Southeastern Naturalist 85 C.B. Eads, J.E. Price, and J.F. Levine 22001155 SOUTHEASTERN NATURALIST Vo1l4.( 114):,8 N5–o9. 71 Fish Hosts of Four Freshwater Mussel Species in the Broad River, South Carolina Chris B. Eads1, Jennifer E. Price2, and Jay F. Levine1,* Abstract - Freshwater mussel distributions are heavily reliant upon the range and movement of host fishes and are subject to range restrictions when fish migration is blocked. The Columbia Dam on the Broad River in Columbia, SC, has been a barrier to the migration of anadromous species and other fish in the river since 1824. As a result, 5 freshwater mussel species are restricted to reaches of the river downstream of the dam. In 2006, a fish passage was created to facilitate fish movement between stream reaches above and below the dam. Fish hosts that use the passage could facilitate the recolonization of reaches above the dam by freshwater mussels. We conducted laboratory trials to determine the fish hosts of 4 of the species limited to reaches below the dam. The most suitable hosts for Lampsilis cariosa (Yellow Lampmussel) were Morone chrysops (White Bass), Morone saxatilis (Striped Bass), and Pomoxis nigromaculatus (Black Crappie), whereas Micropterus salmoides (Largemouth Bass) and Micropterus dolomieu (Smallmouth Bass) transformed fewer juvenile mussels. Lampsilis siliquoidea (Fatmucket) hosts were Largemouth Bass and Perca flavescens (Yellow Perch). Yellow Perch, Largemouth Bass, Lepomis macrochirus (Bluegill), and Lepomis gibossus (Pumpkinseed) were the best hosts for Ligumia nasuta (Eastern Pondmussel). We suspected that Elliptio roanokensis (Roanoke Slabshell) used anadromous fishes as hosts because its distribution is limited to mainstem rivers below the downstreammost dam. We confirmed that 2 Clupeidae, Dorosoma cepedianum (Gizzard Shad) and Alosa aestivalis (Blueback Herring), and 1 Moronidae, Morone americana (White Perch), are hosts for Roanoke Slabshell. Many of the host-fish species identified in this study are highly mobile, and we expect the range of these mussels to eventually expand upstream of the Columbia Dam as fish make use of the new passage. Introduction Freshwater mussels (Unionidae) have a unique lifecycle in which their larvae (glochidia) must attach to a host (usually a fish) to metamorphose into their next life stage (McMahon 1991). This requirement makes freshwater mussels especially susceptible to environmental alterations because their habitat must support the adult mussels, which are sessile, benthic filter-feeders, as well as their free-swimming fish hosts to successfully reproduce. Fish are the mollusks’ primary means of dispersal and facilitate colonization of new habitats by freshwater mussels (Strayer 2008). When physical barriers such as dams block fish migrations, upstream mussel dispersal is also blocked (Brainwood et al. 2008, Dean et al. 2002, Fritts et al. 2012, Locke et al. 2003, Watters 1996). 1North Carolina State University, College of Veterinary Medicine, Raleigh, NC 27607. 2John Tyler Community College, 800 Charter Colony Parkway, Midlothian, VA 23114- 4383. *Corresponding author - jay_levine@ncsu.edu. Manuscript Editor: Arthur Bogan Southeastern Naturalist C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 86 On the Broad River in Columbia, SC, a diversion dam and its associated Columbia Canal were completed in 1824 (National Register Information System 2014). Since that time, the dam has blocked freshwater mussel and fish migration in the river causing changes in mussel assemblages upstream and downstream of the dam (Price et al. 2009). Price and coworkers (2009) found 8 species of mussels immediately downstream of the dam, including Lampsilis cariosa (Say) (Yellow Lampmussel), Lampsilis radiata (Gmelin) (Eastern Lampmussel), Ligumia nasuta (Say) (Eastern Pondmussel), Villosa delumbis (Conrad) Eastern Creekshell, Elliptio roanokensis (I. Lea) (Roanoke Slabshell), Elliptio complanata (Lightfoot) (Eastern Elliptio), Elliptio congaraea (I. Lea) (Carolina Slabshell), and Elliptio angustata (I. Lea) (Carolina Lance). The same study detected only 4 species