FRESHWATER MUSSEL
(Hyridella menziesi)
An
elongate, smooth-surfaced mollusc whose shell is dark olive-brown
on the outside and grey-white on the inside. It can reach a
diameter of 9cm and is found in lakes, ponds, streams and rivers
throughout New Zealand, especially those with a bottom of fine
sand or mud.
| These
animals have a complex life-cycle involving many stages.
Initially, the larval young, called glochidium larvae, are
retained within the shell of the parent. Then during the
breeding season, in summer, |
 |
the larvae are released complete with small hooks attached to
their developing shells. They use these hooks to attach to the
lips, gills and fins of bullies and galaxiids (native freshwater
fish). They remain with the fish for some time, but eventually
detach and sink to the bottom where they grow to adulthood.
Did
you know?
There is no indication that the mussel larvae cause any harm
to the fish it attaches to!
