Physical, Chemical and Vegetative Characteristics of the Homosassa River. Prepared for: Citrus County Task Force 10 September 2012

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1 Physical, Chemical and Vegetative Characteristics of the Homosassa River Prepared for: Citrus County Task Force 10 September 2012

Homosassa River A spring and surface water fed river located in western Citrus County Located in the Chassahowitzka Coastal Strip, an area with elevations of 3 m or less, which transitions into an

2 Homosassa River A spring and surface water fed river located in western Citrus County Located in the Chassahowitzka Coastal Strip, an area with elevations of 3 m or less, which transitions into an extensive marsh complex bordering the Gulf of Mexico. The river runs west approximately 5 km from the main spring complex to the beginning of the associated coastal marsh complex and then another 7 km to the Gulf of Mexico. The upper portion of the Homosassa River, above the confluence with the Halls River is narrower, approximately 70 m. Below the confluence, the width increases to approximately 150 m or more. Above the marsh complex, mid-stream channel depth averages 2.3 m. The marsh complex of the river is extensive and water clarity is substantially reduced in this area. Water clarity increases again with distance seaward of the mouth. Dense patches of seagrass and attached macroalgae characterize the nearshore coastal waters; unattached macroalgae can be abundant.

3 Homosassa River Sampling Program Multi-year synoptic sampling program of Springs Coast rivers Sampled quarterly from 1998 through 2011 Twenty transects from near headsprings to 2 km offshore Physical, chemical, and biological parameters Program allows the description of temporal and spatial variation in a number of key characteristics of this river. Funding provided by SWFWMD

4 Homosassa dissolved oxygen (mg/l) (meet Class 3 standards, > 5 mg/l) Average (± std. err.) dissolved oxygen concentrations (mg/l) by transect. Data collected between August 1998 and December Transects 1 to 15, N=138, Transects 16 to 20, N = 46.

5 Homosassa water color (PCU) (higher values indicate darker water color) Halls River confluence Average (± std. err.) water color (Pt-Co units) by transect. Data collected between August 1998 and December Transects 1 to 15, N=138, Transects 16 to 20, N = 46.

6 Homosassa light attenuation (lower values indicate increased water clarity) Average (± std. err.) light attenuation coefficient values (Kd/m, where depth > 0.5 m) by transect. Data collected between August 1998 and December Transects 1 to 15, N=138, Transects 16 to 20, N = 46.

7 Homosassa salinity ( ) (this is a brackish system, seawater is ~35 ) Average (± std. err.) salinities ( ) by transect. Data collected between August 1998 and December Transects 1 to 15, N=138, Transects 16 to 20, N = 46.

8 Homosassa salinity by time Average (± std. err) salinity concentrations ( ) by time period and transect. Within each transect there are four time periods, from left to right they correspond to the oldest to the most recent).

9 Homosassa Springs increasing salinity in the upper river (transect closest to springs) Oneway Analysis of SALINITY ( ) By Time Period RIVER=Homosassa Transect 1 only Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 138 Means Comparisons for each pair using Student's t Level Mean A A B B Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

10 Homosassa chlorophyll concentrations (µg/l) (peak values correspond to areas with longer retention times) Average (± std. err.) chlorophyll concentrations (µg/l, uncorrected) by transect. Data collected between August 1998 and December Transects 1 to 15, N=138, Transects 16 to 20, N = 46.

11 Homosassa SRP conc. (µg P/L) (ground water is a source, declines with distance downstream) Average (± std. err.) soluble reactive phosphorus concentrations (µg P/L) by transect. Data collected between August 1998 and December Transects 1 to 15, N=138, Transects 16 to 20, N = 46.

12 Homosassa NO 3 conc. (µg N/L) (ground water is a source, declines with distance downstream) Average (± std. err) nitrate concentrations (µg N/L) by transect. Data collected between August 1998 and December Transects 1 to 15, N=138, Transects 16 to 20, N = 46. Similar values to Chassahowitzka, about half Weeki Wachee. Elevated above non-impacted background levels which should be < 100 (µg N/L).

