Seasonal Diversity and Abundance of Larval and Juvenile Fishes in The Upper Barataria Estuary

1. Seasonal Diversity and Abundance of Larval and Juvenile Fishes in The Upper BaratariaEstuary Sean Jackson

2. Introduction Barataria Estuary • 1.7 million hectares • Diverse Habitats • Freshwater swamps • Salt marshes

3. IntroductionStudy location

4. IntroductionUpper Barataria Estuary • Land Use • 41.5% forested wetlands • 38.0% agricultural lands • 5.2% urban land

5. Study Area • Upper Barataria Estuary • Large river floodplain • Leveed from Mississippi river • No annual flood pulse • Precipitation only water source • Wind can influence water level • Major Water Bodies • Bayou’s Chevreuil and Citamon • St. James Canal • Lac des Allemands

6. IntroductionHabitat Description • Canal Habitats • Dredged straight channel • High banks • Bayou Habitats • Meandering curves • Low banks

7. Large River Floodplain Ecology • Floodplain Ecology • Hydrology driving force • Flood Pulse • Habitat access • Flush nutrients into system • Homogenize water quality

8. IntroductionLarge River Floodplain Ecology • Flood Pulse Concept • Predictable annual flood pulse • Spawning and nursery habitat • Timing and duration important • Atchafalaya River Basin • Low Flow Recruitment Hypothesis • No predictable annual flood pulse • Opportunistic use of floodplain • Brazos River floodplain

9. IntroductionLarge River Floodplain Ecology • Water Types • Brown • Well mixed, high DO • Green • Stratified, high/low DO • Black • Low turbidity, low DO • Tea colored • High turbidity, Low DO

10. IntroductionFish Reproduction • Successful Fish Reproduction • Cues • Photoperiod (day length) • Temperature • Environmental requirements • Access to spawning habitat • Acceptable water quality

11. IntroductionFish Reproduction • Quality Nursery Habitat • Food availability • Water quality • Dissolved oxygen • Normoxic = >2.0 mg/L • Hypoxic = < 2.0 mg/L • Specific conductance

12. IntroductionFish Reproduction Large Adult Size No Parental Care Short Spawning Season High Fecundity Periodic Dorosoma spp. Small Bodied Rapid Maturation Low Fecundity Short Brood Period Long Spawning Season Large Egg Size High Parental Care Long Spawning Season Intermediate Fecundity Opportunistic Gambusia spp. Equilibrium Lepomis spp. Citation?

13. IntroductionEcosystem Health • V-O-R model • Vigor – production • Organization – structure or diversity • Resilience – maintain or rebuild • Environmental Indicators • Water quality • Fisheries catch • Habitat diversity / availability

14. Purpose • Describe distribution and abundance of larval and juvenile fishes in the upper Barataria Estuary

15. Predictions • Natural bayou habitats will support higher levels of fish reproduction than dredged canal habitats

16. Specific objectives • Determine spawning period for each taxonomic group of fish collected in the upper Barataria Estuary • Compare relative abundance between canal and bayou habitats for all species and for each taxonomic group during their spawning period. • Compare water quality data between canal and bayou habitats. • Determine the relationship between larval fish abundance and water quality

17. IntroductionSite Locations 1 2 3 4 6 5 7

18. Methods • Weekly Collections • 9 February 2007 – 25 September 2007 • 4 Bayou sites and 3 Canal sites • Three traps per site

19. Methods • Light traps • Powered by chemical light stick • 500µm nitex mesh screen • Sample edge of waterways • Samples kept on ice

20. Methods • Light traps • Set two hours before sunset • Pick up 2.5 hours after official sunset • Water Quality • Temperature, DO, Conductivity, and Water Color • Vegetation

21. 1 2 3 x5 x6 x7 x4 x2 x1 x3 4 Canal (XC) 5 Bayou (XB) 6 7 Experimental Design N= 3 N= 4

22. Methods • Samples processed within 24 hours • Fish placed in 70% alcohol solution • Fish identified, counted, and photographed • CPUE = number per hour

23. MethodsData Analysis • All analysis performed at genus level • Log transformed if needed • Analysis of variance (ANOVA) • CPUE, temperature, dissolved oxygen, and specific conductance between habitats • Regression Analysis • Determine relationship b/t CPUE and environmental variables • Principal Components Analysis (PCA) • Water quality variables and habitat types • Habitat types and CPUE for each fish genera and developmental stage

24. ResultsFish • 4,110 larval and juvenile fish collected • 11 Families, 15 genera represented

25. ResultsFish

26. ResultsWater Quality • Water Temperature • No difference between habitats • Specific Conductance • Higher in canal habitat than bayou habitat (P = <0.0001, α = 0.05) • Dissolved Oxygen • Higher in canal habitat than bayou habitat (P = <0.0001, α = 0.05)

27. ResultsWater Quality • Hypoxic Waters • Canal - solid • 15% of trips • Bayou - dashed • 62% of trips • 54 day period

28. ResultsWater Quality • Water Color • Sediment laden = black • Mixed = gray • Tea = open • No green or black water

29. ResultsWater Quality Floodplain inundation

30. ResultsWater Quality PCA • PC1 (x-axis) and PC2 (y-axis) account for 86.4% of variation

31. Results Vegetation • Submerged Aquatic Vegetation • Coontail - Ceratophyllum demersum • Hydrilla - Hydrilla verticillata * • Fanwort - Cabomba caroliniana • Floating Aquatic Vegetation • Salvinia - Salvinia minima * • Water hyacinth - Eichhoria crassipes * • Water lettuce - Pistia stratiotes *

32. ResultsVegetation • No vegetation at canal sites 1 and 2

33. ResultsLarval Fish • 2,164 Larval fish collected

34. ResultsLarval Fish • Rare Larvae • Cyprinus carpio N=2

35. ResultsLarval Fish

36. ResultsLarval Fish Normoxic (black) VS Hypoxic (open) Collections

37. Results Larval Dorosoma spp. • Greatest CPUE - 17 March 2007 • Canal VS Bayou • CPUE was greater in canal habitat

38. Percentage of spent and not-spent females collected in Bayou Chevreuil 7/31/06 3/28/06

39. Larval Dorosoma spp. • CPUE / Water Quality • Weakly negatively correlated to temperature (P=0.0011, R2=0.093) • No correlation with specific conductance • No correlation with dissolved oxygen

40. Results Larval Ictiobus spp. • Greatest CPUE - 17 March 2007 • Canal VS Bayou • CPUE was greater in canal habitat • CPUE / Water Quality • No correlations

41. ResultsLarval Ictiobus spp.

42. Results Larval Lepomis spp. • Greatest CPUE - 31 May 2007 • Canal VS Bayou • CPUE was greater in canal habitat • CPUE / Water Quality • No correlation with temperature • Weakly positively correlated with specific conductance (P=0.0005, R2=0.0813) • Weakly positively correlated with dissolved oxygen (P=<0.0001, R2=0.1264)

43. ResultsLarval Lepomis spp.

44. ResultsLarval Lepomis spp.

45. ResultsLarval Lepomis spp.

46. Results Larval Pomoxis spp. • Greatest CPUE - 17 March 2007 • Canal VS Bayou • CPUE not different • No larvae collected at sites 1 and 3 • CPUE / Water Quality • No correlation with temperature • Weakly negatively correlated with specific conductance (P=0.013, R2=0.282) • No correlation with dissolved oxygen

47. ResultsLarval Pomoxis spp.

48. ResultsJuvenile Fish • 1,936 Juvenile fish collected

49. ResultsJuvenile Fish

50. ResultsJuvenile Fish