1. Production of Fish and Benthos on Georges Bank Estimates of benthic biomass and production Preliminary estimates of energy flow Dynamic fish population models Jeremy Collie, Allison DeLong, and Richard Bell Graduate School of Oceanography University of Rhode Island

2. Benthivorous Fish Pelagic Invertebrate Predators Micro- Phytoplankton (>20  m) Seabirds Deposit-feeding Benthos Suspension- feeding Benthos Detritus Ammonia Fishing R Micro- Zooplankton (2-200  m) Meso- Zooplankton (>200  m) Nitrate Nano- Phytoplankton (<20  m) Planktivorous Fish Piscivorous Fish Pre-recruits Marine Mammals spawning recruitment

3. Time periodLocationBiomassP:BProduction 1960sEntire Bank Suspension190.916 Deposit641.586 Total831.2102 1977Southern Flank Suspension541.054 Deposit201.739 Total741.393 1983Southern Flank Suspension301.030 Deposit312.056 Total611.486 1990sNorthern Edge Suspension1130.545 Deposit890.760 Total2020.5105 Benthic macrofaunal biomass (kcal m -2 ) and production (kcal m -2 yr -1 ) on Georges Bank

4. Benthic Production on Georges Bank unfished fished closed open

5. Benthic production on the northern edge of Georges Bank is significantly lower in fished areas compared with unfished areas at the same depth Fished area, depth 79 mUnfished area, depth 84 m From Hermsen et al. 2003, MEPS 260:97-108

6. Benthic production has increased in the northern part of Closed Area II relative to an area just outside the closed area that remains open to fishing Inside closed area, depth 48 mOutside closed area, depth 47 m From Hermsen et al. 2003, MEPS 260:97-108 Area closed

7. P: Production (Kcal m -2 yr -1 ) available for next consumer Functional Guild Name B: Biomass (Kcal m -2 ) C: Consumption (Kcal m -2 yr -1 ) Key to Preliminary Energy Budget

8. Marine Mammals C: 7.8 P: 2.2 Benthivores B: 4.4, C: 17.8 Pelagic Invertebrate Predators P: 1197 Micro- Phytoplankton Seabirds C: 0.1 P: 55.5 Deposit Feeders B: 31 P: 30 Suspension- Feeders B: 30 P: 1034 Detritus P: 3374 Ammonia Fishing C: 2 R P: 285 Micro- Zooplankton P: 202 Meso- Zooplankton P: 741 Nitrate P: 2793 Nano- Phytoplankton P: 5.7 Planktivores B: 10.9, C: 54 P: 4.9 Piscivores B:8.3, C: 39 P: 5.4 Recruits B: 0.4, C: 15.9 spawning recruitment P: 10 Recruits B: 0.8, C: 30.1 P: 13 Recruits B: 1.1, C: 39.5

9. Dynamic models of the upper trophic levels Fishing Benthivorous Fish Piscivorous Fish Planktivorous Fish Pre-recruits Benthos Zooplankton rBrB rbrb rhrh rPrP rprp FBFB FHFH FPFP cPcP cpcp cbcb dbdb dpdp gbgb gpgp predation spawning recruitment bottom-up forcing Top-down control

10. Equations for fish model - Planktivore P (t ) = Planktivore post-recruit p (t ) = Planktivore recruit H (t ) = Piscivore post-recruit r = intrinsic growth K = carrying capacity d = recruit to post-recruit g = recruitment to recruits F = harvest rate c = predation rate Bottom-up forcing Top-down forcing

11. Deterministic Simulation 010203040 0 100 200 300 400 Benthivores Piscivores Planktivores Year Biomass (KT) 1960’s biomass 1990’s biomass

12. Planktivore Bottom-up Forcing Simulate autocorrelated growth rates Biomass (KT)

13. Historic harvest patterns 1960s High: Planktivore & Piscivore Low: Benthivore

14. On-going work Refine estimates of benthic production Balance the entire energy budget Account for energy imports and exports Statistical parameter estimation of multispecies biomass-dynamics models