At-risk Freshwater Mussel Survey of Bogue Chitto National Wildlife Refuge

PROJECT ID: FWS/R4/NWRS/DSRM/Inventory-Monitoring Branch

Principal Investigators: Daniel Breaux Refuge Manager Bogue Chitto NWR Southeast Louisiana Refuge Complex 61389 Hwy 434 Lacombe, LA 70445 Office Phone: 985-882-2030 Fax Phone: 985-882-9133 [email protected]

Gary Vitrano Louisiana Department of Wildlife and Fisheries Inland Fisheries Biologist Manager - District VIII 61384 Fish Hatchery Road P.O. Box 1190 Lacombe, LA 70445 Office: 985-882-0027 Fax: 985-8820-0029 [email protected]

FINAL REPORT

ABSTRACT

Timed, qualitative searches were performed at established sample sites within the boundaries of the Bogue Chitto National Wildlife Refuge (BCNWR), and waterways adjacent to the refuge within the Pearl River watershed, to determine freshwater mussel assemblage structure, species richness, relative abundance, diversity, and to document species of greatest conservation need. Twenty-three sample sites within the refuge were surveyed, plus an additional twenty-seven sites on adjacent water ways and tributaries. A total of 10,086 individual mussels were collected with an estimated species richness of 29, a Shannon-Wiener Diversity H’ Index of 2.35 and a catch- per-unit-effort (CPUE) of 201.72 mussels per 90-minute sample. Cyclonaias refulgens was the most common species, representing 24% by total number, while Megalonaias nervosa, Lasmigona complanata, and Villosa vibex were the least abundant species. Within the boundaries of the refuge, 6,526 individual mussels were collected, with an estimated species richness of 27, a Shannon-Wiener Diversity H’ Index of 2.239 and a CPUE of 283.74 mussels per 90-minute sample. Quadrula nobilis was the most common species, representing 24% by total number, while Obovaria unicolor, Utterbackia imbecillis, and Villosa vibex were the least abundant species. Potamilus inflatus, federally listed as Threatened, was not found in the sampled areas of this project.

INTRODUCTION

Freshwater mussels are the most endangered freshwater organisms in North America, with three quarters of the species in the United States considered species of concern (Strayer, 2008). Mussels are particularly susceptible to habitat disturbances and disruption of host fish dispersal. Inventories of mussel populations, relative abundances and species composition are important for future conservation efforts. The primary focus of the project is to provide a baseline comprehensive survey of freshwater mussels on the Bogue Chitto National Wildlife Refuge (BCNWR), and to describe species assemblages across the refuge’s major waterways and many of the smaller tributary streams and sloughs. In addition to waters in the BCNWR, mussel communities were sampled in adjacent tributaries and other waters of the basin, resulting in a comprehensive survey of the waters of the Bogue Chitto and Lower Pearl River of Louisiana.

PROJECT OBJECTIVES

Objective 1 – Conduct twenty-three qualitative samples (timed searches) on sites located within the boundaries of the BCNWR in Louisiana. These surveys were distributed across sites within the Bogue Chitto River, Holmes Bayou, Wilson Slough, the West Pearl River and the Pearl River proper, along with adjacent backwater sloughs and remnant river channels. This distribution of sample sites contains a representative cross section of aquatic habitats within the BCNWR. In addition to the BCNWR sites, 27 locations on waterways and tributaries across the Pearl River Watershed adjacent to the refuge were sampled.

Objective 2 – Document the presence or absence of endangered federally listed mussel species or species of concern, and other freshwater mussel species that may occur in these waterways, and determine an estimate of relative abundance and relative composition.

Objective 3 – Provide a report that describes estimated species richness, relative abundance, relative composition, diversity and abiotic variables, to be used to create future management plans for protection or improvement of habitat to encourage conservation for mussels found within the BCNWR along with GIS locations and maps of assemblage results.

METHODS

Study Areas / Sample Site Established in 1980, BCNWR is located within the Pearl River watershed. The 36,502-acre refuge is bisected by the West Pearl River, the Bogue Chitto River, and Holmes Bayou. The refuge is bounded by the Pearl River, East Pearl River, and the Pearl River Navigation Canal. The Mississippi Old River Wildlife Management Area (15,400 acres) and the State of Louisiana's Pearl River Wildlife Management Area (35,031) are adjacent to the refuge, forming an 87,000-acre block of protected forested wetlands and adjacent uplands within the Pearl River Basin. In addition to these protected areas, the Pearl River extends 61 river miles north of the refuge in Louisiana, and the Bogue Chitto River continues 56 miles to the northwest in Louisiana. Impediments to the passage of aquatic organisms within the watershed include the diversion at Walkiah Bluff, the low water sill on the Bogue Chitto River, and the low water sill on the Pearl River at Pools Bluff. Fifty sites were sampled across the watershed to achieve the project objectives (Table 1, Appendix I Maps 1-10).

Within BCNWR The BCNWR can be further delineated into 5 sectors: 1. Upper West Pearl / Wilson Sough (Table 1, Appendix I Map 3). a. Sites: 12, 13, 14, 16, 17, 18 ,19, 20, 23, and 24 2. East Pearl River - south of the Walkiah Diversion / Holmes Bayou (Table 1, Appendix I Map 4). a. Sites: 15, 21 and 22 3. Upper Pearl River - north of the Walkiah Diversion (Table 1, Appendix I Map 5). a. Sites: 25, 26, 27 and 28 4. Bogue Chitto - below the sill (Table 1, Appendix I Map 6). a. Sites: 38 and 39 5. Lower West Pearl River - south of the confluence at Holmes Bayou (Table 1, Appendix I Map 7). a. Sites: 8, 9, 10 and 11

Pearl River Watershed within Louisiana, outside BCNWR Sample sites beyond the boundaries of the BCNWR were selected in an attempt to quantify the presence or absence of the threatened and endangered Potamilus inflatus and delineate differences in community structure at impediment points for river fish passage. Areas outside the BCNWR can be delineated further into distinct habitat sectors which include: 1. Bogue Chitto - north of the sill (Table 1, Appendix I Map 8). a. Sites: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 and 50 2. Pearl River - north of the sill (Table 1, Appendix I Map 9). a. Sites: 29, 30, 31, 32, 33, 34, 35, 36 and 37 3. Lower West Pearl River - south of the confluence at Holmes Bayou (Table 1, Appendix I Map 10). a. Sites: 1, 2, 3, 4, 5, 6 and 7

Table 1. BCNWR freshwater mussel sample stations and associated GPS coordinates (decimal degree) sampled in the summer of 2018. Site LDEQ sub- Number Site Reference basin BCNWR Latitude Longitude 1 5554-1 90202 30.29347 -89.69859 2 5555-2 90202 30.30693 -89.70453 3 5556-3 90202 30.31670 -89.69516 4 5557-4 90202 30.32215 -89.69537 5 5558-5 90202 30.33400 -89.70845 6 5559-6 90202 30.36252 -89.71880 7 5519-7 90202 30.36532 -89.72173 8 5560-8 90202 30.40430 -89.74327 9 5517-9 90202 30.42953 -89.73873 10 5561-10 90202 30.44280 -89.74966 11 5562-11 90202 X 30.45227 -89.75474 12 5534-12 90201 X 30.46527 -89.77250 13 5563-13 90201 X 30.46875 -89.77893 14 5516-14 90201 X 30.47531 -89.78063 15 5564-15 90106 X 30.49549 -89.75723 16 5565-16 90201 X 30.50227 -89.80411 17 5533-17 90201 30.50621 -89.80044 18 5566-18 90201 X 30.51600 -89.79739 19 5520-19 90201 X 30.51792 -89.80422 20 5567-20 90201 X 30.52454 -89.80506 21 5568-21 90106 X 30.53687 -89.77347 22 5569-22 90106 X 30.54716 -89.79994 23 5532-23 90201 X 30.54731 -89.82764 24 5570-24 90201 X 30.55209 -89.83430 25 5521-25 90107 X 30.60367 -89.82175 26 5571-26 90107 X 30.60630 -89.82022 27 5572-27 90107 X 30.62497 -89.82203 28 5573-28 90107 X 30.65430 -89.83021 29 5522-29 90101 30.72484 -89.83945 30 5574-30 90101 30.80422 -89.81394 31 5575-31 90101 30.80842 -89.80214 32 5576-32 90101 30.81033 -89.78843 33 5577-33 90101 30.82075 -89.78177 34 5578-34 90101 30.85129 -89.79042 35 5579-35 90101 30.88629 -89.77388 36 5580-36 90101 30.96217 -89.73891 37 5581-37 90101 30.99261 -89.72809 38 5548-38 90203 X 30.59772 -89.84586 39 5547-39 90203 30.61117 -89.85210 40 5524-40 90501 30.62213 -89.87791 41 5582-41 90501 30.62854 -89.90935 42 5583-42 90501 30.63882 -89.96250 43 5584-43 90501 30.66528 -89.99035 44 5585-44 90501 30.66153 -89.99719 45 5586-45 90501 30.67353 -90.01984 46 5587-46 90501 30.69823 -90.06481 47 5588-47 90501 30.73129 -90.10610 48 5589-48 90501 30.74787 -90.12136 49 5590-49 90501 30.76084 -90.13691 50 5591-50 90501 30.94955 -90.20414

