Synchrony between Reproductive Phase and Flood Period: A Dispersion Mechanism for the Freshwater Clam Corbicula fluminea (Bivalvia: Corbiculidae) in a Brazilian Neotropical Floodplain

© 2021 Academia Sinica, Taiwan Open Access Synchrony between Reproductive Phase and Flood Period: A Dispersion Mechanism for the Freshwater Clam Corbicula fluminea (Bivalvia: Corbiculidae) in a Brazilian Neotropical Floodplain Claudenice Dei Tos1,*, Camila Antoniassi Cardim2, Vanessa de Brito Pereira2, and Roger Paulo Mormul1 1Departamento de Biologia, Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia), Universidade Estadual de Maringá. Av. Colombo 5790, Bloco H90, Jd. Universitário, Maringá, PR CEP 87020-900, Brazil. *Correspondence: E-mail: [email protected] (Tos) E-mail: [email protected] (Mormul) 2Curso de graduação em Ciências Biológicas, Departamento de Biologia, Universidade Estadual de Maringá. Av. Colombo 5790, Bloco G90, Jd. Universitário, Maringá, PR CEP 87020-900, Brazil. E-mail: [email protected] (Cardim); [email protected] (Pereira) Received 14 October 2020 / Accepted 31 December 2020 / Published 24 February 2021 Communicated by Benny K.K. Chan This study evaluates the gonadal histology of Corbicula fluminea present in the upper Paraná River floodplain and samples of limnological variables to understand its reproductive cycle. Corbicula fluminea was monitored monthly from December 2013 to February 2015. Spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa were identified in the male follicles of the hermaphrodites. Oogonia, oogonial nests, previtellogenic oocytes, early vitellogenic oocytes, middle vitellogenic oocytes and full-grown vitellogenic oocytes were identified in the female follicles of the hermaphrodites and females. The reproductive phases were described as developing, active spawning/sperm releasing, regression and regeneration. Higher values of temperature, dissolved oxygen, total nitrogen and total phosphorous were identified during flood periods, while higher values of pH and conductivity were obtained during dry periods. The species either does not reproduce or reduces the intensity of reproduction in cold months, with the sex ratio not differing significantly between hermaphrodites and females with regard to month and reproductive phase. Thus, reproduction is synchronized with the flood period and its limnological characteristics and when the increase in connectivity between floodplain environments facilitates the larval dispersion of this non-native species into other environments. Key words: Propagule pressure, Invasion, Bivalve reproduction, Spermatogenesis, Oogenesis. BACKGROUND The bivalve Corbicula fluminea (Müller 1774) is native to Asia (Santos et al. 2012). It invaded South America in the 1970s and dispersed through the Río de la Plata river basin (Ituarte 1981). It currently occupies several hydrographic regions of South America, and mapping reveals that it occurs from Venezuela to Argentina (Patagonia) (Darrigran 2002; Lasso et al. 2009; Santos et al. 2012; Crespo et al. 2015; Darrigran et al. 2020). Its densities in South American ecosystems vary widely. A total of 192 ind./m2 occur in the Paraguay Citation: Tos CD, Cardim CA, Pereira VB, Mormul RP. 2021. Synchrony between reproductive phase and flood period: a dispersion mechanism for the freshwater clam Corbicula fluminea (Bivalvia: Corbiculidae) in a Brazilian neotropical floodplain. Zool Stud 60:3. doi:10.6620/ZS.2021.60-03. Zoological Studies 60: 3 (2021) doi:10.6620/ZS.2021.60-03 1 © 2021 Academia Sinica, Taiwan ecoregion (Callil and Mansur 2002), while more elevated densities of 10,000 ind./m2 have been identified from the Lower Uruguay ecoregion (Castillo et al. 2007). Brazilian aquatic ecosystems also support a great variety of C. fluminea densities (e.g., 0.35–217.13 ind./m2 from the Tapajos-Juruena River (Poleze and Callil 2015), 6.66–7.3 ind./m2 from the Amazonas Estuary & Coastal Drainages (Beasley et al. 2003), 39.6–265.6 ind./m2 from the Iguassu River (Meyer et al. 2017), and 6154 ind./m2 from the Upper Paraná River ecoregions (França et al. 2007)). Moreover, a larger variety of C. fluminea densities have been recorded from within the latter ecoregion: 0–300 ind./m2 (Rodrigues et al. 2007), 3223 ind./m2 (Suriani et al. 2007), 0–1282 ind./m2 (Vianna and Avelar 2010), 4–519 ind./m2 (Luca et al. 2012), 12–235 ind./m2 (Beghelli et al. 2014), 105.5–274.1 ind./m2 (Oliveira et al. 2014), and 144.9 ind./m2 (Ragonha et al. 2014). High densities