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Recovery Strategy for the Wavyrayed Lampmussel (Lampsilis fasciola) in Canada (Final)

I. Background

Species Information

Scientific Name:  Lampsilis fasciola

Common Name:  Wavyrayed Lampmussel

Current COSEWIC Status & Year of Designation:  Endangered (1999)

Range in Canada (provinces and territories where found):  Ontario

Rationale for Status:  The Wavyrayed Lampmussel has declined significantly in recent years across its historical range. Its numbers have been reduced in Great Lakes waters by the zebra mussel while populations in the Thames, Sydenham and Ausable Rivers are disappearing or have been lost primarily as a result of agricultural impacts.


Global Range: In the United States, the Wavyrayed Lampmussel is considered nationally secure and currently occurs in Alabama, Indiana, Illinois, Kentucky, Michigan, New York, North Carolina, Pennsylvania, Tennessee, West Virginia and Virginia (Figure 2), however recent declines have been observed across its distribution (Parmalee and Bogan 1998). It historically occurred in Georgia and Ohio, but the status of the species in these states is currently unknown. In Canada the Wavyrayed Lampmussel is considered critically imperiled and occurs only in southwestern Ontario (Figure 3; Table 1) (Metcalfe-Smith et al. 2000).

Figure 2: North American distribution of the Wavyrayed Lampmussel (modified from Parmalee and Bogan 1998)
Figure 2: North American distribution of the Wavyrayed Lampmussel (modified from Parmalee and Bogan 1998)


Figure 3: Current and historic distribution of the Wavyrayed Lampmussel in Canada.

Canadian Range: The current Canadian distribution of the Wavyrayed Lampmussel is restricted to the upper Grand River and its tributaries (Metcalfe-Smith and McGoldrick 2003), the upper Thames River (T. Morris, Fisheries and Oceans, Burlington, unpublished data), all four branches of the Maitland River (Janice Metcalfe-Smith, NWRI, Burlington, pers. comm. October 2003), a small section of the Ausable River (Metcalfe-Smith and McGoldrick 2003) and the Canadian waters of the Lake St. Clair delta (Zanatta et al. 2002) (Figure 3).

Percent of Global Range in Canada: Less than 5% of the species' global distribution is found in Canada.

Distribution Trend: The range of the Wavyrayed Lampmussel has been significantly reduced as it has been extirpated from its historical range in the western basin of Lake Erie, the majority of Lake St. Clair, the Detroit River, and the Sydenham River. Distributions in the Ausable and Grand rivers have been reduced while the full extent of the historic range appears to still be occupied in the Thames River. The trend in the Maitland River can not be assessed since no historical surveys exist. The largest populations of this species occupy a 60 km stretch of the upper Grand River, a 45 km stretch of the Maitland River, 65 km in the upper Thames watershed divided between the North, Middle and South Thames Rivers and an area of approximately 12 km² in the Lake St. Clair Delta (Metcalfe-Smith and McGoldrick 2003).

Table 1: Canadian and U.S. national and provincial/state heritage status ranks (NatureServe 2004).
Canada (N1)ON (S1)
United States (N4)AL (S1S2), GA (S2?), IL (S2), IN (S2), KY (S4S5), MI (S2), NY (S1), NC (S1), OH (S?), PA (S4), TN (S4), VA (S4), WV (S2)

Population Abundance

Global Range: The Wavyrayed Lampmussel is globally secure (G4) but is an uncommon species throughout its range usually comprising less than 2% of the mussel community where it is found (Metcalfe-Smith and McGoldrick 2003).

Canadian Range: The Maitland River, upper reaches of the Grand River and the upper Thames River support the largest populations of this species in Canada while a smaller population exists in the Lake St. Clair delta. The Wavyrayed Lampmussel also occurs in the Ausable River but is represented only by large individuals with no evidence of successful reproduction. A single live specimen was found in a recent benthic survey at one location on the St. Clair River

Percent of Global Abundance in Canada: Less than 1%

Population Trend: The rate of population change for the Wavyrayed Lampmussel is unknown. The only stable population of this species in Canada occurs in the Upper Grand River while the status of the second largest population (Maitland R.) is unknown due to a lack of historical information. The Grand R. population appears to have recovered from the poor water quality conditions present in the 1970's and early 1980's. Overall densities of all mussel species in the St. Clair delta appear to be declining over time although the small numbers of Wavyrayed Lampmussels make it difficult to interpret results for this species specifically (Metcalfe-Smith et al. 2004). All other Canadian populations have declined sharply to only a few individuals or have been extirpated.

