Impacts of Hypoxia on Impacts of Hypoxia on Reproductive Function in the Reproductive Function in the

Gulf Killifish, Gulf Killifish, Fundulus Fundulus grandisgrandis

Ann Oliver Cheek

EaGLeEaGLe

Chl a

Grass shrimp Benthic consumers

N cycle Bacteria Aerobic BacteriaLand Use

decomposition

N nutrients

N, P nutrients

Gulf killifish

Blue crabs Atlantic croaker

1° producers

3° consumers

1° consumers

2° consumers

larval

juvenile

juvenile

Pensacola Bay, Garcon Point marsh July 2003

0

2

4

6

8

10

12

7/25/030:00

7/26/030:00

7/27/030:00

7/28/030:00

7/29/030:00

7/30/030:00

7/31/030:00

8/1/030:00

DO

(m

g/L

)

Marsh Creek sonde

GOALS & HYPOTHESISGOALS & HYPOTHESIS

1.1. Develop indicators of hypoxic effects Develop indicators of hypoxic effects in a common marsh resident – in a common marsh resident – Fundulus grandisFundulus grandis

2.2. Advance understanding of Advance understanding of howhow hypoxia regulates reproduction in fishhypoxia regulates reproduction in fish

Hypoxia impairs Hypoxia impairs reproductionreproduction

Gulf killifishGulf killifish

REPRODUCTIVE LIFE REPRODUCTIVE LIFE HISTORYHISTORY

J F M A M J J A S O N D

Batch SpawnerBatch SpawnerR

epro

du

ctiv

e P

aram

eter

sR

epro

du

ctiv

e P

aram

eter

s

INDICATORS of EFFECTINDICATORS of EFFECTFulton’s condition factor (100,000*W/LFulton’s condition factor (100,000*W/L33))

Gonadosomatic index (100*WGonadosomatic index (100*Wgonadgonad/W/Wbodybody))

Estradiol (females)Estradiol (females)

Testosterone (males & females)Testosterone (males & females)

11-Ketotestosterone (males)11-Ketotestosterone (males)

Vitellogenin (females)Vitellogenin (females)

Reproductive Hormone Reproductive Hormone FunctionFunction

liverliver

ovaryovary

pituitarypituitary

estrogenestrogen

brainbrain

FSHFSH

testosteronetestosterone

VITELLOGENINVITELLOGENIN

Reproductive Hormone Reproductive Hormone FunctionFunction

liverliver

testistestis

pituitarypituitary

brainbrain

FSH, LHFSH, LHT, 11KTT, 11KT

Laboratory ExposureLaboratory ExposureChronic HypoxiaChronic Hypoxia

15 ppt salinity15 ppt salinity2727°C°C

Chronic HypoxiaChronic HypoxiaFemalesFemales

0.0

2.0

4.0

6.0

8.0

GSI T E2 VTG

6.68 mg/L

1.34 mg/L

**

Chronic HypoxiaChronic HypoxiaEgg ProductionEgg Production

0

5

10

15

20

25

30

35

7/10 7/11 7/12 7/13 7/14 7/15 7/16 7/17 7/18

Da

ily #

eg

gs

/fe

ma

le

6.68 mg/L1.34 mg/L

Chronic HypoxiaChronic HypoxiaMalesMales

0.0

0.5

1.0

1.5

2.0

GSI T 11KT

6.68 mg/L

1.34 mg/L

*

How do indicators respond in GOM estuaries?

Weeks Bay, ALWeeks Bay, ALPensacola Bay, FLPensacola Bay, FL

Weeks Bay Creek

Weeks Bay Mouth

Mobile Bay

Weeks Bay Mouth & Creek, Jul - Aug 2004

0

2

4

6

8

10

12

7/12/04 12:00 7/19/04 12:00 7/26/04 12:00 8/2/04 12:00

DO

(m

g/L

)

Weeks Bay Mouth sonde Weeks Bay Creek sonde

2 mg/L 2 mg/L 41 41 mmHgmmHg@ 31C @ 31C

WBM 4.03 mg/L = 82 mmHg

0.79 hr 3/18

WBC 0.93 mg/L = 19 mmHg

3.40 hr 18/19

Severe Hypoxia reduces Severe Hypoxia reduces Sex Steroid ConcentrationsSex Steroid Concentrations

WB Jul 04 - MALES

0.0

1.0

2.0

3.0

GSI T KT

WBS WBC

******

WB Jul 04 - FEMALES

0.0

2.0

4.0

6.0

8.0

GSI T E2 VTG

WBS WBC

*** ***

***p < 0.001

WBS = Mild hypoxia WBC = Severe hypoxia, PO2 ~ 82 mmHg PO2 ~ 19 mmHg

2 mg/L 2 mg/L 41 41 mmHgmmHg

WBM 4.65 mg/L = 91 mmHg

0 0/6

WBC 2.61 mg/L = 51 mmHg

0.63 3/6

Weeks Bay Jul 15-22, 2005

0

1

2

3

4

5

6

7

8

9

10

7/15/05 7/16/05 7/17/05 7/18/05 7/19/05 7/20/05 7/21/05 7/22/05 7/23/05

DO

(m

g/L

)

