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

Introduction Barataria Estuary 1.7 million hectares Diverse Habitats –Freshwater swamps –Salt marshes

Introduction Study location

Introduction Upper Barataria Estuary Land Use –41.5% forested wetlands –38.0% agricultural lands –5.2% urban land

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

Introduction Habitat Description Canal Habitats –Dredged straight channel –High banks Bayou Habitats –Meandering curves –Low banks

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

Introduction Large 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

Introduction Large 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

Introduction Fish Reproduction Successful Fish Reproduction –Cues Photoperiod (day length) Temperature –Environmental requirements Access to spawning habitat Acceptable water quality

Introduction Fish Reproduction Quality Nursery Habitat –Food availability –Water quality Dissolved oxygen –Normoxic = >2.0 mg/L –Hypoxic = < 2.0 mg/L Specific conductance

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

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

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

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

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

Introduction Site Locations

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

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

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

1 2 3 x1x1 x2x2 x3x3 Canal (X C ) Bayou (X B ) x4x4 x5x5 x6x6 x7x7 Experimental Design N= 3N= 4

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

Methods Data 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

Results Fish 4,110 larval and juvenile fish collected 11 Families, 15 genera represented

Results Fish

Results Water 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)

Results Water Quality Hypoxic Waters Canal - solid –15% of trips Bayou - dashed –62% of trips –54 day period

Results Water Quality Water Color Sediment laden = black Mixed = gray Tea = open No green or black water

Results Water Quality Floodplain inundation

Results Water Quality PCA PC1 (x-axis) and PC2 (y-axis) account for 86.4% of variation VariablePC1PC2 Temperature (°C) Dissolved Oxygen (mg/L) Specific Conductance (µS)

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 *

Results Vegetation No vegetation at canal sites 1 and 2

Results Larval Fish 2,164 Larval fish collected

Results Larval Fish SpeciesCollection PeriodNTemperatureDO Specific Conductance Dorosoma spp.3/17/07 – 7/21/0776*25.7 ± ± 0.19*249 ± 7.7* Ictiobus spp.3/7/07 – 3/29/07972*20.8 ± ± 0.36*221 ± 6.5* Lepomis spp.3/29/07 – 9/5/071,050*27.6 ± ± 0.18*223 ± 7.0* Pomoxis spp.3/17/07 – 3/29/ ± ± 0.22*228 ± 7.8* Rare Larvae –Cyprinus carpio N=2

Results Larval Fish

Normoxic (black) VS Hypoxic (open) Collections

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

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

Larval Dorosoma spp. CPUE / Water Quality –Weakly negatively correlated to temperature (P=0.0011, R 2 =0.093) –No correlation with specific conductance –No correlation with dissolved oxygen

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

Results Larval Ictiobus spp.

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, R 2 =0.0813) –Weakly positively correlated with dissolved oxygen (P=<0.0001, R 2 =0.1264)

Results Larval Lepomis spp.

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, R 2 =0.282) –No correlation with dissolved oxygen

Results Larval Pomoxis spp.

Results Juvenile Fish 1,936 Juvenile fish collected

Results Juvenile Fish SpeciesCollection DateNTemperatureDO Specific Conductance Gambusia affinis3/29/07 – 9/25/071, ± ± 0.17*218.2 ± 6.9* Heterandria formosa 4/12/07 – 9/5/0784*27.7 ± ± 0.19*221.0 ± 7.3* Lepomis spp.5/13/07 – 9/25/ ± ± 0.20*194.2 ± 7.4*

Results Juvenile Fish SpeciesCollection dateNCollection Sites Lepisosteus oculatus5/19/2007 – 6/20/200784, 5, 6, 7 Anchoa mitchilli5/31/2007 – 6/20/200761, 2, 3 Notemigonus crysoleucas8/16/ Ictalurus punctatus5/13/2007 – 6/15/200751, 2, 6 Poecilia latipinna6/7/2007 – 9/5/ , 3, 4, 5, 6, 7 Menidia beryllina5/31/2007 – 6/7/ Syngnathus scovelli6/7/ Pomoxis spp.4/12/2007 – 5/19/200731, 3, 7 Elassoma zonatum4/18/2007 – 7/12/ , 3, 5, 6, 7