Biologically Limiting Factors

Reproductive Attributes

The Wavyrayed Lampmussel, like all unionids, has a complicated reproductive cycle characterized by a period of obligate parasitism. This parasitic phase makes the Wavyrayed Lampmussel particularly sensitive to external factors that may indirectly affect them via their hosts (Bogan 1993).

The Wavyrayed Lampmussel is a medium sized, moderately long-lived, sexually dimorphic species. During spawning season, males release sperm into the water column and females located downstream take in the sperm via their incurrent siphons. Females brood the young from egg to larval stage in the posterior portions of the outer gills. Distended shells which swell along the posterior-ventral margins to allow room for expanded gill pouches (Metcalfe-Smith et al. 2000) characterize mature female Wavyrayed Lampmussels. Wavyrayed Lampmussels are long-term brooders (bradytictic) with spawning occurring in August and glochidial release occurring the following year (May through August in Virginia (Zale and Neves 1982), June through August in Canada (Woolnough 2002)).

When the larvae are mature they are released by the female and must undergo a period of encystment on the gills of a suitable host. Two host species have been identified for the Wavyrayed Lampmussel in the U.S.. Zale and Neves (1982) reported successful laboratory infestations of smallmouth bass (Micropterus dolomieu) with Wavyrayed Lampmussel glochidia while G.T. Watters (Ohio State University, cited in Metcalfe-Smith et al. 2000) reported success with largemouth bass (M. salmoides). The largemouth bass and smallmouth bass have recently been confirmed as hosts for the Wavyrayed Lampmussel in Canada (McNichols et al. 2005). Researchers at the University of Guelph have also successfully infected mottled sculpin (Cottus bairdii) and brook stickleback (Culaea inconstans) with Wavyrayed Lampmussel glochidia although it is unclear whether these species functions as hosts under natural conditions (K. McNichols, University of Guelph, pers. comm., September 2003).

To increase the likelihood of encountering an appropriate host and facilitate successful encystment, female Wavyrayed Lampmussels have developed specialized mantle tissue to function as a lure (Strayer and Jirka 1997). Three co-occurring mantle lure morphologies have been observed on displaying female Wavyrayed Lampmussels during field surveys of the Grand, Thames, Ausable and Maitland Rivers. The three morphologies consist of a black lure, a bright red lure, and a fish-like lure (Figure 4). It is unknown if the three lure morphologies constitute sibling species or if they are ecomorphs. Molecular phylogenetic analysis is required to resolve this knowledge gap.

When a suitable host fish touches the mantle lure the mantle flaps are retracted into the shell, placing pressure on the marsupia and causing the release of the mature larvae (glochidia). The structure of the lure (e.g., eyespots and pigmentation consistent with a small minnow-shaped fish in the fish-like lure morph) and the method of glochidial release are consistent with a host species which is a visual predator. This indicates that water clarity likely plays a critical role in the successful completion of the reproductive cycle of the Wavyrayed Lampmussel.

Figure 4: Three lure morphologies of the Wavyrayed Lampmussel: black (a), red (b) and fish-like (c). All three animals were observed in the North Thames River during 2004. Photos courtesy of T. Morris, Fisheries and Oceans Canada.
Figure 4: Three lure morphologies of the Wavyrayed Lampmussel: black (a), red (b) and fish-like (c).  All three animals were observed in the North Thames River during 2004. Photos courtesy of T. Morris, Fisheries and Oceans Canada.


Adult Wavyrayed Lampmussels have very limited dispersal abilities. Although adult movement can be directed upstream or downstream, studies have found a net downstream movement through time (Balfour and Smock 1995; Villella et al. 2004). The primary means for large scale dispersal, upstream movement, and the invasion of new habitat or evasion of deteriorating habitat, is limited to the encysted glochidial stage on the host fish.


The Wavyrayed Lampmussel is subject to a broad array of threats across its range. The eight categories identified in Table 2 represent the most likely threats to Canadian populations of the Wavyrayed Lampmussel.

