Sinotaia aeruginosa

S. aeruginosa inhabits rice paddies, lakes, pools, slow flowing rivers, streams, ditches, ponds, and canals called khlongs in Vietnam.[1][8] It has a benthic lifestyle and lives mainly in shallow littoral areas,[12] usually in soft mud rich in organic matter.[8] It can actively glide over the sediment or bury into it.[13] This species is not actively migrating, rather its dispersal appears to be caused passively by floods, animals (zoochory), and accidentally by humans.[6] The species prefers water temperatures typical of subtropical habitats, e.g., 6 to 30.1 °C (42.8 to 86.2 °F) in Lake Tai.[13]

Populations can reach densities of up to 400 snails/m².[8] In Chao Lake, it is the dominant gastropod species with an abundance 2-128 snails/m² and an average biomass of 87.5 g/m².[14] It is similarly dominant in Lake Tai.[15]

S. aeruginosa has been found to respond well to laboratory conditions with a water temperature of 24 °C, pH 8 and a 1:4 ratio of sediment to water.[8]

Populations of S. aeruginosa at high densities are able to alter the physicochemical features of water. They decrease the concentration of chlorophyll a and thus directly increase water transparency. This indirectly decreases the concentration of dissolved oxygen through consumption of oxygen-producing algae.[12] The species affects the composition of the phytoplankton community by decreasing the biomass of mostly toxic cyanobacteria and flagellates and promoting the biomass of mostly colonial green algae.[9][12] Nitrogen concentrations may also be decreased.[9] Its pronounced effect on water chemistry and community composition makes S. aeruginosa a keystone species in its habitat.[5]

S. aeruginosa is a herbivorous deposit feeder.[8][16] It consumes mainly epiphytic algae,[17] but its diet also includes detritus, bacteria,[8] aquatic plants,[16] sand grains, diatoms, green algae,[18] and cyanobacteria such as Microcystis.[19] Its consumption of cyanobacteria during algal blooms may result in bioaccumulation of toxic microcystins (microcystin-LR, microcystin-RR) from Microcystis in the gonads, the hepatopancreas and the digestive tract.[19] Adult snails feeding ad libitum under ideal laboratory conditions eat 16.0 mg of fish food daily.[8]

S. aeruginosa is gonochoristic, which means that each individual animal is distinctly male or female.[6] The species is ovoviviparous.[16] Newborn snails attach to non-sediment substrates (shells of adults or other material) in their first 2–3 days.[8]

The shell length of juvenile snails starts at about 3 mm and grows rapidly by about 190 μm daily. Juveniles become adults at the age of nine weeks, when they reach a shell height of 12.15–16.09 mm; from then on, they grow more slowly at about 30 μm daily. Snails can be reliably sexed at this age.[8]

Individuals start mating and reproducing in at water temperatures of 16–18 °C, although a temperature of 24–26 °C is optimal. Females start to give birth to the first newborn snails at the age of 18 weeks, when they reach a shell height of 15–16 mm and a body weight of 0.81–0.94 g.[8][16] Gravidity of adult females lasts the entire year.[8] The average number of newborn snails in the wild is 0.24 snails per day (50 per year)[8][16] or up to 0.55 snails per day in the laboratory.[8] Each gravid female carries 19–21 embryos inside her.[8]

Generation time is quite short at about four months.[6][8] The species can have three generations per year in the aquarium.[8] The reproductive cycle is about six months.[16]

S. aeruginosa has been the subject of various aquatic toxicology studies into the effects of copper,[8][20] cadmium,[21] lead,[22] ethylbenzene,[23] 2,2',4,4'- tetrabromodiphenyl ether,[21][24] tributyltin,[25] microcystin,[26] multi-walled carbon nanotubes,[27] and 17β-estradiol.[28] The species has a high sensitivity to copper exposure and could thus be used for monitoring of sediment toxicity caused by environmental copper pollution.[8]

Sinotaia aeruginosa snails from West Lake in Hanoi, Vietnam were found to be contaminated with copper, lead and zinc.[29] The concentration of these elements in these snails exceeded standards of Food and Drug Administration and of Food Standards Australia New Zealand.[29]

Distribution of rare-earth elements was studied in a labolatory. Results shown bioaccumulation of lanthanum, samarium, gadolinium and yttrium in Sinotaia aeruginosa and there was found no bioaccumulation of cerium in this snail.[30]

The species' population trend is unknown,[1] but population sizes are mostly large.[6] Water pollution and sedimentation are threats to local populations,[1] while more general threats include habitat fragmentation by damming and habitat destruction.[6] The genetic diversity of this species was found to be high in China.[6] S. aeruginosa is currently classified as Least Concern by the IUCN.[1]

S. aeruginosa serves as an intermediate host for Angiostrongylus cantonensis[31][32] and for Echinochasmus fujianensis.[33]

Predators of the species include the black carp Mylopharyngodon piceus; S. aeruginosa is one of the main food sources for this fish, making it important in the freshwater food chain.[8]