Sampling Protocol Sampling adhered to the qualitative protocol (timed searches) established by Louisiana Department of Wildlife and Fisheries (LDWF) and Louisiana State University (LSU), and concentrated on primary mussel habitat parameters. Qualitative surveys produce a more complete species list, especially when determining the presence of a rare species (Strayer et al. 2003).

Timed qualitative searches were performed at each established sample site. Biologists located mussels by tactile search along the littoral zones (<1 m depth), retrieving both living mussels and shell. Target effort for each sample site was 90 person minutes. For example, if the mussel crew included three people, each person would sample for 30 minutes, for a total of 90 person-minutes of effort at that site. All collected mussels were brought to the surface, identified to species, and replaced in the substrate (Appendix I. Figures 1 and 2). Nomenclature follows scientific and common names presented by Williams, et al. (2017). At each site, water quality parameters were collected, including salinity (ppt), water temperature (degree C), conductivity (millimohs/cm2), turbidity (ntu) dissolved oxygen (mg/l), pH, and flow (fps). Flow was determined with the FP111 GLOBAL Water Flow Probe and the remaining parameters were determined with the In- SituAqua Troll 500. Reference in this document to any specific commercial product, process, or service, or the use of any trade, firm or corporation name is for the information and convenience of the public, and does not constitute endorsement, recommendation, or favoring by LDWF or the Department of the Interior. Analysis of these data included CPUE (total number of mussels collected per sample in 90 minutes), species richness, and Shannon-Wiener Diversity H’ Index.

RESULTS

Mussel Community Data Twenty-three sample sites within the refuge were surveyed, plus an additional 27 sites on adjacent water ways and tributaries (Table 1 and Figure 1). A total of 10,086 individual mussels were collected, with an estimated species richness of 29, a Shannon-Wiener Diversity H’ Index of 2.35 and a CPUE of 201.72 mussels per 90-minute sample. Cyclonaias refulgens was the most common species, representing 24% by total number, while Megalonaias nervosa, Lasmigona complanata, and Villosa vibex were the least abundant species (Table 2). Within the boundaries of the refuge, 6,526 individual mussels were collected, with an estimated species richness of 27, a Shannon-Wiener Diversity H’ Index of 2.239 and a CPUE of 283.74 per 90- minute sample. Quadrula nobilis was the most common species, representing 24% by total number, while Obovaria unicolor, Utterbackia imbecillis, and Villosa vibex were the least abundant species (Table 3). Outside the boundaries of the refuge, 3,519 individual mussels were collected, with an estimated species richness of 29, a Shannon-Wiener Diversity H’ Index of 2.43 and a CPUE of 130.33 mussels per 90-minute sample. In these locations, Cyclonaias refulgens was the most common species, representing 27% by total number, while Reginaia ebenus, Megalonaias nervosa, and Lasmigona complanata were the least abundant species (Table 4). Mussel species collected are illustrated in Appendix II, Figure 1 – 27.

Table 2. BCNWR freshwater mussel data summary from all samples collected in the summer of 2018.

Species Common Name Total count Relative Composition Cyclonaias refulgens Purple Pimpleback 2461 0.244001586 Quadrula nobilis Gulf Mapleleaf 1983 0.196609161 Glebula rotundata Rounded Pearlshell 1371 0.135930993 Quadrula apiculata Southern Mapleleaf 1121 0.11114416 Potamilus purpuratus Bleufer 590 0.058496926 Obliquaria reflexa Threehorn Wartyback 527 0.052250644 Lampsilis teres Yellow Sandshell 408 0.040452112 Plectomerus Bankclimber 213 0.021118382 dombeyanus Tritogonia verrucosa Pistol Grip 201 0.019928614 Elliptio crassidens Eleaphantear 185 0.018342257 Amblema plicata Three Ridge 144 0.014277216 Pleurobema Mississippi Pigtoe 134 0.013285743 beadleianum Fusconaia cerina Southern Pigtoe 118 0.011699385 Lampsilis straminea Southern Fatmucket 108 0.010707912 Leptodea fragilis Fragile Papershell 98 0.009716439 Villosa lienosa Little Spectaclecase 75 0.00743605 Reginaia ebenus Ebony Shell 65 0.006444577 Pyganodon grandis Giant Floater 64 0.006345429 Lampsilis ornata Southern Pocketbook 47 0.004659925 Arcidens confragosus Rock Pocketbook 42 0.004164188 Toxolasma parvum Lilliput 25 0.002478683 Toxolasma texasiense Texas Lilliput 23 0.002280389 Utterbackia imbecillis Pond Papershell 22 0.002181241 Utterbackiana Cypress Floater 20 0.001982947 hartfieldorum Obovaria unicolor Alabama Hickorynut 17 0.001685505 Ligumia subrostrata Pondmussel 8 0.000793179 Megalonaias nervosa Washboard 8 0.000793179 Villosa Vibex Southern Rainbow 7 0.000694031 Lasmigona complanata White Heelspliter 1 0.00009915 Total 10086 1

Table 3. BCNWR freshwater mussel data summary from samples collected within the refuge boundaries in the summer of 2018.

Species Common Name Total count Relative Composition Quadrula nobilis Gulf Mapleleaf 1595 0.244406987 Cyclonaias refulgens Purple Pimpleback 1525 0.233680662 Quadrula apiculata Southern Mapleleaf 912 0.139748698 Glebula rotundata Rounded Pearlshell 733 0.112319951 Obliquaria reflexa Threehorn Wartyback 342 0.052405762 Potamilus purpuratus Bleufer 328 0.050260496 Lampsilis teres Yellow Sandshell 203 0.031106344 Tritogonia verrucosa Pistol Grip 140 0.021452651 Amblema plicata Three Ridge 128 0.019613852 Elliptio crassidens Eleaphantear 124 0.019000919 Plectomerus Bankclimber dombeyanus 79 0.012105424 Reginaia ebenus Ebony Shell 63 0.009653693 Leptodea fragilis Fragile Papershell 60 0.009193993 Villosa lienosa Little Spectaclecase 46 0.007048728 Pyganodon grandis Giant Floater 41 0.006282562 Fusconaia cerina Southern Pigtoe 39 0.005976096 Arcidens confragosus Rock Pocketbook 38 0.005822862 Pleurobema Mississippi Pigtoe beadleianum 37 0.005669629 Lampsilis straminea Southern Fatmucket 30 0.004596997 Utterbackiana Cypress Floater hartfieldorum 13 0.001992032 Toxolasma parvum Lilliput 10 0.001532332 Toxolasma texasiense Texas Lilliput 9 0.001379099 Lampsilis ornata Southern Pocketbook 9 0.001379099 Utterbackia imbecillis Pond Papershell 7 0.001072633 Megalonaias nervosa Washboard 7 0.001072633 Obovaria unicolor Alabama Hickorynut 6 0.000919399 Villosa Vibex Southern Rainbow 2 0.000306466 Total 6526 1

Table 4. BCNWR freshwater mussel data summary from samples collected outside the refuge boundaries in the summer of 2018.