Table 2: Threats to the Wavyrayed Lampmussel
ThreatRelative Impact
probable/ speculative/ unknown
Siltation/Suspended solidspredominantwidespread / chronicprobable
Exoticspredominantlocal / chronicprobable
Impoundmentscontributinglocal / chronicprobable
Water Quality – contaminants & nutrientscontributingwidespread / chronicprobable
Disruption of host fish relationshipcontributinglocal / chronicspeculative
Predationcontributinglocal / ephemeralspeculative
Urbanizationcontributinglocal / chronicspeculative
Recreational activitycontributinglocal / ephemeralunknown

Siltation/Suspended Solids: High silt inputs can act to suffocate mussels by clogging gill structures and may also disrupt reproductive functions by decreasing the likelihood of encountering a suitable host fish (a visual predator). Susceptibility to siltation varies from species to species and the Wavyrayed Lampmussel has been shown to be mildly tolerant of high silt conditions during periods of low flow (Dennis 1984). However, recent studies in southern Ontario show that the Wavyrayed Lampmussel is associated with areas of low silt loads. Mean water clarity is higher in areas where Wavyrayed Lampmussels are found than in areas where they are not found and catch-per-unit-effort is positively correlated with water clarity (Metcalfe-Smith and McGoldrick 2003).

Exotics: Zebra mussels (Dreissena polymorpha) have decimated populations of freshwater mussels in the Lower Great Lakes by virtually eliminating historical habitats in Lake St. Clair (Nalepa et al. 1996) and western Lake Erie (Schloesser and Nalepa 1994). Although the Wavyrayed Lampmussel is primarily a riverine species, and therefore at lower risk to zebra mussel infestation, the presence of impoundments may increase the risk (see section on impoundments below). Zebra mussels pose a much greater risk for the St. Clair delta population: the last known lake population in Canada.

Other exotic species may indirectly affect the Wavyrayed Lampmussel by disrupting host fish relationships. For example, the mottled sculpin has shown recruitment failure and steep declines in abundance in the Great Lakes basin since the introduction of the exotic round goby (Neogobius melanostomus) (Dubs and Corkum 1996, Jannsen and Jude 2001).

Impoundments: Damming of the stream channel has been shown to detrimentally affect mussels in many ways. Reservoirs alter downstream flow patterns and disrupt the natural thermal profiles of the watercourse while impoundments act as physical barriers potentially separating mussels from their host fish. Impoundments also act to increase water retention times thereby making river systems more susceptible to invasion by exotics such as the zebra mussel. Reservoirs with retention times greater than 20-30 days allow enough time for veligers to settle and act as seed populations for downstream sites (Metcalfe-Smith et al. 2000). Zebra mussels were reported from the Fanshawe Reservoir (UTRCA 2003) and Springbank Reservoir (pers. comm., S. Hohn, UTRCA, June 2003) on the Thames River during 2003 (UTRCA 2003). At present, both of these zebra mussel infestations are downstream of most sections where Wavyrayed Lampmussels are found. Similar infestations, should they occur in Wildwood or Pittock reservoirs, higher up in the system could prove very harmful to the Wavyrayed Lampmussel populations in the North and South Thames. The Grand River is heavily impounded with 34 dams or weirs (GRCA 1998) and establishment of zebra mussels in the Luther, Belwood, Guelph, or Conestogo reservoirs could seriously impact the reach where the Wavyrayed Lampmussel is found.

Water Quality

Contaminants: Evidence suggests that mussels are sensitive to PCBs, DDT, Malathion and Rotenone that can inhibit respiration and accumulate in mussel tissue (USFWS 1994). PCBs have been detected in mussel tissue in the Middle Maitland River (pers. comm. D. Kenny, MVCA, July 2003). The glochidial stage appears to be particularly sensitive to heavy metals (Kellar and Zam 1990), ammonia (Goudreau et al. 1993; Mummert et al. 2003)), acidity (Huebner and Pynnonen 1992) and salinity (Liquori and Insler, as cited in USFWS 1994). While freshwater mussels, as a group, appear to be sensitive to poor water quality, two contaminants stand out as being particularly problematic. Recent research has shown that Lampsilis fasciola, and most freshwater mussel species tested, are among the most sensitive organisms to ammonia and copper (Mummert et al. 2003; Jacobsen et al. 1997; Ingersoll unpublished data). A comparison of the reported toxicity data for these two contaminants with Canadian water quality guidelines for the protection of aquatic life shows that current objectives for unionized ammonia are probably sufficient to protect L. fasciola (Table 3). On the other hand, the EC50 for copper reported by Ingersoll (unpublished data) falls within the range of the current objectives for the protection of aquatic life in Canadian waters. Considering that 50% of L. fasciola tested showed effects (reduced growth or death) at copper concentrations of ranging from less than 5 to 7 µg/L, the current objectives of 2-5 µg/L are unlikely to protect this species from harm. Copper levels exceed federal guidelines in several sub-basins of the Thames River in which the Wavyrayed Lampmussel is still found. Only the upper reaches of the Grand River have copper levels that fail to exceed the federal guidelines and these correspond to the only portions of the watershed where the Wavyrayed Lampmussel is found (Metcalfe-Smith et al. 2000). Copper levels exceed federal guidelines in the Middle Maitland River as well (pers. comm. D. Kenny, MVCA July 2003).

