- Scientific name: Lampsilis cariosa
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
- Endangered (MA Endangered Species Act)
Description
Yellow lampmussel
The yellow lampmussel is a medium-sized to large mussel that is usually less than 134 mm (5.25 in) in length. The shape is ovate and the shells are laterally inflated (1). Shells of sexually mature females are usually more rounded toward the posterior ventral margin (2), and thus more distinctly oval-shaped, than males or adolescent females. The shells are thick and very strong, particularly toward the anterior end (3). Beaks (4) are prominent and raised above the hinge line (5). Pseudocardinal teeth are well developed; the left valve has two and the right valve has two or three (6). Pseudocardinal teeth are usually stout, with distinct striations on the surface, and are located nearly directly under the beak. Lateral teeth are also well developed; the left valve has two and the right valve has its luster and become darker with age. Most individuals (particularly young ones) have faint green rays (9) on the periostracum, especially toward the dorsal-posterior portion of the shell. The nacre (10) is usually white or bluish-white.
It is often very difficult to distinguish this species from the tidewater mucket, especially for the novice. Compared to the tidewater mucket, the yellow lampmussel is larger, it has a thicker shell, and it has more robust hinge teeth. Its shell is much more shiny and yellow than the shell of the tidewater mucket. The nacre of the yellow lampmussel is white or bluish-white, whereas it is usually pinkish or salmon-colored in the tidewater mucket. Other differences are described in Nedeau et al. (2000) and Nedeau (2008). The only place in Massachusetts where these two species overlap is the Connecticut River.
Illustrations by Ethan Nedeau.
Life cycle and behavior
Yellow lampmussels are essentially sedentary filter feeders that spend most of their lives partially burrowed into the bottoms of rivers and streams. Like all freshwater mussels, larvae (called glochidia) of the yellow lampmussel must attach to the gills or fins of a vertebrate host to develop into juveniles. Spawning females have a mantle margin with bright pigmentation, a swollen appearance, and fleshy lobes that are used to lure host fish toward them. A dark “eyespot” near the inhalent aperture makes the display look even more fish-like. Wick (2003) found that females displayed their mantle lure actively at night and postulated that this was an adaptation to take advantage of piscivorous fish that move into shallow areas to feed at night. Their reliance on the visual acuity of their fish hosts also indicates the potential importance of turbidity in interfering with reproduction. Viable fish hosts in the wild include white perch and yellow perch (Kneeland and Rhymer 2008) with other potential hosts from lab experiments including striped bass, largemouth bass, smallmouth bass and black crappie (Eads et al. 2015, Martell 2020). The striped bass is closely related to the white perch (in the genus Morone) and has made a recent resurgence in the Connecticut River. If the striped bass is a host, it is possible that the recent range expansion of the yellow lampmussel in the Connecticut River, particularly the discovery of young yellow lampmussels in Connecticut, is related to the resurgence of the striped bass.
Distribution and abundance
The yellow lampmussel is distributed throughout the Atlantic coastal watersheds from Georgia to Nova Scotia and Cape Breton Island. In Massachusetts, the yellow lampmussel presently occurs in the Connecticut River with shell records in the Merrimack River from the 1800s.
The yellow lampmussel is listed as Endangered in Massachusetts. For several years, biologists thought it had been eliminated from the mainstem Connecticut River. In the last 25 years, exhaustive surveys in the Connecticut River have documented fairly large populations with successful reproduction. More animals are now being encountered outside of the core range and these tend to be younger animals; this suggests that new recruits are now dispersing into new areas. For example, the yellow lampmussel was not observed in Connecticut for more than 75 years but at least three young animals were discovered in 2006 (Nedeau 2008). There is reason to be optimistic about the potential for recovery of the yellow lampmussel in the Connecticut River. Nevertheless, it will remain critically imperiled in coming decades because it exists in a relatively small area and it is vulnerable to catastrophic events.
Distribution in Massachusetts.
1999-2024
Based on records in the Natural Heritage Database.
Habitat
Within the limited range of the yellow lampmussel in the Connecticut River, it has been found in shallow sandbars less than 1m (3 ft) deep and in areas more than 9.1 m (30 ft) deep, usually in slow to moderate flow conditions. Studies conducted in 2005 in the Connecticut River found that it was more abundant in shallow sandbars than it was in nearby areas that were deeper and had a rocky or muddy substrate. In contrast, the other two species consistently found with it—the eastern elliptio and alewife floater—were more common in nearby deeper rockier habitats and in muddy habitats near banks. Outside of the Connecticut River watershed, the yellow lampmussel has been found in medium to large rivers and lakes, including free-flowing rivers with rocky substrates and a mussel fauna more characteristic of smaller rivers (Strayer and Fetterman 1999, Nedeau et al. 2000). For example, it was found alongside the eastern pearlshell, brook floater, creeper, and triangle floater in several rivers in Maine (Nedeau et al. 2000). Thus, the limited range of habitats that the yellow lampmussel occupies in Massachusetts is uncharacteristic for the species and may be the result of historic pollution, loss of habitat, or perhaps natural limiting factors.
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Large river habitat typical for yellow lampmussel.