Species Common Name Total count Relative Composition Cyclonaias refulgens Purple Pimpleback 936 0.265984655 Glebula rotundata Rounded Pearlshell 638 0.181301506 Quadrula nobilis Gulf Mapleleaf 388 0.110258596 Potamilus purpuratus Bleufer 241 0.068485365 Quadrula apiculata Southern Mapleleaf 209 0.059391873 Lampsilis teres Yellow Sandshell 205 0.058255186 Obliquaria reflexa Threehorn Wartyback 185 0.052571753 Plectomerus Bankclimber 114 0.032395567 dombeyanus Pleurobema Mississippi Pigtoe 97 0.027564649 beadleianum Fusconaia cerina Southern Pigtoe 79 0.02244956 Lampsilis straminea Southern Fatmucket 78 0.022165388 Elliptio crassidens Elephantear 61 0.01733447 Tritogonia verrucosa Pistol Grip 61 0.01733447 Lampsilis ornata Southern Pocketbook 38 0.010798522 Leptodea fragilis Fragile Papershell 38 0.010798522 Villosa lienosa Little Spectaclecase 29 0.008240978 Pyganodon grandis Giant Floater 23 0.006535948 Amblema plicata Three Ridge 16 0.004546746 Toxolasma parvum Lilliput 15 0.004262575 Utterbackia imbecillis Pond Papershell 15 0.004262575 Toxolasma texasiense Texas Lilliput 14 0.003978403 Obovaria unicolor Alabama Hickorynut 11 0.003125888 Ligumia subrostrata Pondmussel 8 0.002273373 Utterbackiana Cypress Floater 7 0.001989201 hartfieldorum Villosa Vibex Southern Rainbow 5 0.001420858 Arcidens confragosus Rock Pocketbook 4 0.001136687 Reginaia ebenus Ebony Shell 2 0.000568343 Megalonaias nervosa Washboard 1 0.000284172 Lasmigona complanata White Heelspliter 1 0.000284172 Total 3519 1

BCNWR Delineated Results 1. Upper West Pearl River/ Wilson Sough A total of 2,261 individual mussels were collected with an estimated species richness of 24 and a Shannon-Wiener Diversity H’ Index of 2.04. Quadrula nobilis was the most common species, representing 29% by total number, while Toxolasma parvum, Megalonaias nervosa, and Pleurobema beadleianum were the least abundant species (Appendix III, Table 1). 2. East Pearl River - south of the Walkiah Diversion / Holmes Bayou A total of 900 individual mussels were collected with an estimated species richness of 18 and a Shannon-Wiener Diversity H’ Index of 1.68. Quadrula nobilis was the most common species, representing 44% by total number, while Utterbackia imbecillis, Amblema plicata, and Pyganodon grandis were the least abundant species (Appendix III, Table 2). 3. Upper Pearl River - north of the Walkiah Diversion A total of 1,434 individual mussels were collected with an estimated species richness of 21 and a Shannon-Wiener Diversity H’ Index of 2.08. Quadrula apiculata was the most common species, representing 26% by total number, while Reginaia ebenus, Amblema plicata, and Villosa vibex were the least abundant species (Appendix III, Table 3). 4. Bogue Chitto - below the sill A total of 922 individual mussels were collected with an estimated species richness of 23 and a Shannon-Wiener Diversity H’ Index of 2.38. Cyclonaias refulgens was the most common species, representing 35% by total number, while Villosa lienosa, Villosa vibex, and Toxolasma texasiense were the least abundant species (Appendix III, Table 4). 5. Lower West Pearl River - south of the confluence at Holmes Bayou A total of 1,009 individual mussels were collected with an estimated species richness of 16 and a Shannon-Wiener Diversity H’ Index of 1.9. Glebula rotundata was the most common species, representing 35% by total number, while Villosa lienosa, Pyganodon grandis, and Toxolasma parvum were the least abundant species (Appendix III, Table 5).

Pearl River Watershed Within Louisiana, north and south of major impediment on the Pearl River and the Bogue Chitto 1. Bogue Chitto - north of the sill A total of 1,153 individual mussels were collected with an estimated species richness of 24 and a Shannon-Wiener Diversity H’ Index of 1.76. Cyclonaias refulgens was the most common species, representing 57% by total number, while Leptodea fragilis, Ligumia subrostrata, and Reginaia ebenus were the least abundant species (Appendix III, Table 6). 2. Bogue Chitto - south of the sill A total of 922 individual mussels were collected with an estimated species richness of 23 and a Shannon-Wiener Diversity H’ Index of 2.38. Cyclonaias refulgens was the most common species, representing 28% by total number, while Toxolasma texasiense, Villosa vibex, and Villosa lienosa were the least abundant species (Appendix III, Table 7). 3. Pearl River - north of the sill A total of 824 individual mussels were collected with an estimated species richness of 27 and a Shannon-Wiener Diversity H’ Index of 2.03. Cyclonaias refulgens was the most common species, representing 29% by total number, while Megalonaias nervosa, Reginaia ebenus, and Toxolasma parvum were the least abundant species (Appendix III, Table 8). 4. Pearl River - south of the sill A total of 7,187 individual mussels were collected with an estimated species richness of 21 and a Shannon-Wiener Diversity H’ Index of 2.15. Quadrula nobilis was the most common species, representing 26% by total number, while Ligumia subrostrata, Elliptio crassidens, and Villosa vibex were the least abundant species (Appendix III, Table 9).

Inflated Heelsplitter, Potamilus inflatus Specimens of Potamilus inflatus, listed as threatened, were not found in the sampled areas of this project.

Physical Data Mid-stream flow ranged from 0.1 feet per second (fps) to 1.4 fps, with a mean of .59 fps and pH ranged from 6.42 to 9.01 with a mean of 7.25. All critical water quality parameters can be found in Appendix III, Table 10.

DISCUSSION

Freshwater mussel community structure was dominated by four species, Quadrula nobilis, Cyclonaias refulgens, Quadrula apiculata, and Glebula rotundata, accounting for 69% of the total population across the Pearl River watershed. Within the BCNWR, the same four species dominated the community, accounting for 73 % of the population. This structure is typical in North American mussel assemblages (Haag 2012). Ligumia subrostrata, Megalonaias nervosa, Villosa vibex and Lasmigona complanata were the least abundant species in the watershed, while Utterbackia imbecillis, Megalonaias nervosa, Obovaria unicolor and Villosa vibex were the least abundant species in the refuge. Leptodea fragilis, which incurred high mortality during the Temple-Inland Incident fish and mollusk kill in 2011 (78.9% of total mussel mortality), have reoccupied their position within the community assemblage structure across the watershed and within the refuge. Specimens of Potamilus inflatus, listed as threatened, were not found in the sampled areas of this project, and have not been found in recent surveys in the Pearl River watershed. Their population seems to be greatly diminished, or possibly extirpated. Further surveys targeting suitable habitats of P. inflatus should be conducted. Villosa vibex continues to display low numbers and is considered a species of concern. Elliptio crassidens, a species of concern, was present in high numbers at station reference 5547-39, and also present at station reference 5548-38 and 5520-19 within the BCNWR. They were also present outside of the refuge in smaller numbers on the Bogue Chitto, north of the sill. The habitat between the confluence of the Bogue Chitto and the Pearl River and the sill on the Bogue Chitto is a critical area for Elliptio crassidens as well as Megalonaias nervosa, Obovaria unicolor and Villosa lienosa. Lasmigona complanata was the rarest of the mussels surveyed in the watershed, and is not present within the BCNWR. It was located at station reference 5524-40, which is on the Bogue Chitto just north of the sill. More research is needed to determine if the sill has impeded the Lasmigona complanata distribution in the watershed.

ACKNOWLEDGEMENTS

Recognition to LDWF staff, Matthew Duplessis, Jonathan Winslow and Jeffery Thompson for their tireless effort and vast knowledge of the subject that made this project possible. Additional thanks to Nate Johnson and Chase Smith for their contributing expertise.

LITERATURE CITED:

Haag, W. R. 2012. North American freshwater mussels: natural history, ecology, and conservation. Cambridge University 505p.

Strayer, D.L. and D.R. Smith. 2003. A guide to sampling freshwater mussel populations. American Fisheries Society Monograph 8.