in the Broad River upstream of the dam: Eastern Creekshell, Eastern Elliptio, Carolina Lance, and Uniomerus carolinianus (Bosc) (Florida Pondhorn). In 2006, the city of Columbia, SC, constructed a fishway on the dam to facilitate the passage of anadromous fish such as Alosa sapidissima (Wilson) (American Shad) and Morone saxatilis (Walbaum) (Striped Bass). Freshwater mussel populations should have also benefited from this fishway, which may have facilitated dispersal upstream on fish hosts. However, little is known about the host fishes of mussels limited to reaches downstream of the dam. Tedla and Fernando (1969) and Wick (2006) studied the hosts of Yellow Lampmussel and Eastern Lampmussel at the northern part of the species’ range, but hosts for the remaining species are unknown. The Yellow Lampmussel ranges from the Ogeechee River Basin in Georgia north to Nova Scotia and Cape Breton Island and westward into the St. Lawrence River Basin to the lower Ottawa and Madawaska River Basins (Johnson 1970). Morone americana (Gmelin) (White Perch) and Perca flavescens (Mitchill) (Yellow Perch) were previously shown to serve as hosts for Yellow Lampmussels in the laboratory (Wick 2006), and wild White Perch were also found to be a common host in Maine (Kneeland and Rhymer 2008). Eastern Lampmussels are found from the Pee Dee River in South Carolina, north to the St. Lawrence River Basin and west to Lake Ontario (Johnson 1970). Yellow Perch serve as hosts for the Eastern Lampmussel in the wild. Eastern Pondmussel occurs from the Savannah River in South Carolina, north to the St. Lawrence River basin and westward through the Mohawk River, Erie Canal, and Lake Erie (Johnson 1970). The host fish of this species was unknown prior to our study (Bogan and Alderman 2004). The range of the Roanoke Slabshell has been reported to extend from the Savannah River in Georgia, to several watersheds in Virginia (Williams et al. 1993). Nothing was known about the host requirements of Roanoke Slabshell, but because it is generally limited to mainstem rivers below the downstream-most dam on a system, we believed it might use an anadromous fish as its host. Dams reduce hydrologic and habitat variability (McManamay et al. 2012) and can geographically isolate fish and mussel populations (Brainwood et al. 2008, Dean et al. 2002, Fritts et al. 2012, Locke et al. 2003, Watters 1996). Impoundments are detrimental to many mussel species (Blalock and Sickel 1996, Vaughan and Taylor 1999), and altered flow regimes and habitat can impact mussel populations Southeastern Naturalist 87 C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 downstream of dams (Vaughan and Taylor 1999). Dam removal and construction of fish passages can potentially mitigate these alternations to stream habitat and fauna (Lenhart 2010). However, the process of dam removal can be detrimental to remaining mussel populations (Sethi et. al. 2004), and may benefit or harm fish populations, thus affecting mussel species that rely on them as hosts (Sethi et. al. 2004). The hosts of many imperiled mussel species are unknown or poorly described (Watters 1996). As part of a project to evaluate the fish passage constructed in Columbia, SC, and its potential benefits to freshwater mussels, we conducted laboratory host-trials on 4 mussel species currently found only downstream of the dam—Yellow Lampmussel, Eastern Lampmussel, Eastern Pondmussel, and Roanoke Slabshell)—to determine which fish species in the Broad River would potentially serve as hosts. Methods In the spring of 2007, we collected gravid Yellow Lampmussel, Eastern Lampmussel, Eastern Pondshell, and Roanoke Slabshell from the Broad River near Columbia, SC. We collected most host fish by boat electrofishing in the Congaree River or backpack-electrofishing in Crane Creek near Columbia, SC; Anguilla rostrata (Lesueur) (American Eel) were collected by boat electrofishing in the canal between Lake Moultrie and the Santee River in Berkeley County, SC. We purchased Alosa aestivalis (Mitchill) (Blueback Herring) from a bait store in Columbia, SC, and all Yellow Perch tested were collected