Threats
Because yellow lampmussels are essentially sedentary filter feeders, they are unable to flee from degraded environments and are vulnerable to the alterations of water bodies. Primary threats to the mainstem Connecticut River where the yellow lampmussel occurs include bank erosion and sedimentation, pollution (especially stormwater runoff and combined sewer overflows), alteration of natural flow regimes, encroachment of river corridors by development, habitat fragmentation caused by dams, and a legacy of land use that has greatly altered the natural dynamics of river corridors (Nedeau 2008). In addition, the long-term effects of regional or global problems such as acidic precipitation, mercury, and climate change are considered severe but little empirical data relates these stressors to mussel populations. Effects from climate change including extreme flows and sustained droughts, threaten the yellow lampmussel population.
Conservation
Survey and monitoring
Standardized surveys are critically needed to monitor known populations, evaluate habitat, locate new populations, and assess population viability at various spatial scales (e.g., stream, watershed, state). Survey efforts should continue to search for new populations via physical and potentially eDNA surveys particularly in the Merrimack River and expand our knowledge on the species distribution in extant watersheds every 5 years. Establishment of long-term monitoring sites in extant watersheds are needed to acquire critical demographic and population trend data. Monitoring these sites should continue to occur annually in multi-year blocks or as needed.
Management
Discovery and protection of viable mussel populations is critical for the long-term conservation of freshwater mussels. Currently, much of the available mussel occurrence data are the result of limited presence/absence surveys. In addition, regulatory protection under MESA only applies to rare species occurrences that are less than 25 years old. Other conservation and management recommendations include: maintain or restore naturally variable river flow; identify, mitigate, or eliminate sources of pollution to water bodies; addressing the problems of combined sewer overflows and the other effects of urban, industrial, and agricultural runoff in the Connecticut River; identify host fish and encourage the dispersal of these fish in the Connecticut River and its major tributaries; maintain adequate vegetated riparian buffer along river; understand and mitigate the effects of shoreline development, bank stabilization, docks and marinas, bridge maintenance, and other projects that might threaten yellow lampmussels.
Research needs
Research needs for yellow lampmussel include population-level data on survival rate, mortality rate, individual growth rates, population size trends, age at reproduction, sex ratio, and age structure. This data will help develop population viability models to identify when populations may need active restoration via introduction of propagated mussels. A better understanding of host fish relationships in the Connecticut River for the yellow lampmussel is needed; this information might help guide fisheries management at the fishways located at the major hydropower dams in the lower Connecticut River and its principal tributaries. Reintroduction of yellow lampmussel will require habitat suitability evaluation of historically occupied watersheds. Habitat mapping of large rivers can aid in evaluation of suitable physical habitat for potential reintroduction and direct future survey effort. Climate change projections for water temperature and streamflow in occupied and potential watersheds for species introduction are also needed to assess current and future population risks and identify potential flow refuges during drought and flooding conditions. Population genetic study is needed to identify the most closely related populations that can inform propagation and reintroduction efforts. Other research that will benefit this species include: investigation of impacts of invasive species, basket clam (Corbicula fluminea) and rusty crayfish (Faxonius rusticus), on yellow lampmussel; assess the responses of yellow lampmussel distribution after changes in flow regulation downstream of hydropower facilities.
References
Eads, C.B., J.E. Price, and J.F. Levine. 2015. Fish hosts of four freshwater mussel species in the Broad River, South Carolina. Southeastern Naturalist 14(1):85-97.
Kneeland, S.K., and J.M. Rhymer. 2008. Determination of fish host use by wild populations of rare freshwater mussels using a molecular identification key to identify glochidia. Journal of the North American Benthological Society 27(1): 150-160.
Lefevre, G., and W.C. Curtis. 1911. Metamorphosis without parasitism in the Unionidae. Science 33: 863-865.
Martell, V., 2020. Improving growth and survival of cultured yellow lampmussel (Lampsilis cariosa) for restoring populations, Thesis, University of Massachusetts Amherst: https:// doi. org/ 10. 7275/ 16000 174.
Nedeau, E.J. 2008. Freshwater Mussels and the Connecticut River Watershed. Connecticut River Watershed Council, Greenfield, Massachusetts. xviii+ 132 pp.
Nedeau, E.J., and J. Victoria. 2003. A Field Guide to the Freshwater Mussels of Connecticut. Connecticut Department of Environmental Protection, Hartford, CT.
Nedeau, E.J., M.A. McCollough, and B.I. Swartz. 2000. The Freshwater Mussels of Maine. Maine Department of Inland Fisheries and Wildlife, Augusta, Maine.
Strayer, D.L., and A.R. Fetterman. 1999. Changes in the Distribution of Freshwater Mussels (Unionidae) in the Upper Susquehanna River Basin, 1955–1965 to 1996–1997. The American Midland Naturalist 142: 328-339.
Vaughn, C. 1993. Can biogeographic models be used to predict the persistence of mussel populations in rivers? pp.117-122 in K.S Cummings, A.C. Buchanan and L.M. Koch (eds)., Conservation and Management of Freshwater Mussels: proceedings of a UMRCC symposium, 12-14 October 1992, St. Louis, Missouri. Upper Mississippi River Cons. Com., Rock Island, Illinois. 189 pp.
Wick, P.C. 2003. Fish hosts and demographics of Lampsilis cariosa and Leptodea ochracea, two threatened freshwater mussels in Maine. M.S. Thesis, University of Maine, Orono, Maine.
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| Date published: | March 28, 2025 |
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