Underwater encounters – Octopus gardens and shark stacks

“It was winter and the water was a chilly 14 degrees. I inhaled sharply as it soaked through my wetsuit, 7 millimetres of neoprene doesn’t stop you getting goose bumps. Ignoring the cold, we kept swimming out. There was something offshore we’d come to see and it only happened once a year…”

We have another guest post for this series! Marine biologist and keen macro photographer Mitch joined us to chat about his favourite underwater encounters. Let’s dive in!

Meet Mitch (the one on the left)

Huskisson, N.S.W

Today we’re taking you to Huskisson, a small coastal town on the south coast of NSW. Husky, as the locals call it, sits in the Jervis Bay Marine Park. This makes exploring temperate reefs really accessible if you pop on a tank and swim straight out from the beach. Mitch and his buddy had come to dive a site called Dent Rock.

“Dent rock is a small rocky reef sitting 150 metres offshore from Orion beach. It’s marked by a buoy on the surface because the reef can be only 2-5 metres below the surface depending on the tide. This makes it perfect for diving because boats avoid it. We hauled our gear down a steep set of stairs and walked out through the shallow breakers. Picking our way over rocks we began to swim out, the water was only about three metres deep over the weed banks.”

Swimming out over the seaweed Mitch and his buddy kept an eye out for interesting critters to photograph.

“As you move along you find patches in the weed, surrounded by shells. Empty shells from clams, scallops, mussels, pipis, every kind of mollusc that usually buries itself in the sand were piled up in circular clumps. In the centre of the shell piles was a hole that seemed to drop down to nowhere, but if you’re lucky it drops down to an orange, brown and cream speckled octopus.”

Mitch points out one of two octopi/octopuses (whichever you prefer). Can you spot the other one?

Octopus Gardens

These strange homes are called octopus gardens (we know you just started humming the Beatles song). A lot of creatures like the taste of octopus so to avoid being eaten they hide in dens. The octopus camouflages its home by building gardens of shells and rocks around it, some even have a rock ‘door’ they pull over the opening to seal themselves safely inside.

An octopus in its garden of shells

“It’s clear these creatures are full of personality. Some can’t keep their eyes off you, they pop as far out of their hole as they can when you approach. If you float down to the weed bank they float higher to keep an eye on you. Others want absolutely nothing to do with you and sink deep into their holes, pulling shells over their heads for cover.”

Close up of an octopus

“All that and we hadn’t even hit the reef yet! Jervis Bay is a pretty special spot because it serves as a breeding aggregation site for Port Jackson sharks. Breeding aggregation, that doesn’t sound particularly special but you end up with hundreds of sharks piling on top of each other, all with no concept of personal space.”

Port Jackson Sharks

Each year between winter to early spring, Port Jackson sharks migrate to shallow reefs to mate. Here they congregate in small groups, in caves, under overhangs, and in gutters along the rocky bottom.

“So what psychopath is getting in the water with hundreds of sharks? Well that’s the other bonus, Port Jackson’s or PJ’s as we call them, are the puppy dogs of the ocean. These bottom feeders eat sea urchins, crabs and molluscs (invertebrates with shells), anything they can root out of the sandy bottom. They’re really not interested in you unless you give them a hard time.”

“PJ’s for anyone that hasn’t seen one, don’t look like your stereotypical shark. They’re a square headed fish reaching a maximum length of 1.65 metres. Their skin is brown with black lines that make it look like they’re wearing a harness. They have rounded fins with small spines just in front of their dorsal fins. Even their teeth are unusual. They have flattened plates perfect for crushing and grinding up their food, very different to the pointed teeth you normally associate with sharks.”

A Port Jackson shark up close, note its unusual teeth

The divers had finally arrived at Dent Rock. But could they find the sharks?

“It wasn’t hard, they were scattered everywhere over the bottom. Heads and tails were going in every direction, no one was fussed that they were being lain on or were laying on someone else. The great thing is these sharks just don’t care. We spent a lot of the dive just hovering above the sand watching them, face to face. They watch you back. There are honestly few encounters with sharks where you can feel this comfortable.”

Stacks on! Three Port Jackson sharks lay in a gap in the reef

It never ceases to amaze me what you can find by simply swimming off the beach and having a look around. Mitch had researched the timing of the shark aggregation but didn’t expect to see the octopus gardens. He can’t wait to explore more underwater in his own backyard once it’s possible to travel again.

Images are a mix of my own photographs and those provided by Mitch.

Weekends away – shore diving photography

Dent rock and the octopus garden

One Friday afternoon in mid-February we snuck out of Canberra, driving 2 hours and 40ish minutes to reach Huskisson, a coastal town in Jervis Bay, N.S.W. Husky, as everyone calls it, is our favourite close spot for a dose of ocean (for those tropical creatures that go into withdrawal) and some diving. It is part of the Jervis Bay Marine Park and has some really accessible temperate reefs, just a short fin from the shore.  Nearby is also the magnificent Boderee National Park. Although more effort to shore dive, Murray’s beach makes a great snorkelling spot at the right time (and tide).