of invasive species are of great concern. Despite the potential positive impacts of C. fluminea, such as furnishing shelter and substrate for other species and being a source of food for pelagic and benthonic species, it has many negative impacts (Sousa et al. 2008 for a revision). According to these authors, this invader, for example, causes the dislocation of or reduction in the habitats available to other species, competes for benthonic food—thus possibly limiting planktonic food for other species—due to its elevated filtration rates, and can ingest a large number of spermatozoa of other species. A laboratory experiment with C. fluminea and Unio delphinus showed a decline in carbohydrate concentration in the latter taxon as a response to the higher density of C. fluminea. The ecological requirements of both species can sometimes overlap and may negatively interfere with native unionids and explain, in part, the loss of up to 30% of U. delphinus populations in native areas (FerreiraRodríguez et al. 2018). Moreover, economic impacts such as the shutdown of hydroelectric plants and urban water supply systems due to the obstruction of this species have also been recorded in Brazil (Santos et al. 2012). Successful invasions depend on fast colonization and dispersion, and could be related to many individual characteristics. For example, invasive animal species guarantee dispersion and colonization success by associating with human activities (Sousa et al. 2008). These authors also comment that invasive species can possess a large geographic distribution with the capacity to colonize new habitats due to genetic variability and phenotypical plasticity, and physiological tolerance to abiotic changes. Furthermore, invasive species can have particular reproductive aspects that facilitate their dispersion, such as a short reproduction period, precocious sexual maturity, high fecundity rates and fertilized females capable of colonizing new environments alone (Sousa et al. 2008). Although what was mentioned by these authors occurred with C. fluminea on the coast of the Río de la Plata, where this species was first identified in South America, these environmental conditions are not necessarily constant over time and this variation can adversely affect invasive species. For example, the populations of Corbicula inhabiting the Río de la Plata are currently contracting (Reshaid et al. 2017). Considering the reproductive aspects of invasive species, it is worth noting that gonadal alterations reflect the development of germ cells in different phases, which, in turn, allows for the characterization of different development stages. Thus, understanding the gametogenesis, reproductive phases and timing, and other aspects of the reproduction of invasive species could increase the evaluation precision of these population parameters. Moreover, invasion success can be understood using gametogenesis data, especially if this is related to environmental parameters. Knowledge of the reproductive cycle and the factors that influence reproduction could be an important tool to determine future control or management of this invasive species (e.g., Giglio et al. 2016). Other studies have described the gonadal cycle of C. fluminea in southern neotropical streams and potential environmental variables related to it (Cao et al. 2017). However, a proper evaluation of the relationship between the reproductive activities of C. fluminea and environmental variables is lacking, particularly in floodplain areas, which vary seasonally. In addition, evaluating the reproductive activities of C. fluminea in floodplain areas could increase our knowledge concerning the dispersion of this invasive species, since another invasive bivalve, Limnoperna fortunei, seems to synchronize its reproductive cycle with the flood to reach longer distances and colonize new habitats (e.g., Ernandes-Silva et al. 2016). Investigations of C. fluminea and other bivalves in different environments in Ilha Grande National Park, Paraná State, Brazil, through the evaluation of factors such as physical composition of granulometric texture, organic matter and macrophyte banks that encourage the establishment of bivalves, showed that C. fluminea was found only in Jatobá Lake, with the high density of this invasive species associated with the low percentages of finer sediments that allowed the establishment of a connection to the Paraná River (Ragonha et al. 2014). Thus, in order to better understand the