13 Homosassa NO 3 conc. by time (NO 3 concentrations are increasing with time) Average (± std. err) nitrate concentrations (µg N/L) by time period and transect. Within each transect there are four time periods, from left to right they correspond to the oldest to the most recent).

14 Submersed Aquatic Vegetation (SAV) Sampling Protocol SAV includes submersed forms of both vascular plants and macroalgae Sampled annually during the summer 100 stations sampled each event (5 locations across river at each of 20 transects), from below headsprings to the upper marsh complex Parameters include: SAV species present, coverage, biomass, and periphyton abundance

15 SAV sampling locations

SAV sampling results SAV is relatively sparse, abundance declines with distance downstream, and has become less abundant over the sampled years Twelve types of SAV observed Most common- filamentous

16 SAV sampling results SAV is relatively sparse, abundance declines with distance downstream, and has become less abundant over the sampled years Twelve types of SAV observed Most common- filamentous algae, 22% of observations Most common vascular plant- Southern Naiad (Najas guadalupensis), 15% of observations Second most common vascular plant- European milfoil (Myriophyllum spicatum), 12% of observations

17 Filamentous algae

19 Eurasian water milfoil

21 Southern naiad

23 Homosassa SAV biomass (kg/m 2 ) Average (± std. err.) submersed aquatic vegetation (SAV) biomass (kg/m 2 wet weight) by transect. Data collected during August or September between1998 and Transects 1 to 10, N < 60 per transect.

24 Homosassa angiosperm biomass (kg/m 2 ) Average (± std. err.) angiosperm (vascular plant) biomass (kg/m 2 wet weight) by transect. Data collected during August or September between1998 and Transects 1 to 10, N < 60 per transect.

25 Homosassa macroalgae biomass (kg/m 2 ) Average (± std. err.) macroalgae (filamentous algae) biomass (kg/m 2 wet weight) by transect. Data collected during August or September between1998 and Transects 1 to 10, N < 60 per transect.

26 Homosassa SAV Conclusions The dominant component is filamentous algae SAV abundance declines with distance downstream Factors that are limiting SAV abundance include: reduced light availability (from colored water inputs and phytoplankton), increased salinity, and disturbance (e.g., people and manatees).

27 Homosassa in context How does it compare to neighboring spring fed rivers (all transects considered) Chassahowitzka and Weeki Wachee?

28 Homosassa flow is less than neighboring rivers Oneway Analysis of FLOW (m/s) By RIVER (transect 1 15 data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 6113 Means Comparisons for each pair using Student's t Level Mean Weeki Wachee A Chassahowitzka B Homosassa C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

29 Homosassa dissolved oxygen is intermediate to neighboring rivers Oneway Analysis of DO (mg/l) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 6888 Means Comparisons for each pair using Student's t Level Mean Chassahowitzka A Homosassa B Weeki Wachee C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

30 Homosassa water color is similar to Chassahowitzka, and much higher than Weeki Wachee Oneway Analysis of COLOR (Pt-Co) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 6838 Means Comparisons for each pair using Student's t Level Mean Homosassa A Chassahowitzka A Weeki Wachee B Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

31 Homosassa light attenuation is similar to Chassahowitzka and higher than Weeki Wachee Oneway Analysis of Average Kd (depth >= 0.5 m) By RIVER (transect 1 10 data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 5946 Means Comparisons for each pair using Student's t Level Mean Chassahowitzka A Homosassa B Weeki Wachee C Levels not connected by same letter are significantly different (t= , Alpha = 0.05).