by angling in Jordan Lake (Cape Fear River Basin) in Chatham County, NC. We transported all fish to the Aquatic Epidemiology and Conservation Laboratory at North Carolina State University in Raleigh, NC, in aerated coolers of ambient water and slowly acclimated them to laboratory conditions. Because some of the fish species tested for Eastern Pondmussel and Roanoke Slabshell were difficult to maintain in laboratory conditions, we infested host fish with those species within 5 days of bringing the fish into the laboratory. Additionally, the timing of brood release from short-term brooders such as Roanoke Slabshell was more difficult to control compared to long-term brooders, so we had to initiate that trial upon glochidial release from available females. Fish exposed to Yellow Lampmussel and Eastern Lampmussel were held for 6 weeks prior to the initiation of the host trial to ensure that any attached glochidia from the wild would transform prior to the laboratory exposure. We extracted glochidia from Yellow Lampmussel (1 individual), Eastern Lampmussel (2 individuals), and Eastern Pondmussel (2 individuals) by flushing their marsupia with a water-filled syringe. Gravid Roanoke Slabshells were held individually in 8-liter containers of laboratory water at 20–22 °C and monitored daily for released glochidia. The Roanoke Slabshell trial was initiated when a single female released a brood that consisted primarily of fertilized and actively snapping glochidia. Glochidia were loose and had little to no associated mucous. For Eastern Pondmussel and Roanoke Slabshell trials, we anesthetized all fish ≥20 cm total length with tricaine methanosulfate (MS-222), and pipetted glochidia onto left and right gill arches until adequate attachment was observed after rinsing the Southeastern Naturalist C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 88 gills gently with conditioned water. Direct application was necessary because there were not sufficient glochidia available to suspend them at adequate concentrations in a tank large enough to comfortably hold and infest all the larger fish tested for these species. We infected other fish by placing them together for 10–30 minutes in a vigorously aerated bath of glochidia (2000–4000 glochidia/liter) from the species being tested. We monitored the fish for glochidial attachment, after which we separated all fish by species, transferred them to individual aquaria of various sizes maintained at 20–24 °C. All fish were held individually except for Blueback Herring, which were held as a group of 25 fish in a single oval 370-liter tank; 12 of those individuals survived to the end of the trial. We routinely monitored the tanks for transformed juvenile mussels by siphoning the bottom of the tank through a 105-μm sieve. Time and personnel constraints prevented us from monitoring sloughed glochidia. We identified juvenile mussels either by foot movement or the presence of adductor muscles. We ended the trial when we no longer found juvenile mussels in the aquaria. We tested 11 fish species representing 4 families as potential hosts for Yellow Lampmussel (Table 1) and 10 species from the same 4 families as potential hosts for Eastern Lampmussel (Table 2). Because Lampsilis spp. use mantle lures for host-fish attraction (Haag and Warren 1999, Zanatta and Murphy 2006), we focused primarily on more piscivorous fish as test subjects for these mussel species. We tested 21 fish species representing 7 families as hosts for Eastern Pondshell (Table 3) and 20 species from 8 different families as hosts for Roanoke Slabshell (Tables 4, 5). Results We recovered Yellow Lampmussel juveniles from 7 of the 11 fish species tested, but there was substantial variation among fish species in the number of juveniles Table 1. Results of fish-host trial with Lampsilis cariosa. Mean # juveniles/ Common name Scientific name # fish tested fish (range) Anguillidae American Eel Anguilla rostrata 2 0.0 Centrarchidae Redbreast Sunfish Lepomis auritus 2 0.0 Bluegill Lepomis macrochirus 2 1.0 (0–2) Redear Sunfish Lepomis microlophus (Günther) 2 0.0 Smallmouth Bass Micropterus