reproductive characteristics of C. fluminea (by means of light microscopy methods and protocols) and verify the relationship between the abiotic parameters and page 2 of 16Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan the reproductive phases of the invader, the present study aimed to: i) histologically identify the types of germ cells and reproductive phases of C. fluminea, ii) determine the species’ reproduction timing through an examination of its reproductive phases, iii) verify the monthly sex ratio of females and hermaphrodites, iv) identify the sex ratio (females: hermaphrodites) in different reproductive phases and v) identify the main abiotic factors that may be related to the reproductive activities of C. fluminea. MATERIALS AND METHODS Sampling area Corbicula fluminea was sampled in December 2013 and monthly from February 2014 to February 2015 at the mouth of “Garças Lake Channel,” which connects this shallow floodplain lake to the Paraná River, Brazil (22°44'58"S; 53°15'36"W) (Fig. 1). Sampling was carried out manually when the water level of the channel was low or with a Petersen grab during the flood season. A monthly average of 24 (minimum 17 and maximum 34) C. fluminea individuals were collected and taken to the laboratory of the Research Group in Limnology, Ichthyology and Aquaculture - NUPÉLIA (Porto Rico, Paraná State, Brazil). The length (mm), width (mm) and weight (g) of the shells were measured using a pachymeter and a precision scale (0.01 g). The valves were separated by incision of the anterior and posterior adductor muscles and the viscera with gonad removed. The viscera were weighed (g) and fixed in Bouin solution for 48 hours. The samples were preserved in 70% ethanol. Histology and Light microscopy The preserved gonad was prepared for routine light microscopy for morphological study in a series Fig. 1. Map of the upper Paraná River showing the sampling area of the bivalve C. fluminea originating at the mouth of “Garças Lagoon Channel,” Paraná River (Porto Rico). (Courtesy of Jaime Luiz Lopes, 2019). N page 3 of 16Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan of ascending ethanol concentrations (70%, 80%, 90% and 95%) and embedded in historesin (Leica). The samples were sectioned at 5-μm thickness and the slides were stained using Periodic Acid-Schiff (PAS)/Metanil Yellow/Ferric Hematoxylin (Quintero-Hunter et al. 1991). The male and female germ cells were identified in most cases according to Park and Chung (2004). The reproductive phases were diagnosed according to the most advanced germ cell types, and abundance and distribution in the periphery of the germinal epithelium and follicular lumen. The reproductive phases were categorized as developing, sperm releasing capable/active spawning, regression and regeneration. This scale was adopted because of its simplicity to diagnose the reproductive phases of another invasive bivalve: Limnoperna fortunei (Dei Tos et al. 2016). Limnological variables We measured the limnological variables monthly from February 2014 to February 2015. Hydrometric level data from the Paraná River were taken daily by means of a limnetic ruler installed at the field station on the banks of the Paraná River (22°45'53.91"S; 53°15'27.92"W). The hydrometric level measurements occurred in the morning and afternoon (daily average used in the present study). In addition, water temperature (°C), dissolved oxygen (mg l-1), electrical conductivity (µS cm-1) and pH were also measured in the field. Moreover, water samples were taken to later evaluate the concentration of total nitrogen (µg l-1) (Bergamin et al. 1978) and total phosphorus (µg l-1) (Mackereth et al. 1978). Statistical analyses Reproduction time was found through the number of hermaphrodites, females and grouped sexes per reproductive phases and month. The sex ratio for hermaphrodites and females with different sizes per month and in the different reproductive phases was estimated through the chi-square test using Statistica 7.1 (StatSoft Inc. 2005). In order to summarize the main abiotic factors that could affect the reproductive activities of the species, a principal component analysis (PCA) was also carried out using Statistica 7.1 (StatSoft Inc. 2005). The scores of the axes retained according to the Broken-Stick criterion were then grouped into flood period (December, January, February, March and April) and dry period (May, June, July, August, September, October and November). Lastly, analysis of