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

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 NutrientsA comparison of Large Marine Ecosystems Impacted by Nutrients

Basin Basin

Morphology Latitude

Surface

Temperature oC

Surface Salinity Range

Stratification Pattern

Tidal Range (cm)

Primary Production

(g C m-2 y-1)

Annual Fishery Yield

(103 mt)

Major Fisheries

Mediterranean --N. Adriatic

Mostly enclosed sea1 Semi-enclosed gulf1

-- 45oN

-- 6-277

-- 26-387,8

-- Moderate, seasonal

--

50-12022

-- 10014

-- Sardine

Chesapeake Bay Semi-enclosed bay 38oN 2-2811 11-2011 Strong, seasonal -- 40020 27514 Menhaden Seto Inland Sea Semi-open sea1 34oN 10-27 28-32 Moderate, seasonal -- 21823 83013,+ Anchovy, oyster Baltic Sea Mostly enclosed sea1 57oN 0-17 2-1312 Strong, semi-permanent 2-3 13520 622++ Herring, sprat, cod Black Sea Mostly enclosed sea1 43oN 4-20 12-18 Strong, permanent 8-9 12025 80016 Sprat, whiting Neuse R. Estuary River estuary 35oN 5-30 0-12 Moderate, seasonal -- -- -- Crabs, oysters Mobile Bay Mostly enclosed bay 30oN 10-34 0-32 Moderate, seasonal 15-45 19424 8 Menhaden, shrimp Delaware Bay Open bay 39oN 2-28 10-30 Weak, seasonal -- 30724 3 Crabs Dutch Wadden Sea Semi-open bay 53 oN -- -- Weak, seasonal 130-21020 48020 -- Flatfish Long Is. Sound Semi-enclosed bay 41oN -- -- Strong, seasonal 32-106 30020 18 Gulf of Mexico

--La, Ms, Tx Shelf Semi-open gulf1

Open shelf --

29oN --

12-32 --

15-35 --

Strong, seasonal

32

30021 --

769** --

Menhaden, shrimp

Basin

Principal Watershed (103 km2)

Mean Depth

(m)

Annual Freshwater

Input (109 m3)

P Loading

mmol m-2 y-1

N Loading

mmol m-2 y-1

Suboxic* area

(103 km2)

Basin to Suboxic

Area

Basin Surface

Area (103 km2)

Watershed to Basin

Area

Basin Volume

(103 km3)

System Residence

Time (months)

Mediterranean --N. Adriatic

-- 709

1502 3022

48

--

--

-- 1.0

-- 139:1

2,5102 1397

0.6:11

0.5:1 3771 357

long moderate

Chesapeake Bay 166 6.5 125 4020 143020 1-26 6:1 12 14.4:1 0.075 64 Seto Inland Sea 25 3710 7017 -- -- 2.23 10:1 2213 1.2:11 1.06 1518 Baltic Sea 1,729 55 670 1020 21020 8415 5:1 413 4.2:11 38 26220 Black Sea 2,405 1,191 30025 -- -- 20 25:1 423 5.7:11 605 very long Neuse R. Estuary 16 3.6 -- -- -- -- -- -- -- -- 2 Mobile Bay 115.5 3.0 7124 21824 260524 0.4 2.5:1 1 115:1 .003 short Delaware Bay 34.8 6.4 18 19324 163224 0 -- 2 17.5:1 12.7 weeks Dutch Wadden Sea 18520 3.9 23.6 24020 55020 0 -- 1.5 120:1 5.920 0.520 Long Is. Sound 41 20 38 7020 104020 0.2-0.4 7:1 3 13.7:1 .06 <3620 Gulf of Mexico

--La, Ms, Tx Shelf 2,901

2,1642 3519

580

--

--

10-205

290:1 6:1

1,813 12619

1.6:1 --

3923 4.4

long wks.-mo.

Rotated Factor Loadings for Large Marine Systems

Large marine systems impacted by nutrientsLarge marine systems impacted by nutrients

High FlowStrong perm.StratificationLarge

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 FlowWeak&seasonalStratificationSmall

Factor 4GreenGreen Low or no % suboxic (open) YellowYellow Moderate RedRed 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)

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

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

SpeciesWater Column

DistributionPrincipal Adult

HabitForaging Habits

Principal Nursery Habitat

Spawning Location Spawning Season

Atlantic Stingray, Dasyatis sabini Demersal Inshore/Estuary Benthos Inshore/Estuary Inshore/Estuary summer

Bc. Tonguefish Symphurus plagiusa Demersal Nearshore-Estuary Small Benthos Nearshore-Estuary Nearshore-Estuary Summer

Blue Crab, Callinectes sapidus Demersal Nearshore-Estuary Omnivorous Nearshore-Estuary Nearshore/Inshore Spring-Fall

Fringed Flounder, Etropus crossotus Demersal Nearshore-Estuary Benthic Copepods Estuary Nearshore summer

Hogchoker, Trinectes maculatus Demersal Nearshore-Estuary small Benthos Nearshore-Estuary Estuary summer

Lined Sole, Achirus lineatus Demersal Nearshore/Inshore Small Benthos Inshore/Estuary Nearshore Summer

Mantis shrimp, Squilla empusa Demersal Offshore/Nearshore Benthos Nearshore-Estuary Offshore-Nearshore winter-summer

rock sea bass, Centropristis philadelphica Demersal Offshore/Nearshore Nekton/Benthos Nearshore/Inshore Offshore/Nearshore Summer