dolomieu 2 60.5 (57–64) Largemouth Bass Micropterus salmoides 3 156.7 (0–423) Black Crappie Pomoxis nigromaculatus 1 816.0 Moronidae White Perch Morone americana 2 Died White Bass Morone chrysops 1 1276.0 Striped Bass Morone saxatilis 1 4079.0 Percidae Yellow Perch Perca flavescens 2 0.5 (0–1) Southeastern Naturalist 89 C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 Table 2. Results of fish-host-trial with Lampsilis radiata. # juveniles / Common name Scientific name # fish tested fish (range) Anguillidae American Eel Anguilla rostrata 1 0.0 Centrarchidae Redbreast Sunfish Lepomis auritus 2 0.0 Bluegill Lepomis macrochirus 2 1.0 Redear Sunfish Lepomis microlophus 3 0.0 Smallmouth Bass Micropterus dolomieu 1 0.0 Largemouth Bass Micropterus salmoides 2 415.5 (314–517) Black Crappie Pomoxis nigromaculatus 1 Died Moronidae White Perch Morone americana 2 Died Striped Bass Morone saxatilis 2 1.0 (0–2) Percidae Yellow Perch Perca flavescens 2 333.0 (242–424) Table 3. Results of fish-host trial with Ligumia nasuta. # juveniles / Common name Scientific name # fish tested fish (range) Anguillidae American Eel Anguilla rostrata 2 0.0 Catostomidae Quillback Carpiodes cyprinus (Lesueur) 1 0.0 Northern Hogsucker Hypentelium nigricans (Lesueur) 1 0.0 Spotted Sucker Minytrema melanops (Rafinesque) 1 0.0 Shorthead Redhorse Moxostoma macrolepidotum (Lesueur) 1 0.0 Centrarchidae Redbreast Sunfish Lepomis auritus 5 9.0 (1–28) Pumpkinseed Lepomis gibbosus 1 78.0 Bluegill Lepomis macrochirus 3 172.3 (91–335) Redear Sunfish Lepomis microlophus (Günther) 2 2.0 (0–4) Largemouth Bass Micropterus salmoides 1 91.0 Cyprinidae Whitefin Shiner Cyprinella nivea (Cope) 3 0.0 Spottail Shiner Notropis hudsonius (Clinton) 4 0.0 Coastal Shiner Notropis petersoni (Fowler) 3 0.0 Ictaluridae Flat Bullhead Ameiurus platycephalus (Girard) 1 0.0 Channel Catfish Ictalurus punctatus (Rafinesque) 1 0.0 Flathead Catfish Pylodictis olivaris (Rafinesque) 1 0.0 Moronidae White Perch Morone americana 1 0.0 Striped Bass Morone saxatilis 1 0.0 Percidae Tessellated Darter Etheostoma olmstedi (Storer) 3 0.0 Yellow Perch Perca flavescens 2 301.0 (258–344) Piedmont Darter Percina crassa (Jordan and Brayton) 2 0.0 Southeastern Naturalist C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 90 detected (Table 1). Morone chrysops (Rafinesque) (White Bass) and Striped Bass yielded the highest number of juveniles. Juvenile mussels were obtained from 5 other species. Transformation was lower and variable on centrachid species, with Pomoxis nigromaculatus (Lesueur) (Black Crappie) and Micropterus sp. harboring the most juveniles. Transformation on Lepomis sp. and Yellow perch was low and inconsistent (Table 1). Juvenile mussels remained attached to viable hosts for 14–22 days with a peak drop-off between days 16 and 18 for all host species. We recovered Eastern Lampmussel juveniles from 4 of the 10 fish species tested (Table 2). Micropterus salmoides (Lacépède) (Largemouth Bass) and Yellow Perch produced the most juveniles. Of the centrachids evaluated, we recovered only one juvenile from a Lepomis macrochirus Rafinesque (Bluegill); only 1 of 4 percids yielded juveniles. Juvenile mussels remained encysted on viable hosts for 14–26 days with no noticeable differences between host species. Peak excystment for all hosts came between days 18 and 22. Table 4. Results of fish-host trial with Elliptio roanokensis. All Blueback Herring were maintained in a single tank. Mean # juveniles/ Common name Scientific name # fish tested fish (range) Anguillidae American Eel Anguilla rostrata 1 0.0 Catostomidae Quillback Carpiodes cyprinus 2 0.0 Northern Hogsucker Hypentelium nigricans 1 Died Spotted Sucker Minytrema melanops 1 0.0 Notchlip Redhorse Moxostoma collapsum (Cope) 1 0.0 Shorthead Redhorse Moxostoma macrolepidotum 1 0.0 Centrarchidae Redbreast Sunfish Lepomis auritus 2 0.0 Bluegill Lepomis macrochirus 1 0.0 Redear Sunfish Lepomis microlophus 2 0.0 Largemouth Bass Micropterus salmoides 2 0.0 Smallmouth Bass Micropterus dolomieu 2 0.0 Black Crappie Pomoxis nigromaculatus 1 0.0 Clupeidae Blueback Herring Alosa aestivalis 10 