Freshwater mussel records collected by the Maryland Department of ...

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In 2009, E. complanata remained the most frequently encountered mussel; collected at 44 sites (Table 1). Since 1995, they have been collected 251 times from 209 sites, a distribution spanning 46, 8-digit watersheds in Maryland (Figure 7); most of these observations were made in the Chester River basin. Five confirmed host fishes were common to very frequent at sites with E. complanata (Table 3). Anguilla rostrata was found at nearly every site where E. complanata was also present. Other documented, but uncommon host fishes were represented primarily by non-native and migratory species. Congenerics of confirmed host fish and hosts of congeneric mussels were rarely collected. The distribution and means of nearly every environmental variable examined was different between sites of E. complanata presence (N = 97) and absence (N = 187) (Figure 8). Means of 12 water chemistry variables were higher at sites with E. complanata than sites without. The conditions documented in those variables were also much lower at sites where E. complanata was absent. Conversely, much of the observed dissolved oxygen and chloride concentrations at sites with E. complanata fell within a narrow range compared to the concentrations at sites without. Scores of habitat metrics at sites they were present usually ranged from marginal to optimal and were higher than habitat scores at sites where they were absent. Furthermore, biological index scores were rarely
Table 3. Frequency of occurrence for fishes collected at sites throughout the range of E. complanata (EC) in Maryland. Non-native fishes are indicated with an asterisk (*). Confirmed fish hosts Frequency of occurrence EC Present N=194 EC Absent N=547 Anguilla rostrata American eel 0.92 0.49 Fundulus diaphanus Banded killifish 0.06 0.04 Lepomis auritus Redbreast sunfish 0.63 0.31 Lepomis cyanellus* Green sunfish 0.25 0.23 Lepomis gibbosus Pumpkinssed 0.71 0.34 Lepomis macrochirus* Bluegill 0.69 0.49 Micropterus dolomieu* Smallmouth bass 0.07 0.08 Micropterus salmoides* Largemouth bass 0.46 0.22 Morone americana White perch 0.02 0.00 Perca flavescens Yellow perch 0.17 0.03 Pomoxis annularis* White crappie 0.01 0.00 Congenerics of confirmed fish hosts Lepomis microlophus* Redear sunfish 0.01 0.00 Morone saxatalis Striped bass 0.01 0.00 Pomoxis nigromaculatus* Black crappie 0.06 0.03 Confirmed fish hosts of congeneric mussels Etheostoma nigrum Johnny darter 0.00 0.00 Gambusia holbrooki Eastern mosquitofish 0.10 0.06 Dorosoma cepedanium Gizzard shad 0.02 0.01 19
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Page 6 and 7: List of Figures Figure Number Page
Page 8 and 9: List of Tables Table Number Page 1.
Page 11 and 12: INTRODUCTION The diversity of fresh
Page 13 and 14: species richness, host abundance, a
Page 15 and 16: Table 1. Number of sites sampled by
Page 17 and 18: Table 2. Frequency of occurrence fo
Page 19 and 20: Figure 3. continued A P A P A P p =
Page 21 and 22: Figure 3. continued A P A P A P 0 5
Page 23 and 24: Since 2007, A. undulata Say 1817 ha
Page 25: Anodonta implicata Say 1829 was enc
Page 29 and 30: Figure 8. continued A P A P A P p =
Page 31 and 32: Figure 8. continued A P A P A P 0 5
Page 33 and 34: In 2009, E. fisheriana was collecte
Page 35 and 36: Figure 10. Box-and-whisker plots of
Page 37 and 38: Figure 10. continued. A P A P A P 0
Page 39 and 40: Figure 10. continued A P A P A P 0
Page 41 and 42: Elliptio producta Conrad 1836 has p
Page 43 and 44: Lampsilis radiata radiata Gmelin 17
Page 45 and 46: Leptodea ochracea Say 1817 has been
Page 47 and 48: Pyganodon cataracta had previously
Page 49 and 50: Figure 19. Box-and-whisker plots of
Page 55 and 56: Corbicula fluminea is a non-native
Page 57 and 58: (Black 2001, Wang 2007b). A lack of
Page 59 and 60: Maryland (Cummings and Watters 2009
Page 61 and 62: REFERENCES Allan, J.D., & A.S. Flec
Page 63 and 64: Kelly, M.W., & J.M. Rhymer. 2005. P
Page 65 and 66: ——. 1999a. Effects of alien spe
Page 67 and 68: Young, D. 1911. The implantation of
Page 70 and 71: 8-digit watershed Number 8-digit wa

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