32 Homosassa salinity is greater than neighboring rivers Oneway Analysis of SALINITY ( ) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 6889 Means Comparisons for each pair using Student's t Level Mean Homosassa A Chassahowitzka B Weeki Wachee C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

33 Homosassa chlorophyll is more than neighboring rivers Oneway Analysis of CHL (µg/l, uncorrected) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 6894 Means Comparisons for each pair using Student's t Level Mean Homosassa A Chassahowitzka B Weeki Wachee C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

34 Homosassa SRP is slightly more than Chassahowitzka, and higher than Weeki Wachee Oneway Analysis of SRP (µg P/L) By RIVER (all transect data) Std Error uses a pooled estimate of error variance Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 6638 Means Comparisons for each pair using Student's t Level Mean Homosassa A Chassahowitzka B Weeki Wachee C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

35 Homosassa NO 3 is less than neighboring rivers Oneway Analysis of NO 3 (µg N/L) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 6878 Means Comparisons for each pair using Student's t Level Mean Weeki Wachee A Chassahowitzka B Homosassa C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

36 Homosassa periphyton abundance is intermediate to neighboring rivers Oneway Analysis of Peri (mg chl / g plant dry wt) By RIVER (transect 1 10 data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 1190 Means Comparisons for each pair using Student's t Level Mean Chassahowitzka A Homosassa B Weeki Wachee C Levels not connected by same letter are significantly different (t= , Alpha = 0.05).

37 Homosassa SAV coverage is less than neighboring rivers Oneway Analysis of TOTAL SAV COVERAGE (%) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 2700 Means Comparisons for each pair using Student's t Level Mean Weeki Wachee A Chassahowitzka B Homosassa C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

38 Homosassa SAV biomass is less than neighboring rivers Oneway Analysis of Total SAV Biomass (kg/m2) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 3600 Means Comparisons for each pair using Student's t Level Mean Weeki Wachee A Chassahowitzka B Homosassa C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

39 Homosassa angiosperm biomass is much less than neighboring rivers Oneway Analysis of Angiosperm Biomass (kg/m2) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 3600 Means Comparisons for each pair using Student's t Level Mean Weeki Wachee A Chassahowitzka B Homosassa C Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

40 Homosassa macroalgae biomass is similar to Chassahowitzka and less than Weeki Wachee Oneway Analysis of Macroalgae Biomass (kg/m2) By RIVER (all transect data) Oneway Anova Summary of Fit R square Adj. R square Root Mean Square Error Mean of Response Observations 3600 Means Comparisons for each pair using Student's t Level Mean Weeki Wachee A Homosassa B Chassahowitzka B Levels not connected by same letter are significantly different (t = , Alpha = 0.05).

41 Among the measured parameters, what is affecting the SAV community in the Homosassa River?

42 SAV coverage is correlated to salinity Bivariate Fit of Mean TOTAL SAV COVERAGE (%) By Mean SALINITY ( ) Average values for each transect, all years (N = 10). SAV coverage is negatively correlated to salinity, freshwater plants are salt sensitive. This is consistent with our knowledge of aquatic ecology. Linear Fit Mean(TOTAL SAV COVERAGE (%)) = *Mean(SALINITY ( )) Summary of Fit R Square R Square Adj Root Mean Square Error Mean of Response Observations 10 Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Model Error Prob > F C. Total *

43 Angiosperm biomass is correlated to salinity Bivariate Fit of Mean Angiosperm Biomass (kg/m2) By Mean SALINITY ( ) Average values for each transect, all years (N = 10). Angiosperm biomass is negatively correlated to salinity, freshwater plants are typically salt sensitive. This is consistent with our knowledge of aquatic ecology. Linear Fit Mean(Angiosperm Biomass (kg/m2)) = *Mean(SALINITY ( )) Summary of Fit R Square R Square Adj Root Mean Square Error Mean of Response Observations 10 Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Model Error Prob > F C. Total *

44 Macroalgae biomass is correlated to salinity Bivariate Fit of Mean Macroalgae Biomass (kg/m2) By Mean SALINITY ( ) Linear Fit Mean(Macroalgae Biomass (kg/m2)) = *Mean(SALINITY ( )) Summary of Fit R Square R Square Adj Root Mean Square Error Mean of Response Observations 10 Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Model Error Prob > F C. Total Average values for each transect, all years (N = 10). Macroalgae biomass is negatively correlated to salinity, but less so than angiosperms. There are many types of filamentous algae that thrive in brackish and salt water. This is consistent with our knowledge of aquatic ecology.

