Investigation on Aspidogastrea infection in freshwater mussels in Anhui Province / 中国血吸虫病防治杂志

Objective To investigate the prevalence of trematode Aspidogastrea in freshwater mussels in Anhui Province, China. Methods The freshwater mussels living in different water areas within Anhui territory were harvested and dissected from April to May,2015. Then the flukes were collected from the pericardial cavities of the clams into a petri dish containing small amount of saline. After rinsing,the flukes were transferred into a bottle containing 70%ethanol for following identification by staining of the specimens prepared as previous protocol. Results A total of 3 007 calms in 12 species,including Unio doug?lasiae(603),Acuticosta chinensis(90),Lamprotula caveat(150),Lamprotula leai(250),Lanceolaria grayana(47),An?odonta pacifica(60),Anodonta woodiana(350),Cuneopsis heudei(100),Solenaia oleivora(150),Cristaria plicata (567),Hyriopsis cumingii(550)and Arconaia lanceolata(90)were dissected,in which 1 467 mussels were infected with the trematode Aspidogastrea,with an infection rate of 48.79%(1 467/3 007). Totally,7 306 flukes belonging to 3 genera under the subclass of Aspidogastrea were isolated. These trematodes were genera of Aspidogaster,Lophotaspis and Cotylaspis. The in?fection density was from 1 to 128 capita for individual positive clam,with a mean infectiosity of 4.98(7306/1467)for each mus?sel. Conclusion The freshwater bivalves living in different water areas in Anhui Province are infected with the trematode Aspi?dogastrea. These flukes were identified as Aspidogaster sp. Lophotaspis sp. and Cotylaspis sp. belonging to subclass Aspidogas?tridae of family Aspidogastrea.

Molecular markers for genetic diversity, gene flow and genetic population structure of freshwater mussel species

Freshwater mussel species are in global decline. Anthropogenic changes of river channels and the decrease of autochthonous fish population, the natural hosts of mussels larval stages (glochidia), are the main causes. Therefore, the conservation of mussel species depends not only on habitat conservation, but also on the availability of the fish host. In Portugal, information concerning most of the mussel species is remarkably scarce. One of the most known species, Unio pictorum is also in decline however, in the basins of the rivers Tua and Sabor (Northeast of Portugal), there is some indication of relatively large populations. The aforementioned rivers can be extremely important for this species conservation not only in Portugal, but also in the remaining Iberian Peninsula. Thus, it is important to obtain data concerning Unio pictorum bioecology (distribution, habitat requirements, population structure, genetic variability, reproductive cycle and recruitment rates), as well as the genetic variability and structure of the population. Concomitantly, information concerning fish population structure, the importance of the different fish species as glochidia hosts and their appropriate density to allow effective mussel recruitment, will also be assessed. The achieved data is crucial to obtain information to develop effective management measures in order to promote the conservation of this bivalve species, the conservation of autochthonous fish populations, and consequently the integrity of the river habitats.

As espécies de mexilhões de água doce estão em declínio global. Mudanças antropogénicas do canal dos rios e diminuição das populações de peixes autóctones, os hospedeiros naturais do mexilhão nos estágios larvais (glochidia), são as principais causas. Portanto, a conservação de espécies de mexilhão depende não só da conservação dos habitats, mas também da disponibilidade do hospedeiro peixe. Em Portugal, a informação relativa à maioria das espécies de mexilhão é extremamente escassa. Uma das espécies mais conhecidas, Unio pictorumtambém está em declínio, no entanto, nas bacias dos rios Tua e Sabor (Nordeste de Portugal), existe indicação de populações relativamente grandes. Os rios acima mencionados podem ser extremamente importantes para a conservação das espécies, não só em Portugal, mas também na restante Península Ibérica. Assim, é importante obter dados relativos à bioecologia do Unio pictorum (distribuição, requisitos de habitat, estrutura populacional, variabilidade genética, ciclo reprodutivo e as taxas de recrutamento), bem como a variabilidade e estrutura genética da população. Concomitantemente, informações sobre a estrutura da população de peixes, a importância das diferentes espécies de peixes como hospedeiros e sua densidade adequada para permitir o recrutamento eficaz do mexilhão, também será avaliada. Os resultados obtidos serão cruciais para obter informações que permitam o desenvolvimento de medidas de gestão eficazes, a fim de promover a conservação destas espécies de bivalves, a conservação das populações de peixes autóctones e, consequentemente, a integridade dos habitats fluviais.

