But, ironically, by far the most plentiful form of animal life found in the Otago Harbour is also the most obscure and least studied.
Marine biologist Dr Daniel Leduc, a University of Otago graduate, points out that marine nematodes, tiny worms ranging from half a millimetre to about two centimetres long, are by far the most commonly occurring animals in the harbour.
Living in or on marine sediments, they are obviously not short of companions. An average square metre of coastal sea floor contains about one million nematodes.
On this basis, an estimated 40,000 billion nematodes live in the the Otago Harbour, he says. This amounts to more than 100 tonnes of nematodes.
"Nematodes are as much a part of New Zealand's native biodiversity as the larger, more charismatic animals, and as such deserve our attention," he says.
Dr Leduc, who is a postdoctoral researcher at Otago University's Portobello Marine Laboratory, devoted his recent PhD study to marine nematodes and is continuing his research.
He believes there is a huge amount more to be learned about the worms, which play an important role in the marine food web, as a high quality food source for larger animals like juvenile fish, shrimps, and crabs.
They are also used as a food source in aquaculture.
Because they are sensitive to environmental conditions, nematodes are also commonly used overseas to monitor the health of marine ecosystems.
Dr Leduc believes there are several hundred nematode species previously unknown to science lurking in the harbour sediments waiting to be discovered.
And Dr Leduc took a few sediment samples from Papanui Inlet, elsewhere on the Otago Peninsula, in 2006.
In about half a litre of sediment, he found about 85 nematode species, only two of them known to science.
Six of the previously unknown species have since been formally named, two of them after his daughter and stepson.
Many of the harbour species were likely to be found only in New Zealand, he said.
Nematodes were essential in driving important ecological processes such as decomposition and nutrient cycling, playing a similar role to earthworms.