Table 3. Toxicity of ammonia and copper to the glochidia and juveniles of Lampsilis fasciola
ContaminantLife stage testedResultSourceWater Quality Guidelines

Unionized Ammonia





LC50 (mg/L):
24h : 0.28-0.36
48h : 0.21-0.24
72h : 0.21-0.24
96h : 0.21-0.25
Mummert at al. (2003)

CCMEa: 0.019 mg/L

PWQOb: 0.020 mg/L

Ammonia (Total)



48h EC50:
6 mg/L
10d EC50:
1.7 mg/L
Ingersoll (unpublished data)








24h LC50:
26-48 µg/L1
48h EC50:
7 µg/L2
72h EC50:
4.7 µg/L2
10d EC50:
4.8 µg/L2
1Jacobsen et al. (1997)
2Ingersoll (unpublished data)

CCME: 2-4 µg/L

PWQO: 5 µg/L

a Canadian Council of Ministers of the Environment (CCME 2005)
b Ontario Provincial Water Quality Objectives (PWQO 2005)

Nutrients: The primary land use in the Ausable and Sydenham River basins is agriculture. Row crops (corn, beans) predominate in the Ausable River watershed while cash crops dominate the Sydenham River watershed (Nelson 2000). Water quality in the Ausable River is generally considered poor resulting from agricultural runoff and manure seepage (ABCA 1995, ARRT 2003). In the Grand River, clearing of riparian vegetation and allowing livestock to access the river has resulted in poor water quality with increased sediment loads (WQB 1989a). Agricultural activity is expected to increase in the Grand River basin over the next 25 years leading to a predicted increase in sediment, pesticide, fertilizer, and manure runoff. Water quality in the Thames River basin has historically suffered greatly from agricultural activities. Tile drainage, wastewater drains, manure storage and spreading, and insufficient soil conservation have all contributed to poor water quality within the Thames basin (Metcalfe-Smith et al. 2000). Phosphorus and nitrogen loadings have increased steadily and some of the highest livestock loadings for the entire Great Lakes basin have been reported for the Thames River watershed (WQB 1989b). Mean ammonia concentrations in all sub-basins of the Thames River exceed the federal freshwater aquatic life guidelines (Metcalfe-Smith et al. 2000). It has recently been reported that juvenile freshwater mussels are among the most sensitive aquatic organisms to unionized ammonia toxicity, typically showing adverse responses at levels well below those used as guidelines for aquatic safety in U.S. waterways (Newton 2003; Newton et al. 2003). The recently discovered Maitland River population faces threats from agricultural run-off with 75% of nitrate samples on the Middle Maitland exceeding the federal guidelines for negatively impacting aquatic health while 56% of total phosphorus levels exceed those indicating a high likelihood of algal blooms (pers. comm. D. Kenny, MVCA, July 2003).

Disruption of Host Fish Relationship: Any factors that directly or indirectly affect host fish distributions will impact Wavyrayed Lampmussel distributions. mallmouth bass, the likely host species, are very rare in the Sydenham River system (M. Poos, University of Guelph, cited in Metcalfe-Smith and McGoldrick 2003) which may explain the disappearance of Wavyrayed Lampmussels from this watershed. Smallmouth bass populations have also been reduced in the Grand River between Cambridge and West Montrose, likely as a result of angling pressure (Cooke et al. 1998).

Urbanization: The Grand River watershed has a population of approximately 780,000 and is expected to increase by nearly 40% over the next 20 years (GRCA 1998; Krause et al. 2001). More than 80% of the population occupies less than 7% of its area. Wastewater discharge is a major input in these urban areas and will only increase with increasing population. Within the Thames River basin all industrial outfalls and 70% of municipal outfalls are located within the heavily populated upper reaches where the Wavyrayed Lampmussel is found.

Recreational Activities: Reaches of the Grand River where Wavyrayed Lampmussels occur are popular areas for canoeists. Metcalfe-Smith et al. (2000) observed that paddlers in shallow water often disturbed the riverbed creating the potential for dislodging mussels and promoting downstream transport. Increasing popularity of recreational activities like canoeing may further increase stresses on unstable populations.

