Mucking About in the Gold Coast Seaway
by Nigel Marsh and Helen Rose
The Seaway is one of Queensland’s best kept diving secrets, and it was surprisingly created by man. Located at the northern end of the Gold Coast at Southport, The Seaway was built in 1984 when rock break walls were constructed to form a permanent mouth for the Nerang River. Prior to this the river mouth was constantly moving and silting up. But by stabilising the river mouth with break walls it created a permanent channel that is safe for boating and great for divers.
It would take a week to explore all the dive sites in The Seaway. The outer sections of the break walls, north and south are best dived from a boat, unless you don’t mind a long walk and a climb over big boulders. Out here depths reach 12-20 metres and you will see the big stuff: turtles, stingrays, shovelnose rays, eagle rays, gropers, sharks, wobbegongs and lots of reef and pelagic fish. But the inner sections of the break walls are where the muck critters can be found.
The South Wall is the most popular dive site at The Seaway and each weekend dozens of divers and snorkellers can be seen jumping in the water here. This site, like all areas in The Seaway, is best dived on the high tide, to get the best visibility and to avoid the strong currents between tides. Entry at the South Wall is from a concrete platform and over a few rocks, generally not too difficult, unless you have a camera in hand.
Once in the water divers will see a huge elevated pipe that is always swarming with fish life. This is an effluent pipe that is flushed two hours after high tide, so it is best to be out of the water prior to this dump! This pipe is around 40 metres long and is a haven for marine life. Around the pipe and rocks, in depths from seven to 12 metres, divers will encounter thick schools of bream, trevally, yellowtail, sweetlip and surgeonfish.
The resident reef fish here are unbelievable. Countless species of angelfish, butterflyfish, leatherjackets, morwong, wrasse, hawkfish, rock cod, scorpionfish, cardinalfish, globefish, parrotfish, damsels, surgeonfish, pufferfish, soapfish, boxfish, and many, many more. Moray eels can be seen between the rocks, while on the sand are flatheads, flounder and pipefish. Invertebrate species are also seen in high numbers, including cuttlefish, octopus, urchins, sea cucumbers, shrimps, crabs, sea stars, squid and nudibranchs.
Continue east of this pipe and there is another pipe that goes right across the channel. This one is known as the sand pipe, and it has just as many fish around it. One of the reasons there are so many fish at these pipes is the shelter and food they provide, another is that they are cleaning stations, with a resident population of cleaner wrasse and cleaner shrimps.
As for muck critters, besides the invertebrate species already mentioned, divers should keep an eye out for stonefish, leaf scorpionfish, Caledonian ghouls, ghost pipefish and cockatoo waspfish. These critters can be hard to find, and not always in residence, but are spectacular to see and photograph. But there are also some unique Aussie critters here as well. Amongst the boulders you will sometimes find pineapplefish, yes a fish that looks like a pineapple! and even has a flashlight under each eye. Also here are estuary catfish. These huge catfish, up to a metre in length, look like a cross between a catfish and a moray eel!
Further in The Seaway is the best muck diving site known as the Southwest Wall. This site has an easy entry and exit point on a sandy beach, with a maximum depth of eight metres. Here there is a small boulder wall with a good population of reef fish. Leatherjackets are very common and will follow you around at times. Moray eels are also abundant, and several species are found here sheltering in the rocks. This is a good site to find mourning cuttlefish, and on one dive here we witnessed two of these cuttlefish mating.
Sharp eyes are needed to see the critters, keep an eye out for pipefish, lionfish, nudibranchs, octopus, velvetfish, dragonets, ghost pipefish and scary Caledonian ghouls. But the main attraction is the high crown seahorse. These spectacular animals are endemic to the region and sometimes hard to find in the weed. It can take up to an hour to find one, but you will see plenty of other critters while searching for them.
Night diving is also wonderful at both the South Wall and Southwest Wall. At night a different variety of fish species debut, the morays eels are more active, decorator crabs appear and a range of mollusc species star.
Conditions at The Seaway are generally good all year. It is an all weather dive site, with the clearest water after southerly winds and little rain. Visibility can vary from three to 25 metres, but averages nine to 12 metres. Water temperature varies from 27˚C in summer to 18˚C in winter.
There are a few hazards to watch out for when diving The Seaway, beside the stonefish. Be wary of fishing lines from fishermen and never surface in the channel, as there is a great deal of boat traffic in The Seaway.
While the northern side of The Seaway is protected as part of the Moreton Bay Marine Park, unfortunately the southern side is exploited by fishermen, spearfishermen and aquarium collectors. It would be wonderful to see this unique area fully protected, so future generations could enjoy its amazing marine life and bizarre muck critters.
A great website for information about The Seaway is