Story: Marine animals without backbones

Bath sponges

Bath sponges

The natural sponges we use in our baths are actually animal skeletons. Bath sponges consist of a highly porous network of fibres made from a collagen protein called spongin. The skeletons are obtained by cutting the growing sponges and soaking the cut portions in water until the flesh rots away. The exposed network of spongin fibres is cleaned and bleached. In recent years New Zealand scientists have investigated the possibility of farming a native species of bath sponge, Spongia manipulatus, for commercial production. Sea sponges have been over-harvested from the major sponge-gathering areas around the Mediterranean, Caribbean and Florida coasts, but demand remains high. Pictured here are two New Zealand bath sponge skeletons, bleached (right) and unbleached.

Using this item

NIWA – National Institute of Water and Atmospheric Research

This item has been provided for private study purposes (such as school projects, family and local history research) and any published reproduction (print or electronic) may infringe copyright law. It is the responsibility of the user of any material to obtain clearance from the copyright holder.

All images & media in this story

How to cite this page:

Dennis Gordon and Maggy Wassilieff, 'Marine animals without backbones - Sponges and jellies', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/photograph/5790/bath-sponges (accessed 24 July 2019)

Story by Dennis Gordon and Maggy Wassilieff, published 12 Jun 2006