Acute Bladder Snail (Physella acuta)

Journal details:

Confirmed identification: Acute Bladder Snail (Physella acuta) (Draparnaud, 1805) (Family: Physidae) is an invasive snail with a sinistral, air-breathing mechanism, that dwells in freshwater rivers, streams, ponds and swamps. It is also found in anthropogenic reservoirs and power station discharges, surviving under short-lived harsh conditions including extreme weather and pollution. It feeds on dead plant and animal matter, and other detritus. In the wild, it forages mainly on epiphytic vegetation and on macrophytes. Its presence potentially encourages the proliferation of invasive non-native macrophytes like Nuttall’s waterweed (Elodea nuttallii). It rapidly reproduces and has adapted well to UK waters. It is a self-compatible hermaphrodite and in experimental conditions, it is capable of self-fertilization over 20 generations. Its ecological impact on native flora and fauna was assessed by the UK Technical Advisory Group as ‘unknown’ under the Water Framework Directive Guidelines for Alien Species.

Initial consideration: Wandering Pond Snail, UK (Ampullaceana balthica, Linnaeus, 1758) (Class: Gastropoda, Order: Hygrophila, Family: Lymnaeidae). A very common snail in UK where it also leaves weed-filled pond environments, especially in still waters, onto damp patches, emergent vegetation and/or on to muddy banks. It remains in close proximity to the ponds and is a detritus feeder on water plants, algae and plant detritus. Specimens are also seen gliding on the top of water surfaces. Its shell diameter reaches ca.11-14mm and is tall-spired with a large operculum.

Specifics of the current observation: Tank snail associated with Elodea sp. pondweed; ca.0.8-1cm in length; angle of carapace projection ca.20°; mottled pale brown dark green camouflage shell markings with irregular borders (visible x40 optical microscope with 20um eyepiece divisions); glide speed on submerged transparent polystyrene ca.1.5cm/min.; consumes algae deposits and strong attraction to pelleted Daphnia sp. feed; precise subspecies identification unknown.

Posted on December 15, 2023 07:00 PM by rgcooper2023