Demography and ecological impacts of the invading mollusc Dreissena polymorpha (original) (raw)
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Northeastern Naturalist, 2015
Over the past 25 years, unionid mussels in the Laurentian Great Lakes of North America have been adversely impacted by invasive dreissenid mussels, which directly (e.g., by attachment to unionid shells) and indirectly (e.g., by competing for food) cause mortality. Despite the invasion, unionids have survived in several areas in the presence of dreissenid mussels. We investigated current spatial patterns in these native mussel refuges based on surveys for unionid mussels across 48 sampling locations (141 sites) in 2011 and 2012, and documented species abundance and diversity in coastal areas of lakes St. Clair and Erie. The highest-quality assemblages of native mussels (densities, richness, and diversity) appear to be concentrated in the St. Clair delta, where abundance continues to decline, as well as in in Thompson Bay of Presque Isle in Lake Erie and in just a few coastal wetlands and drowned river-mouths in the western basin of Lake Erie. The discovery of several new refuge areas suggests that unionids have a broader distribution within the region than previously thought.
2002
The introduction and spread of the exotic zebra mussel (Dreissena polymorpha) throughout the Great Lakes has decimated native unionid populations. However, significant communities have continued to survive in several nearshore areas of Lake Erie. This study documents the discovery of a "refuge" site for unionids in Lake St. Clair. Ninety-five sites in various areas around the lake were surveyed between 1998 and 2001, and 2,356 live unionids of 22 species were found alive at 33 of these sites. Almost all sites (31) were in shallow (mainly < 1 m) waters of the St. Clair delta, in habitats similar to refugia in Lake Erie, i.e., nearshore areas with firm sandy substrates and marshy bays with soft, muddy sediments. Species richness ranged from 1 to 12 species per site, and relative abundance ranged from 2 to 302 unionids per person-hour of sampling effort. Densities at nine sites ranged from 0.03 to 0.07 per m 2 . Five species considered to be at risk were found alive. Infestation rates at sites near the St. Clair delta ranged from 0 to 286 zebra mussels per unionid, which is slightly higher than rates at other known refuge sites. The community is now dominated by thick-shelled species such as Fusconaia flava and Lampsilis cardium, which are known to be least susceptible to zebra mussels. Further studies are needed to determine if unionid populations in the delta are stable, and to understand the mechanisms responsible for unionid survival at this and other refugia. Such information could be used to predict the locations of other natural sanctuaries and to guide their management for the preservation of the Great Lakes unionid fauna.
Characteristics of a refuge for native freshwater mussels (Bivalvia: Unionidae) in Lake St. Clair
Journal of Great Lakes Research, 2009
The Lake St. Clair delta (∼ 100 km 2 ) provides an important refuge for native freshwater mussels (Unionidae) wherein 22 of the ∼ 35 historical species co-occur with invasive dreissenids. A total of 1875 live unionids representing 22 species were found during snorkeling surveys of 32 shallow (∼ 1 m) sites throughout the delta. Richness and density of unionids and zebra mussel infestation rates varied among sites from 3 to 13 unionid species, 0.02 to 0.12 unionids/m 2 , and b 1 to 35 zebra mussels/unionid, respectively. Zebra mussel infestation of unionids in the delta appears to be mitigated by dominant offshore currents, which limit densities of zebra mussel veligers in nearshore compared to offshore waters (13,600 vs. 28,000/m 3 , respectively). Glycogen concentrations in the tissues of a common and widespread species in the delta (Lampsilis siliquoidea) suggest that zebra mussels may be adversely affecting physiological condition of unionids in a portion of the Lake St. Clair delta. Physiological condition and community structure of unionids within the delta may also be influenced by differences in food quantity and quality resulting from the uneven distribution of water flowing from the St. Clair River. The delta likely supports the largest living unionid community in the lower Great Lakes and includes several species that have been listed as Endangered or Threatened in Canada and/or the state of Michigan, making it an important refuge for the conservation of native unionids.
Canadian Journal of Fisheries and Aquatic Sciences, 1993
. Colonization, ecology, and population structure of the "quagga" mussel (Bivalvia: Dreissenidae) in the lower Great Lakes. Can. J. Fish. Aquat. Sci. 50:2305-2314. An invasive dreissenid mussel given the working name of "quagga" has a present (spring 1993) distribution in the Laurentian Great Lakes from the western basin of Lake Erie to Quebec City, in Lake Erie, quaggas were ColIected as early as 1989 and now are most common in the eastern basin, in Lakes Erie and Ontario, proportions of quaggas increased with depth and decreasing water temperature. In the eastern basin or Lake Erie, quaggas outnumbered zebra mussel (Dreissena polymorpha) by 14 to 1 in deeper waters (> 20 m). In Lake Ontario, quaggas were observed at depths as great as 130 m, and both quagga and zebra mussel were found to survive at depths (> 50 m) where temperatures rarely exceed 5°C. Quaggas were sparse or absent along inland waterways and lakes of New York State. Mean shell size of quagga mussel was larger than that of zebra mussel at sites in the Niagara River, Lake Ontario, and the St. Lawrence River. The largest quaggas (38 mm) were observed in the St. Lawrence River at Cape Vincent.