45 SAV coverage is correlated to light availability Bivariate Fit of Mean TOTAL SAV COVERAGE (%) By Mean Kd (depth >= 0.5 m) Linear Fit Mean(TOTAL SAV COVERAGE (%)) = *Mean(Average Kd (depth >= 0.5 m)) Summary of Fit R Square R Square Adj Root Mean Square Error Mean of Response Observations 10 Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Model Error Prob > F C. Total <.0001* Average values for each transect, all years (N = 10). SAV coverage is negatively correlated to light availability. SAV is dependent on adequate light availability, light is commonly a limiting factor in aquatic environments. This is consistent with our knowledge of aquatic ecology.

46 SAV biomass is correlated to light availability Bivariate Fit of Mean Total SAV Biomass (kg/m2) By Mean Kd (depth >= 0.5 m) Linear Fit Mean(Total SAV Biomass (kg/m2)) = *Mean(Average Kd (depth >= 0.5 m)) Summary of Fit R Square R Square Adj Root Mean Square Error Mean of Response Observations 10 Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Model Error Prob > F C. Total * Average values for each transect, all years (N = 10). SAV biomass is negatively correlated to light availability. SAV is dependent on adequate light availability, light is commonly a limiting factor in aquatic environments. This is consistent with our knowledge of aquatic ecology.

47 Light availability is a function of what is in the water (dissolved and particulate matter) Average values for each transect, all years (N = 20). Standard Least Squares model, comparing actual light attenuation versus predicted light attenuation based on two parameters: 1) water color and 2) chlorophyll concentration. 92 % of the variation in light attenuation can be explained by these two parameters. This is consistent with our knowledge of aquatic ecology.

48 Conclusions The nutrient concentrations (N and P) delivered to the Homosassa River via the headsprings are elevated relattive to historical background concentrations. Submersed aquatic vegetation, particularly more desirable forms, such as vascular plants, appear to be limited by light availability and elevated salinities. Management goals of reducing nutrient loading and increasing spring flow might benefit water clarity and support a more desirable aquatic plant community.

49 WEEKI WACHEE SPRINGS 1 NO3 - (mg/l) YEAR Data provided by the Southwest Florida Water Management District and UF

50 Data from Hornsby et al. 2002, 2003, 2004 and 2005 (slide courtesy of M. Cohen)

51 WEEKI WACHEE SPRINGS 1 NO3 - (mg/l) YEAR Data provided by the Southwest Florida Water Management District and UF

52 Data from Hornsby et al. 2002, 2003, 2004 and 2005 (slide courtesy of M. Cohen)

53 Is increased nutrient delivery compromising the ecological integrity of Florida s spring-fed coastal rivers?

54 Image credit: Google Earth Study Rivers

55 Homosassa River Chassahowitzka River

56 Chassahowitzka River Nitrate 500 Mean NITRATE (µg N/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Nitrate concentration has increased by 20% Nitrate loading in the headwater region has increased by 43%

57 Chassahowitzka River Soluble Reactive Phosphorus Mean S. R. PHOSPHORUS (µg P/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT SRP concentration has increased by 19% SRP loading in the headwater region has increased by 44%

58 Effect of Nutrient Addition on Periphyton - Chassahowitzka River 9 2 µ ug Chl per cm C N P N+P Treatment Figure from Notestein et al. 2003

59 Chassahowitzka River Submersed Aquatic Vegetation 5 Mean Total SAV Biomass (kg/m2) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Total SAV biomass has decreased by 31% Rooted vascular plants have declined by 20%

60 Chassahowitzka River Periphyton Mean Periphyton (mg chl/g wet wt host plant) Time Period Periphyton associated with macrophytes has increased by 30%

61 Homosassa River Nitrate 500 Mean NITRATE (µg N/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Nitrate concentration has increased by 6% Nitrate loading in the headwater region has increased by 56%

62 Homosassa River Soluble Reactive Phosphorus Mean S. R. PHOSPHORUS (µg P/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT SRP concentration has increased by 15% SRP loading in the headwater region has increased by 46%