Williams, J. D., A. E. Bogan, R. S. Butler, K. S. Cummings, J. T. Garner, J. L. Harris, N. A. Johnson, and G. T. Watters 2017. A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20:33–58.

Vidrine, Malcolm F. 1993. The Historical Distributions of Freshwater Mussels in Louisiana. Gail Q. Vidrine Collectibles. Eunice, Louisiana.

APPENDIX I

Figure 1. Biologist conducting mussel surveys on the Pearl River watershed in the summer of 2018.

Figure 2. Biologist conducting mussel surveys on the Pearl River watershed in the summer of 2018.

Map 1. Pearl River watershed freshwater mussel sampling stations sampled in the summer of 2018.

Map 2. BCNWR freshwater mussel sampling stations sampled in the summer of 2018.

Map 3. Upper West Pearl / Wilson Sough freshwater mussel sampling stations sampled in the summer of 2018.

Map 4. East Pearl River - south of the Walkiah Diversion / Holmes Bayou freshwater mussel sampling stations sampled in the summer of 2018.

Map 5. Upper Pearl River - north of the Walkiah Diversion freshwater mussel sampling stations sampled in the summer of 2018.

Map 6. Bogue Chitto - below the sill freshwater mussel sampling stations sampled in the summer of 2018.

Map 7. Lower West Pearl River - south of the confluence at Holmes Bayou freshwater mussel sampling stations sampled in the summer of 2018.

Map 8. The Bogue Chitto - north of the sill freshwater mussel sampling stations sampled in the summer of 2018.

Map 9. Pearl River - north of the sill freshwater mussel sampling stations sampled in the summer of 2018.

Map 10. Lower West Pearl River - south of the confluence at Holmes Bayou freshwater mussel sampling stations sampled in the summer of 2018.

APPENDIX II

Figure 1. Amblema plicata

Figure 2. Arcidens confragosus

Figure 3. Cyclonaias refulgens

Figure 4. Elliptio crassidens

Figure 5. Fusconaia cerina

Figure 6. Glebula rotundata

Figure 7. Lampsilis ornata

Figure 8. Lampsilis straminea

Figure 9. Lampsilis teres

Figure 10. Lasmigona complanata

Figure 11. Leptodea fragilis

Figure 12. Ligumia subrostrata

Figure 13. Megalonaias nervosa

Figure 14. Obliquaria reflexa

Figure 15. Plectomerus dombeyanus

Figure 16. Pleurobema beadleianum

Figure 17. Potamilus purpuratus

Figure 18. Pyganodon grandis

Figure 19. Quadrula apiculata

Figure 20. Quadrula nobilis

Figure 21. Reginaia ebenus

Figure 22. Toxolasma parvum

Figure 23. Tritogonia verrucosa

Figure 24. Utterbackia imbecillis

Figure 24. Utterbackiana hartfieldorum

Figure 26. Villosa lienosa

APPENDIX III

Table 1. BCNWR freshwater mussel data summary from Upper West Pearl / Wilson Sough collected in the summer of 2018 Species Total count Relative Composition Quadrula nobilis 664 0.293675365 Cyclonaias refulgens 638 0.282176028 Quadrula apiculata 279 0.123396727 Potamilus purpuratus 138 0.06103494 Glebula rotundata 107 0.047324193 Obliquaria reflexa 90 0.039805396 Lampsilis teres 89 0.039363114 Tritogonia verrucosa 83 0.036709421 Reginaia ebenus 51 0.022556391 Pyganodon grandis 23 0.01017249 Villosa lienosa 22 0.009730208 Amblema plicata 15 0.006634233 Utterbackiana hartfieldorum 13 0.005749668 Arcidens confragosus 9 0.00398054 Leptodea fragilis 9 0.00398054 Lampsilis straminea 7 0.003095975 Plectomerus dombeyanus 7 0.003095975 Utterbackia imbecillis 5 0.002211411 Toxolasma texasiense 4 0.001769129 Elliptio crassidens 2 0.000884564 Fusconaia cerina 2 0.000884564 Toxolasma parvum 2 0.000884564 Megalonaias nervosa 1 0.000442282 Pleurobema beadleianum 1 0.000442282 Total 2261 1 Station Species Total count Relative Composition 5516 - 14 Quadrula nobilis 40 0.338983051 5516 - 14 Cyclonaias refulgens 25 0.211864407 5516 - 14 Quadrula apiculata 19 0.161016949 5516 - 14 Lampsilis teres 10 0.084745763 5516 - 14 Obliquaria reflexa 9 0.076271186 5516 - 14 Potamilus purpuratus 7 0.059322034 5516 - 14 Glebula rotundata 5 0.042372881 5516 - 14 Amblema plicata 1 0.008474576 5516 - 14 Pyganodon grandis 1 0.008474576 5516 - 14 Tritogonia verrucosa 1 0.008474576 Total 118 1 Station Species Total count Relative Composition 5520 - 19 Cyclonaias refulgens 205 0.665584416 5520 - 19 Quadrula nobilis 31 0.100649351 5520 - 19 Tritogonia verrucosa 17 0.055194805 5520 - 19 Lampsilis teres 15 0.048701299 5520 - 19 Quadrula apiculata 12 0.038961039 5520 - 19 Potamilus purpuratus 9 0.029220779 5520 - 19 Pyganodon grandis 6 0.019480519 5520 - 19 Glebula rotundata 4 0.012987013 5520 - 19 Obliquaria reflexa 3 0.00974026 5520 - 19 Elliptio crassidens 2 0.006493506 5520 - 19 Leptodea fragilis 1 0.003246753 5520 - 19 Megalonaias nervosa 1 0.003246753 5520 - 19 Reginaia ebenus 1 0.003246753 5520 - 19 Toxolasma parvum 1 0.003246753 Total 308 1 Station Species Total count Relative Composition 5532 - 23 Lampsilis teres 16 0.457142857 Utterbackiana 5532 - 23 6 0.171428571 hartfieldorum 5532 - 23 Potamilus purpuratus 4 0.114285714 5532 - 23 Pyganodon grandis 3 0.085714286 5532 - 23 Cyclonaias refulgens 1 0.028571429 5532 - 23 Lampsilis straminea 1 0.028571429 5532 - 23 Leptodea fragilis 1 0.028571429 5532 - 23 Obliquaria reflexa 1 0.028571429 5532 - 23 Quadrula apiculata 1 0.028571429 5532 - 23 Toxolasma parvum 1 0.028571429 Total 35 1 Station Species Total count Relative Composition 5533 - 17 Cyclonaias refulgens 229 0.708978328 5533 - 17 Quadrula apiculata 29 0.089783282 5533 - 17 Quadrula nobilis 22 0.068111455 5533 - 17 Potamilus purpuratus 12 0.037151703 5533 - 17 Lampsilis teres 10 0.030959752 5533 - 17 Obliquaria reflexa 10 0.030959752 5533 - 17 Tritogonia verrucosa 4 0.012383901 5533 - 17 Glebula rotundata 3 0.009287926 5533 - 17 Amblema plicata 2 0.00619195 Plectomerus 5533 - 17 1 0.003095975 dombeyanus 5533 - 17 Reginaia ebenus 1 0.003095975 Total 323 1 Station Species Total count Relative Composition 5534 - 12 Quadrula nobilis 415 0.615727003 5534 - 12 Quadrula apiculata 89 0.132047478 5534 - 12 Cyclonaias refulgens 51 0.075667656 5534 - 12 Reginaia ebenus 48 0.071216617 5534 - 12 Obliquaria reflexa 21 0.03115727 5534 - 12 Tritogonia verrucosa 14 0.020771513 5534 - 12 Potamilus purpuratus 10 0.014836795 5534 - 12 Lampsilis teres 5 0.007418398 5534 - 12 Villosa lienosa 5 0.007418398 5534 - 12 Arcidens confragosus 4 0.005934718 5534 - 12 Glebula rotundata 4 0.005934718 5534 - 12 Leptodea fragilis 3 0.004451039 5534 - 12 Fusconaia cerina 2 0.002967359 5534 - 12 Pyganodon grandis 2 0.002967359 Plectomerus 5534 - 12 1 0.00148368 dombeyanus Total 674 1 Station Species Total count Relative Composition 5563 - 13 Glebula rotundata 40 0.24691358 5563 - 13 Potamilus purpuratus 35 0.216049383 5563 - 13 Cyclonaias refulgens 29 0.179012346 5563 - 13 Quadrula nobilis 12 0.074074074 5563 - 13 Lampsilis teres 10 0.061728395 5563 - 13 Quadrula apiculata 10 0.061728395 5563 - 13 Obliquaria reflexa 9 0.055555556 5563 - 13 Tritogonia verrucosa 8 0.049382716 5563 - 13 Pyganodon grandis 4 0.024691358 5563 - 13 Arcidens confragosus 1 0.00617284 5563 - 13 Lampsilis straminea 1 0.00617284 5563 - 13 Leptodea fragilis 1 0.00617284 5563 - 13 Toxolasma texasiense 1 0.00617284 Utterbackiana 5563 - 13 1 0.00617284 hartfieldorum Total 162 1 Station Species Total count Relative Composition 5565 - 16 Quadrula apiculata 38 0.258503401 5565 - 16 Cyclonaias refulgens 37 0.25170068 5565 - 16 Potamilus purpuratus 36 0.244897959 5565 - 16 Quadrula nobilis 13 0.088435374 5565 - 16 Obliquaria reflexa 7 0.047619048 5565 - 16 Glebula rotundata 6 0.040816327 5565 - 16 Villosa lienosa 3 0.020408163 5565 - 16 Pyganodon grandis 2 0.013605442 5565 - 16 Lampsilis teres 1 0.006802721 5565 - 16 Leptodea fragilis 1 0.006802721 5565 - 16 Toxolasma texasiense 1 0.006802721 5565 - 16 Utterbackia imbecillis 1 0.006802721 Utterbackiana 5565 - 16 1 0.006802721 hartfieldorum Total 147 1 Station Species Total count Relative Composition 5566 - 18 Cyclonaias refulgens 17 0.278688525 5566 - 18 Glebula rotundata 10 0.163934426 5566 - 18 Lampsilis teres 7 0.114754098 5566 - 18 Potamilus purpuratus 7 0.114754098 5566 - 18 Obliquaria reflexa 6 0.098360656 5566 - 18 Quadrula nobilis 6 0.098360656 5566 - 18 Villosa lienosa 3 0.049180328 5566 - 18 Leptodea fragilis 2 0.032786885 5566 - 18 Pyganodon grandis 1 0.016393443 5566 - 18 Quadrula apiculata 1 0.016393443 5566 - 18 Tritogonia verrucosa 1 0.016393443 Total 61 1 Station Species Total count Relative Composition Utterbackiana 5567 - 20 5 0.185185185 hartfieldorum 5567 - 20 Utterbackia imbecillis 4 0.148148148 5567 - 20 Cyclonaias refulgens 3 0.111111111 5567 - 20 Pyganodon grandis 3 0.111111111 5567 - 20 Quadrula apiculata 3 0.111111111 5567 - 20 Lampsilis straminea 2 0.074074074 5567 - 20 Lampsilis teres 2 0.074074074 5567 - 20 Potamilus purpuratus 2 0.074074074 5567 - 20 Toxolasma texasiense 2 0.074074074 5567 - 20 Obliquaria reflexa 1 0.037037037 Total 27 1 Station Species Total count Relative Composition 5570 - 24 Quadrula nobilis 125 0.307881773 5570 - 24 Quadrula apiculata 77 0.189655172 5570 - 24 Cyclonaias refulgens 41 0.100985222 5570 - 24 Tritogonia verrucosa 38 0.093596059 5570 - 24 Glebula rotundata 35 0.086206897 5570 - 24 Obliquaria reflexa 23 0.056650246 5570 - 24 Potamilus purpuratus 16 0.039408867 5570 - 24 Lampsilis teres 13 0.032019704 5570 - 24 Amblema plicata 12 0.02955665 5570 - 24 Villosa lienosa 11 0.027093596 Plectomerus 5570 - 24 5 0.012315271 dombeyanus 5570 - 24 Arcidens confragosus 4 0.009852217 5570 - 24 Lampsilis straminea 3 0.007389163 5570 - 24 Pleurobema beadleianum 1 0.002463054 5570 - 24 Pyganodon grandis 1 0.002463054 5570 - 24 Reginaia ebenus 1 0.002463054 Total 406 1