variance (ANOVA) was used to verify significant differences between the periods as regards the PCA scores, adult abundance and the active spawning phase. RESULTS During the study period, we sampled 341 individuals (106 hermaphrodites and 235 females) of the bivalve Corbicula fluminea, whose shell length ranged from 0.98 to 3.11 cm among the hermaphrodites and 0.92 to 3.54 cm among the females. Total weight varied from 0.49 to 13.0 g in the hermaphrodites and 0.43 to 14.7 g in the females. The spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa of hermaphroditic individuals were identified during the histological examination of the follicles and their germ cells (Table 1; Fig. 2). Moreover, it was possible to recognize four reproductive phases: developing, sperm releasing capable, regression and regeneration (Table 2; Fig. 3). Regarding the females, the ovarian follicles were composed of germ cells such as oogonia, oogonial nests, previtellogenic oocytes, and early, middle and full-grown vitellogenic oocytes (Table 3; Fig. 4). Depending on the dominance of the germ cell types, four reproductive phases for females were also defined: developing, active spawning, regression and regeneration (Table 4; Fig. 5). The reproductive period for females and hermaphrodites was long (almost one year) (Fig. 6A, B, C). There were no reproductive activities (or very few) in May, June and July. The number of individuals with gonads in the developing phase was higher in these months. Moreover, females occurred slightly more than hermaphrodites during the study period; however, according to the chi-square test, there was no significant predominance of one sex (d.f. = 1 and χ2 > 3.84 for p < 0.05; Table 5). The ratio between females and hermaphrodites, considering each reproductive phase during the study period, showed that neither sex predominated (d.f. = 1 and χ2 > 3.84 for p < 0.05; Table 6). Principal component analysis (PCA) indicated that pH, electrical conductivity and total nitrogen were the main abiotic variables that may have affected the reproductive pattern of C. fluminea, considering the distribution of the samples on axis 1 of the analysis, with pH and electrical conductivity having positioned the collections negatively on the axis and total nitrogen having positioned them positively (Fig. 7). On the other hand, dissolved oxygen and temperature positioned the collections positively on axis 2, while total phosphorus positioned them negatively. This pattern explained 58.81% of the distribution of the C. fluminea page 4 of 16Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan Table 1. Diagnosis of the germ cells present in the follicles of the testicles of the bivalve C. fluminea originating at the mouth of the Garças Lagoon Channel, Paraná River (Porto Rico) Description of the germ cells Spermatogonia (sg) the largest cells of the germinal lineage, located in the germinal epithelium of the testicles. They present slightly granular cytoplasm and a spherical or elliptical, central, basophilic nucleus and delicate nucleolar chromatin, with 1, 2 or 3 basophilic nucleoli (Fig. 2A). Spermatogonia enter into meiosis and originate primary spermatocytes. Primary spermatocytes (pc) spherical cells that have less cytoplasm than spermatogonia; therefore, they are smaller, with a condensed and basophilic nucleus (Fig. 2A). Primary spermatocytes have completed the first division of meiosis and originate secondary spermatocytes. Secondary spermatocytes (sc) frequent, spherical and similar in size to primary spermatocytes, with their nucleus possessing chromatin in the form of an umbrella (Fig. 2A, B, E) and after the second consecutive meiotic division originate spermatids. Early spermatids (st) spherical and smaller than primary and secondary spermatocytes. They possess scarce cytoplasm and a spherical nucleus (Fig. 2A, B, C, E). They do not divide any more, but transform morphologically through the process of spermiogenesis (become more elongated) into spermatozoa. Spermatozoa (sz) possess a conical head, with a long, condensed nucleus. Two flagella project from the basal region of the head. Spermatozoa form dense groupings that are spherical or semispherical or in the form of a bunch of bananas connected by slightly lilac Sertoli cells, with their flagella facing the lumen of the testicle. They detach from the Sertoli cells in the spawning period and are liberated into the lumen of the testicle tubules during spermiation (Fig. 2C, D, E). Fig. 