63 Homosassa River Submersed Aquatic Vegetation 5 Mean Total SAV Biomass (kg/m2) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Total SAV biomass has decreased by 67% Rooted vascular plants have declined by 80%

64 Homosassa River Periphyton Mean Periphyton (mg chl/g wet wt host plant) Time Period Periphyton associated with macrophytes has increased by 85%

65 EUTROPHICATION PROGRESSION SCHEME INCREASED NUTRIENT DELIVERY ENHANCED MICROALGAL AND MACROALGAL GROWTH INCREASED SHADING AND BENTHIC RESPIRATION Adapted from C.M.Duarte (1995) MACROPHYTE LOSS

66 Habitat Alterations Change in habitat use and foraging behavior Increased risk predation Decreased growth survival rates and Change in species composition or diversity

67 HOMOSASSA RIVER CHASSAHOWITZKA RIVER Images created in ArcMap

68 Fish Biomass Estimates HOMOSASSA CHASSAHOWITZKA Biomass (g/m 2 ) Freshwater Fishes - Electrofishing Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Saltwater Fishes - Electrofishing Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Freshwater Fishes - Seine Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Saltwater Fishes - Seine Estimates Reach 1 Reach 2 Reach 3

69 Freshwater Fish Community Composition Homosassa-Electrofishing Chassahowitzka-Electrofishing Percent Biomass sa-seining Largemouth bass Gar Bullheads Chain pickerel Homosassa-Seining Chassahowitzka-Seining American eel Lepomis spp. Killifish Mosquitofish Golden shiner Inland silverside Coastal shiner Lake chubsucker

70 Fish Diet Analysis Diet Composition (%) Freshwater Omnivorous Fishes Algae/Plant Aquatic Invertebrate HOMOSASSA CHASSAHOWITZKA Detritus Fish Terrestrial Misc Homosassa River Chassahowitzka River Amphipods Crustacean Clam/Oyster Snails Isopods Beetles Caddisflies Mayflies Other Dipterans Megaloptera Odonates Polychaetes Unidentified Zooplankton Amphipods Crustacean Clam/Oyster Snails Isopods Beetles Caddisflies Mayflies Other Dipterans Megaloptera Odonates Polychaetes Unidentified Zooplankton

71 Fish Diet Analysis Diet Composition (%) Freshwater Piscivorous Fishes Algae/Plant Aquatic Detritus Fish Terrestrial Misc Invertebrate HOMOSASSA CHASSAHOWITZKA Homosassa River Chassahowitzka River Pinfish Killifish Drum Silversides Sunfish Needlefish Shiners Goby Bass Mojara Seatrout Toadfish Unidentified Pinfish Killifish Drum Silversides Sunfish Needlefish Shiners Goby Bass Mojara Seatrout Toadfish Unidentified

72 Length at Age Relationships for Largemouth Bass in the Chassahowitzka and Homosassa Rivers

73 Kernel density home range estimates of largemouth bass in the Chassahowitzka and Homosassa Rivers

74 Acknowledgments

75 Mark-Recapture Electrofishing Surveys Large-bodied fishes Closed model 3-passes over consecutive days Probability of capture (p cap ) = MLE of logbinomial function

76 Seine Depletion Surveys Small-bodied and juvenile fishes 3 sites per reach (20x10 m, closed) P cap, N = MLE of logmultinomial (Gould and Pollock 1997)

77 Probability of Capture Estimates HOMOSASSA RIVER CHASSAHOWITZKA RIVER ELECTROFISHING M-R Bass Age-0 Bass Bluegill Age-0 Bluegill Sunfish Age-0 Sunfish Gar Bullhead Snapper Red drum Sheepshead Mojarra p-cap Bass Sunfish Age-0 Sunfish Chubsucker Snapper Mullet Mojarra Pinfish p-cap SEINE DEPLETIONS Goby Pinfish Mojarra Killifish Silverside Age-0 sunfish MudCrab Shrimp p-cap p-cap Goby Pinfish Mojarra Killifish Bluefin killifish Silverside Shiner Age-0 sunfish Needlefish Anchovy Hogchoker Pipefish MudCrab Shrimp