Results Juvenile Fish

Normoxic (black) VS Hypoxic (open) Collections

Results Juvenile Gambusia affinis Greatest CPUE - 21 July 2007 Canal VS Bayou –CPUE not different CPUE / Water Quality –Weakly positively correlated with temperature (P = , R² = 0.067) –Weakly negatively correlated with specific conductance (P = , R² = 0.045) –No correlation with dissolved oxygen

Results Juvenile Gambusia affinis

Results Juvenile Heterandria formosa Greatest CPUE - 2 May 2007 Canal VS Bayou –CPUE greater in bayou habitat CPUE / Water Quality –No correlations

CPUE / Lunar Illumination –Greater at illuminations of ≥75% –Weakly positively correlated with lunar illumination (P = , R² = 0.362)

Results Juvenile Heterandria formosa

Results Juvenile Lepomis spp. Greatest CPUE - 13 May 2007 Canal VS Bayou –CPUE not different CPUE / Water Quality –Weakly negatively correlated to temperature (P=0.0019, R 2 =0.08) –No correlation with specific conductance –No correlation with dissolved oxygen

Results Juvenile Lepomis spp.

Results Larval and Juvenile PCA PC I (x-axis) and PC II (y-axis) account for 42.1% of the variation SpeciesPC1PC2 Dorosoma spp Ictiobus spp Gambusia affinis Heterandria formosa Lepomis spp. larvae Lepomis spp. juveniles Pomoxis spp Periodic Equilibrium Opportunistic

Results

Conclusions Spawning / Collection Period Similar to expected Tidal Influence –Menidia beryllina –Anchoa mitchilli

Conclusions Absent Species Absent Species –Amia calva – Bowfin or Choupic –Ameiurus spp. – Bullhead –Aphredoderus sayanus – Pirate Perch –Fundulus chrysotus – Golden Topminnow –Morone spp. – Yellow Bass –Micropterus salmoides – Largemouth Bass Possible causes –No reproduction –Not present in littoral zone –Not vulnerable to sampling gear –Size (opening = 3.2 ± 0.5mm)

Conclusions Upper Barataria Estuary Hydrology N o Predictable Flood Pulse –Lack of reproductive cue –Limit access to floodplain habitat Lack of Flushing –Chronic hypoxia Barrier to Fish Movement –Small diversions –Gulf Intracoastal Waterway

Conclusions Upper Barataria Estuary Hydrology Canal Habitat –Straight channel –High banks –Sediment laden –Little vegetation –Higher DO –Higher conductivity –More lotic Bayou Habitat –Meandering curves –Low banks –Tea colored water –Heavy vegetation –Lower DO –Lower conductivity –More lentic

Conclusions Upper Barataria Estuary Fish Reproduction Periodic strategists –Prefer canal habitat –No difference b/t hypoxic / normoxic waters –May prefer lotic habitat Equilibrium strategists –Prefer canal habitat –Prefer normoxic waters –Extended reproductive period Spawn during optimal environmental conditions Opportunistic strategists –Common in both habitats –Adapted to hypoxic waters –Exploit shallow edge habitat –High reproduction rate

Conclusions Upper Barataria Estuary Fish Reproduction Effects of Altered Hydrology –Non-opportunistic species prefer dredged canal habitats –Lepomis spp. / Bayou Habitat Abundant spawning habitat Little larval production –May conform to Low Flow Recruitment Hypothesis –May affect all components of V-O-R model

Conclusions Upper Barataria Estuary Ecosystem Health Vigor –Reduction of fisheries production Loss of habitat Chronic hypoxia Organization –Shift in species composition –Reduction of diversity Resilience –Loss of river connectivity –Slow repopulation after environmental stress

Recommendations Restore Mississippi River Connection –River water flushing NOT 

Research Suggestions Fixed continuous water quality data recorders Fish reproduction and recruitment –Quarterly electrofishing surveys at fixed sites in different habitats –Multiple year light trap and push net monitoring of larval and juvenile fish

Questions?

Larval Fish Preflexion larvae Postflexion larvae Early juvenile Fully formed fins

Larval Fish Identification Postanal myomeres Preanal myomeres 1810 Melanophores Swim bladder pigmentation Genus: Lepomis