Shell-free Biomass and Population Dynamics of Dreissenids in Offshore Lake Michigan, 2001–2003
Journal of Great Lakes Research, 2007
The USGS-Great Lakes Science Center has collected dreissenid mussels annually from Lake Michigan since zebra mussels (Dreissena polymorpha) became a significant portion of the bottomtrawl catch in 1999. For this study, we investigated dreissenid distribution, body mass, and recruitment at different depths in Lake Michigan during [2001][2002][2003]. The highest densities of dreissenid biomass were observed from depths of 27 to 46 m. The biomass of quagga mussels (Dreissena bugensis) increased exponentially during [2001][2002][2003], while that of zebra mussels did not change significantly. Body mass (standardized for a given shell length) of both species was lowest from depths of 27 to 37m, highest from 55 to 64 m, and declined linearly at deeper depths during . Recruitment in 2003, as characterized by the proportion of mussels < 11 mm in the catch, varied with depth and lake region. For quagga mussels, recruitment declined linearly with depth, and was highest in northern Lake Michigan. For zebra mussels, recruitment generally declined non-linearly with depth, although the pattern was different for north, mid, and southern Lake Michigan. Our analyses suggest that quagga mussels could overtake zebra mussels and become the most abundant mollusk in terms of biomass in Lake Michigan.
FRESHWATER MUSSEL COMMUNITY IN FALLS LAKE: A CHANGE IN THE ECOSYSTEM
Theoecology Journal, 2012
The freshwater bivalve fauna of the North Carolina is comprised of 80 species from three bivalve families. The focus of this paper is the diversity of freshwater bivalves in the family Unionidae found in the Neuse River basin. This includes 25 species of Unionidae in the Neuse River basin with only 3 native and one introduced species found in Falls Lake. These mussels have an obligate parasitic larval stage on the gills or fins of certain host fish. A relatively short residency on the host fish is necessary for the mussel to complete its reproductive cycle. This mussel fauna is characteristic of a free-flowing river system. Impounding the river limits the movement of migratory fish and may exclude host fish necessary for the reproduction of native mussels. Thus, the mussel fauna of Falls Lake is different from that occurring in the headwaters and in the free flowing sections of the Neuse River downstream of the lake. The quiet water, soft bottoms and restricted fish fauna only supports a reduced number of mussel species. Freshwater mussels are also impacted by degradation in water quality.
Effects of water movement on the distribution of invasive dreissenid mussels in Lake Simcoe, Ontario
Journal of Great Lakes Research, 2011
The effects of invasive organisms on an aquatic ecosystem will depend, in part, on the distribution and biomass of the invasive organisms in the system. Here we present the results of a lake-wide survey of the distribution of invasive dreissenid mussels (Dreissena spp.) in Lake Simcoe, Ontario and discuss some of the factors that shape their distribution pattern in the lake. Dreissenid biomass averaged 27.2 g shell-free dry mass (SFDM)/m 2 in the main basin of Lake Simcoe and 12.4 g SFDM/m 2 in macrophyte-dominated Cook's Bay. We argue that water movement is an important determinant of dreissenid distribution, both through catastrophic disturbance in shallow water and through non-catastrophic effects on substrate distribution and possibly food supply rates. In areas of dense macrophyte growth, mussel abundance was shown to be associated with that of preferred macrophyte taxa, in particular with that of Ceratophyllum demersum. We used the results of our survey and the relationships between environmental variables and dreissenid biomass to estimate the total biomass of dreissenids in Lake Simcoe: 11,897 tonnes SFDM. This study contributes to the understanding of dreissenid ecology and provides a baseline for future studies of dreissenid distribution and impacts in Lake Simcoe.
Impact of the( Dreissena ) invasion on native unionid bivalves in the upper St. Lawrence River
Canadian Journal of Fisheries and Aquatic Sciences, 1996
Introduced Eurasian mussels (Dreissena polymorpha and Dreissena bugensis) colonized native unionid bivalves in the upper St. Lawrence River in the early 1990s. From 1992 to 1995, we examined the infestation and impact of Dreissena on unionids at several sites near the Island of Montréal. Unionids suffered heavy (90-100%) mortality at sites where Dreissena occurred in high densities (i.e., 4000-20 000/m 2). Mean infestations (<100 dreissenids/unionid) were 10-100 times lower than those reported for infested unionid populations in Lake Erie and Lake St. Clair, yet resulted in similarly high mortality levels. At two St. Lawrence River sites, significant declines in unionid density were first observed when mean infestations exceeded 10/unionid. North American data suggest that populations of unionids that carry, on average, a mass of Dreissena nearly equal to or greater than their own mass will become extirpated. We hypothesize that dreissenid infestation enhances unionid mortality primarily by interfering with normal activity (feeding, respiration, locomotion) in such a way as to cause the unionid to expend energy reserves required for surviving winter. Résumé : Au début des années 1990 dans le cour supérieur du Saint-Laurent, des moules eurasiennes (Dreissena polymorpha et Dreissena bugensis) introduites ont colonisé des bivalves de la famille des unionidés, indigènes dans ces eaux. De 1992 à 1995, nous avons étudié l'infestation et évalué l'impact des Dreissena chez les unionidés de diverses stations situées à proximité de l'île de Montréal. Là où la densité des Dreissena était élevée (c'est à dire de 4000 à 20 000 m-2), la mortalité a été très forte chez les unionidés (90-100%). Les infestations moyennes (<100 Dreissena/unionidé) étaient 10-100 fois moindres que celles qui ont touché les populations d'unionidés des lacs Érié et Saint-Clair, mais la mortalité a atteint des valeurs à peu près aussi élevées. Dans deux stations du fleuve Saint-Laurent, la densité des unionidés a baissé dans une mesure significative lorsque l'infestation moyenne a dépassé 10 Dreissena/unionidé. D'après les données recueillies en Amérique du Nord, lorsque la masse des Dreissena est, en moyenne, presque égale ou supérieure à la masse de la population d'unionidés hôte, cette dernière est destinée à disparaître. Selon notre hypothèse, l'infestation de Dreissena fait augmenter la mortalité chez les unionidés principalement en nuisant aux activités normales (alimentation, respiration, locomotion) de son hôte, celui-ci devant puiser dans les réserves énergétiques qui lui permettrait normalement de survivre en hiver. [Traduit par la Rédaction]