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Explore the evolution of modeling techniques for stock, single species, and multispecies assessments within the ecosystem framework, emphasizing the importance of considering predation and environmental cues. Discover how various models and approaches are applied to create a holistic view of marine systems at NEFSC.
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Ecosystem & Multispecies Modeling at the NEFSC NEMoW Aug. 30, 2007
Gradient of Possibilities Stock/Single Species Multi-species Aggregate Biomass Ecosystem Messy Picture Here Gadids Pelagics Flatfish SS models, forget ecosystem issues Whole System Models, forget pop dy Multi-species assessments Aggregate Biomass Models SS assessments with explicit M2 or habitat or climate considerations Multiple SS assessments in “harmony”
SS Add-ons • Increasing #s of extant cases incorporated into assessments • Still slow “uptake kinetics” in overall Mgt process • Yields generally lower if predation is considered as a component of total mortality • Remains critical for most “forage” species • Starting to include environmental cues
e.g., Larval Fish Trophodynamic Model Lough et al. 2005. Fish. Oceanogr. 14:4, 241-262
e.g., Linked Climate-Population Models Climate (IPCC Air Temperature to Estuarine Temperature) Fisheries (Environmentally-explicit population model: R as a function of T) F=0.8 550 ppm Management (Link Forecasted SSB to Management Benchmarks) Based on mechanistic hypothesis developed in Hare and Able (2007) Fish Oceanogr 16: 31-45.
Multispecies Models • MSVPA, MSProd, AggProd etc. • Formal review process for 1 region, 2nd planned • Effects of predation the main emphasis
e.g., MSVPA • >15 spp • Age/size structured • Focuses on M2 of main “forage” stocks Temporal Variation in Fishing vs. Predation Mortality, Atlantic Herring ages 0-2
ICNAF & Two-Tiers • Historical example of Two-tier quotas • Precedence in tropical systems • Rationale is to account for: • Overall system production • Biological and technical interactions • An additional level of “precaution” • MS & Aggregate Production models • Currently exploring “guild” or functional group, or aggregate group, or etc. as potential Mgt “stocks”
250 Guild Biomass- Base Scenario 200 150 100 50 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Time Benthivores Planktivores Shrimp-Amphipods Shrimp-Fish Piscivores Base Scenario
250 Guild Biomass- Scenario 3 200 150 100 50 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Time Benthivores Planktivores Shrimp-Amphipods Shrimp-Fish Piscivores Scenario 3: Over-Fish Pelagics
EMAX • Energy Budgets/ Network Analyses • Emerging as a tool for: • Heurism • Strategic Mgt • Tradeoff Evaluation • MSE • Considered as part of formal trade-off analysis • Dynamic models next
ECOGOMAGG • A home grown dynamic model • Builds off of EMAX (energy budget) outputs
ATLANTIS NEUS • Full blown ecosystem simulations • Still in validation & development stage • An important Mgt tool • Systemic Perspective • Virtual “perturbations” • MSE
2 1995 1999 1.5 1973 1977 1 0.5 1968 1985 PC 2 0 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 -0.5 1980 1989 -1 -1.5 -2 PC 1 Ecological Indicators • Outputs both from empirical and modeling studies • Evaluate a broad suite of ecosystem properties • Vetting ongoing, MV Approaches • Translation to Decision Criteria is key • Remains to be incorporated into Mgt Process
Summary • Several modeling efforts at various stages along the modeling gradient • Working at both ends of the gradient to make ecosystem-based mgt advice operational • Several research/development activities • A few instances of review in SAW/SARC like process • Not as data limited as elsewhere, but have identified clear data gaps • Tool and software development ongoing
If you think you can or think you can’t, you’re right.- Henry Ford