Predation: Predation by terrestrial predators such as muskrats (Ondatra zibethicus) and raccoons (Procyon lotor) has been shown to be an important limiting factor for some populations (Neves and Odom 1989). Neves and Odom (1989) reported that muskrats are both size and species specific predators and that they actively choose Wavyrayed Lampmussels when available. Metcalfe-Smith and McGoldrick (2003) reported observing raccoon predation on mussels in Ontario waters. Human-related activities, such as the adoption of conservation tillage practices, have resulted in surges in predator populations which may increase the importance of predation related threats in the future (Metcalfe-Smith and McGoldrick 2003). Southwestern Ontario farmers have reported a surge in raccoon numbers in recent years that may correspond with the adoption of conservation tillage practices (Metcalfe-Smith and McGoldrick 2003). This anecdotal observation needs verification in order to quantify the effects of human-related activities on predator populations.

Table 4: Predominant threats to the Wavyrayed Lampmussel in each currently or historically occupied locality
LocalityPredominant Threat
Ausable R.Siltation, Water Quality
Grand R.Host Fish, Urbanization
Lake St. Clair deltaExotics (dreissenid mussels)
Maitland R.Unknown
Thames R.Water Quality; Siltation, Exotics
Great Lakes (extirpated)Exotics (dreissenid mussels)
Sydenham R. (extirpated)Siltation (disruption of reproductive cycle); Loss of Host

Habitat Description

The Wavyrayed Lampmussel is typically found in clear, hydrologically stable rivers and streams. Clarke (1981) and Cummings and Mayer (1992) reported the species from gravel or sandy bottoms of riffle-areas in medium sized streams. Strayer (1983) reported the Wavyrayed Lampmussel in Michigan from medium-sized and large streams characterized by low gradients, clear waters, steady flows and substrates of sand and gravel. Dennis (1984) examined the habitat preferences of 72 species in the Tennessee River basin and reported L. fasciola from small (2nd to 4th order creeks) and medium (5th to 7th order) sized streams. Dennis (1984) reported that the most productive habitat consisted of stable substrates with a mixture of fine particles, gravel and rocks. Within Ontario waters it is usually found in clean sand or gravel substrates in shallow (< 1m) riffle areas. In the Great Lakes it has been found along shallow wave-washed shoals (Metcalfe-Smith and McGoldrick 2003).

Currently Occupied Habitat

Geospatial Description:

Habitat in need of conservation for the Wavyrayed Lampmussel has been geospatially located using the methods developed by McGoldrick et al. (in press) (Figure 5 - 8) who recommend using the Ontario Ministry of Natural Resource's Aquatic Landscape Inventory Software (ALIS version 1) (Stanfield and Kuyvenhoven 2005) as the base unit for definition of important habitat within riverine systems. The ALIS system employs a valley classification approach to define river segments with similar habitat and continuity on the basis of hydrography, surficial geology, slope, position, upstream drainage area, climate, landcover and the presence of instream barriers. For Great Lakes populations where ALIS segments can not be employed, McGoldrick et al. (in press) recommend using a 5 km buffer around known species occurrences. The 5 km buffer was selected in light of the spatial extent of historic sampling within Lake St. Clair. Within all identified river segments the width of the habitat zone in need of protection is defined as the area from the mid-channel point to bankfull width on both the left and right banks.

  • Currently occupied habitat for the Wavyrayed Lampmussel can be summarized as:
  • A 60 km stretch of the Grand River between Inverhaugh and Cambridge (Metcalfe-Smith and McGoldrick 2003).
  • A 30 km section of the North Thames River above London including Medway and Fish creeks. A 25 km section of the Middle Thames River from London to Dorchester as well as the lower reaches of the Middle Thames from Thamesford to its confluence with the Middle Thames (T. Morris, Fisheries and Oceans Canada, Burlington, unpublished data).
  • The lower reaches of the Middle, Little and South Maitland Rivers and the 45 km section of the main branch of the Maitland River from Wingham to the confluence with the South Maitland.
  • The lower section of the Little Ausable River and a 12 km stretch of the main channel of the Ausable River upstream of Nairn (Metcalfe-Smith et al. 1999).
  • A 12 km² region of the St Clair delta (Zanatta et al. 2002).
Functional Description:

Within the area defined under Geospatial Description only areas meeting the characteristics described below are deemed to represent habitat in need of conservation:

  • permanently wetted and
  • of a stream order greater than 2 (riverine populations only) and
  • having clean sand/gravel substrates sometimes stabilized by larger material (rubble, boulder or bedrock) and
  • riffle/run habitat (riverine populations only) or
  • shallow sand flats (Great Lakes populations) and
  • providing access to suitable host specimens during the period of female gravidity (June 1 – October 15).
Activities Likely to Impact Currently Occupied Habitat

The currently occupied habitat of the Wavyrayed Lampmussel could be negatively affected by a variety of activities. Direct destruction of habitat could result from in-stream activities such as dredging, road crossings and pipeline crossings or the construction of dams. Currently occupied habitat could also be negatively affected by any land-based activities that affect water quality or quantity. Such activities would include (but are not limited to) the input of nutrients, sediment and toxic substances through improperly treated storm water, cultivation of riparian lands, unfettered access of livestock to the river, channelization and drainage works, water taking, aggregate extraction, and the release of improperly treated sewage.

