Understanding Patterns of Fishery Production in Coastal Marine Ecosystems Impacted by Hypoxia Edward J. Chesney 1, Donald M. Baltz 2 and Theodore S. Switzer 3 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

 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.

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

A comparison of Large Marine Ecosystems Impacted by Nutrients

Rotated Factor Loadings for Large Marine Systems

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

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.

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

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

PCA of life history characteristics of 52 species of nekton (nGOM) VariableFactor 1Factor 2Factor 3 Principal Nursery Habitat Principal Adult Habitat Foraging Habits Spawning Habitat Spawning Season Water Column Distribution Eigenvalues % Variance explained Cumulative % variance explained

Offshore Principal Adult & Nursery Habitat Estuary Water Column Distribution Spawning Season & Habitat Summer Estuary Winter Offshore Pelagic Demersal 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.

Coastal species of the nGOM with high risks of being affected by hypoxia Species Water Column Distribution Principal Adult Habit Foraging Habits Principal Nursery Habitat Spawning LocationSpawning Season Atlantic Stingray, Dasyatis sabiniDemersalInshore/Estuary Benthos Inshore/Estuary summer Bc. Tonguefish Symphurus plagiusaDemersalNearshore-EstuarySmall BenthosNearshore-Estuary Summer Blue Crab, Callinectes sapidusDemersalNearshore-EstuaryOmnivorousNearshore-EstuaryNearshore/InshoreSpring-Fall Fringed Flounder, Etropus crossotusDemersalNearshore-EstuaryBenthic CopepodsEstuaryNearshoresummer Hogchoker, Trinectes maculatusDemersalNearshore-Estuarysmall BenthosNearshore-EstuaryEstuarysummer Lined Sole, Achirus lineatusDemersalNearshore/InshoreSmall BenthosInshore/EstuaryNearshoreSummer Mantis shrimp, Squilla empusaDemersalOffshore/NearshoreBenthosNearshore-EstuaryOffshore-Nearshorewinter-summer rock sea bass, Centropristis philadelphicaDemersalOffshore/NearshoreNekton/BenthosNearshore/InshoreOffshore/NearshoreSummer Shoal Flounder, Syacium gunteriDemersalInshore-OffshoreSmall BenthosNearshoreNearshore/Estuarysummer Silver Perch, Bairdiella chysuraDemersalNearshore-EstuarySmall BenthosInshore/EstuaryNearshore-Estuarysummer southern stingray, Dasyatis americanaDemersalNearshore-EstuaryDecapods/NektonInshore/Estuary summer Star Drum, Stellifer lanceolatusDemersalOffshore/NearshoreSmall BenthosNearshore-EstuaryOffshore/Nearshoresummer stone crab, Menippe mercenariaDemersalNearshore-EstuaryBenthosInshore-Estuary summer

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. Principal Adult & Nursery Habitat Winter Offshore Offshore Estuary Water Column Distribution Spawning Season & Habitat Summer Estuary Pelagic Demersal 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

Coastal species of the nGOM with economic or ecological significance & moderate risks of being affected by hypoxia Species Water Column Distribution Principal Adult Habit Foraging Habits Principal Nursery Habitat Spawning LocationSpawning Season Atlantic Croaker, Micropogonias undulatusDemersalOffshore/NearshoreBenthosInshore/EstuaryOffshorefall/winter Brown Shrimp, Farfontepenaeus aztecusDemersalOffshore/NearshoreSmall BenthosEstuaryOffshorewinter/spring Gulf Butterfish, Peprilus burtiEpi-demersalOffshoreOmnivorousNearshoreOffshore/Nearshorewinter longspined porgy, Stenostomus caprinusEpi-demersalOffshore/NearshoreBenthosNearshore/InshoreOffshorewinter Sand Seatrout, Cynoscion arenariusDemersalOffshore/NearshorePiscivororousInshore/EstuaryOffshorespring/summer Red Drum, Sciaenops ocellatusEpi-DemersalInshore-OffshoreNektonEstuaryInshore/Estuaryfall Red snapper, Lutjanus campechanusEpi-demersalOffshoreBenthos/NektonOffshore/NearshoreOffshoresummer Silver Seatrout, Cynoscion nothusDemersalNearshore-EstuaryPiscivorous/NektonOffshore/Nearshore summer Southern Flounder, Paralichthys lethostigmaDemersalNearshore-EstuaryPiscivorous/NektonFreshwater/EstuaryOffshoreWinter/Spring Southern Kingfish, Menticirrhus americanusDemersalOffshore/NearshoreSmall BenthosNearshore-InshoreOffshoreSummer White Shrimp, Litopenaeus setiferusDemersalOffshore/NearshoreSmall BenthosEstuaryOffshore/NearshoreSpring/ summer

Coastal species of the nGOM with economic or ecological significance & lower risks of being affected by hypoxia Species Water Column Distribution Principal Adult Habit Foraging Habits Principal Nursery Habitat Spawning LocationSpawning Season Atlantic Bumper, Chloroscombrus chrysurusPelagicNearshoreZooplanktonEstuaryNearshoresummer Atlantic Spadefish, Chaetodipterus faberNektonicNearshore/InshorePlankton/BenthosInshore/EstuaryNearshore/Inshoresummer Atlantic Threadfin, Polydactylus octonemusNektonicOffshore/NearshoreShrimp/CrustaceaNearshore-EstuaryOffshorewinter/spring Bay Anchovy, Anchoa mitchilliPelagicInshore/EstuaryZooplantivorousEstuaryInshore/Estuarysummer blue runner, Caranx crysosPelagicOffshore/NearshoreSm nekton/ZooplanktonOffshore/NearshoreOffshorewinter-summer Cobia, Rachycentron canadumNektonicOffshoreNektonOffshore/NearshoreOffshoresummer Gulf Menhaden, Brevoortia patronusPelagicNearshore/InshorePlanktivorousEstuary/freshwaterOffshore/Nearshorewinter/spring King Mackerel, Scomberomorus cavallaPelagicOffshorePiscivorousOffshore/NearshoreOffshoresummer shortfin anchovy, Anchoa lyolepisPelagicEstuaryZooplanktonEstuary summer Spanish Mackerel, Scomberomorus maculatusPelagicOffshore/NearshorePiscivorousNearshore/InshoreOffshore/Nearshoresummer Spotted Seatrout, Cynoscion nebulosusNektonicNearshore-EstuaryPiscivorousEstuaryInshore/Estuarysummer Squid, Lolliguncula brevisNektonicNeashore/InshoreZooplankton/Sm nektonInshore/EstuaryNearshore/Inshorespring/summer striped anchovy, Anchoa hepsetusPelagicInshoreZooplanktonInshore/EstuaryInshorespring/summer

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

Suitability analyses based upon fisheries independent data

SEAMAP Data Texas Mississippi Louisiana

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 km 2 ) –Moderate (9,500 – 16,000 km 2 ) –Severe (16,000 + km 2 ) WTX ETX WLA CLA Hypoxia

Habitat Suitability – Star Drum

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

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

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

Figure 4 from De Leiva Moreno et al 2000

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

The Pelagic to demersal ratio for the nGOM is ~3.8

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

Pelagic to Demersal Ratio for the Fertile Crescent nGOM Data Source: NOAA Fisheries Statistics

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.

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