78 WEEKI WACHEE SPRINGS 1 NO3 - (mg/l) YEAR Data provided by the Southwest Florida Water Management District and UF

79 Data from Hornsby et al. 2002, 2003, 2004 and 2005 (slide courtesy of M. Cohen)

80 Is increased nutrient delivery compromising the ecological integrity of Florida s spring-fed coastal rivers?

81 Image credit: Google Earth Study Rivers

82 Homosassa River Chassahowitzka River

83 Chassahowitzka River Nitrate 500 Mean NITRATE (µg N/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Nitrate concentration has increased by 20% Nitrate loading in the headwater region has increased by 43%

84 Chassahowitzka River Soluble Reactive Phosphorus Mean S. R. PHOSPHORUS (µg P/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT SRP concentration has increased by 19% SRP loading in the headwater region has increased by 44%

85 Effect of Nutrient Addition on Periphyton - Chassahowitzka River 9 2 µ ug Chl per cm C N P N+P Treatment Figure from Notestein et al. 2003

86 Chassahowitzka River Submersed Aquatic Vegetation 5 Mean Total SAV Biomass (kg/m2) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Total SAV biomass has decreased by 31% Rooted vascular plants have declined by 20%

87 Chassahowitzka River Periphyton Mean Periphyton (mg chl/g wet wt host plant) Time Period Periphyton associated with macrophytes has increased by 30%

88 Homosassa River Nitrate 500 Mean NITRATE (µg N/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Nitrate concentration has increased by 6% Nitrate loading in the headwater region has increased by 56%

89 Homosassa River Soluble Reactive Phosphorus Mean S. R. PHOSPHORUS (µg P/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT SRP concentration has increased by 15% SRP loading in the headwater region has increased by 46%

90 Homosassa River Submersed Aquatic Vegetation 5 Mean Total SAV Biomass (kg/m2) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Total SAV biomass has decreased by 67% Rooted vascular plants have declined by 80%

91 Homosassa River Periphyton Mean Periphyton (mg chl/g wet wt host plant) Time Period Periphyton associated with macrophytes has increased by 85%

92 EUTROPHICATION PROGRESSION SCHEME INCREASED NUTRIENT DELIVERY ENHANCED MICROALGAL AND MACROALGAL GROWTH INCREASED SHADING AND BENTHIC RESPIRATION Adapted from C.M.Duarte (1995) MACROPHYTE LOSS

93 Habitat Alterations Change in habitat use and foraging behavior Increased risk predation Decreased growth survival rates and Change in species composition or diversity

94 HOMOSASSA RIVER CHASSAHOWITZKA RIVER Images created in ArcMap

95 Fish Biomass Estimates HOMOSASSA CHASSAHOWITZKA Biomass (g/m 2 ) Freshwater Fishes - Electrofishing Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Saltwater Fishes - Electrofishing Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Freshwater Fishes - Seine Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Saltwater Fishes - Seine Estimates Reach 1 Reach 2 Reach 3

96 Freshwater Fish Community Composition Homosassa-Electrofishing Chassahowitzka-Electrofishing Percent Biomass sa-seining Largemouth bass Gar Bullheads Chain pickerel Homosassa-Seining Chassahowitzka-Seining American eel Lepomis spp. Killifish Mosquitofish Golden shiner Inland silverside Coastal shiner Lake chubsucker

97 Fish Diet Analysis Diet Composition (%) Freshwater Omnivorous Fishes Algae/Plant Aquatic Invertebrate HOMOSASSA CHASSAHOWITZKA Detritus Fish Terrestrial Misc Homosassa River Chassahowitzka River Amphipods Crustacean Clam/Oyster Snails Isopods Beetles Caddisflies Mayflies Other Dipterans Megaloptera Odonates Polychaetes Unidentified Zooplankton Amphipods Crustacean Clam/Oyster Snails Isopods Beetles Caddisflies Mayflies Other Dipterans Megaloptera Odonates Polychaetes Unidentified Zooplankton

