Current understanding of trophic dynamics
In the Mid-Atlantic Bluefish diets, Mid Atlantic and Southern New England, NEFSC surveys
100% All others All Flatfish 90% Unid fish Unid Unid fish Unid fish Unid fish Scup 80% Scup Unid fish Scup Bluefish Butterfish Bluefish 70% Mackerel Bluefish Butterfish Butterfish Hakes 60% Loligo Drums Butterfish Unid Squid Ocean pout Round herring 50% Butterfish Ctenophores Menhaden Loligo Loligo Loligo
40% Loligo Unid Squid Round herring Illex Bay anchovy Unid Squid Unid Squid Silver anchovy Round herring Round herring 30% Bay anchovy Menhaden Unid herring Bay anchovy Menhaden Bay anchovy Striped anchovy 20% Silver anchovy Unid anchovies Bay anchovy Striped anchovy Unid anchovies 10% Striped anchovy Unid anchovies Sand lances Unid anchovies Sand lances Sand lances Sand lances 0% 1977-86 1987-96 1997-2006 2007-2013
Food web models partition mortality
100%
90%
80% If Pred > F, 70% Pred Re-evaluate 60% constant M 50%
40%
Proportion of total Mortality total Proportion of F 30%
20%
10% Proportion of total mortality total of Proportion
0% Longnose skate P. Halibut W. Pollock Squids
Gaichas et al. 2010 Fishing Predation Other
Link et al. 2008. The Northeast U.S. continental shelf Energy Modeling and Analysis exercise (EMAX): Ecological network model development and basic ecosystem metrics. Journal of Marine Systems 74: 453-474 Intermediate tactical multispecies models An intermediate-complexity tactical ecosystem assessment tool combines:
Standard stock assessment Ecosystem considerations • Structured population • Species interactions and dynamics tradeoffs • Statistical parameter • Environmental effects on estimation using multiple key population processes data sources • Populations and fisheries in space • Biological reference points and stock status for management … WITHOUT requiring time machines, expensive new surveys, or supercomputers
Kraken: Multispecies Production Model
g G ig N g iG NG p dNi Ni 1 1 ri Ni (1 ) Ni ip N p Hi Ni dt KG KG (K KG ) 1 Groundfish Atlantic cod (GB) American plaice Atlantic cod (GOM) Windowpane (GOM-GB) Haddock (GB) Windowpane (SNE) Gulf of Haddock (GOM) Winter fldr (GB) Maine Halibut Winter fldr (GOM) Georges Ocean pout Winter fldr (SNE) SNE Bank Pollock Witch flounder Redfish Yellowtail (GOM) White hake Yellowtail (GB) Yellowtail (SNE) Elasmobranchs Small pelagics Skates and rays Atlantic herring Spiny dogfish Butterfish Mackerel Gamble, R.J. and J.S. Link. 2009. Analyzing the tradeoffs among ecological and fishing effects on an example fish community: A multispecies (fisheries) production model. Ecol. Mod. 220: 2570-2582. Hydra model target capabilities
• Multispecies: fish and commercial invertebrates • Size structured • Estimates predation mortality • Environmental covariates on growth, maturity, fecundity • Multiple recruitment functions • Likelihood (or Bayesian) parameter estimation in ADMB • Spatial • Flexible framework, outputs Species 1 Area & Fleet 1
L
Species 2
L
L
Area & Fleet 2 Species 1 Hydra model current state
• 10 species: 2 elasmos, 2 pelagics, 4 groundfish, 2 flatfish • 5 size categories for each species Simulated survey time series • Size specific pred mortality • 2 growth forms • Temp covariate on growth • 3 recruitment forms • 3 fleets (2 trawl + fixed gear) Simulated catch time series • Running in simulation mode • 1 area, “Georges Bank” • Dimensioned for expansion
Multispecies model initial testing Later, Environment multispecies assessments
• Covariate on process(es) – Growth X i,k p,k p,k ,t – Mortality li,k,a,t i,k ai,k e – Recruitment
E X i,k i,k i,k ,tr pk p Ni,1,k,t i,k E i,k,tre
• Shifts in distribution or overlap
Black sea bass distribution How can we transition from single species to multispecies/multi-fleet models? Conceptual models of interactions
Develop a common “big picture” for everyone to work from Powerful strategic tools
• Risk assessment methods • Management strategy evaluationEvaluate level of detail Prioritize which needed, best interactions to strategies consider first under uncertainty
Redrawn with permission of Beth Fulton A spectrum of tools, a spectrum of uses
Stock/Single Multi-species Aggregate Ecosystem Species Biomass
Gadids
Pelagics Flatfish
Single stock models Functional Stock assessments group models Whole system with add-ons: models Multi-species explicit M2 or assessments habitat or climate considerations Integrated Continue ecosystem Multiple stock assessments assessments building the in “harmony” toolbox Multi Model Inference
•More robust prediction
•Analogous to climate models
•Model averaging available now
•Methods established •Qualitative: differently structured models giving similar results increase confidence. Can construct “envelope” for prediction. •Quantitative: Bayesian, other ensemble methods Introduction to IEAs and full ecosystem models
(More detail this afternoon) Integrated Ecosystem Assessment is a Process NOAA’s Integrated Ecosystem Assessment (IEA) Program IEAs Provide an Analytical Framework to Implement EBM
http://www.noaa.gov/iea/ 25 Integrating external drivers, interactions
• Ecological interactions • Invasives + range shifts • Food webs ?
? Temp and pH changes
Verges et al., 2014. Proc. R. Soc. B 281: 20140846 ATLANTIS Northeast US 45 Functional Groups 0 Pelagic
50
120+
300+
Epibenthic Sediment
18 Fishing fleets
Link JS, Gamble RJ, Fulton EA. 2011. NEUS – Atlantis: Construction, Calibration, and Application of an Ecosystem Model with Ecological Interactions, Physiographic Conditions, and Fleet Behavior. NOAA Tech Memo NMFS NE-218 247 p. Available at http://www.nefsc.noaa.gov/nefsc/publications/. Questions
How to include interactions in fishery management? – Within linked single species assessments? – Using multispecies assessments? – As an adjustment to policy (OFL, buffers, etc.)?
How to balance multiple objectives for yield, healthy stocks and fisheries, robust ecosystems? – Possible with current data, multispecies models, BUT knowledge of all interactions insufficient for precise engineering – Managing tradeoffs a new level of policy – Reference points conditioned on other reference points? Multiple objectives—a space
Fay et al. In Review. Mar. Pol.