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by Nigel Marsh


Australia has a number of world class dive destinations and you can now add another one to that list – The Mackerel Islands


I thought I had either dived or heard about every diving destination in Australia, so I was quite surprised to receive an email from the Pilbara Tourism Association inviting me to dive the Mackerel Islands. I didn’t even know where the Mackerel Islands were, let alone that there was diving there, so jumped onto their website to discover they were located just north of the famous Ningaloo Reef off Western Australia.


The website informed me that there was a resort on Thevenard Island, 22km off the town of Onslow, and that the islands were a popular fishing site. Diving information was limited, no dive site details, just mentioning ‘world class diving’ – quite a big boast I thought, but if the diving was half as good as Ningaloo Reef this could be true. It also mentioned that the dive operation was opening soon. I was intrigued, so replied that I would love to dive the Mackerel Islands, so they booked my wife, Helen, and I in for a week in May.


Getting to the Mackerel Islands was no easy task, even for someone living on the east coast of Australia. First a flight to Perth, five hours, then a flight to Karratha, two hours, then a 300km drive to Onslow, three hours. After staying the night in Onslow we transferred by boat to Thevenard Island, another hour. We could have flown to London in the same time it took to reach this destination in our own country!


Upon arriving on the island we were surprised to discover that Thevenard Island not only has a resort, but also a Chevron Texaco oil storage and refinery facility - at the same end of the island as the resort! I could vaguely remember reading something about that on the website, as this part of the country contains Australia’s richest oil fields, but didn’t realise the facility was right next to the resort!


The resort, Club Thevenard, is an ex-mining camp and is still shared with the oil field workers, and consists of 11 beach bungalows and 30 motel rooms in the village complex. This complex also includes a pool, bar, games room, dining room, general store and now a dive shop. Although basic, the resort is quite comfortable, but I should mention the island itself is no tropical paradise – covered in low scrub, it is more like a desert surrounded by water.


After unpacking our gear, Greg Lowry, the resort Dive Manager, arrived to take us for a late afternoon dive to the eastern end of the island. Greg had only arrived on the island the previous week to setup the dive operation, but had done numerous trips to the Mackerel Islands over the years, and assured us that this area was an undiscovered gem. Well we weren’t convinced after the first dive.


Slippy into the water to dive the East Coral Gardens we were greeted by 2m visibility. The coral gardens at this site, only 4m deep, looked very healthy and reef fish and invertebrates were plentiful, but hard to appreciate in the poor water clarity. Greg later informed us the visibility was a little poor at the moment due to recent coral spawning and onshore winds, but he was confident it would return to the usual 12m to 15m as the winds dropped.


The next day we headed off to explore nearby Trap Reef. The water was still green, but the visibility had improved to 8m. We descended onto the reef top, only 4m deep, to find it completely covered in lush hard corals. We then dropped over the reef edge to the sand at 8m and explored the rocky wall. Even though the visibility was poor this didn’t matter as this dive site proved how rich the Mackerel Island were. For a start the wall was completely covered in spiky soft corals, gorgonians, ascidians, sponges, tubastra corals and hydroids – an amazing kaleidoscope of colour in such shallow water. And in between the corals were hundreds of nudibranchs. Nudies were to become a feature on every dive, not just the high numbers, but the great diversity of species, we recorded over twenty species.


But it wasn’t just the nudies; there were also flatworms, shrimps, crabs, sea stars, feather stars, crayfish and octopus. However, the real highlight was the fish life. Reef fish were in large numbers darting about the reef, I have never seen so many angelfish in one spot. There were also sweetlips, snapper, rabbitfish, surgeonfish, fusiliers, wrasse, butterflyfish, rock cod, hawkfish, lionfish, gobies, blennies, coral trout, coral cod and the list could go on and on. But the most impressive of all was a school of thread-fin pearl perch, a species generally only found in this part of Australia and these were the first I had ever seen. This reef was richer than any of the sites I had dived on Ningaloo Reef.


Our next couple of dives on the local reefs were just as good, each covered in wonderful corals and thriving with invertebrate species and reef fish. At Sultan’s Reef we also encountered a crocodilefish, several moray eels and an olive sea snake, which are quite common to the area.


After a couple of days the water started to clear, still green but with fewer particles, allowing us to explore more of the dive sites around Thevenard Island itself. The island is 12km long and a nature reserve where sea birds and turtles nest, plus the entire island is fringed by coral reef. We dived a site called Great Australia Bight and had great fun diving around an endless collection of bommies in 8m of water. Many of these were coloured by soft corals and gorgonians and housed a good range of invertebrate species. But the highlight continued to be the incredible fish life, which amazed us as the islands have been fished for a long time. We encountered Chinamen snapper, angelfish, trevally, lionfish, tuskfish, gropers, rock cod, stingrays and reef sharks.


At Rob’s Bommie we investigated several bommies packed with colourful corals and fish in 6m. But the standout feature of this site was a 2m long tawny nurse shark and two northern wobbegongs; the smallest, rarest and cutest member of this shark family.


With much of the Mackerel Islands unexplored we had a chance to do some exploratory dives with Greg looking for new dive sites. Exploratory diving is a bit like playing Russian roulette, for every good site you find you generally have to do plenty of duds, but this was not the case at Bessers Island.