Table 2. BCNWR freshwater mussel data summary from East Pearl River (south of the Walkiah Diversion) / Holmes Bayou collected in the summer of 2018

Species Total count Relative Composition Quadrula nobilis 396 0.4400 Cyclonaias refulgens 233 0.2589 Quadrula apiculata 110 0.1222 Potamilus purpuratus 36 0.0400 Obliquaria reflexa 27 0.0300 Leptodea fragilis 20 0.0222 Lampsilis teres 17 0.0189 Villosa lienosa 15 0.0167 Glebula rotundata 11 0.0122 Tritogonia verrucosa 11 0.0122 Lampsilis straminea 7 0.0078 Plectomerus 5 0.0056 dombeyanus Pleurobema 3 0.0033 beadleianum Reginaia ebenus 3 0.0033 Arcidens confragosus 2 0.0022 Utterbackia imbecillis 2 0.0022 Amblema plicata 1 0.0011 Pyganodon grandis 1 0.0011 Total 900 1 Station Species Total count Relative Composition 5564 - 15 Quadrula nobilis 104 0.497607656 5564 - 15 Cyclonaias refulgens 37 0.177033493 5564 - 15 Quadrula apiculata 15 0.071770335 5564 - 15 Potamilus purpuratus 13 0.062200957 5564 - 15 Villosa lienosa 13 0.062200957 5564 - 15 Lampsilis teres 12 0.057416268 5564 - 15 Obliquaria reflexa 6 0.028708134 5564 - 15 Glebula rotundata 3 0.014354067 5564 - 15 Lampsilis straminea 3 0.014354067 5564 - 15 Leptodea fragilis 1 0.004784689 5564 - 15 Pleurobema beadleianum 1 0.004784689 5564 - 15 Utterbackia imbecillis 1 0.004784689 Total 209 1 Station Species Total count Relative Composition 5568 - 21 Cyclonaias refulgens 122 0.570093458 5568 - 21 Quadrula nobilis 35 0.163551402 5568 - 21 Quadrula apiculata 23 0.107476636 5568 - 21 Tritogonia verrucosa 8 0.037383178 5568 - 21 Leptodea fragilis 6 0.028037383 5568 - 21 Potamilus purpuratus 6 0.028037383 5568 - 21 Obliquaria reflexa 4 0.018691589 5568 - 21 Lampsilis teres 3 0.014018692 5568 - 21 Glebula rotundata 2 0.009345794 5568 - 21 Pleurobema beadleianum 2 0.009345794 5568 - 21 Reginaia ebenus 2 0.009345794 Plectomerus 5568 - 21 1 0.004672897 dombeyanus Total 214 1 Station Species Total count Relative Composition 5569 - 22 Quadrula nobilis 257 0.538784067 5569 - 22 Cyclonaias refulgens 74 0.155136268 5569 - 22 Quadrula apiculata 72 0.150943396 5569 - 22 Obliquaria reflexa 17 0.035639413 5569 - 22 Potamilus purpuratus 17 0.035639413 5569 - 22 Leptodea fragilis 13 0.027253669 5569 - 22 Glebula rotundata 6 0.012578616 5569 - 22 Lampsilis straminea 4 0.008385744 Plectomerus 5569 - 22 4 0.008385744 dombeyanus 5569 - 22 Tritogonia verrucosa 3 0.006289308 5569 - 22 Arcidens confragosus 2 0.004192872 5569 - 22 Lampsilis teres 2 0.004192872 5569 - 22 Villosa lienosa 2 0.004192872 5569 - 22 Amblema plicata 1 0.002096436 5569 - 22 Pyganodon grandis 1 0.002096436 5569 - 22 Reginaia ebenus 1 0.002096436 5569 - 22 Utterbackia imbecillis 1 0.002096436 Total 477 1