McGoldrick et al. (in press) have earlier identified a number of threshold values which can be used to gage the likelihood that an activity will negatively impact or destroy currently occupied habitat. Any activity that results in an exceedance of the threshold values in Table 5 should be considered likely to destroy currently occupied habitat.

Table 5: Threshold values for determining the likelihood that an activity will negatively impact currently occupied habitat
unionized ammonia
0.21 mg/L
total ammonia
1.7 mg/L
4.7 µg/L
total phosphorus
0.05 mg/L
nitrate-nitrite ratio
2.0 mg/L
6 mg/L

When dealing with freshwater mussels it is necessary to consider not only the physical and chemical components of habitat but also the biological. Any activity which disrupts the connectivity between Wavyrayed Lampmussel populations and their host species (see section on Life Cycle and Reproduction) may result in the destruction of currently occupied habitat. Activities which may disrupt the mussel-host relationship include, but are not limited to, damming, dewatering and harvest. Note that activities occurring outside the currently occupied habitat zone may affect the host population within the zone (e.g., downstream damming activities may prevent the movement of fish into the currently occupied habitat zone during the period of mussel reproduction (June 1 – October 15)). Any activity that impacts a host population within an area of currently occupied habitat should be evaluated to ensure that the reproductive cycle is not disrupted.

Figure 5: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Great Lakes and connecting channels.
Figure 5: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Great Lakes and connecting channels.

Figure 6: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Upper Thames and Ausable rivers.
Figure 6: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Upper Thames and Ausable rivers.

Figure 7: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Maitland River.
Figure 7: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Maitland River.

Figure 8: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Upper Grand River.
Figure 8: Currently occupied habitat for the Wavyrayed Lampmussel (Lampsilis fasciola) in the Upper Grand River.

Historically Occupied Habitat

Historically occupied habitat includes a 40km stretch of the East Sydenham River and a small stretch of the lower Grand River near York. Although the St Clair and Detroit rivers, Lake St Clair (excluding the delta) and the western basin of Lake Erie represent historically occupied habitat they are low priority sites for recovery/re-establishment due to the presence of high abundances of dreissenid mussels.

Critical Habitat

The identification of Critical Habitat requires a thorough knowledge of the species needs during all life stages as well as an understanding of the distribution, quantity, and quality of habitat across the range of the species. At present, this information is not available for the Wavyrayed Lampmussel although Table 6 outlines activities that would assist with obtaining the required information. The activities listed in Table 6 are not exhaustive but outline the range and scope of actions identified by the OFMRT as necessary to identify Critical Habitat for the Wavyrayed Lampmussel. It is likely that the process of investigating the actions in Table 5 will lead to the discovery of further knowledge gaps that will have to be addressed. Until Critical Habitat can be defined the recovery team has identified the areas listed in the Currently Occupied Habitat section as areas in need of conservation.

Table 6: Schedule of activities to identify Critical Habitat
ActivityApproximate Time Frame1
Conduct mussel population surveys2006-2008
Assess habitat conditions in occupied areas (e.g., flow, substrate, water clarity and quality)2006-2008
Determine any life stage differences in habitat use2007-2009
Survey and map areas of suitable but unused habitat within historical range2008-2010
Assess genetic structure of populations2006-2008
Determine host fish species2006
Conduct host fish population surveys2006-2008
Assess habitat use by host species2006-2008
Determine areas of overlap between mussel and host habitat2009-2010

1 timeframes are subject to change as new priorities arise or as a result of changing demands on resources or personnel

Habitat Trends

The majority of Lake St. Clair (excluding the delta) the Detroit River and the western basin of Lake Erie are no longer suitable habitat for the Wavyrayed Lampmussel because of the infestation of dreissenid mussels. There is strong evidence that poor water clarity limits the distribution of the Wavyrayed Lampmussel (Metcalfe-Smith & McGoldrick, 2003). High turbidity and suspended solids in the Sydenham and Ausable rivers have rendered large portions of habitat unsuitable. Water clarity in the occupied reaches of the Grand, Thames and Maitland Rivers does not seem to be a problem.