Molecular markers for genetic diversity, gene flow and genetic population structure of freshwater mussel species / Marcadores moleculares para estudo da diversidade genética, fluxo génico e estrutura genética de populações de espécies de mexilhões de água doce

Freshwater mussel species are in global decline. Anthropogenic changes of river channels and the decrease of autochthonous fish population, the natural hosts of mussels larval stages (glochidia), are the main causes. Therefore, the conservation of mussel species depends not only on habitat conservation, but also on the availability of the fish host. In Portugal, information concerning most of the mussel species is remarkably scarce. One of the most known species, Unio pictorum is also in decline however, in the basins of the rivers Tua and Sabor (Northeast of Portugal), there is some indication of relatively large populations. The aforementioned rivers can be extremely important for this species conservation not only in Portugal, but also in the remaining Iberian Peninsula. Thus, it is important to obtain data concerning Unio pictorum bioecology (distribution, habitat requirements, population structure, genetic variability, reproductive cycle and recruitment rates), as well as the genetic variability and structure of the population. Concomitantly, information concerning fish population structure, the importance of the different fish species as “glochidia” hosts and their appropriate density to allow effective mussel recruitment, will also be assessed. The achieved data is crucial to obtain information to develop effective management measures in order to promote the conservation of this bivalve species, the conservation of autochthonous fish populations, and consequently the integrity of the river habitats.

As espécies de mexilhões de água doce estão em declínio global. Mudanças antropogénicas do canal dos rios e diminuição das populações de peixes autóctones, os hospedeiros naturais do mexilhão nos estágios larvais (glochidia), são as principais causas. Portanto, a conservação de espécies de mexilhão depende não só da conservação dos habitats, mas também da disponibilidade do hospedeiro peixe. Em Portugal, a informação relativa à maioria das espécies de mexilhão é extremamente escassa. Uma das espécies mais conhecidas, Unio pictorum também está em declínio, no entanto, nas bacias dos rios Tua e Sabor (Nordeste de Portugal), existe indicação de populações relativamente grandes. Os rios acima mencionados podem ser extremamente importantes para a conservação das espécies, não só em Portugal, mas também na restante Península Ibérica. Assim, é importante obter dados relativos à bioecologia do Unio pictorum (distribuição, requisitos de habitat, estrutura populacional, variabilidade genética, ciclo reprodutivo e as taxas de recrutamento), bem como a variabilidade e estrutura genética da população. Concomitantemente, informações sobre a estrutura da população de peixes, a importância das diferentes espécies de peixes como hospedeiros e sua densidade adequada para permitir o recrutamento eficaz do mexilhão, também será avaliada. Os resultados obtidos serão cruciais para obter informações que permitam o desenvolvimento de medidas de gestão eficazes, a fim de promover a conservação destas espécies de bivalves, a conservação das populações de peixes autóctones e, consequentemente, a integridade dos habitats fluviais.

Distribution of natural radionuclide 40K in biotic and abiotic components of the Cauvery river system, Tiruchirapalli, India.

Abiotic components like water and sediment, and biotic components such as mussels, fish and grass collected from Cauvery river at Tiruchirapalli were analysed for 40K activity. The highest level of 40K activity was found in the sediment (342 mBq g–1 dry weight) and the lowest activity was found in water (2·209 mBq ml–1). In the freshwater mussel Parreysia favidens (Benson) 40K activity was estimated in the total soft tissues and shells of mussels belonging to three different size groups· In all the size groups 40K activity was two times higher in shells (68–39 mBq g–1 fresh weight) than in the total soft tissues (25–17 mBq g–1 fresh weight)· The results indicate that the younger mussels accumulated more 40K than the older ones. The ability of internal organs of mussels belonging to group III to accumulate 40K was in the following order: gills > digestive gland > foot > mantle. The values ranged from 47 to 18 mBq g–1 fresh weight in the various organs. Concentration of 40K in the mussel was distinctly higher than in the grass Echinochloa colonum (J Koenig) (95 mBq g–1 fresh weight), and the concentration of 40K in the bone of the fish Cirrhina cirrhosa (Bloch) (126 mBq g–1 fresh weight) was higher than to that of muscle (113 mBq g–1 fresh weight)·