Stella McQueen

Mussel populations are full of geriatrics with no younger generations coming through to replace them

Kākahi, aka freshwater mussels, feed by filtering tasty particles from the water. They poke out these two tubes, called siphons, using one to suck water into and the other to blow the filtered water out of.

It is not uncommon to find kākahi (aka freshwater mussels) in pet shops, sold as a cheap living filter for aquaria. Unfortunately this condemns them to a slow death by starvation.

Smaller, paler freshwater mussels can be aged by counting the dark rings, one ring shows one year of growth. This one is four and a half years old. Apparently they can live as long as 50! Although a more usual age is 20-25 years.