Habitat Protection

The federal Species at Risk Act (SARA) was proclaimed in June of 2003. Under SARA there are general prohibitions against killing, harming, taking, possessing, capturing, and collecting the Wavyrayed Lampmussel and against damaging or destroying its residences, as well as prohibitions on the destruction of Critical Habitat. The Fisheries Act represents an important tool for habitat protection and along with other federal environmental legislation is complimentary to the Species at Risk Act. Under the federal Fisheries Act mussels are considered shellfish, falling under the definition of "fish", and their habitat is therefore protected from harmful alteration, disruption or destruction unless authorized by the Minister of Fisheries and Oceans, or his/her delegate. Planning authorities must be consistent with the provincial Policy Statement under Section 3 of Ontario's Planning Act, which prohibits development and site alteration in the significant habitat of endangered species. The Ontario Lakes and Rivers Improvement Act prohibits the impoundment or diversion of a watercourse if siltation will result while the voluntary Land Stewardship II program of the Ontario Ministry of Agriculture, Food and Rural Affairs is designed to reduce erosion on agricultural lands. Stream-side development in Ontario is managed through floodplain regulations enforced by local conservation authorities.

A majority of the land adjacent to the rivers where Wavyrayed Lampmussels are found is privately owned, however, the river bottom is generally owned by the Crown. The Municipality of Southwestern Middlesex (formerly Mosa Township) owns a 20 ha section of forest along the reach of the Sydenham River where Wavyrayed Lampmussel shells were found in 1997 (Muriel Andreae, St. Clair Region Conservation Authority, cited in Metcalfe-Smith et al. 2000) and the SCRCA owns approximately 1816 ha of property in the watershed. The Ausable Bayfield Conservation Authority (ABCA) owns approximately 1830 ha of property split between a number of locations in the Ausable River basin (K. Vader, ABCA, cited in Metcalfe-Smith et al. 2000) and the Maitland Valley Conservation Authority owns 28 properties covering 1800 ha within the Maitland River watershed including one site where the Wavyrayed Lampmussel was found (Wawanosh Conservation Area). Much of the land adjacent to the refuge site identified in the Lake St. Clair delta is within the boundaries of the Walpole Island First Nation (Zanatta et al. 2002).

Ecological Role

Freshwater mussels play an integral role in the functioning of aquatic ecosystems. Vaughn and Hakenkamp (2001) have summarized much of the literature relating to the role of unionids and identified numerous water column (size-selective filter-feeding; species-specific phytoplankton selection; nutrient cycling; control of phosphorus abundance) and sediment processes (deposit feeding decreasing sediment organic matter; bio-deposition of feces and pseudo-feces; epizoic invertebrates and epiphytic algae colonize shells; benthic invertebrate densities positively correlated with mussel density) mediated by the presence of mussel beds. Welker and Walz (1998) have demonstrated that freshwater mussels are capable of limiting plankton in European rivers while Neves and Odom (1989) reported that mussels also play a role in the transfer of energy to the terrestrial environment through predation by muskrats and raccoons.

Importance to People

Although this species has no immediate economic significance, freshwater mussels are sensitive to environmental pollution and a diverse mussel community indicates a healthy aquatic ecosystem. Besides decreased biodiversity in Canada, the decline of the Wavyrayed Lampmussel may indicate further environmental degradation of southern Ontario watercourses which would adversely affect those people who use surface water for drinking, recreation or watering livestock. Recovery of the species may require the participation of recreational anglers as the likely host species, smallmouth bass, are popular sportfish.

Anticipated Conflicts or Challenges

A general shortage of malacological experts in southern Ontario and the specific retirements of two prominent experts are going to pose a problem of continuity over the 5 year implementation period of this recovery strategy. There will be a need to fill the voids created by these retirements and to train new experts to carry on the research programs of these scientists to ensure that the approaches outlined in this strategy are effectively addressed.

The re-establishment of viable populations in the Ausable and Sydenham Rivers will require watershed scale recovery prior to any re-introduction of the Wavyrayed Lampmussel. Critical improvements to riparian zones can be accomplished over the short term however these can be ephemeral solutions as they are subject to reversal with changes in land ownership.

Knowledge Gaps

Survey Needs
AusableHay Swamp, Little Ausable, main channel downstream of NairnTo determine the extent, abundance, and population demographics of the Wavyrayed Lampmussel.
GrandTributaries including Conestogo R.
Maitland RiverUpper reaches of all 4 branches.
ThamesLower reaches and tributaries
Lake St. ClairDelta

These locations represent areas identified by the Recovery Team as ones for which data are currently insufficient. Further areas in need of survey may be identified in the future as needs arise. No additional surveys are foreseen for the Sydenham River as the OFMRT feels that the river has been adequately surveyed.

