This aquatic plant grows mainly under the water surface of Lake Sambell in Beechworth. It is around 2m tall and has a shallow fibrous root system. It has recently become dislodged in large numbers, floating to the water surface. This is not typical for this location. I am unsure of the species let alone the cause, any help would be much appreciated.
A native plant (despite its common name). Apologies for delay in responding, just picked this up recently. In most cases, dislodging of vVallisneria is caused by one or more of the following: wave action (from wind, power boats), fish (carp, mumbling).