Trunk Reef - Great Barrier Reef

Deep Ridge is exactly what it sounds like, a deep cut in the seabed, and it’s a site we always recommend to advanced divers looking for that PNW thrill. Forget your tropical reefs; this is about big animals and rugged beauty. You drop down into the chill, that unmistakable cold water bite, and the visibility can surprise you, often holding a good 15-20 meters on a calm day. We love the sheer scale of the place. Giant plumose anemones cling to the walls, their feathery crowns swaying in the subtle current. Look closely for wolf eels peeking from crevices, their grumpy faces always a welcome sight. But the real draw here, for us, is the pelagic life. We’ve had incredible encounters with harbour porpoises darting past, and those Gray Whale sightings are something you just don't forget, their massive forms gliding through the blue. Keep an eye out for schooling salmon – coho and chinook – especially when they’re running; it’s a breathtaking sight, a living silver river. Strong currents can pick up, so timing your dive with slack tide is absolutely crucial, or you’ll be on a very fast tour. Bring your drysuit, of course, and a good light to really make the colors pop in the depths. This is diving for those who appreciate the wild, untamed side of the ocean, a true taste of the Pacific Northwest.

Location: Great Barrier Reef, Australia, Australasia
Coordinates: -18.350000, 146.833330
Type: reef

Best Time to Dive in Great Barrier Reef

The warmest water temperatures in Great Barrier Reef occur in February, averaging 29.5°C. The coolest conditions are in August at 25.0°C.

Monthly Water Temperatures

January: 29.4°C
February: 29.5°C
March: 29.2°C
April: 28.4°C
May: 26.9°C
June: 25.8°C
July: 25.1°C
August: 25.0°C
September: 25.4°C
October: 26.6°C
November: 27.7°C
December: 29.0°C

Nearest Dive Centres to Trunk Reef

Marine Life in Great Barrier Reef

Home to 163 recorded species including 88 reef fish, 61 hard corals, 9 seagrass & algae, 2 sharks & rays, 1 starfish, 1 sea snails & nudibranchs.

Notable Species

thalassia (Thalassia hemprichii) - Seagrass & Algae
halodule (Halodule uninervis) - Seagrass & Algae
cymodocea (Cymodocea rotundata) - Seagrass & Algae
Great hammerhead (Sphyrna mokarran) - Sharks & Rays
Bullethead Parrotfish (Chlorurus sordidus) - Reef Fish
seagrass (Halophila ovalis) - Seagrass & Algae
Cauliflower coral (Pocillopora damicornis) - Hard Corals
Lineated Butterflyfish (Chaetodon trifasciatus) - Reef Fish
Dusky Parrotfish (Scarus niger) - Reef Fish
Blackspot Surgeonfish (Acanthurus nigrofuscus) - Reef Fish
Bird wrasse (Gomphosus varius) - Reef Fish
Blue-lined Tang (Zebrasoma scopas) - Reef Fish
Telescopefish (Epibulus insidiator) - Reef Fish
Banded thicklip (Hemigymnus fasciatus) - Reef Fish
Fluorescence grass coral (Galaxea fascicularis) - Hard Corals
Blunt-head Parrotfish (Chlorurus microrhinos) - Reef Fish
Staghorn coral (Acropora hyacinthus) - Hard Corals
Chameleon Parrotfish (Scarus chameleon) - Reef Fish
Citron Butterfly (Chaetodon citrinellus) - Reef Fish
Black-back Butterflyfish (Chaetodon melannotus) - Reef Fish

Recommended Packing List for Trunk Reef

Based on average water temperature of 27.3°C, currents 17 cm/s.

Shorty or Rashguard - warm 27°C water needs minimal exposure protection
Mask - essential for every dive
Fins
BCD - buoyancy compensator
Regulator - your most safety-critical piece of gear
Dive Computer - tracks depth, time, and NDL
Surface Marker Buoy (SMB) - essential for boat pickups
Dive Torch - useful for crevices and colour at depth
Underwater Camera - capture your diving memories