Biological/Ecological Research requirements

Research Requirement
Host fish identification
Investigate other potential hosts.

Develop a protocol for rearing juvenile mussels under laboratory conditions.

Juvenile propagation
Genetics – variability
Examine degree of variation across Canadian range and compare with variability across global distribution to assist in determining appropriateness of augmentation efforts and selecting source populations if action is warranted.

Genetics – propagation guidelines
Develop genetically sound propagation guidelines for freshwater mussels estimating the number of individuals needed to maintain or reintroduce 95% of the known genetic variation in propagated populations.

Genetics - molecular phylogenetics
Determine if the three lure morphologies found in Canadian populations are actually monophyletic or are sister taxa.

Threat Clarification Requirements

Examine the zebra mussel threat to Wavyrayed Lampmussels within the St. Clair delta refuge site.
Examine host fish dynamics in relation to exotic species (e.g., mottled sculpins and gobies).

Recreational Activity
Determine if recreational activity poses a serious threat to the Wavyrayed Lampmussel.

Quantify predation levels. Track changes in predator abundance in response to human-induced changes in the environment (e.g., urbanization, agricultural practices).

Determine the vulnerability of all life stages to known and suspected pollutants. Initial focus on glochidial and juvenile stages which are known to be most sensitive.

Water clarity
Test hypothesis that water clarity limits the reproductive success of the Wavyrayed Lampmussel.

Biological and Technical Feasibility of Recovery

Recovery of the Wavyrayed Lampmussel is believed to be both biologically and technically feasible as reproducing populations still exist as potential sources to support recovery, suitable habitat can be made available through recovery actions, threats can be mitigated and proposed recovery techniques are anticipated to be effective.

  1. Mussels are slow growing and sedentary animals dependant on their host fishes for the survival and dispersal of their young. The slow rate of population growth makes the natural recovery of decimated populations a lengthy process.

  2. The habitat that supports this species in the Upper Grand River and Thames rivers appears to be of high quality due to high water clarity and ample evidence of successful reproduction. Current habitat in the Ausable River is of low quality because of high turbidity or poor water quality. The habitat formerly occupied in the Sydenham River is also of low quality due to poor water clarity and the absence of its host fish. The waters of Lake St. Clair delta are clear and clean but the habitat is of marginal quality due to the presence of dreissenid mussels. Habitat in the Maitland River appears to be of high quality but there is still a need for further assessment.

  3. The habitat in the Sydenham and Ausable Rivers could be improved significantly with proper stewardship of both agricultural and urban lands in each watershed.

  4. Reductions in soil erosion and turbidity in all the watersheds are achievable goals but would be challenging due to the number and intensity of the impacts.

  5. Eliminating the impacts of dreissenid mussels on the Great Lakes populations is not possible although the establishment of managed refuge sites in the Lake St. Clair delta may be possible.

  6. Artificial propagation of the Wavyrayed Lampmussel has been successful in the U.S. (Hanlon and Neves 2000).

The Wavyrayed Lampmussel is naturally a rare component of the mussel community where it is found. The level of effort required for recovery of this species would be low (e.g. habitat preservation) for the Grand, Thames and Maitland Rivers, moderate for the St. Clair delta (managed refuge sites, zebra mussel cleaning), high for the Ausable (e.g. translocation, long-term population augmentation), and high for the Sydenham River which likely requires the re-introduction of both the mussel and smallmouth bass.

Recommended Scale of Recovery

Although the Wavyrayed Lampmussel has a geographically restricted range at a national scale it is relatively broadly distributed across southern Ontario where it is still found alive in 4 major rivers (Ausable, Grand, Maitland, Thames) and in Lake St. Clair. Aquatic Ecosystem Recovery Strategies are in development for the Ausable and Thames Rivers. Although these ecosystem strategies give consideration to the Wavyrayed Lampmussel they can not be relied upon to provide the sole means of protecting this species as each focuses on only a small portion of the total range. Boersma et al. (2001) reported that species covered by ecosystem plans are 4 times less likely to show improvement relative to species covered by single species plans in part because less time and money are typically spent per species in ecosystem plans. A single species approach is necessary to ensure that no critical elements are omitted from the ecosystem plans and to represent the only means of protection in watersheds where ecosystem strategies are lacking (Grand R., Maitland R., Lake St. Clair). If ecosystem plans are developed in the future for these watersheds the single species strategy will provide a strong foundation to build upon.