When I was young my cousins and I used to swim in Lake Rotorua.
From dad's small boat we could see the bottom most of the way out to Mokoia. On such excursions we would from time to time catch glimpses of the concentric ridged circles - whakairoiro - of sand radiating outward.
Dad, a trained scientist used to call them environmental indicators. At the centre of these carved sand circles or whakairoiro, lived the leader of the wider hapu of freshwater mussels - a grandfather sized kakahi.
Our elders taught us that in times of approaching climatic crisis these special kakahi would emerge from hiding, warning us of approaching danger.
It was not only a scientifically based observation likely associated with barometric pressure change, but also a metaphor applied to rangatira of Ngati Whakaue who emerged from every day duties to lead our people in times of crisis: Te kakahi whakairoiro o Ngati Whakaue.