30.4 Gizzard Shad Dorosoma cepedianum 2 22.0 (20–24) Cyprinidae Whitefin Shiner Cyprinella nivea 3 0.0 Ictaluridae Channel Catfish Ictalurus punctatus 1 0.0 Flathead Catfish Pylodictis olivaris 1 0.0 Moronidae White Perch Morone americana 2 17.5 (0–35) Striped Bass Morone saxatilis 1 0.0 Percidae Yellow Perch Perca flavescens 1 0.0 Southeastern Naturalist 91 C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 We recovered transformed Eastern Pondmussel juveniles from 6 of the 21 fish species tested (Table 3). Yellow Perch yielded the most juveniles overall. Lepomis gibbosus (L.) (Pumpkinseed), Bluegill, and Largemouth Bass as well as several other centrachids were also relatively good hosts. The duration of glochidial attachment on host fish ranged from 15–24 days. Excystment from Lepomis auritus L. (Redbreast Sunfish) was completed by day 17 on 4 of the 5 individuals tested, but other more efficient hosts had peak excystment of juveniles between days 20 and Table 5. Results of fish-host trial with Elliptio roanokensis. # juveniles Common name Scientific name Replicate produced Anguillidae American Eel Anguilla rostrata A 0 Catostomidae Quillback Carpiodes cyprinus A 0 Quillback Carpiodes cyprinus B 0 Northern Hogsucker Hypentelium nigricans A Died Spotted Sucker Minytrema melanops A 0 Notchlip Redhorse Moxostoma collapsum A 0 Shorthead Redhorse Moxostoma macrolepidotum A 0 Centrarchidae Redbreast Sunfish Lepomis auritus A 0 Redbreast Sunfish Lepomis auritus B 0 Bluegill Lepomis macrochirus A 0 Redear Sunfish Lepomis microlophus A 0 Redear Sunfish Lepomis microlophus B 0 Largemouth Bass Micropterus salmoides A 0 Largemouth Bass Micropterus salmoides B 0 Smallmouth Bass Micropterus dolomieu A 0 Smallmouth Bass Micropterus dolomieu B 0 Black Crappie Pomoxis nigromaculatus A 0 Clupeidae Blueback Herring Alosa aestivalis 12 304 Gizzard Shad Dorosoma cepedianum A 24 Gizzard Shad Dorosoma cepedianum B 20 Cyprinidae Whitefin Shiner Cyprinella nivea A 0 Whitefin Shiner Cyprinella nivea B 0 Whitefin Shiner Cyprinella nivea C 0 Ictaluridae Channel Catfish Ictalurus punctatus A 0 Flathead Catfish Pylodictis olivaris A 0 Moronidae White Perch Morone americana A 0 White Perch Morone americana B 35 Striped Bass Morone saxatilis A 0 Percidae Yellow Perch Perca flavescens A 0 Southeastern Naturalist C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 92 22. There was no noticeable difference in transformation time between the more viable host species. Transformed Roanoke Slabshell juveniles were recovered from only 3 of the 20 fish species tested. Two Clupeidae species, Blueback Herring and Dorosoma cepedianum (Lesueur) (Gizzard Shad) were hosts, and 1 of the 2 White Perch evaluated also facilitated transformation (Table 5). Juveniles remained encysted on hosts for 10–16 days with no noticeable difference between host species. Discussion The unique double-edged relationship between freshwater mussels and their fish hosts necessitates that conservationists carefully consider both the health and well being of host fish and mussel populations when making conservation decisions. Dam removal or the creation of a fish passage has intuitive benefits to freshwater mussel-population health; however, any construction activity within a stream or riparian areas poses a risk to remaining populations (Sethi et al. 2004, Vaughn and Taylor 1999). A working knowledge of the fish-hosts required to sustain an individual species of mussel is needed to understand the potential benefit or hazards posed by dam removal or fish-passage construction. The Columbia Dam fish passage was constructed in 2006, and planned assessments of fish and mussel distribution and diversity prompted these host-fish trials. The hosts we observed to be most effective for Yellow Lampmussel—White Bass, Striped Bass, and Black Crappie—had not been previously reported in the literature. White Perch have been shown to be effective hosts for this species at the northern end of its range both in the laboratory (Wick 2006) and in the wild (Kneeland and Rhymer 2008) but did not survive to the end of the encystment period in our