Our first site was off the northwest end of the island where the sounder showed some interesting terrain. Fortunately the visibility had finally improved to 15m as we were starting to worry that we wouldn’t see any clear water. We hit the bottom at 19m to find a flat plain with numerous bommies rising several metres off the bottom. The first bommie we explored was covered in cardinalfish, soft corals and home to a group of angelfish. We investigated several more bommies before moving onto an area of coral ridges. These ridges were swarming with fish; snapper, sweetlips, coral trout, red emperor, fusiliers and white tip reef sharks. One of the locals was surprised to see us, a very large potato cod that proceeded to follow us around the reef, peering over my shoulder every time I took a photo. We called this site Tukula Corner, after the friendly potato cod.


Our next dive was on a ridge of rock off the northern end of Bessers Island and was again a wonderful dive. More lovely soft corals and sponges, plus moray eels, gropers, reef sharks, stingrays, mackerel, batfish, coral trout and even a mantis shrimp. But the reptiles stole the show, with performances from an olive sea snake, a green turtle, a hawksbill turtle and finally a very curious loggerhead turtle that circled us several times.


The third dive was just as good, this time we dived a group of bommies on the northeast end of the island in 15m. These bommies, including some of the biggest mounds of porites coral I have ever seen (which looked like giant scoops of ice cream, so we called the site The Scoops) were covered in fish; more snapper, sweetlips, parrotfish, gropers, mackerel and reef sharks. We even saw two mobula rays glide over one of the bommies.


With the clear water hanging in it was time to head to Black Flag, the premier dive site in the area. Greg had told us about this site, but he hadn’t quite prepared us for how good it was. As soon as we descended we were surrounded by fish – a massive school of stripy snapper, and circling them were also schools of batfish, silver drummer and fusiliers. Settling on the bottom we had a quick look around us and could see coral trout, angelfish, pufferfish, rock cod, red emperors, pearl perch, surgeonfish, mangrove jacks, sweetlips, coral cod and plenty of other fish species.


The rocky reef at this site is 9m on top and 17m on the sand, and riddled with caves, ledges, canyons and swim-thrus. Exploring the first of these swim-thrus we found it packed with bullseyes, cardinalfish, sweetlips, mangrove jacks and home to two large estuary gropers. If the reef structure itself weren’t interesting enough it was also covered in soft corals, gorgonians, sponges and black coral trees – the most colourful reef we had so far seen. With so much to see we didn’t even bother photographing the invertebrate species, but they were also well represented.


For over an hour we explored this amazing reef, following the reef edge and encountering turtles, stingrays, a tawny nurse shark, a tasselled wobbegong, a dozen white tip reef sharks, several grey reef sharks and plenty of pelagic fish like trevally, mackerel and jobfish. I surfaced with a huge smile – this was world class diving – not only that it was one of the best dive sites I have ever seen. Greg then proceeded to tell us that there are usually sea snakes, leopard sharks and giant Queensland gropers at the site.


Our next dive was at Greg’s Grotto, another reef packed with colourful corals and fish life. But this dive also revealed to us why these reefs are so rich; currents, very strong currents. The tidal flow in this region is immense, and up until now we had been enjoying the neap tides.


Our final day found us Brewis Reef and another exploratory dive. We hit the reef on high tide, to avoid the currents, and explored a reef in only 8m of water. We first explored a wall covered in corals, but the feature of this site was a collection of bommies arranged like some ancient druid temple (we called the site Stonehenge). These were covered in colourful corals, the most interesting being the blue gorgonians. As we swam in and out of the bommies we encountered the usual marine life and also two tasselled wobbegongs, a grey reef shark, a bull shark and several turtles. We were also joined by mackerel, cobia, jobfish and a thick school of trevally. It looked like you could jump in anywhere around the Mackerel Islands and have a fantastic dive!


The final dive had us looking for a sheltered site with little current. Greg knew of a ledge that had never been dived and suspected since it was in deeper water it might be less current prone. And he was right. We didn’t know what to expect as we descended onto a rocky ridge that dropped from 16m to 18m. But what we found was astonishing!


This ridge was pulsating with life; billions of cardinalfish were swarming the ridge and the caves that cut under it. And swimming between them were estuary gropers, coral trout, coral cod, sweetlips, pearl perch, lionfish, snapper and red emperors. But the most impressive fish were the rankin cod, at least forty of them. These large fish are rarely seen, being heavily targeted by fishermen, and here were forty of them staring at us like we had gatecrashed their party!


We set off to explore the ridge, finding white tip reef sharks, barramundi cod, crocodilefish, curious olive sea snakes, a thorny stingray and a sleepy loggerhead turtle. But the whole time we were being followed by the rankin cod. This was great fun, but very frustrating to photograph, and I found this on many of the dives in the area, these fish had never seen a diver before and were curious, but unfortunately not curious enough for me to get close enough for a decent picture.


With the rankin cod following us we continued this dive and watched a parade of pelagic fish zoom by; mackerel, trevally, grey reef sharks, barracuda and even a school of rare queenfish. We called this incredible dive site Rankin Road, but it could easily have been called the Fish Shop as it was one of the fishiest dive sites I have ever experienced.


Our week of diving the Mackerel Islands ended all too quickly, it started out pretty average and ended up having some of the best diving we have seen in Australia. The ‘world class diving’ statement on their website was certainly justified and we can’t wait to get another chance to explore the rest of the reefs and islands at the magic Mackerel Islands.


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