Understanding Patterns of Fishery Production in Coastal Marine Ecosystems Impacted by Hypoxia

1. Understanding Patterns of Fishery Production in Coastal Marine Ecosystems Impacted by Hypoxia Edward J. Chesney1, Donald M. Baltz2 and Theodore S. Switzer3 1 Louisiana Universities Marine Consortium 2Department of Oceanography and Coastal Sciences, Louisiana State Univ. 3Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute

2. Eutrophic systems are among the most productive marine systems for fishery production • All ecosystems do not respond to eutrophication in the same ways because of differences in the characteristics of the systems. • All species of nekton are not affected to the same degree by environmental impacts in spite of strong overlap in the habitats they occupy.

3. In terms of ecosystem function what combination of factors dictates vulnerability to eutrophication? • How do those factors compare among large eutrophic marine systems

4. A comparison of Large Marine Ecosystems Impacted by Nutrients

5. Rotated Factor Loadings for Large Marine Systems

6. Factor 4 Green Low or no % suboxic (open) Yellow Moderate Red High % suboxic (mostly enclosed) Baltic High Latitude Slow Turn Black Sea Wadden Sea Factor 3 N.Adriatic LIS Chesapeake Seto High Flow Strong perm. Stratification Large nGOM Mobile Low Latitude Fast Turn Factor 2 Delaware Deep Low PP Large Closed Low Flow Weak&seasonal Stratification Small Factor 1 Shallow High PP Small Open Large marine systems impacted by nutrients Large marine systems impacted by nutrients

7. What species of nekton are most likely to be severely impacted by hypoxia? • Those species with life histories and habitat requirements that chronically affected or have multiple stages of their life history affected increase risks. • Refuges from hypoxia reduce risks at the population level.

8. Evaluated 52 species of nekton for their potential risks associated with the formation of hypoxia based on their life history characteristics • Principal adult habitat • Estuary, inshore (0-5m), nearshore (5-25m), offshore (25-200m) • Principal nursery habitat • Spawning season • Spawning location • Foraging habits • Benthos, piscivorous, omnivorous • Water column distribution • Demersal, epi-demersal, pelagic, nektonic • Other habitat characteristics • Reef associated, marsh associated

9. Unraveling the Effects of Hypoxia • In response to hypoxia, nekton may move: • Vertically • Alongshore • Inshore/offshore • Estuary • Inshore (0-5m) • Nearshore (5-25m) • Offshore (25-200m)

10. Variable Factor 1 Factor 2 Factor 3 Principal Nursery Habitat 0.86174 0.09371 -0.12820 Principal Adult Habitat 0.71291 -0.50409 -0.10680 Foraging Habits 0.68231 -0.02719 0.35962 Spawning Habitat 0.54615 -0.71573 -0.10960 Spawning Season 0.15489 0.87953 -0.15766 Water Column Distribution -0.00666 -0.05685 0.93495 Eigenvalues 2.0386989 1.5526919 1.0681789 % Variance explained 33.98 25.88 17.80 Cumulative % variance explained 33.98 59.86 77.66 PCA of life history characteristics of 52 species of nekton (nGOM)

11. BA=bay anchovy, GM=gulf menhaden, Ca=sand seatrout, AC=Atlantic croaker, HC=hardhead catfish, S=spot, AB=Atlantic bumper, AT=Atlantic threadfin, FF=fringed flounder, SP=silver perch, C=cutlassfish, LP=least puffer, H=hogchoker, AM=Atlantic moonfish, SK=southern kingfish, LS=lined sole, SF=southern flounder, BT=blackcheek tonguefish, SS=spotted seatrout, SD=star drum, GB=gulf butterfish, SM=Spanish mackerel, Cn=silver seatrout, WS=white shrimp, BS=brown shrimp, BC=blue crab, RS=red snapper, Rc=cobia, KM=king mackerel, RD=red drum, Cf=Atlantic spadefish, BW = bay whiff, Sg=shoal flounder, AS=Atlantic stingray, Da= southern stingray, CR=cownose ray, P=pinfish, SA=striped anchovy, Al=shortfin anchovy, MS=mantis shrimp, Lb= brief squid, Mm=stone crab, Sc=longspined porgy, IL=inshore lizardfish, Ps=shortwing searobin, Pa=harvestfish, BR=blue runner. Demersal Water Column Distribution Summer Estuary Pelagic Spawning Season & Habitat Offshore Winter Offshore Principal Adult & Nursery Habitat Estuary