2. Partial photomicrograph recording the germ cells of the germinal compartment of the follicles of the bivalve C. fluminea. A. Spermatogonia (sg), primary spermatocytes (pc), secondary spermatocytes (sc) and spermatids (st); B. Secondary spermatocytes and spermatids; C, D. Spermatozoa (sz) and their organization around Sertoli cells (S); Sertoli cell (S) and flagella (fl); E, F. Spermatozoa (sz). Germinal epithelium (ge). Light microscopy/Periodic Acid-Schiff /Hematoxylin /Metanil Yellow. Scale bar: A, B, C, D, E, F = 24 µm. page 5 of 16Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan Table 3. Diagnosis of the germ cells present in the ovarian follicles of the bivalve C. fluminea originating at the mouth of the Garças Lagoon Channel, Paraná River (Porto Rico) Description of the germ cells Stages Phases Diagnoses Oogonial proliferation stage Oogonial nests Oogonia (og) are the smallest germline cells, associated with the periphery of the germinal epithelium (Fig. 4A). They possess scarce cytoplasm, a basophilic nucleus and an evident nucleolus. Oogonial proliferation produces oogonial nests (Fig. 4B). Early prophase stage Leptotene, zygotene, pachytene and diplotene phases Nest with germline cysts (Fig. 4B). Oocytes possess a voluminous, spherical nucleus with a regular scarce ooplasm. The distinct pattern of the chromatin indicates that the oocyte nest is in the pachytene phase of meiosis prophase I (Fig. 4C). Previtellogenic stage Previtellogenic oocytes (pov) are larger than those from the previous phase and connected to the epithelium of the ovarian follicle. They possess basophilic ooplasm and a slightly basophilic nucleus with one, two or multiple nucleoli (Fig. 4D). Vitellogenic stage Early vitellogenic oocytes Early vitellogenic oocytes (ev) are larger than those from the previous phase and connected by a peduncle to the epithelium of the ovarian follicle. They possess acidophilic ooplasm, indicating the start of yolk deposition. The nucleus is voluminous and contains 1, 2, 3 or 4 nucleoli (Fig. 4E). Middle vitellogenic oocytes Middle vitellogenic oocytes (mv) are very similar to early vitellogenic oocytes; however, they are slightly larger. Their ooplasm is acidophilic and the nucleus voluminous and spherical or elliptical with 1 to 4 nucleoli that may be connected to or disconnected from the ovarian follicle (Fig. 4F, G, H). Full-grown vitellogenic oocytes Full-grown vitellogenic oocytes (fg) are the largest germ cells. They possess acidophilic ooplasm replete with yolk granules. The nucleus is located in the center and is elliptical, semielliptical or almost spherical with one or 2 nucleoli (Fig. 4H, I). Full-grown oocytes may be linked to or unlinked from the epithelium of the ovarian follicle. The disconnected full-grown oocytes move toward the gonadal duct. Table 2. Diagnosis of the reproductive phases of the hermaphrodites of the bivalve C. fluminea originating at the mouth of the Garças Lagoon Channel, Paraná River (Porto Rico) Diagnosis of the reproductive phases development the male follicles are small and carry proliferating spermatogonia, primary and secondary spermatocytes and spermatids (Fig. 3A, B, C). sperm releasing capable the male follicles are expanded and branched and present spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa (Fig. 3D, E, F). The spermatozoa are abundant and organized in the form of a circle, semicircle or bunch of bananas stuck to Sertoli cells and/or dispersed in the lumen of the follicle (Fig. 3F). regression (equivalent to spawned), the branched follicles are smaller compared to the previous phase and possess spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa (Fig. 3G, H). The spermatozoa are scarce in this phase and dispersed in the lumen of the follicles (Fig. 3I). regeneration the follicles are smaller compared to the previous phase, with no evidence of lumen. Spermatogonia, primary and secondary spermatocytes and vestiges of spermatozoa occur (Fig. 3J, K, L). page 6 of 16Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan Fig. 3. Photomicrography illustrating spermatogenic follicles in different reproductive phases of the bivalve C. fluminea (hermaphrodite). A and B, General view of male follicles in developing phase. C, Detail of primary spermatocytes. Scale bar: A = 238 µm, B = 116 µm and C = 24 µm. D and E, General view of male follicles in sperm releasing capable phase. F, Detail illustrating spermatogonia, primary spermatocytes, spermatids and