98 Fish Diet Analysis Diet Composition (%) Freshwater Piscivorous Fishes Algae/Plant Aquatic Detritus Fish Terrestrial Misc Invertebrate HOMOSASSA CHASSAHOWITZKA Homosassa River Chassahowitzka River Pinfish Killifish Drum Silversides Sunfish Needlefish Shiners Goby Bass Mojara Seatrout Toadfish Unidentified Pinfish Killifish Drum Silversides Sunfish Needlefish Shiners Goby Bass Mojara Seatrout Toadfish Unidentified

99 Length at Age Relationships for Largemouth Bass in the Chassahowitzka and Homosassa Rivers

100 Kernel density home range estimates of largemouth bass in the Chassahowitzka and Homosassa Rivers

101 Acknowledgments

102 Mark-Recapture Electrofishing Surveys Large-bodied fishes Closed model 3-passes over consecutive days Probability of capture (p cap ) = MLE of logbinomial function

103 Seine Depletion Surveys Small-bodied and juvenile fishes 3 sites per reach (20x10 m, closed) P cap, N = MLE of logmultinomial (Gould and Pollock 1997)

104 Probability of Capture Estimates HOMOSASSA RIVER CHASSAHOWITZKA RIVER ELECTROFISHING M-R Bass Age-0 Bass Bluegill Age-0 Bluegill Sunfish Age-0 Sunfish Gar Bullhead Snapper Red drum Sheepshead Mojarra p-cap Bass Sunfish Age-0 Sunfish Chubsucker Snapper Mullet Mojarra Pinfish p-cap SEINE DEPLETIONS Goby Pinfish Mojarra Killifish Silverside Age-0 sunfish MudCrab Shrimp p-cap p-cap Goby Pinfish Mojarra Killifish Bluefin killifish Silverside Shiner Age-0 sunfish Needlefish Anchovy Hogchoker Pipefish MudCrab Shrimp

105 Is increased nutrient delivery compromising the ecological integrity of Florida s spring-fed coastal rivers?

106 Image credit: Google Earth Study Rivers

107 Homosassa River Chassahowitzka River

108 Chassahowitzka River Nitrate 500 Mean NITRATE (µg N/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Nitrate concentration has increased by 20% Nitrate loading in the headwater region has increased by 43%

109 Chassahowitzka River Soluble Reactive Phosphorus Mean S. R. PHOSPHORUS (µg P/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT SRP concentration has increased by 19% SRP loading in the headwater region has increased by 44%

110 Effect of Nutrient Addition on Periphyton - Chassahowitzka River 9 2 µ ug Chl per cm C N P N+P Treatment Figure from Notestein et al. 2003

111 Chassahowitzka River Submersed Aquatic Vegetation 5 Mean Total SAV Biomass (kg/m2) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Total SAV biomass has decreased by 31% Rooted vascular plants have declined by 20%

112 Chassahowitzka River Periphyton Mean Periphyton (mg chl/g wet wt host plant) Time Period Periphyton associated with macrophytes has increased by 30%

113 Homosassa River Nitrate 500 Mean NITRATE (µg N/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Nitrate concentration has increased by 6% Nitrate loading in the headwater region has increased by 56%

114 Homosassa River Soluble Reactive Phosphorus Mean S. R. PHOSPHORUS (µg P/L) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT SRP concentration has increased by 15% SRP loading in the headwater region has increased by 46%

115 Homosassa River Submersed Aquatic Vegetation 5 Mean Total SAV Biomass (kg/m2) Open Circles = 1998 to 2000, Closed Circles = 2003 to 2005 within TRANSECT Total SAV biomass has decreased by 67% Rooted vascular plants have declined by 80%

116 Homosassa River Periphyton Mean Periphyton (mg chl/g wet wt host plant) Time Period Periphyton associated with macrophytes has increased by 85%

117 EUTROPHICATION PROGRESSION SCHEME INCREASED NUTRIENT DELIVERY ENHANCED MICROALGAL AND MACROALGAL GROWTH INCREASED SHADING AND BENTHIC RESPIRATION Adapted from C.M.Duarte (1995) MACROPHYTE LOSS

