The Underwater Landscape
Bull kelp
The point gets its name from a series of large boulders, 2 to 3m in diameter, which are visible from the shore during low tides. These form part of a large, spectacular, rocky reef that extends offshore 150m to the sandy sea-floor at depths of 7 to 10m. The reef is dissected by numerous gutters 1-2m deep. Water temperatures range from a cool 8°C in winter to 20°C on a warm summers day. Underwater visibility can be reduced by storms and high river flows. In the salt layer visibility is often 10-15m.
Flora - the Seaweeds and Sea-grasses
The southern shores of Ninepin Point are exposed to the force of southerly gales sweeping up the D'Entrecasteaux Channel from the Tasman Sea. Here in the shallow waters the brown kelps dominate the seaweed communities. Bull kelp, strap weed, cray-weed and string kelp survive the stormy seas. North-west of the point are more sheltered waters. Neptune's necklace, sea-lettuce and sticky weed (or
Sargassum) are the best known species of the diverse seaweed communities found here.
Out on the reef where the light is rapidly extinguished by the tannin rich waters of the Huon River, a diverse array of red seaweeds are able to flourish. Many of these are delicate and finely branched; others are like thin, membranous sheets, crinkled and folded at the edges; while the coralline red algae form hard, calcified encrustations covering rocky surfaces. Over 80 species of red algae have been recorded on the reef.
Fauna - Invertebrates and Fish
In the absence of light-loving seaweeds, invertebrate animal and fish communities that would normally be found below 20m proliferate in the shallow waters.
Sponges of different types and colours are common on the reef. Many other invertebrates adhere to the rocks and the holdfasts of the red seaweeds, such as delicate lacework bryozoans, feather-like hydroids, ascidians and anemones. Colourful and brightly patterned, firebrick and biscuit seastars are particularly abundant on the reef.
Many of the fish found at Ninepin Point are typical of deep water habitats of Tasmania's east coast. The most abundant species include blue-throat and rosy wrasse, butterfly perch, barber perch, trachinops and little rock whiting. You may be lucky enough to catch a glimpse of a red-velvet fish, a rare and unusual creature with venomous spines that is known to inhabit the reef.