spermatozoa. Scale bar: D = 460 µm, E = 238 µm and F = 60 µm. G, Panoramic view of branched male follicles in regression. H and I, Follicles exhibiting spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa. Scale bar: G = 238 µm, H = 60 µm and I = 24 µm. J and K, General structure of male follicles in recuperation. L, Detail of a follicle in recuperation showing primary and secondary spermatocytes and vestiges of spermatozoa. Scale bar: J = 238 µm, K = 115 µm and L = 24 µm. Light microscopy/Periodic Acid-Schiff/Hematoxylin/Metanil Yellow. Spermatogonia (sg), primary spermatocytes (pc), secondary spermatocytes (sc), spermatids (st), spermatozoa (sz), interconnective tissue (ct) and digestive gland (dg). page 7 of 16Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan Fig. 4. Photomicrography illustrating germ cells of ovarian follicles of the bivalve C. fluminea. A, Germinal epithelium with oogonia. B, Oogonial cyst. C, Nest with pachytene oocytes. D, General view of previtellogenic oocytes. E, General view of early vitellogenic oocytes. F, Follicle showing oogonia, previtellogenic oocytes, early vitellogenic oocytes and middle vitellogenic oocytes. G, Follicle with middle vitellogenic oocytes. H, Follicle with early vitellogenic oocytes, middle vitellogenic oocytes and full-grown oocytes. I, General view of full-grown oocytes showing yolk granules and nucleus. Scale bar: A, B, C, D = 24 µm, E, F, G and I = 60 µm and H = 115 µm. Light microscopy/Periodic Acid-Schiff/Hematoxylin/Metanil Yellow. Oogonia (og), pachytene (pe), previtellogenic oocytes (pvo), early vitellogenic oocytes (ev), middle vitellogenic oocytes (mv), full-grown vitellogenic oocytes (fg) and interconnective tissue (ct). Table 4. Diagnosis of the reproductive phases of females of the bivalve C. fluminea originating at the Garças Lagoon Channel, Paraná River (Porto Rico) Diagnosis of the reproductive phases Developing the ovarian follicles are expanding and previtellogenic oocytes and early and middle vitellogenic oocytes are found in them (Fig. 5A, B, C). Full-grown vitellogenic oocytes are absent. Active spawning the follicles are replete with full-grown oocytes that move toward the gonadal duct (Fig. 5D, E, F), but abundant early and middle vitellogenic oocytes can be seen in nearby tubules. Regression (equivalent to spawned), the ovarian follicles remain disorganized (Fig. 5G) and early and middle vitellogenic oocytes are found (Fig. 5H, I). There are also follicles with only oogonia and oogonial nests. Regeneration the follicles contain oogonia, oogonial nests, previtellogenic oocytes and early and middle vitellogenic oocytes (Fig. 5J, K, L). page 8 of 16Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan Fig. 5. Photomicrography showing the different reproductive phases of the ovarian follicles of the bivalve C. fluminea. A, General view of a female follicle in the developing phase. B and C, Details of previtellogenic oocytes and early vitellogenic oocytes. Scale bar: A = 460 µm, B = 238 µm and C = 115 µm. D and E, General view of female follicles in active spawning. F, Detail illustrating full-grown vitellogenic oocytes passing through the gonadal duct. Scale bar: D = 460 µm, E = 230 µm and F = 115 µm. G and H, Panoramic view of female follicles in regression. I, Follicle exhibiting oogonia, early and middle vitellogenic oocytes and empty follicles except for a germinal epithelium with oogonia. Scale bar: G = 460 µm, H = 238 µm and I = 115 µm. J and K, General structure of female follicles in recuperation. L, Detail of a follicle in recuperation showing oogonial cysts and early vitellogenic oocytes. Scale bar: J = 460 µm, K = 238 µm and L = 115 µm. Light microscopy/Periodic Acid-Schiff/Hematoxylin/Metanil Yellow. Oogonia (og), previtellogenic oocyte (pvo), early vitellogenic oocyte (ev), middle vitellogenic oocyte (mv), full-grown vitellogenic oocyte (fg), interconnective tissue (ct), gonadal duct (gd), digestive gland (dg), inner demibranch (id). page 9 of 16 Zoological Studies 60: 3 (2021) © 2021 Academia Sinica, Taiwan of Corbicula fluminea over native freshwater mussels. Hydrobiologia 810(1):85–95. doi:10.1007/s10750-016-3059-1. França RS, Suriani AL, Rocha O. 2007. Composição das espécies de moluscos bentônicos nos reservatórios do baixo rio Tietê (São Paulo, Brasil) com uma avaliação do impacto causado pelas espécies exóticas invasoras. Rev Bras Zool 24(1):41–51. doi:10.1590/S0101-81752007000100005. 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