Diving in SE Tasmania

Kahala, Underwater Adventures, heading down to a Bruny Island dive site

Reefs, wrecks, and unique and varied marine life are highlights of the diving around Hobart.

What makes this part of south east Tasmania special is the combination of rugged coastline and sheltered waters with estuaries, islands, bays, inlets and channels. These waterways make for diverse marine habitats and with diverse habitats comes diverse marine life and some of the most varied diving you’ll ever experience.

The area – the Bruny bio-region – is known to be a biodiversity hotspot and is a mecca for anyone with an interest in marine life and photography!

Diver in Bruny Island kelp forest

In close proximity are ocean waters with rocky reefs and masses of invertebrate life; rocky shorelines with mixed weed and sponge beds; extensive giant or string kelp forests; seagrass beds; and sand and silty bottoms in sheltered bays and estuaries.

Kelp forests thrive in several locations including outside Bruny Island year round and seasonally at Tinderbox. Nothing beats drifting through a kelp forest with sunbeams filtering through!

The sheltered bays and estuaries provide ideal habitat for several species of handfish. The critically endangered Spotted Handfish is only found in the Derwent estuary close to Hobart. Tasmanian numbfish thrive in those same sheltered waters. Skates and rays are often seen and the area includes several nurseries.

Water links the nearby mountains and sea: water that carries tannins from high country forests and buttongrass moorlands to the estuaries feeding the Channel. The dark, clear tannin-rich waters trick deeper water species into shallow water than usual, providing diving conditions that are commonplace for locals but a rare and unique experience for visitors.

Sponge beds in shallow water. Simpsons Pt

The constant outflow of rivers combined with tides provides conditions in which invertebrate life can flourish. You’ll often find sea whips and sea pens, jewel anemones and rich sponge beds in only a few metres of water whereas at other areas you’d only see them in depths of 20m or more.

It’s no surprise then that there are two no-take Marine Reserves close by – Tinderbox and Ninepin Point. Tinderbox is located at the junction of the Derwent River, Storm Bay, the D’Entrecasteaux Channel and North West Bay and the resulting currents enable invertebrates and diverse algae to flourish.

Further down the D’Entrecasteaux Channel and close to the mouth of the Huon River, the tannin-rich waters of Ninepin Point Marine Reserve encourage deeper water species into shallower water than usual. Offshore is the geologically significant Arch Rock with diverse marine life including large hinge-back shrimps.

Sites such as Simpsons Pt, Tinderbox and even some around Bruny Island feature a rich mix of weed and sponge beds in depths as shallow as a few metres. At other locations in Tasmania you would often find such beds at far greater depths and below the kelp-line.

Wreck in the Betsey Island ships graveyard

It’s not only the range of marine life that’s readily accessible when diving out of Hobart – the Betsey Island ships graveyard includes a number of wrecks, barges and old bridge pontoons in close proximity, in depths averaging from 20-3om. The wrecks can be explored externally by Open Water Divers or penetrated by those with (or seeking) higher qualifications. Where else could you explore several wrecks in the one dive?!

Within the river there’s also a sunken bridge pontoon and the wreck of the Lake Illawarra lying against the Tasman Bridge. There aren’t many locations that can boast a wreck within 5 mins of a city centre! The Lake Illawarra is our most challenging wreck: she lies in silt and the water is dark and the visibility low. It can be reduced to zero when silt is disturbed.

In short, the diving out of Hobart is varied and readily accessible. (Many of the sites, and sights, that are unique to the area are even accessible for non-qualified divers doing a Discover Scuba experience!) The presence of marine life, not to mention the ships graveyard, in relatively shallow water means that divers have longer for exploration and discovery, and more time to take more photos!

Of course, this is only the briefest overview of the local diving – you can read more in the Highlights and Dive Sites pages as well as the Dive Blog posts.

Here’s some important information about local conditions:

• TEMPERATURES   Ocean water can reach a comfortable 17-18C in summer, dropping to a crisp 11C that brings greater clarity in winter. Estuarine waters can be even warmer in summer and colder in winter due to snowmelt. Locals wear two-piece 7mm wetsuits or good quality dry-suits, while dry suits provide for a higher level of ease and comfort year round.
• VISIBILITY   The vis is better in winter than in summer. The spring plankton bloom can drop visibility from 25m to 5m overnight. Estuarine waters tend to have consistently lower visibility than ocean waters.
• WEATHER   The calmest weather is in autumn; the windiest months tend to be in spring.
• DEPTHS  Vary from as shallow as you can get to (mostly) a max of not much more than 30m. There are some deeper sites that are more technical in nature (ie strong currents, dark water, or lots of silt) or that are further afield and not on our regular calendar because of the cost to you in getting there. Of course, we can take you to those deeper sites but it’s important to note that this corner of SE Tas is not another Bicheno or Tasman Peninsula.

View towards Mt Wellington above One Tree Pt