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Salinity and temperature tolerance of the invasive freshwater gastropod Tarebia granifera
Nelson A.F. Miranda,Renzo Perissinotto,Christopher C. Appleton
South African Journal of Science , 2010, DOI: 10.4102/sajs.v106i3/4.156
Abstract: Invasive aquatic species, such as the gastropod Tarebia granifera, can cause ecological isturbances and potentially reduce biodiversity by displacing indigenous invertebrates. In South Africa, T. granifera was first recorded in an estuarine environment in the St Lucia Estuary. Its tolerance to salinity and temperature was investigated through the experimental manipulation of these factors. T. granifera can tolerate temperatures between 0 oC and 47.5 oC, allowing it to survive high temperature extremes. The species may also survive cold snaps and invade higher altitude areas. More remarkably, this snail survives high salinity for a relatively long time, as LS50 (lethal salinity for 50% of the population) was reached at 30 psu over 65–75 days. However, higher salinity adversely affected the T. granifera population. Snails acclimated to freshwater conditions and suddenly transferred to 30 psu experienced 100% mortality within 48 h. Snail activity also declined with increasing salinity. T. granifera’s environmental tolerance and parthenogenetic characteristics are the keys to successful introduction and establishment. Therefore, the management of T. granifera may prove diffcult in the short to medium term. The present findings constitute a contribution to the knowledge of biological invasions in Africa and to the understanding of estuarine invasions by T. granifera.
Allometry of the Gastropod Melanopsis praemorsa (Thiaridae: Prosobranchia) From Azraq Oasis, Jordan  [PDF]
Ali Z. Elkarmi,Naim S. Ismail
Pakistan Journal of Biological Sciences , 2006,
Abstract: A total of 300 specimens of the freshwater gastropod Melanopsis praemorsa (Thiaridae: Prosobranchia) from Azraq Oasis, Jordan, were studied for age, growth and shell morphometrics. Nonlinear and linear allometric analysis, Von Bertalanfi`s and Richard`s growth models were used to analyze the results. The results show the life span to be five years and the mean observed lengths of the five age cohorts range from 9.6 to 20.6 mm. The theoretical maximum length of this snail may reach 25.7 and 21.4 mm, respectively while the shell and dry body weights averaged 380.8 and 239.8 mg, respectively. The relationships of the shell length to shell and dry body weights are curvilinear and the relationships of the shell length to shell width, aperture length and aperture width are linear. These results are mainly in agreement with the results reported for other snails with similar relationships between the measured snail parameters.
Tarebia granifera (Lamarck, 1822) en la región hidrológica Grijalva-Usumacinta en Tabasco, México
Acta zoológica mexicana , 2011,
Abstract: after the first finding of tarebia granifera in september 2007 in lake tintal in the reserva de la biosfera pantanos de centla, a search was conducted in 40 lakes, 6 rivers, 1 stream and two drains: 14 sites from the municipality of centla, 3 from centro, 11 from paraiso, 1 from nacajuca, 3 from cardenas, 14 from jonuta and 3 from macuspana. sampling was conducted in september 2008 and may and september 2009. the sampling was random taking 10 samples using five liters van veen grab. tarebia granifera was collected in 11 sites out of 49 in three municipalities: in the town of centro is was found in l. pucte and l. la ceiba; centla in l. guanal, l. san isidro, l. viento, l. larga, l. tintal and l. concepcion; and macuspana in l. loncho, l. ismate-chilapilla and l. chilapa. the polygon of distribution of t. granifera is between the coordinates utm 509588-590058 x and 1989183-1976233 y (17°59'27.3"-17°52'19.3"ny92°54'34.0"-92°08'59.7"w).thecityofvillahermosaisconsideredas an introduction and dispersal center. the localities that presented the highest abundance values were: l. tintal with a total 7,944 individuals, l. pucte with 7,048 and l. ismate-chilapilla with 1,268. this study confirms the competence between t. granifera and melanoides tuberculata being the former favored.
