The ecology of the estuary
Its presence gave the estuary ecology. Even the huge quantity of sperm and eggs it would release that did not fertilise and grow on to become part of the settlement, even these joined the other plankton in the food chain to become valuable nutrients for other creatures, big and small, who in turn attracted other predators. These spat formed a critical plank in the food pyramid. Those that did fertilise and cluster together in their hundreds of thousands, even millions, yes millions, created reefs that became shelter for other creatures, their hard shells making a stable rock face for plant life to establish and root, their bulk protecting the marsh grasses from the outrageous currents of the seas, their craggy bulk providing shelter for other shellfish under which to hide.
The oyster is not really comparable to species. The oyster was at the start of life, a benign coloniser. Its presence created if not a marine civilisation, at least an environmental parallel. The oyster was the Eden in the estuary. Its presence was blessing.
Once established, the colony grew in perpetuity. Some oysters might live perhaps to be 100 years old, but even when they finally die, their shells became part of the landscape, the spawning ground for their children and their children’s children, the rocks on which the colony can survive and eventually even when finally the incredibly hard shell crumbles it washes into toothlike fragments on the seabed, its multifarious elements broken down into tiny particles that become gravel, limestone and what we just dismissively shorthand as…rock.