will …recovery will …
reduce phytoplankton biomass and inorganic particulate reduce phytoplankton biomass and inorganic particulate matter in water columnmatter in water column
improve water clarity locally but reduced effect regionallyimprove water clarity locally but reduced effect regionally
decrease production of zooplankton but not menhadendecrease production of zooplankton but not menhaden
decrease bay anchovy production by 30-40% yrdecrease bay anchovy production by 30-40% yr-1-1
– likely to affect production of top piscivores likely to affect production of top piscivores
decrease ctenophore productiondecrease ctenophore production
– likely to reduce predation on oyster larvaelikely to reduce predation on oyster larvae
Have a larger effect on 2Have a larger effect on 2o o production than nutrient production than nutrient reduction due to seasonalityreduction due to seasonality