Impacts of an Invasive Snail (Tarebia granifera) on Nutrient Cycling in Tropical Streams: The Role of Riparian Deforestation in Trinidad, West Indies  [PDF]
Jennifer M. Moslemi, Sunny B. Snider, Keeley MacNeill, James F. Gilliam, Alexander S. Flecker
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038806
Abstract: Non-native species and habitat degradation are two major catalysts of environmental change and often occur simultaneously. In freshwater systems, degradation of adjacent terrestrial vegetation may facilitate introduced species by altering resource availability. Here we examine how the presence of intact riparian cover influences the impact of an invasive herbivorous snail, Tarebia granifera, on nitrogen (N) cycling in aquatic systems on the island of Trinidad. We quantified snail biomass, growth, and N excretion in locations where riparian vegetation was present or removed to determine how snail demographics and excretion were related to the condition of the riparian zone. In three Neotropical streams, we measured snail biomass and N excretion in open and closed canopy habitats to generate estimates of mass- and area-specific N excretion rates. Snail biomass was 2 to 8 times greater and areal N excretion rates ranged from 3 to 9 times greater in open canopy habitats. Snails foraging in open canopy habitat also had access to more abundant food resources and exhibited greater growth and mass-specific N excretion rates. Estimates of ecosystem N demand indicated that snail N excretion in fully closed, partially closed, and open canopy habitats supplied 2%, 11%, and 16% of integrated ecosystem N demand, respectively. We conclude that human-mediated riparian canopy loss can generate hotspots of snail biomass, growth, and N excretion along tropical stream networks, altering the impacts of an invasive snail on the biogeochemical cycling of N.
Tarebia granifera (Lamarck, 1822) en la región hidrológica Grijalva-Usumacinta en Tabasco, México
Luis José Rangel Ruiz,Jaquelina Gamboa Aguilar,Miguelina García Morales,óscar Manuel Ortiz Lezama
Acta zoológica mexicana , 2011,
Abstract: Después del primer hallazgo de Tarebia granifera en septiembre de 2007 en la laguna Tin-tal, en la Reserva de la Biósfera Pantanos de Centla (RBPC), se realizó una búsqueda en 40 lagunas, 6 ríos, un arroyo y dos drenes: 14 sitios en el municipio de Centla, 3 en Centro, 11 en Paraíso, 1 en Nacaju-ca, 3 en Cárdenas, 14 en Macuspana y 3 en Jonuta. Los muestreos se realizaron en mayo y septiembre de 2008 y mayo y septiembre de 2009. El muestreo fue al azar tomándose 10 muestras con una draga Van Veen de cinco litros. De los 49 sitios, sólo en 11 de tres municipios se recolectó T. granifera: en el municipio de Centro en L. Pucte y L. la Ceiba; Centla en L. Guanal, L. San Isidro, L. Viento, L. Larga, L. Tintal y L. Concepción; y Macuspana en L. Loncho, L. Ismate-Chilapilla y L. Chilapa. El polígono de distribución de T. granifera está entre las coordenadas UTM 509588-590058 X y 1989183-1976233 Y (17o59'27.3"-17o52'19.3" N y 92o54'34.0"-92o08'59.7" O). Se considera como centro de introducción y dispersión a la Ciudad de Villahermosa. Las localidades que presentaron las máximas abundancias fueron: L. Tintal con 7,944 individuos, L. Pucte con 7,048 y L. Ismate Chilapilla con 1,268. Se comprueba la competencia de esta especie con Melanoides tuberculata siendo favorecida T. granifera.
Modificación del coeficiente peso/área del pié en relación con la agregación en Tarebia granifera
Rodríguez de la Vega,Ricardo Alejandro; Diéguez Fernández,Lorenzo; Quirós Espinosa,Angel; Herrera García,Ada María;
Revista de Saúde Pública , 2003, DOI: 10.1590/S0034-89102003000300006
Abstract: objective: to analyze specimens dispersion in a population of tarebia granifera and its relationship with the change of morphometric parameters. methods: two samplings by parcels including two types of substrata in opposite aggregation conditions were carried out, and the specimen abundance was compared between both samplings and substrata. the samples were stratified into classes according to shell height and for each of these the coefficient weight/foot-area was calculated and correlated with class size. it was experimentally evaluated whether specimens with a lower foot load had a better persistence in emerged substratum as well as the interaction between two class groups of shell height. results: the abundance difference between samplings was t=5.874 (p<0.001), and t=10.15 (p<0.001) between emerged rocky and sandy substrata, only under conditions of high aggregation where foot load decreases with the size for higher specimens (r=-0.98, p<0.05). experimentally, the abundance of specimens of opposed sizes were mutually limited (r=-0.87, p<0.01), waves' height limits the abundance of smaller snails (r=-0.94, p<0.01) but it is tolerated by larger ones (r=0.72, p<0.05), and foot load diminishes with the waves' height (r=-0.93, p<0.001). conclusions: under high aggregation conditions larger specimens emigrate toward substratum of difficult capture by smaller ones, which are limited by the environment's mechanical influence. the decrease of foot load facilitates specimens' dispersion.