Table 3. BCNWR freshwater mussel data summary from Upper Pearl River (north of the Walkiah Diversion) collected in the summer of 2018 Species Total count Relative Composition Quadrula apiculata 377 0.262900976 Quadrula nobilis 284 0.19804742 Cyclonaias refulgens 246 0.171548117 Glebula rotundata 179 0.124825662 Obliquaria reflexa 114 0.079497908 Potamilus purpuratus 78 0.054393305 Lampsilis teres 45 0.031380753 Leptodea fragilis 25 0.017433752 Pleurobema 19 0.013249651 beadleianum Arcidens confragosus 15 0.010460251 Pyganodon grandis 11 0.007670851 Plectomerus 9 0.006276151 dombeyanus Toxolasma parvum 7 0.00488145 Fusconaia cerina 6 0.0041841 Villosa lienosa 5 0.00348675 Megalonaias nervosa 4 0.0027894 Tritogonia verrucosa 4 0.0027894 Lampsilis straminea 3 0.00209205 Amblema plicata 1 0.00069735 Reginaia ebenus 1 0.00069735 Villosa Vibex 1 0.00069735 Total 1434 1 Station Species Total count Relative Composition 5521 - 25 Cyclonaias refulgens 98 0.443438914 5521 - 25 Obliquaria reflexa 27 0.122171946 5521 - 25 Potamilus purpuratus 25 0.113122172 5521 - 25 Glebula rotundata 24 0.108597285 5521 - 25 Lampsilis teres 24 0.108597285 5521 - 25 Quadrula apiculata 13 0.058823529 5521 - 25 Leptodea fragilis 3 0.013574661 5521 - 25 Pleurobema beadleianum 3 0.013574661 5521 - 25 Quadrula nobilis 2 0.009049774 5521 - 25 Toxolasma parvum 2 0.009049774 Total 221 1 Station Species Total count Relative Composition 5571 - 26 Cyclonaias refulgens 50 0.505050505 5571 - 26 Glebula rotundata 17 0.171717172 5571 - 26 Lampsilis teres 10 0.101010101 5571 - 26 Obliquaria reflexa 10 0.101010101 5571 - 26 Potamilus purpuratus 6 0.060606061 5571 - 26 Toxolasma parvum 4 0.04040404 5571 - 26 Quadrula apiculata 1 0.01010101 5571 - 26 Quadrula nobilis 1 0.01010101 Total 99 1 Station Species Total count Relative Composition 5572 - 27 Quadrula apiculata 243 0.385103011 5572 - 27 Quadrula nobilis 138 0.218700475 5572 - 27 Glebula rotundata 79 0.125198098 5572 - 27 Cyclonaias refulgens 70 0.110935024 5572 - 27 Obliquaria reflexa 46 0.072900158 5572 - 27 Potamilus purpuratus 16 0.025356577 Plectomerus 5572 - 27 8 0.012678288 dombeyanus 5572 - 27 Pyganodon grandis 8 0.012678288 5572 - 27 Arcidens confragosus 7 0.011093502 5572 - 27 Leptodea fragilis 5 0.00792393 5572 - 27 Lampsilis teres 4 0.006339144 5572 - 27 Villosa lienosa 3 0.004754358 5572 - 27 Tritogonia verrucosa 2 0.003169572 5572 - 27 Reginaia ebenus 1 0.001584786 5572 - 27 Villosa Vibex 1 0.001584786 Total 631 1 Station Species Total count Relative Composition 5573 - 28 Quadrula nobilis 143 0.296066253 5573 - 28 Quadrula apiculata 120 0.248447205 5573 - 28 Glebula rotundata 59 0.122153209 5573 - 28 Obliquaria reflexa 31 0.064182195 5573 - 28 Potamilus purpuratus 31 0.064182195 5573 - 28 Cyclonaias refulgens 28 0.057971014 5573 - 28 Leptodea fragilis 17 0.035196687 5573 - 28 Pleurobema beadleianum 16 0.033126294 5573 - 28 Arcidens confragosus 8 0.016563147 5573 - 28 Lampsilis teres 7 0.014492754 5573 - 28 Fusconaia cerina 6 0.01242236 5573 - 28 Megalonaias nervosa 4 0.008281573 5573 - 28 Lampsilis straminea 3 0.00621118 5573 - 28 Pyganodon grandis 3 0.00621118 5573 - 28 Tritogonia verrucosa 2 0.004140787 5573 - 28 Villosa lienosa 2 0.004140787 5573 - 28 Amblema plicata 1 0.002070393 Plectomerus 5573 - 28 1 0.002070393 dombeyanus 5573 - 28 Toxolasma parvum 1 0.002070393 Total 483 1

Table 4. BCNWR freshwater mussel data summary from Bogue Chitto (below the sill) collected in the summer of 2018 Species Total count Relative Composition Cyclonaias refulgens 260 0.281995662 Elliptio crassidens 122 0.132321041 Amblema plicata 111 0.120390456 Glebula rotundata 79 0.085683297 Quadrula nobilis 56 0.060737527 Quadrula apiculata 51 0.055314534 Obliquaria reflexa 50 0.054229935 Plectomerus 43 0.046637744 dombeyanus Tritogonia verrucosa 37 0.040130152 Fusconaia cerina 31 0.03362256 Lampsilis teres 18 0.019522777 Pleurobema 14 0.015184382 beadleianum Lampsilis straminea 13 0.014099783 Reginaia ebenus 8 0.00867679 Obovaria unicolor 6 0.006507592 Potamilus purpuratus 6 0.006507592 Arcidens confragosus 5 0.005422993 Pyganodon grandis 4 0.004338395 Leptodea fragilis 2 0.002169197 Megalonaias nervosa 2 0.002169197 Toxolasma texasiense 2 0.002169197 Villosa Vibex 1 0.001084599 Villosa lienosa 1 0.001084599 Total 922 1 Station Species Total count Relative Composition 5547 - 39 Elliptio crassidens 116 0.337209302 5547 - 39 Glebula rotundata 79 0.229651163 Plectomerus 5547 - 39 27 0.078488372 dombeyanus 5547 - 39 Quadrula apiculata 21 0.061046512 5547 - 39 Quadrula nobilis 17 0.049418605 5547 - 39 Cyclonaias refulgens 16 0.046511628 5547 - 39 Lampsilis teres 13 0.037790698 5547 - 39 Pleurobema beadleianum 9 0.026162791 5547 - 39 Reginaia ebenus 8 0.023255814 5547 - 39 Amblema plicata 7 0.020348837 5547 - 39 Obliquaria reflexa 6 0.01744186 5547 - 39 Potamilus purpuratus 6 0.01744186 5547 - 39 Obovaria unicolor 5 0.014534884 5547 - 39 Pyganodon grandis 4 0.011627907 5547 - 39 Lampsilis straminea 2 0.005813953 5547 - 39 Leptodea fragilis 2 0.005813953 5547 - 39 Toxolasma texasiense 2 0.005813953 5547 - 39 Arcidens confragosus 1 0.002906977 5547 - 39 Fusconaia cerina 1 0.002906977 5547 - 39 Megalonaias nervosa 1 0.002906977 5547 - 39 Villosa Vibex 1 0.002906977 Total 344 1 Station Species Total count Relative Composition 5548 - 38 Cyclonaias refulgens 244 0.422145329 5548 - 38 Amblema plicata 104 0.179930796 5548 - 38 Obliquaria reflexa 44 0.076124567 5548 - 38 Quadrula nobilis 39 0.067474048 5548 - 38 Tritogonia verrucosa 37 0.064013841 5548 - 38 Fusconaia cerina 30 0.051903114 5548 - 38 Quadrula apiculata 30 0.051903114 Plectomerus 5548 - 38 16 0.027681661 dombeyanus 5548 - 38 Lampsilis straminea 11 0.019031142 5548 - 38 Elliptio crassidens 6 0.010380623 5548 - 38 Lampsilis teres 5 0.008650519 5548 - 38 Pleurobema beadleianum 5 0.008650519 5548 - 38 Arcidens confragosus 4 0.006920415 5548 - 38 Megalonaias nervosa 1 0.001730104 5548 - 38 Obovaria unicolor 1 0.001730104 5548 - 38 Villosa lienosa 1 0.001730104 Total 578 1

