The ocean is one of Mother Nature's best kept secrets and while scientists have made numerous discoveries over the years, they are still finding new marine marvels.

Each year the University of Waikato's Coastal Marine Field Station at Sulphur Point opens its doors to the public for people who are curious about marine life.

Seahorses were just one of the many creatures at the Costal Marine Field Staion at Sulphur Point. Photos: Tracy Hardy.

The annual open day, with a range of activities and specimens on show, is part of national Seaweek – from February 28 to March 8.

Describing today's event, Waikato University coastal marine science professor Chris Battershill says the day has been great.

'I think we had the biggest bike ride contingent ever. There was close to 50 people who went around the estuary.

'They asked some fantastic questions and gave us some insight to the ecology of the system and some good anecdotal evidence of how it was in the past.”

The bike ride around the Waikareao Estuary allowed people to see marine life in its natural habitat and ask questions about the coastal scene.

'Today, it was interesting. Last year there was a low tide and today it was a glassy, calm high tide. It was insane,” says Chris.

'We could see ripples of fish movement on there and allowed us to see everything when the tide was in.

'It was a unique situation where we have one year where it low tide and the following year a high tide, and you see totally different things.”

Every year a new contingent of riders is coming through along with a couple of faces Chris recognises from the previous year.

'The field station had everything from a display of things that has washed up on the shore to items which people have seen but have never been able to put a name to.

'We have some videos from some of the underwater work we have done in the Antarctic. We will be continuing that.”