Tītiko/Mudflat Snail Amphibola crenata
Endemic. Not threatened
As you look over the Estuary as the tide recedes, what appears to be numerous bumps is in fact this species of snail. Not only here but it is a very common species on most Estuary mudflats around Aotearoa New Zealand but is found nowhere else in the world.
It is not a true marine or land snail and is able to survive briefly at high tide for an hour or so and then begins to breath air again as the tide falls back.
They feed by grazing the surface for decomposing matter and waste is secreted in wavy strands, clearly visible in the picture opposite.