Table 5. BCNWR freshwater mussel data summary Lower West Pearl River (south of the confluence at Holmes Bayou) collected in the summer of 2018 Species Total count Relative Composition Glebula rotundata 357 0.353815659 Quadrula nobilis 195 0.193260654 Cyclonaias refulgens 148 0.146679881 Quadrula apiculata 95 0.094152626 Potamilus purpuratus 70 0.069375619 Obliquaria reflexa 61 0.060455897 Lampsilis teres 34 0.033696729 Plectomerus dombeyanus 15 0.014866204 Lampsilis ornata 9 0.008919722 Arcidens confragosus 7 0.006937562 Tritogonia verrucosa 5 0.004955401 Leptodea fragilis 4 0.003964321 Toxolasma texasiense 3 0.002973241 Villosa lienosa 3 0.002973241 Pyganodon grandis 2 0.001982161 Toxolasma parvum 1 0.00099108 Total 1009 1 Station Species Total count Relative Composition 5517 - 9 Glebula rotundata 100 0.425531915 5517 - 9 Quadrula nobilis 37 0.157446809 5517 - 9 Cyclonaias refulgens 22 0.093617021 5517 - 9 Obliquaria reflexa 22 0.093617021 5517 - 9 Lampsilis teres 17 0.072340426 5517 - 9 Quadrula apiculata 15 0.063829787 5517 - 9 Potamilus purpuratus 11 0.046808511 5517 - 9 Arcidens confragosus 4 0.017021277 Plectomerus 5517 - 9 3 0.012765957 dombeyanus 5517 - 9 Toxolasma texasiense 2 0.008510638 5517 - 9 Lampsilis ornata 1 0.004255319 5517 - 9 Leptodea fragilis 1 0.004255319 Total 235 1 Station Species Total count Relative Composition 5560 - 8 Glebula rotundata 130 0.778443114 5560 - 8 Lampsilis teres 14 0.083832335 5560 - 8 Potamilus purpuratus 9 0.053892216 Plectomerus 5560 - 8 5 0.02994012 dombeyanus 5560 - 8 Quadrula nobilis 4 0.023952096 5560 - 8 Quadrula apiculata 3 0.017964072 5560 - 8 Obliquaria reflexa 1 0.005988024 5560 - 8 Toxolasma parvum 1 0.005988024 Total 167 1 Station Species Total count Relative Composition 5561 - 10 Cyclonaias refulgens 121 0.430604982 5561 - 10 Quadrula nobilis 65 0.231316726 5561 - 10 Quadrula apiculata 31 0.110320285 5561 - 10 Obliquaria reflexa 19 0.067615658 5561 - 10 Potamilus purpuratus 18 0.06405694 5561 - 10 Glebula rotundata 9 0.03202847 5561 - 10 Lampsilis ornata 8 0.028469751 5561 - 10 Tritogonia verrucosa 5 0.017793594 Plectomerus 5561 - 10 3 0.010676157 dombeyanus 5561 - 10 Arcidens confragosus 1 0.003558719 5561 - 10 Villosa lienosa 1 0.003558719 Total 281 1 Station Species Total count Relative Composition 5562 - 11 Glebula rotundata 118 0.36196319 5562 - 11 Quadrula nobilis 89 0.273006135 5562 - 11 Quadrula apiculata 46 0.141104294 5562 - 11 Potamilus purpuratus 32 0.098159509 5562 - 11 Obliquaria reflexa 19 0.058282209 5562 - 11 Cyclonaias refulgens 5 0.015337423 Plectomerus 5562 - 11 4 0.012269939 dombeyanus 5562 - 11 Lampsilis teres 3 0.009202454 5562 - 11 Leptodea fragilis 3 0.009202454 5562 - 11 Arcidens confragosus 2 0.006134969 5562 - 11 Pyganodon grandis 2 0.006134969 5562 - 11 Villosa lienosa 2 0.006134969 5562 - 11 Toxolasma texasiense 1 0.003067485 Total 326 1

Table 6. Pearl River watershed freshwater mussel data summary of Bogue Chitto north of the sill collected in the summer of 2018 Species Common Name Total count Relative Composition Cyclonaias refulgens Purple Pimpleback 659 0.571552472 Pleurobema Mississippi Pigtoe 97 0.084128361 beadleianum Fusconaia cerina Southern Pigtoe 78 0.06764961 Lampsilis straminea Southern Fatmucket 72 0.062445794 Tritogonia verrucosa Pistol Grip 49 0.042497832 Elliptio crassidens Eleaphantear 34 0.029488291 Quadrula apiculata Southern Mapleleaf 33 0.028620989 Lampsilis teres Yellow Sandshell 22 0.019080659 Potamilus purpuratus Bleufer 16 0.013876843 Villosa lienosa Little Spectaclecase 14 0.012142238 Utterbackia imbecillis Pond Papershell 12 0.010407632 Obovaria unicolor Alabama Hickorynut 11 0.00954033 Obliquaria reflexa Threehorn Wartyback 10 0.008673027 Pyganodon grandis Giant Floater 10 0.008673027 Quadrula nobilis Gulf Mapleleaf 7 0.006071119 Toxolasma parvum Lilliput 6 0.005203816 Amblema plicata Three Ridge 5 0.004336513 Plectomerus Bankclimber 5 0.004336513 dombeyanus Villosa Vibex Southern Rainbow 5 0.004336513 Lampsilis ornata Southern Pocketbook 4 0.003469211 Lasmigona complanata White Heelspliter 1 0.000867303 Leptodea fragilis Fragile Papershell 1 0.000867303 Ligumia subrostrata Pondmussel 1 0.000867303 Reginaia ebenus Ebony Shell 1 0.000867303 Total 1153 1

Table 7. Pearl River watershed freshwater mussel data summary of Bogue Chitto River south of the sill collected in the summer of 2018 Species Common Name Total count Relative Composition Cyclonaias refulgens Purple Pimpleback 260 0.281995662 Elliptio crassidens Eleaphantear 122 0.132321041 Amblema plicata Three Ridge 111 0.120390456 Glebula rotundata Rounded Pearlshell 79 0.085683297 Quadrula nobilis Gulf Mapleleaf 56 0.060737527 Quadrula apiculata Southern Mapleleaf 51 0.055314534 Obliquaria reflexa Threehorn Wartyback 50 0.054229935 Plectomerus Bankclimber 43 0.046637744 dombeyanus Tritogonia verrucosa Pistol Grip 37 0.040130152 Fusconaia cerina Southern Pigtoe 31 0.03362256 Lampsilis teres Yellow Sandshell 18 0.019522777 Pleurobema Mississippi Pigtoe 14 0.015184382 beadleianum Lampsilis straminea Southern Fatmucket 13 0.014099783 Reginaia ebenus Ebony Shell 8 0.00867679 Obovaria unicolor Alabama Hickorynut 6 0.006507592 Potamilus purpuratus Bleufer 6 0.006507592 Arcidens confragosus Rock Pocketbook 5 0.005422993 Pyganodon grandis Giant Floater 4 0.004338395 Leptodea fragilis Fragile Papershell 2 0.002169197 Megalonaias nervosa Washboard 2 0.002169197 Toxolasma texasiense Texas Lilliput 2 0.002169197 Villosa Vibex Southern Rainbow 1 0.001084599 Villosa lienosa Little Spectaclecase 1 0.001084599 Total 922 1

Table 8. Pearl River watershed freshwater mussel data summary of Pearl River River north of the sill collected in the summer of 2018

Species Common Name Total count Relative Composition Cyclonaias refulgens Purple Pimpleback 240 0.291262136 Potamilus purpuratus Bleufer 181 0.219660194 Quadrula apiculata Southern Mapleleaf 131 0.158980583 Obliquaria reflexa Threehorn Wartyback 110 0.133495146 Lampsilis ornata Southern Pocketbook 34 0.041262136 Elliptio crassidens Eleaphantear 27 0.03276699 Lampsilis teres Yellow Sandshell 25 0.030339806 Quadrula nobilis Gulf Mapleleaf 25 0.030339806 Toxolasma texasiense Texas Lilliput 9 0.01092233 Utterbackiana Cypress Floater 7 0.008495146 hartfieldorum Leptodea fragilis Fragile Papershell 6 0.007281553 Villosa lienosa Little Spectaclecase 6 0.007281553 Ligumia subrostrata Pondmussel 4 0.004854369 Plectomerus Bankclimber 4 0.004854369 dombeyanus Pyganodon grandis Giant Floater 4 0.004854369 Tritogonia verrucosa Pistol Grip 4 0.004854369 Amblema plicata Three Ridge 2 0.002427184 Glebula rotundata Rounded Pearlshell 2 0.002427184 Megalonaias nervosa Washboard 1 0.001213592 Reginaia ebenus Ebony Shell 1 0.001213592 Toxolasma parvum Lilliput 1 0.001213592 Total 824 1