As soon as we’d arrived and unpacked we headed to the water. Sailor’s beach was just a short walk from the holiday house we stayed in. At the southern end of the beach is a rock platform, snorkelling around the edge was a real treat. Close to shore in the seagrass we saw rays resting on the sand as a few salps floated past us. Heading out further and exploring along the edge of the rock platform we saw a wrasse resting under a rock ledge. It didn’t look like a particularly comfortable spot with the black spines of sea urchins poking out. Not sure if anyone else feels the same, but when a group of large fish swim super fast from behind you and the water’s a bit murky do you start to wonder what was chasing them? Popping our heads up we noticed a dark mass of storm clouds covering the horizon. They were headed our way so it was time to fin back to shore. We made it home before the storm hit. It rained so hard parts of the roof started leaking, seeing water drip from the bathroom light made using the toilet at night a thrilling (dark) experience!

We like it under our urchin

Waking up to a beautiful calm day on Saturday we had our choice of dive spots. The forecast and prevailing swell made Dent Rock our chosen site. We could’ve gone to Murrays and attempted to dive from the boat ramp. But the day before Sue from Crest Diving showed us the best dive route and where boats usually head out from the boat ramp, it was a shame the two coincided. To dive Dent Rock we drove about five minutes to Orion beach. Dragging all the gear out of the car we set up on the grass then took numerous trips down the wooden stairs to the beach. Chris kept getting distracted by wrens in the bush on either side of the stairs but its more likely this was a ploy to get out of carrying heavy things. Once everything was down on the beach we geared up and headed in, fully kitted out in 5 and 7mm wetsuits. Ahhh the snorkel yesterday was so easy just jumping in wearing a sharkskin and boardies with no camera!

But it was worth the struggle, as Jervis Bay is home to 230 species of algae! Just joking, although the swim out to Dent Rock is about 200 metres over a seagrass bed so you think there’s nothing but weed then all of a sudden you’re at a reef with Port Jackson sharks everywhere. Not at this time of year though, yet there was still plenty to keep us photographing. Swimming out we noticed these large piles of shells. Heading closer to check it out we discovered they were octopus gardens! Some were living very close to neighbours, with two only about 30 centimetres apart. They all had different personalities, some didn’t mind having their photo taken and came out of their holes further for a look. While others retreated as far as they could into their holes while still keeping an eye on the camera laden sea monsters. Check out Blue Planet 2 for some awesome occy filming, the guy in episode 5 also reckons octopus have very different personality types.

I think I’m being watched

Swimming on we came to the rock which is sparsely covered in sponges and coralline algae but has plenty of fish life. I was quickly obsessed with a school of Old Wives while Mitch stuck to the smaller subjects with his macro rig. Schools of baitfish came and went during the dive, we also came across a Red Morwong. He had a great look with his spines up and mouth open.

He’s not posing, Chris’ strobes have just stunned him

Also at the rock was one of the scariest fish I’ve come across. Forget scalloped hammerheads and sea snakes there was one particularly terrifying male Senator wrasse here. I could be over reacting but when something comes out of nowhere and swims straight at you it is a little unnerving…until you realise it’s a pretty little rainbow coloured fish that’s just checking out your strobes. He also really liked playing in the bubbles we breathed out but clumsily swam into most of our heads while he was doing it. Senator wrasse are protogynous hermaphrodites, all starting life as females and changing to males when they reach 2-5 years of age. Maybe this particular fish had just changed or was grumpy because we were in his territory and it was breeding season. We like to think he was just playful.

Don’t be fooled, this is an evil (but pretty) fish

This time of year none of us were getting cold so we could take our time on the swim back. It’s not like we had a choice, we came across more occy’s that liked having their photo taken and Mitch discovered a number of critters in the seagrass. I’m not sure how he spots such tiny things in the mass of green but check out these shrimp. On the slightly larger side there was also a sea hare (slugs which eat nothing but algae – must be spoilt for choice in Jervis!). Mitch also found a couple of pipefish hiding out in the seagrass.

Probably not as fast as land hares

They real trick I’ve found for underwater macro photography (which is different, but no less challenging than the dry land type) is to take your time. Take your time looking, take your time composing and take your time before moving one. A lot of the macro subjects I’ve come across like sea hares, shrimps, pipefish etc are cryptic species. This means they use camouflage to avoid predators or catch prey. What does this mean for photography? They can be hard to find, but don’t move much once found. This pipefish is a great example, it matches the length, colour and movement of the seagrass it was in. I spotted this one because it moved slightly out of sync with the grass so it could keep an eye on me. Slow swimming and getting easily distracted means I actually spot more underwater (at least that’s what I tell Chris). Don’t rush, there’s millions of animals hiding in very different places underwater.

You have to be careful not to spook the wild macro photographer
I’m sea grass!

Husky, while full of tourists at times, always has a laid back vibe. We love being able to stroll into town along the path next to the water and check out the shops. Although, Mitch has recently been banned from buying any more pairs of novelty socks from the bamboo shop, it’s still a favourite to browse in. After a day of diving it’s nice to walk into town and get a cold drink or piece of cake from Nutmeg Cafe before heading off for an afternoon snorkel. But for dinner there’s really only one choice – Mexican!!! Pilgrim’s, a vegetarian place, has Mexican nights on Friday and Saturday. Just go and order anything, it’s that good. Finishing off our little weekend escape here was perfect. Sunday morning the wind had changed bringing in a cloud of dust. Heading home and back to work didn’t seem so bad when you’ve got photos of occy’s to edit and memories of a terrifying wrasse.