Shoal Flounder, Syacium gunteri Demersal Inshore-Offshore Small Benthos Nearshore Nearshore/Estuary summer

Silver Perch, Bairdiella chysura Demersal Nearshore-Estuary Small Benthos Inshore/Estuary Nearshore-Estuary summer

southern stingray, Dasyatis americana Demersal Nearshore-Estuary Decapods/Nekton Inshore/Estuary Inshore/Estuary summer

Star Drum, Stellifer lanceolatus Demersal Offshore/Nearshore Small Benthos Nearshore-Estuary Offshore/Nearshore summer

stone crab, Menippe mercenaria Demersal Nearshore-Estuary Benthos Inshore-Estuary Inshore-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

SpeciesWater Column

DistributionPrincipal Adult

HabitForaging Habits

Principal Nursery Habitat

Spawning Location Spawning Season

Atlantic Croaker, Micropogonias undulatus Demersal Offshore/Nearshore Benthos Inshore/Estuary Offshore fall/winter

Brown Shrimp, Farfontepenaeus aztecus Demersal Offshore/Nearshore Small Benthos Estuary Offshore winter/spring

Gulf Butterfish, Peprilus burti Epi-demersal Offshore Omnivorous Nearshore Offshore/Nearshore winter

longspined porgy, Stenostomus caprinus Epi-demersal Offshore/Nearshore Benthos Nearshore/Inshore Offshore winter

Sand Seatrout, Cynoscion arenarius Demersal Offshore/Nearshore Piscivororous Inshore/Estuary Offshore spring/summer

Red Drum, Sciaenops ocellatus Epi-Demersal Inshore-Offshore Nekton Estuary Inshore/Estuary fall

Red snapper, Lutjanus campechanus Epi-demersal Offshore Benthos/Nekton Offshore/Nearshore Offshore summer

Silver Seatrout, Cynoscion nothus Demersal Nearshore-Estuary Piscivorous/Nekton Offshore/Nearshore Offshore/Nearshore summer

Southern Flounder, Paralichthys lethostigma Demersal Nearshore-Estuary Piscivorous/Nekton Freshwater/Estuary Offshore Winter/Spring

Southern Kingfish, Menticirrhus americanus Demersal Offshore/Nearshore Small Benthos Nearshore-Inshore Offshore Summer

White Shrimp, Litopenaeus setiferus Demersal Offshore/Nearshore Small Benthos Estuary Offshore/Nearshore Spring/ summer

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

SpeciesWater Column

DistributionPrincipal Adult

HabitForaging Habits

Principal Nursery Habitat

Spawning Location Spawning Season

Atlantic Bumper, Chloroscombrus chrysurus Pelagic Nearshore Zooplankton Estuary Nearshore summer

Atlantic Spadefish, Chaetodipterus faber Nektonic Nearshore/Inshore Plankton/Benthos Inshore/Estuary Nearshore/Inshore summer

Atlantic Threadfin, Polydactylus octonemus Nektonic Offshore/Nearshore Shrimp/Crustacea Nearshore-Estuary Offshore winter/spring

Bay Anchovy, Anchoa mitchilli Pelagic Inshore/Estuary Zooplantivorous Estuary Inshore/Estuary summer

blue runner, Caranx crysos Pelagic Offshore/Nearshore Sm nekton/Zooplankton Offshore/Nearshore Offshore winter-summer

Cobia, Rachycentron canadum Nektonic Offshore Nekton Offshore/Nearshore Offshore summer

Gulf Menhaden, Brevoortia patronus Pelagic Nearshore/Inshore Planktivorous Estuary/freshwater Offshore/Nearshore winter/spring

King Mackerel, Scomberomorus cavalla Pelagic Offshore Piscivorous Offshore/Nearshore Offshore summer

shortfin anchovy, Anchoa lyolepis Pelagic Estuary Zooplankton Estuary Estuary summer

Spanish Mackerel, Scomberomorus maculatus Pelagic Offshore/Nearshore Piscivorous Nearshore/Inshore Offshore/Nearshore summer

Spotted Seatrout, Cynoscion nebulosus Nektonic Nearshore-Estuary Piscivorous Estuary Inshore/Estuary summer

Squid, Lolliguncula brevis Nektonic Neashore/Inshore Zooplankton/Sm nekton Inshore/Estuary Nearshore/Inshore spring/summer

striped anchovy, Anchoa hepsetus Pelagic Inshore Zooplankton Inshore/Estuary Inshore spring/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 km2)– Moderate (9,500 – 16,000 km2)– Severe (16,000 + km2)

WTX

ETXWLA CLA

Hypoxia

Habitat Suitability – Star Drum

Salinity (psu)

16 20 24 28 32 36 40

Rel

ativ

e F

requ

ency

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.0

0.5

1.0

Depth (m)

0 20 40 60 80 100 120 1400.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.0

0.5

1.0

Temperature (° C)

12 16 20 24 28 320.0

0.1

0.2

0.3

0.0

0.5

1.0

Dissolved Oxygen (mg / L)

0 2 4 6 8 100.0

0.1

0.2

0.3

0.4

Sta

ndar

dize

d S

uita

bilit

y

0.0

0.5

1.0

AvailabilityUseSuitability

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

How does this compare to troubled coastal Seas How does this compare to troubled coastal Seas Impacted by Eutrophication?Impacted by Eutrophication?

P/D<1.0=Oligotrophic

P/D>10=Eutrophic

Pelagic to Demersal Ratio 1950-2004 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