118 Habitat Alterations Change in habitat use and foraging behavior Increased risk predation Decreased growth survival rates and Change in species composition or diversity

119 HOMOSASSA RIVER CHASSAHOWITZKA RIVER Images created in ArcMap

120 Fish Biomass Estimates HOMOSASSA CHASSAHOWITZKA Biomass (g/m 2 ) Freshwater Fishes - Electrofishing Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Saltwater Fishes - Electrofishing Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Freshwater Fishes - Seine Estimates Reach 1 Reach 2 Reach 3 Biomass (g/m 2 ) Saltwater Fishes - Seine Estimates Reach 1 Reach 2 Reach 3

121 Freshwater Fish Community Composition Homosassa-Electrofishing Chassahowitzka-Electrofishing Percent Biomass sa-seining Largemouth bass Gar Bullheads Chain pickerel Homosassa-Seining Chassahowitzka-Seining American eel Lepomis spp. Killifish Mosquitofish Golden shiner Inland silverside Coastal shiner Lake chubsucker

122 Fish Diet Analysis Diet Composition (%) Freshwater Omnivorous Fishes Algae/Plant Aquatic Invertebrate HOMOSASSA CHASSAHOWITZKA Detritus Fish Terrestrial Misc Homosassa River Chassahowitzka River Amphipods Crustacean Clam/Oyster Snails Isopods Beetles Caddisflies Mayflies Other Dipterans Megaloptera Odonates Polychaetes Unidentified Zooplankton Amphipods Crustacean Clam/Oyster Snails Isopods Beetles Caddisflies Mayflies Other Dipterans Megaloptera Odonates Polychaetes Unidentified Zooplankton

123 Fish Diet Analysis Diet Composition (%) Freshwater Piscivorous Fishes Algae/Plant Aquatic Detritus Fish Terrestrial Misc Invertebrate HOMOSASSA CHASSAHOWITZKA Homosassa River Chassahowitzka River Pinfish Killifish Drum Silversides Sunfish Needlefish Shiners Goby Bass Mojara Seatrout Toadfish Unidentified Pinfish Killifish Drum Silversides Sunfish Needlefish Shiners Goby Bass Mojara Seatrout Toadfish Unidentified

124 Length at Age Relationships for Largemouth Bass in the Chassahowitzka and Homosassa Rivers

125 Kernel density home range estimates of largemouth bass in the Chassahowitzka and Homosassa Rivers

126 Acknowledgments

127 Mark-Recapture Electrofishing Surveys Large-bodied fishes Closed model 3-passes over consecutive days Probability of capture (p cap ) = MLE of logbinomial function

128 Seine Depletion Surveys Small-bodied and juvenile fishes 3 sites per reach (20x10 m, closed) P cap, N = MLE of logmultinomial (Gould and Pollock 1997)

129 Probability of Capture Estimates HOMOSASSA RIVER CHASSAHOWITZKA RIVER ELECTROFISHING M-R Bass Age-0 Bass Bluegill Age-0 Bluegill Sunfish Age-0 Sunfish Gar Bullhead Snapper Red drum Sheepshead Mojarra p-cap Bass Sunfish Age-0 Sunfish Chubsucker Snapper Mullet Mojarra Pinfish p-cap SEINE DEPLETIONS Goby Pinfish Mojarra Killifish Silverside Age-0 sunfish MudCrab Shrimp p-cap p-cap Goby Pinfish Mojarra Killifish Bluefin killifish Silverside Shiner Age-0 sunfish Needlefish Anchovy Hogchoker Pipefish MudCrab Shrimp

Coastal Rivers Aquatic Vegetation Analysis

Coastal Rivers Aquatic Vegetation Analysis For Rivers August 2016 Table of Contents Executive Summary 1 1.0 Introduction 1-1 2.0 Scope of Project 2-1 3.0 Methods 3-1 3.1 Study Area 3-1 3.1.1 Regional Description