World Congress of Malacology Antwerp ... - Unitas Malacologica

Spatio-temporal and biomass dynamics of Corbicula fluminea, an invasive mussel in the
Hungarian Danube section
Bódis, Erika 1 ; Hornung, Erzsébet 2 ; Nosek, János 1 ; Oertel, Nándor 1
1. Hungarian Danube Research Station of the Hungarian Academy of Sciences, H-2131 Göd, Jávorka
S. u. 14., Hungary,
Email: bodler@freemail.hu, oer63@ella.hu, nosek@botanika.hu
2. Szent Istvan University, Faculty of Veterinary Science, Department of Ecology, Institute for
Biology, H-1400 Budapest, POB 2, Hungary,
Email: Hornung.Erzsebet@aotk.szie.hu
Filter-feeding mussels have a significant role in the material cycle of freshwaters. The importance of
the small-sized, but abundant mussels, especially in large rivers, is poorly known. These species of
Hungarian mussel fauna belong to three families: Corbiculidae, Dreissenidae and Sphaeriidae.
Sixteen small-sized mussel species were found in the Hungarian Danube section, which presents
72,7% of the nationwide fauna. Out of the collected species three (Corbicula fluminea, Corbicula
fluminalis, Dreissena polymorpha polymorpha) are of invasive nature, so 18,75% of the small-sized
mussel fauna is non-indigenous spreading rapidly.
C. fluminea is a very successful immigrant in new areas due to its special life history strategy and
human impacts. The genus Corbicula was first detected in the Vén-Duna at Baja (South Hungary) in
1999. Nowadays C. fluminea spreads throughout the River Danube, it has appeared in the active
alluvial floodplain of the Szigetköz area (North-West Hungary), too.
Besides the investigation of occurence pattern of C. fluminea, we studied its density, biomass
dynamics and the body length-body mass relationships in the Danube bend above Budapest. Samples
were taken four times in 2005 at 3 different sampling sites in the littoral zone. C. fluminea
represented 42,42% of the total number of small-sized mussels. The density of C. fluminea ranged
from 10 ind./ m 2 to 736 ind./ m 2 . The biomass of C. fluminea fluctuated between 2,85 -166,90 g/m 2 .
The minimum and maximum size parameters are follows: body height (0,88 - 14,52 mm), body
length (0,95 - 16,24 mm) and body mass (0,11 - 1,93 g). The maximum values of size parameters are
very low compared to published data: C. fluminea can reach 40-50 mm in body length. Lengthfrequency
analysis of the data clearly indicate that C. fluminea has two well defined reproduction
peaks in June and November.
Systematic and distributional studies of Colombian continental mollusks – The land snail
genera Isomeria Beck and Labyrinthus Beck (Gastropoda: Camaenidae)
Borrero, Francisco J. 1 ; Kattan, Gustavo 2 ; Giraldo, Manuel 3
1. Cincinnati Museum Center, 1301 Western Avenue, Cincinnati, OH 45203, USA,
Email: borrerof@countryday.net
2. Fundación EcoAndina/WCS-Colombia Program, Av.2a oeste #10-54, Cali,
Colombia,
Email: gkattan@wcs.org
3. Universidad del Valle, Departamento de Biología, Cali, Colombia,
Email: mgiraldo@univalle.edu.co
Systematic, distributional and ecological information on Isomeria and Labyrinthus from Colombia,
South America is examined using published and newly collected data. Traditionally, discrimination
between the two genera and between species-groups within each genus has been based on
conchological characteristics. Anatomical data (mostly morphology of radulae and genitalia) are
available for just a few species, and no molecular data is available. Further, the ecology of all species
is virtually unknown. Eighteen of the 31 nominal species of Labyrinthus are present in Colombia
(58%). For Isomeria, of the 28-30 nominal species, 14 are present in Colombia (>46%). Moreover, 3
additional and distinct forms of Isomeria were found as part of this study, and are being described as
new species. Labyrinthus has been considered as distributed in low to moderate elevations, and
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