Weeks Bay Mouth sonde Weeks Bay Creek

Moderate Hypoxia reduces Moderate Hypoxia reduces GSI & 11KTGSI & 11KT

**p < 0.01, ***P < 0.001

WBS = Normoxic, PO2 ~ 91 mmHg WBC = Hypoxic, PO2 ~ 51 mmHg

WB Jul 05 - MALES

0.0

1.0

2.0

3.0

GSI T KT

WBS WBC

*****

WB Jul 05 - FEMALES

0.0

2.0

4.0

6.0

GSI T E2 VTG

WBS WBC

*****

Garcon Point

Indian Bayou

2 mg/L 2 mg/L 41 41 mmHgmmHg

GP1 4.39 mg/L = 89 mmHg

0 0/9

IB 2.41 mg/L = 49 mmHg

1.53 4/8

Pensacola Bay marshes July 2005

0

2

4

6

8

10

12

7/18/05 7/19/05 7/20/05 7/21/05 7/22/05 7/23/05 7/24/05 7/25/05 7/26/05 7/27/05 7/28/05

DO

(m

g/L

)

Indian Bayou sonde GP1

Moderate Hypoxia reduces Moderate Hypoxia reduces GSI & 11KTGSI & 11KT

**p < 0.01, ***P < 0.001

GP = Normoxic, PO2 ~ 89 mmHg IB = Hypoxic, PO2 ~ 49 mmHg

PB Jul 05 - MALES

0.0

1.0

2.0

3.0

GSI T KT

GP IB

*** ***

PB Jul 05 - FEMALES

0.0

1.0

2.0

3.0

GSI T E2 VTG

GP IB

******

REPRODUCTIVE IMPACTREPRODUCTIVE IMPACTHypoxi

aSetting M

GSIM T

M 11KT

F GSI

F T

F E2

F VTG

Cyclic 49/1.5/50%

Field PB ● ● ● ● ● ● ●

Cyclic 51/0.6/50%

Field WB ● ● ● ● ● ● ●Cyclic

19/3.4/95%Field WB ● ● ● ● ● ● ●

Cyclic 27/3.0/100

Lab ● ● ● ● ● ●Chronic 25/24/100

Lab ● ● ● ● ● ● ●Not changed by hypoxia

Reduced by hypoxia

Reproductive Impacts of Reproductive Impacts of Diel HypoxiaDiel Hypoxia

• In the fieldIn the field– Male steroid hormones & GSI are Male steroid hormones & GSI are

reducedreduced– Female GSI can be reducedFemale GSI can be reduced

• In the labIn the lab– Male steroid hormones are reducedMale steroid hormones are reduced– Female steroid hormones & GSI are Female steroid hormones & GSI are

reducedreduced– Fecundity is reducedFecundity is reduced

AcknowledgmentsAcknowledgmentsChristie Landry, Christie Landry,

Amy Sutton, Amy Sutton, Stacy Steele, Stacy Steele, Brett Henry, Brett Henry, Sarah Temple, Sarah Temple, Lisa Cohen, Lisa Cohen, Bern Wood, Bern Wood, Ross Turlington; Ross Turlington; SLUSLU

Dick Snyder & lab; Dick Snyder & lab; UWFUWF

Steve Manning, Steve Manning, Thea Hoexum-Thea Hoexum-Brouwer; USMBrouwer; USM

Scott Phipps, Eric Scott Phipps, Eric Brunden; Weeks Brunden; Weeks Bay NERRBay NERR

Shaye Sable, LSUShaye Sable, LSUChad Ellington, Chad Ellington,

UNOUNO

Cyclic HypoxiaCyclic Hypoxia

Cyclic Hypoxia Normoxia

DOmin1.4 mg/L ≈ 26.6

mmHg6.5 mg/L ≈ 123

mmHg

Period ≤ 2 mg/L 3.0 hr 0 hr

0

1

2

3

4

5

6

7

8

7/28/06 8/2/06 8/7/06 8/12/06 8/17/06 8/22/06 8/27/06 9/1/06

DO

(m

g/L

)

Fish placed in tanks

Begin cyclic DO exposure

Cyclic Hypoxia Cyclic Hypoxia Steroids & GSISteroids & GSI

MalesMales FemalesFemales

0

2

4

6

8

10

T E2 GSIng

/ml

Normoxia Cyclic Hypoxia

0

1

2

3

T 11 KT GSI

ng/m

l

Normoxia Cyclic Hypoxia

** *

Cyclic Hypoxia Cyclic Hypoxia Egg ProductionEgg Production

0

10

20

30

40

50

8/3/06 8/10/06 8/17/06 8/24/06 8/31/06

Dai

ly E

gg

s/F

emal

e 6.48 mg/L

1.4 mg/L

Cyclic Hypoxia Cyclic Hypoxia FertilizationFertilization

50

70

90

110

130

8/3/06 8/10/06 8/17/06 8/24/06 8/31/06

% e

gg

s fe

rtil

ized

6.48 mg/L

2 mg/L