trial. Because its congeners White Bass and Striped Bass were robust hosts in our trials, we suspect White Perch may also be effective hosts in the Broad River. In contrast, Wick (2006) found Yellow Perch to be effective hosts for Yellow Lampmussel in Maine, but the 2 Yellow Perch we tested yielded only a single juvenile between them. This freshwater mussel exhibits a relatively high degree of genetic divergence among populations in the formerly glaciated northern end of its range (Kelly and Rhymer 2005). The variability in host efficacy we observed between individual Largemouth Bass has been observed in other mussel–host-fish relationships (Eads et al. 2010, Haag and Warren 1997). Fish develop an immune response to repeated challenges with glochidia (Rogers and Dimock 2003). We may have tested an individual fish that had been previously exposed to glochidia and had become immune (Watters and O’Dee 1996). When possible, to prevent using a fish that has become immune to glochidial attachment, fish used in laboratory host-trials should be collected from places where no mussels exist. However, fish should be collected from the same basin as the mussels whenever possible because fish from the same basin have been shown to serve as more efficient hosts of some mussel species (Rogers et al. 2001). Largemouth Bass and Yellow Perch were strong hosts for Eastern Lampmussel. Largemouth Bass commonly serve as hosts for mussels of the genus Lampsilis Southeastern Naturalist 93 C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 (Haag and Warren 1997, Johnson et al. 2012, Keller and Ruessler 1997). Yellow Perch have been identified as hosts for Eastern Lampmussel in the wild at the northern end of its range (Kneeland and Rhymer 2008, Tedla and Fernando 1969). Kneeland and Rhymer (2008) also found glochidia from this species on a single Pumpkinseed in the wild but could not confirm whether it facilitated transformation. We did not test Pumpkinseed, but no other Lepomis was a suitable host. Hanek and Fernando (1978) reported L. radiata glochidia attached to Pumpkinseed and Ambloplites rupestris (Rafinesque) (Rock Bass) but did not indicate whether it was L. r. radiata (Gmelin) (Eastern Lampmussel) or L. r. siliquoidea (Barnes) (Fatmucket), which they considered to be subspecies at the time. Trdan (1981) reviewed Tedla and Fernando (1969) when he conducted additional life-history work on the Fatmucket and speculated that “the Yellow Perch is one of only a few species of fish that can serve as a host” for Eastern Lampmussel. To our knowledge, little research has been conducted on the early life history of Eastern Pondmussel (Bogan and Alderman 2004), but we found Yellow Perch to be a robust host for this species. We suspect that with its tendency to serve as a host for the mantle-luring Eastern Lampmussel in the wild (Kneeland and Rhymer 2008, Tedla and Fernando 1969), Yellow Perch would likely also be attracted to the lure of Eastern Pondmussel. Juveniles also successfully transformed on Bluegill and several other centrachids. Corey and coworkers (2006) found that Largemouth Bass and Pumpkinseed attacked the lure of Eastern Pondmussel, but Bluegill and Luxilus cornutus (Mitchill) (Common Shiner) responded poorly to its lure in research under controlled conditions. This finding suggests that Bluegills may be poor hosts in nature even though they are suitable laboratory hosts. However, wild Bluegills may behave differently and be more attracted to the lure under natural conditions. The other two species that were attracted to the lure in the study by Corey et al. (2006) also served as hosts in our laboratory study. Differences in the outcomes of laboratory and field studies reflect the need for caution in making extrapolations from laboratory studies. Hosts selected to propagate juveniles in the laboratory due to success of transformation or availability (e.g., hatchery) may not be sympatric with native species or play any role in their natural life-history. As we expected, our results supported the idea that Roanoke Slabshell uses one or more anadromous clupeids as hosts. Because