Modificación del coeficiente peso/área del pié en relación con la agregación en Tarebia granifera  [cached]
Rodríguez de la Vega Ricardo Alejandro,Diéguez Fernández Lorenzo,Quirós Espinosa Angel,Herrera García Ada María
Revista de Saúde Pública , 2003,
Abstract: OBJETIVO: Analizar la dispersión de los ejemplares de una población de Tarebia granifera y su relación con la modificación de los parámetros morfométricos. METODOS: Se colectó por parcelas incluyendo dos tipos de substratos en condiciones opuestas de agregación y se comparó la abundancia relativa tanto entre muestreos, como entre sustratos. Se delimitaron 7 clases de alto a las cuales se les determinó el coeficiente peso/área del pié, el cual se correlacionó con la talla por clase. Se evaluó experimentalmente si los individuos con menor carga del pié tienen mayor persistencia en substratos emergidos, así como la interacción entre dos grupos de clases de alto. RESULTADOS: La diferencia de la abundancia entre los muestreos fue de t=5.874 (p<0.001) y de t=10.15 (p<0.001) entre el substrato rocoso emergido y el arenoso, sólo en condiciones de alta agregación, en las que la carga del pié de los individuos más grandes se reduce con la talla (r=-0.98, p<0.05). Experimentalmente, la abundancia de los ejemplares de tallas opuestas está mutuamente limitada (r=-0.87, p<0.01), la altura del oleaje limita la abundancia de los ejemplares menores (r=-0.94, p<0.001) siendo tolerada por los mayores (r=0.72, p<0.05). La carga promedio del pie disminuye con la altura del oleaje (r=-0.93, p<0.001). CONCLUSIONES: Con elevada agregación los ejemplares mayores emigran hacia substratos de difícil conquista por los menores, que están limitados por la acción mecánica del medio. La disminución de la carga del pie facilita la dispersión de los individuos.
Relative Warp and Correlation Analysis based on Distances of the Morphological shell shape patterns among freshwater gastropods (Thiaridae: Cerithimorpha)  [PDF]
Carlo Stephen O. Moneva,Mark Anthony J. Torres,Cesar G. Demayo
Aquaculture, Aquarium, Conservation & Legislation , 2012,
Abstract: Shell morphology has various details in their architecture that contributes effectively togastropod identification and classification. A conventional approach has been made to study shellmorphology using descriptions of biological shapes. However, descriptions can be strengthened byapplying additional quantitative tools. Relative Warp Analysis and Correlation Analysis based onDistances (CORIANDIS) were used to determine shell shape divergence and ascertain factorsassociated with the shell shape variation in three species of the genus Melanoides of the familyThiaridae namely, Melanoides granifera, Melanoides maculate, and unknown Melanoides speciesbelonging to the family Thiaridae. Relative warp summarizes the vectors of shape variation withinsamples. CORIANDIS on the other hand, examines similarities among samples and interpreted interms of congruence among traits. Results of the relative warp analysis showed significant shellshape variation among the Thiaridae species in the height of the spire, aperture, and apical shapes.Distance matrices were also constructed for the three data sets of shell characters: ventral/aperture,dorsal, and top/whorl shell. Results of the comparison via correlation analyses of distances among thespecies showed that an unknown Melanoides species is closely related to M. maculate than M.granifera. The results of the present study clearly show the importance of geometric morphometricanalysis determination of systematic relationship in Thiarid snails.
Displacement of Biomfhalaria glabrata by thiara granifera under natural conditions in the Dominican Republic
Gomez Perez, Jose;Vargas, Mercedes;Malek, Emile A.;
Memórias do Instituto Oswaldo Cruz , 1991, DOI: 10.1590/S0074-02761991000300008
Abstract: after a study of the population dynamics of biomphalaria glabrata snails in several breeding places in the dominican republic, the snail thiara granifera was introduced in some b. glabrata habitats. t. granifera became established in one point in one habitat in the townof quisqueya, in the east of the country. around this point of establishment 6 points were selected in order to observe the population dynamics of both species of snails and the chemical and biological characteristics at each point. four of these points already harbored b. glabrata. one control point was selected also harboring b. glabrata. after 14 months of observations, the results showed that t. granifera was competing with and displacing b. glabrata. this competition does not seem to be competition for food or vital space. rather, b. glabrata avoids the presence of t. granifera and moves away to new areas, and this is possibly due to a chemical substance(s) secreted by t. granifera or by physical contact with the large number of individuals of t. granifera.
First record of the invasive snail Melanoides tuberculatus (Gastropoda: Prosobranchia: Thiaridae) in the Paran? River basin, GO, Brazil
Rocha-Miranda, F.;Martins-Silva, M. J.;
Brazilian Journal of Biology , 2006, DOI: 10.1590/S1519-69842006000600018
Abstract: the thiarid snail melanoides tuberculatus (müller, 1774), native to asia and east africa was recorded for the first time in the paran? river basin, goiás state. there is no evidence concerning introduction vectors but aquarium releases is the most probable vector. specimens were collected at three different water bodies after twenty-seven rivers were investigated. the possible spread of this species to other habitats and potential effects on native thermal water communities are discussed.
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