The Underwater Landscape
The coarse-grained granite bedrock of Tasmania's north-east outcrops throughout the Bicheno region. Underwater, the granite fractures into large blocks that often overlie each other creating spectacular underwater scenery. Sheer vertical walls and overhanging rock faces are covered with invertebrate life. Deep fissures and caves are brim full of fish both large and small. At depths below 30m, the granite reef slopes into sandy-bottomed trenches scattered with boulders. The Castle, Hairy Wall and Mr Whippy are some of the names given by divers to underwater features.
Flora - the Seaweeds and Sea-grasses
The eastern shores of Governor Island are exposed to the winds, swells and currents of the Tasman Sea. The intertidal areas are dominated by the wave tolerant brown seaweeds, bull kelp and Xiphophora. Below the low tide level, strap weed and cray-weed swirl in the surging currents, while in the deeper and calmer waters, communities of Ecklonia and a variety of red seaweeds become dominant. The green seaweed Caulerpa, finds a niche in sheltered cracks and hollows and among the invertebrates clinging to the rock walls.
Fauna - Invertebrates and Fish
Few seaweeds can grow on the vertical rock walls or at depths below 25m. These areas are covered with spectacular displays of mobile and sedentary invertebrate animals, creating a fairytale octopus's garden. At depths of 20m and more off the north-east of the island, the rocky reef is covered with sea-whips, sea-fans, hydroids, bryozoans, anemones, ascidians, sponges and feather stars. The sea-tulips pictured on the introduction page,
are commonly seen.
Basket-stars clasp onto sea-whips or tall finger sponges and spread their multi-branched arms like spider webs to strain food from the passing currents. Bright yellow sea-spiders, called pycnogonids, can be found feeding on the delicate bryozoans. Purple jewel anemones colonise the dead sea-whips, transforming them into spectacular flower spikes. Everywhere on the vertical and overhanging rock walls there is a brilliant mosaic of yellow zoanthids and the many different coloured colonies of jewel anemones.
In the deep sandy bottom trenches, huge sponges of different shapes and colours crowd onto occasional boulders. Hiding in the caves and crevices in the rocks, eyeing every move, the octopus is also a common inhabitant of the reserve.
Fish are abundant in the reserve. Caves are crowded with bullseyes, cardinal fish, sandpaper fish and cod. There are many large and inquisitive fish such as boarfish and zebrafish. At certain times of the year, large silvery schools of jack mackerel swirl past, sometimes hunted by schools of dolphins. Large abalone and crayfish, with their thorny carapaces and tell-tale antennae, have become common since the reserve was proclaimed.