Rare finds in the Hauraki Gulf

15/10/2021

In April this year, Wentworth college visited Polkinghornes Bay to survey the shore and find out what is living there as part of the Hauraki Gulf Monitoring Project. Discovered were a lot of the common finds of New Zealands northern rocky shore, black nerita snails, common shore and half crabs and a couple species of sea star. But the unexpected find of the day was the hair trumpet snail (Monoplex parthenopeus). This is an uncommon intertidal species which can live as deep as 50 metres. Not much is known about this species but given the shape of the shell it is a predatory snail.
The class from Wentworth also found eggs likely form a mollusc, species unknown, but these jellyfish like egg deposits were scattered all over the survey site. Waiheke Primary school has been surveying Whakanewha beach as part of the Hauraki Gulf Monitoring project since 2018. For the past 3 years, this sandy site has been home to species of snails and shellfish. A special find this time when they were surveying in May this year was a burrowing anemone. These anemones anchors inside sand or mud and feeds on the debris on the surface of the sediment. Unlike the more usual anemone species which anchor on a rock or hard surface, filtering food out of the water.
These fascinating finds show how useful the Mm2 method is as it can reveal the presence of species previously unseen by the surveyors. Both Wentworth College and Waiheke Primary School have learnt how even on your local shore that you know well unexpected and new creatures can be found.

Hairy Trumpet Snail - Top View

Photo of unknown mollusc egg case

Burrowing Anemone