12. Coastal species of the nGOM with high risks of being affected by hypoxia

13. Demersal Water Column Distribution Summer Estuary Pelagic Spawning Season & Habitat Offshore Estuary MS=mantis shrimp SD=star drum BC=blue crab Da= southern stingray AS=Atlantic stingray H=hogchoker BT=blackcheek tonguefish LS=lined sole Mm=stone crab Sg=shoal flounder SP=silver perch BA=bay anchovy, GM=gulf menhaden, Ca=sand seatrout, AC=Atlantic croaker, HC=hardhead catfish, S=spot, AB=Atlantic bumper, AT=Atlantic threadfin, FF=fringed flounder, SP=silver perch, C=cutlassfish, LP=least puffer, H=hogchoker, AM=Atlantic moonfish, SK=southern kingfish, LS=lined sole, SF=southern flounder, BT=blackcheek tonguefish, SS=spotted seatrout, SD=star drum, GB=gulf butterfish, SM=Spanish mackerel, Cn=silver seatrout, WS=white shrimp, BS=brown shrimp, BC=blue crab, RS=red snapper, Rc=cobia, KM=king mackerel, RD=red drum, Cf=Atlantic spadefish, BW = bay whiff, Sg=shoal flounder, AS=Atlantic stingray, Da= southern stingray, CR=cownose ray, P=pinfish, SA=striped anchovy, Al=shortfin anchovy, MS=mantis shrimp, Lb= brief squid, Mm=stone crab, Sc=longspined porgy, IL=inshore lizardfish, Ps=shortwing searobin, Pa=harvestfish, BR=blue runner. Winter Offshore Principal Adult & Nursery Habitat

14. Coastal species of the nGOM with economic or ecological significance & moderate risks of being affected by hypoxia

15. Coastal species of the nGOM with economic or ecological significance & lower risks of being affected by hypoxia

16. How can we fine tune these risks assessments? • Directed studies of species at risks • Additional analyses based upon fisheries data • Modeling

17. Suitability analyses based upon fisheries independent data

18. SEAMAP Data Mississippi Louisiana Texas

19. WLA CLA ETX WTX Hypoxia Subdivided coastal zone • Five alongshore zones:WTX , ETX, WLA, CLA, ELA/MS • Intensity of hypoxia determined by areal extent (Rabalais et al.): • Low (0 – 9,500 km2) • Moderate (9,500 – 16,000 km2) • Severe (16,000 + km2)

20. Habitat Suitability – Star Drum

21. Star Drum Source: FishBase (US FWS) • Similar patterns in summer/fall • Abundances highest in inshore WLA waters • Some differences with respect to intensity of hypoxia

22. Rock Sea Bass Source: FishBase (D. Flescher) • Abundances in nearshore CLA decrease with increasing hypoxia • Abundances in adjacent zones increase with intensity of hypoxia (dependent on season)

23. De Leiva Moreno et al 2000 • Advocated calculating the ratio of pelagics to demersals as an indicator of system condition in eutrophied coastal systems.

24. Figure 4 from De Leiva Moreno et al 2000

25. How does the nGOM look in term of this proposed index?

26. The Pelagic to demersal ratio for the nGOM is ~3.8

27. How does this compare to troubled coastal Seas Impacted by Eutrophication? P/D<1.0=Oligotrophic P/D>10=Eutrophic

28. Pelagic to Demersal Ratio 1950-2004 for the Fertile Crescent nGOM Data Source: NOAA Fisheries Statistics

29. Conclusions • A simple risk assessment framework might be a useful tool for evaluating relative risks from hypoxia. • Simple metrics to index the condition of the ecosystem may not be adequate because no two ecosystems (nor their fauna) are likely to respond exactly the same to nutrient inputs because of variations among the characteristics of ecosystems.

30. Acknowledgements • Funding provided by NOAA Coastal Ocean Program • Data: • National Marine Fisheries Service • Louisiana Department of Wildlife and Fisheries • Mississippi Department of Marine Resources • Texas Parks and Wildlife