Incorporation of ecosystem modeling products into single species stock assessments

Transcription

1 Incorporation of ecosystem modeling products into single species stock assessments Joe O Hop Gulf States Marine Fisheries Commission Menhaden Advisory Committee November 4, 2015

2 Disclosures and Disclaimers Credentials I am neither involved in ecosystem modeling projects nor in analyses of gut contents. My experience with older ecosystem models and concepts was as an undergraduate (we were still using punch cards) and in graduate school (using an analog computer!). Things have changed a bit since then. About models All models are wrong, but some are useful. G. E.P. Box (statistician) Corollary In theory, there is no difference between theory and practice. In practice, there is. Y. Berra (catcher) Practical In practice, there is a lot that we need to know to make these sorts of models useful.

3 Which types of population and ecological factors have been incorporated into stock assessments in the US South Atlantic and Gulf of Mexico (i.e., SEDAR, GDAR, state)? Genetically identifiable stocks, growth rates, etc. (if information exists, considered in all assessments) Epizootic diseases (PaV1 virus, Spiny Lobster [S8 update]) Unusual events (red tide, cold kills: Gag [S10, S33], Red Grouper [S42], Snook [FL]) Discharge/climate regime (blue crabs [G1], Gulf menhaden [Vaughan et al. 2011; Sanchez-Rubio and Perry 2013, S32 sensitivity run] )

4 Monthly red tide area extent from satellite data and cell counts from water sampling, 2005 From Walter et al. 2013

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6 Which types of factors might we expect from ecosystem models? Linkage to climate/oceanographic processes (correlation with ENSO, NAO, AMO, perhaps others) and primary production Response to invasive species (e.g., Lionfish) Quantification of ecosystem services: trends in rates of other natural mortality, losses to predators, growth, and recruitment variability (e.g., Multispecies VPA, Ecopath/Ecosim/Ecospace [EwE], Osmose, Atlantis) For Gulf Menhaden, Geers (2012) and Geers et al. (2013) describe the results from an EwE model for the Northern Gulf of Mexico. Matt Nuttall recently presented to this committee a plan for a Gulf Menhaden-centric EwE model.

7 ENSO and the Peruvian anchoveta Schaefer (1970), Clark (1976), Duffy (1983) and others provide background information on this fishery and the effects of El Niño on upwelling off the western coast of Peru and Ecuador.

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9 La Niña conditions: Warm water is farther west than usual. Normal Pacific pattern: Equatorial winds gather warm water pool toward the west. Cold water upwells along South American coast. (NOAA / PMEL / TAO) El Niño conditions: Warm water pool approaches the South American coast. The absence of cold upwelling increases warming. Diagrams above by Fred the Oyster. Licensed under Public Domain via Commons -

10 So, if we know something about which ENSO phase we re in, and we know something about how anchovetas are affected by ENSO, we should be able to see these effects on landings and other predator populations. Shaefer (1970) explained the effect of El Niño conditions on Peruvian anchoveta landings, and further estimated the effect of the fishery on seabirds that also prey on that stock.

11 . Rubio-Sanchez et al. (2011) observed a relationship between juvenile blue crab abundance and AMO - NAO indices. dry regime (1997-present): AMO warm-nao negative lower abundance. wet regime ( ): AMO cold - NAO positive higher abundance.

12 Rubio-Sanchez et al. (2011) were also cited in the Gulf Menhaden FMP. as observing a relationship between juvenile Gulf Menhaden abundance in the northern Gulf of Mexico and AMO - NAO indices. dry regime (1997-present): AMO warm-nao negative lower abundance. wet regime ( ): AMO cold - NAO positive higher abundance. Maybe this relationship is worth consideration.

13 Ecosystem models need standing stocks and rates (or, it takes guts to tackle predator-prey) Data Sources Research studies FWRI gut analyses lab Estuarine, nearshore, and offshore Catalogue of prey items as identification aid Texas A&M University Lab, GoMexiSI website Frequency of records of prey by predator Frequency of records consumed by prey species

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15 Figure 1: We have processed 27,500+ stomachs to date. Stomachs came from both inshore and offshore species that are not necessarily recreationally or commercially important species. The gut lab started around We started the jaw project around Because of this tool, we are able to identify almost 50% of digested fish found in predator stomachs to family, genus, or species.

16 Figure 3: Three diet data sets of Spotted Seatrout collected in Tampa Bay (Hall-Scharf 2015 in review). The last data set was the only one that had the jaw tool available for use. Even after a common taxonomic denominator was found to compare the three sets, the study had more identifiable fish and less unidentified specimens.

17 References SEDAR-33 SEDAR-42 Alexander, M.A., K.H. Kilbourne, J.A. Nye Climate variability during warm and cold phases of the Atlantic Multidecadal Oscillation (AMO) J. Mar. Sys. 133, Clark, W.G The lessons of the Peruvian anchoveta fishery. FAO Reports 19: Duffy, D.C Environmental uncertainty and commercial fishing: effects on Peruvian guano birds. Biol. Conserv. 26: Geers, T.M Developing an ecosystem-based approach to management of the Gulf menhaden fishery using Ecopath with Ecosim. Master of Science Thesis, School of Marine and Atmospheric Sciences, Stony Brook University. Stony Brook, NY Geers, T.M., E.K. Pikitch, M.G. Frisk An original model of the northern Gulf of Mexico using Ecopath with Ecosim and its implications for the effects of fishing on ecosystem structure and maturity. Deep-Sea Research II. Gray, A.C, C. Ainsworth, D. Chagaris, and B. Mahmoudi Red tide mortality on gag grouper SEDAR33-AW21. SEDAR, North Charleston, SC. 8pp. Sanchez-Rubio, G., H. M. Perry, P.M. Biesiot, D. R. Johnson, R. N. Lipcius Climaterelated hydrological regimes and their effects on abundance of juvenile blue crabs (Callinectes sapidus) in the northcentral Gulf of Mexico. Fish. Bull. 109:

18 References (continued) Shaefer, M.B Men, birds and anchovies in the Peru Current - dynamic interactions. Trans. Amer. Fish. Soc. 99: Schirripa, M.J., R.D. Methot, et al Incorporating various Gulf of Mexico Integrated Assessment products into the Stock Synthesis Integrated Assessment Model framework. SEDAR33-DW10. SEDAR, North Charleston, SC. 17pp. Walter, J.F., M.C. Christman, J. Landsberg, B. Linton, K. Steidinger, R. Stumpt, and J. Tustison Satellite derived indices of red tide severity for input for Gulf of Mexico Gag grouper stock assessment. SEDAR33-DW08. SEDAR, North Charleston, SC. 43pp.

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