Table 9. Pearl River watershed freshwater mussel data summary of Pearl River River south of the sill collected in the summer of 2018. Species Common Name Total count Relative Composition Quadrula nobilis Gulf Mapleleaf 1895 0.263670516 Cyclonaias refulgens Purple Pimpleback 1302 0.181160429 Glebula rotundata Rounded Pearlshell 1290 0.179490747 Quadrula apiculata Southern Mapleleaf 906 0.126060943 Potamilus purpuratus Bleufer 387 0.053847224 Obliquaria reflexa Threehorn Wartyback 357 0.049673021 Lampsilis teres Yellow Sandshell 343 0.047725059 Plectomerus Bankclimber 161 0.022401558 dombeyanus Tritogonia verrucosa Pistol Grip 111 0.015444553 Leptodea fragilis Fragile Papershell 89 0.01238347 Reginaia ebenus Ebony Shell 55 0.007652706 Villosa lienosa Little Spectaclecase 54 0.007513566 Pyganodon grandis Giant Floater 46 0.006400445 Arcidens confragosus Rock Pocketbook 37 0.005148184 Amblema plicata Three Ridge 26 0.003617643 Lampsilis straminea Southern Fatmucket 23 0.003200223 Pleurobema Mississippi Pigtoe 23 0.003200223 beadleianum Toxolasma parvum Texas Lilliput 18 0.002504522 Utterbackiana Cypress Floater 13 0.001808821 hartfieldorum Toxolasma texasiense Lilliput 12 0.001669681 Utterbackia imbecillis Pond Papershell 10 0.001391401 Fusconaia cerina Southern Pigtoe 9 0.001252261 Lampsilis ornata Southern Pocketbook 9 0.001252261 Megalonaias nervosa Washboard 5 0.000695701 Ligumia subrostrata Pondmussel 3 0.00041742 Elliptio crassidens Eleaphantear 2 0.00027828 Villosa vibex Southern Rainbow 1 0.00013914 Total 7187 1

Table 10. Pearl River watershed water quality data summary of all sample sites collected in the summer of 2018.

Water Flow (Feet Station Station Salinity Conductivity Turbidity DO Latitude Longitude Temp pH Per Code Name (ppt) (millimohs/cm2) (ntu) (mg/l) (degree C) Second)

5554 1 30.293 -89.6986 0.04 31.51 0.105 71.94 6.47 7.14 1 5555 2 30.307 -89.7045 0.04 31.71 0.104 . 6.74 7.22 0.6 5556 3 30.317 -89.6952 0.05 31.74 0.105 131.9 6.8 7.27 0.4 5557 4 30.322 -89.6954 0.05 31.74 0.11 108.7 6.9 7.29 0.6 5558 5 30.334 -89.7084 0.05 32.16 0.1 64.5 6.94 7.23 0.4 5559 6 30.363 -89.7188 0.05 31.19 0.11 160.51 7.29 7.39 0.2 5519 7 30.365 -89.7224 0.05 31.41 0.11 88.8 6.86 7.24 0.8 5560 8 30.404 -89.7433 0.04 31.72 0.1 179.76 7.5 7.63 0.2 5517 9 30.43 -89.7393 0.04 32.52 0.09 190.3 7.52 7.64 0.4 5561 10 30.443 -89.7497 0.04 31.99 0.1 86.4 6.83 7.36 0.8 5562 11 30.452 -89.7547 0.05 30.37 0.1 84.01 6.52 7.2 0.6 5534 12 30.466 -89.773 0.05 28.48 0.1 44.64 7.06 7.17 0.8 5563 13 30.469 -89.7789 0.04 33.32 0.1 40.33 9.61 9.01 0.6 5516 14 30.474 -89.7796 0.05 29.18 0.11 46.87 7.91 7.43 1.4 5564 15 30.495 -89.7572 0.05 7.36 0.11 101.59 6.79 7.36 0.6 5565 16 30.502 -89.8041 0.05 31.33 0.11 211.81 9.43 8.21 0.1 5533 17 30.507 -89.8001 0.05 30.84 0.11 87.2 7.8 7.13 0.8 5566 18 30.516 -89.7974 0.05 29.7 0.11 94.39 7.68 7.4 0.8 5520 19 30.519 -89.8038 0.05 30.86 0.11 60.52 8.21 7.54 1 5567 20 30.525 -89.8051 0.05 29.98 0.1 378.71 7.93 7.35 0.6 5568 21 30.537 -89.7735 0.06 29.69 0.12 59.67 7.24 7.46 0.2 5569 22 30.547 -89.7999 0.05 30.03 0.12 51.06 7.47 7.45 1 5532 23 30.55 -89.832 0.05 33.17 0.11 143.96 8.38 7.62 0.2 5570 24 30.552 -89.8343 0.05 33.17 0.11 120.75 7.4 7.62 1.1 5521 25 30.604 -89.8223 0.05 29.26 0.12 107.52 7.09 7.16 1.4 5571 26 30.606 -89.8202 0.05 29.32 0.12 197.17 5.87 7.08 0.6 5572 27 30.625 -89.822 0.05 29.66 0.11 75.95 6.23 7.17 0.3 5573 28 30.654 -89.8302 0.05 28.83 0.11 . 5.63 7.04 0.1 5522 29 30.725 -89.8395 0.03 26.65 0.08 . 6.49 6.93 0.4 5574 30 30.804 -89.8139 0.04 26.96 0.08 . 7.28 7.08 0.4 5575 31 30.808 -89.8021 0.04 27.29 0.08 87.54 7.68 7.24 0.6 5576 32 30.81 -89.7884 0.04 26.97 0.09 54.5 7.55 7.16 0.4 5577 33 30.821 -89.7818 0.04 29.55 0.09 110.1 9.01 7.8 0.2 5578 34 30.851 -89.7904 0.04 29.01 0.09 111.2 7.69 7.28 0.8 5579 35 30.886 -89.7739 0.04 28.98 0.09 388.3 7.58 7.11 0.2 5580 36 30.962 -89.7389 0.04 27.8 0.101 104.7 6.96 7.06 1.4 5581 37 30.993 -89.7281 0.04 27.73 0.102 63.83 7.08 7.1 0.4 5548 38 30.598 -89.8459 0.03 31.84 0.06 186.2 7.3 6.89 1 5547 39 30.611 -89.852 0.03 31.24 0.06 78.1 6.92 6.93 0.8 5524 40 30.622 -89.8773 0.02 30.7 0.45 68.6 7.18 6.9 0.4 5582 41 30.629 -89.9094 0.02 30.53 0.46 304.1 7.29 6.77 0.2 5583 42 30.639 -89.9625 0.019 30.33 0.044 19.35 7.11 7.32 0.2 5584 43 30.665 -89.9904 0.019 28.96 0.044 32.28 7.03 6.89 0.2 5585 44 30.662 -89.9972 0.019 29.23 0.044 37.83 7.16 6.84 0.8 5586 45 30.674 -90.0198 0.019 29.15 0.043 62.23 7.15 6.55 0.4 5587 46 30.698 -90.0648 0.02 27.97 0.042 58.09 6.47 6.42 0.4 5588 47 30.731 -90.1061 0.02 29.44 0.045 106.77 7.68 7.06 0.1 5589 48 30.748 -90.1214 0.02 28.92 0.045 17.05 7.63 7.14 1.2 5590 49 30.761 -90.1369 0.02 29.21 0.045 20.8 7.48 6.8 1 5591 50 30.95 -90.2041 0.02 27.95 0.046 29.43 7.93 7.16 0.2