of their sensitivity to capture, transport, and holding (Chittenden 1971), we were unable to maintain and test Alosa sapidissima Wilson (American Shad) or A. mediocris (Mitchill) (Hickory Shad). However, we confirmed that 2 other Clupeids served as viable hosts in the laboratory. For a fish species to be an efficient mussel host in the wild, the timing of their spawning runs would have to coincide with release of Roanoke Slabshell glochidia. Roanoke Slabshells were found to be gravid from late March to June in the Broad River, but the majority were gravid in late March and mid-April at water temperatures of 14–18 °C (Price and Eads 2011). Typical spawning temperatures reported for Clupeids are 11–14 °C for Hickory Shad (Harris 2010), 12.5–15.5 °C for Alosa pseudoharengus (Wilson) (Alewife) (Bigelow and Schroeder 1953), 14–22°C for Blueback Herring (O’Connell and Angermeier 1999), Southeastern Naturalist C.B. Eads, J.E. Price, and J.F. Levine 2015 Vol. 14, No. 1 94 and 13–20 °C for American Shad (Walburg and Nichols 1967). This timing suggests the later-spawning Blueback Herring and American Shad are likely hosts in the wild. Sampling for naturally infested fish during spawning runs is needed to identify their role as E. roanokensis hosts. White Perch were present above the Columbia Dam prior to the construction of the fish passage (Bettinger et al. 2003). Only 1 of 2 White Perch evaluated supported the transformation of juveniles. The other fish was collected from the Congaree River where Roanoke Slabshell is relatively common, and may have had prior exposure and was immune to glochidial attachment. This semianadromous fish species makes late-winter to early spring spawning runs up coastal rivers (Mansueti 1961) and may be most plentiful in coastal rivers when Roanoke Slabshell is releasing glochidia. Additional studies are needed to further evaluate White Perch as a potential host for this mussel. Many of the hosts we identified in this study, especially the Moronidae and Clupeidae, are highly mobile and will likely benefit from fish passages including the one on the Columbia Dam (Davis et al. 1970, Mansueti 1961, Smith and Hightower 2013). Increased host-fish movement will likely enable mussel species currently restricted to reaches below the dam to colonize upstream habitats. Because of its apparent reliance on anadromous fish, Roanoke Slabshell should especially benefit from attempts to restore fish migration on coastal rivers through dam removal and construction of fish passages. Smith (1985) noted that the range expansion of Anodonta implicata (Say) (Alewife Floater) in the Connecticut River was likely due to the construction of fish passages which allowed their Clupeid host to move upstream. Likewise, efforts to expand mussel populations may also be beneficial to American Shad, the eggs of which were found developing inside 49 out of 757 freshwater mussels examined in the Altamaha River (Wisniewski et al. 2013). A majority of those eggs were found in Elliptio hopetonensis (I. Lea) (Altamaha Slabshell), a congener of Roanoke Slabshell. The mantle of the mussels seemed to provide a clean, well-oxygenated place for eggs to develop where the benthic habitat was otherwise silt-laden and inhospitable to them. The intertwined ecological relationship of freshwater mussels and their fish hosts stresses the need to manage coastal rivers for all native species and for fully functioning ecosystems. Acknowledgments We thank the US Fish and Wildlife Service and the South Carolina Department of Natural Resources for providing funding for this study. We also thank Art Bogan for his helpful editorial suggestions. Literature Cited Bettinger, J., J. Crane, and J. Bulak. 2003. Broad River aquatic resources-inventory completion report. South Carolina Department of Natural Resources, Columbia, SC. Bigelow, H.B., and W.C. Schroeder. 1953. Fishes of the Gulf of Maine. US Fish and Wildlife Service Fishery Bulletin 53. Reprinted 1964, Museum of Comparative Zoology, Harvard University, Cambridge, MA. Southeastern Naturalist 95 C.B. 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