Blue Maomao – Scorpis violacea

Blue maomao. Photograph courtesy of Dick Marquand.
Blue maomao. Photograph courtesy of Dick Marquand.

Blue Maomao – Scorpis violacea

The blue maomao has a laterally compressed body. The tail is deeply forked and the caudal peduncle (where the tail joins the body) is relatively narrow. It has dorsal and anal fins that are quite short. The dorsal fins have 10 spines, and 25 to 28 soft rays, and the anal fins have 3 spines and 24-28 soft rays. The small pectoral fins have 17-19 rays.

The standout feature of the blue maomao is its striking iridescent sky-blue body and fin colouration on adult fish – which is lighter underneath. Once dead, the brilliant blue turns to a dull blue-grey. At night their stunning blue colour scheme changes to a mottled dark green. Blue maomao have tiny scales.  

Juveniles are grey in colour with a contrasting yellow underside and anal fin. They retain this colouration until about 18cm in length. 

Adult fish typically measure between 20 and 30cm. The largest specimens are known to reach 45cm and weigh 3kg. According to Tony Ayling in the Collins Guide to Sea Fishes of New Zealand, blue maomao, despite their small size, can live for a relatively long time. A 38cm long specimen, aged by counting the growth rings on the ear bones, was 15 years old.

Blue maomao are very similar in shape and habits to the closely related Sweep – Scorpio lineolatus, which is also a plankton feeder. The sweep occupies the same distribution in northern New Zealand as blue maomao but can be found as far south as Fiordland. The sweep lacks the beautiful colouration being a silvery-grey colour.

The head and mouth are quite small for the length of the fish. There are rows of small teeth in the mouth that are used to hold larger zooplankton, like shrimps. Prey items are sucked into the mouth by the blue maomao’s protrusible jaws. 

Habitat and Distribution

Large schools of adult fish are often found around headlands and underwater archways where the current brings a steady flow of plankton. Blue maomao schools can number from a few dozen individuals to thousands of fish.

They are found around the North Island and south as far as Cook Strait and Kaikoura. They are often present around Kapiti Island. Blue maomao are more common on the east coast between East Cape and North Cape, especially close to the shore of offshore islands. 

Found at Norfolk Island, Lord Howe Island, and occasionally along the coast of New South Wales down to southern Australia. In Australia, the species is known as violet sweep. Interestingly, my 2004 edition of Grant’s Guide to Fishes makes no mention of this species. Perhaps it is quite rare in Australia.  

Large numbers of blue maomao also inhabit the sea around New Zealand’s subtropical Kermadec Islands which lie approximately 1,000km northeast of New Zealand. The waters around the Kermadecs out to 12 nautical miles are a marine reserve.

Bigger specimens as large as 45cm have been caught around the Poor Knights, Three Kings and White Island. 

Found on the surface to a depth of about 20m. 

What Do Blue Maomao Eat?

Blue maomao are open-water plankton feeders. They feed either mid-water or at the surface on copepods (small crustaceans), euphausids (shrimp-like crustaceans or krill), fish eggs and detrital algae. Weed is also found in their stomachs sometimes, but this most likely is picked up accidentally while feeding. 

Spawning?

Spawning takes place in late winter and spring.

Is Blue Maomao Edibile?

Blue maomao are very good fish to eat cooked by all methods. They are often smoked.

Best Baits for Blue Maomao

Even though blue maomao are plankton feeders they will readily take small baited hooks. Firm baits like squid and mussels will work best and stay on the hooks longer.

Very small cubes of tuna are also excellent bait for maomao. The tuna needs to be fresh to stay on the hook. Frozen tuna, pilchards and mackerel are good oily baits but go mushy very quickly and tend to frustratingly fall off the hook. 

Sabiki rigs are worth a try if the hooks are small enough. A small cube of bait on each hook will make them work even better for attracting maomao.  

Note the beautiful blue colouration of this blue maomao caught and released while saltwater fly fishing in the Bay of Plenty. Photograph courtesy of Dick Marquand.
Note the beautiful blue colouration of this blue maomao caught and released while saltwater fly fishing in the Bay of Plenty. Photograph courtesy of Dick Marquand.

Rigs and Catch Methods

A simple paternoster rig with small size 8 trout or saltwater hooks is all you need to catch them. If you find you are getting nibbles but few hook-ups try even smaller hooks down to 12. They can easily be caught in the wash from rocks with this rig provided you use a small light sinker so it doesn’t get snagged. Berley is always good to attract and hold a school of this species. Any berley of minced fish works well, as does berley made from bread tossed on the surface. 

David H. Graham in A Treasury of New Zealand Fishes recounts how the locals would catch any number of blue maomao using a wire netting drop net that would be lowered from the rock down to an underwater rock platform. This would be baited with bread, or bread dropped down into the net from above. When a good number of blue maomao were in the net they would quickly raise it to the surface by way of ropes attached to each corner.

Blue maomao will also take very small lures and are a great target for ultra-light saltwater fly fishing

A stray line fished on very light spinning gear from rocks into the wash will take plenty of blue maomao when they are present. You might need a split shot or two for casting weight. 

I prefer to pre-tie my rigs at home. This saves a lot of time and stress when out fishing. This is even more important when fishing with very small hooks that can be visually challenging to tie onto light lines (1-3kg).    

Tips

There is no size limit on blue maomao but this species must be included in your allowable daily limit for fin fish in the area being fished.

The blue maomao is another of the large number of species that prefer warmer water and can therefore only be caught around the North Island with just the odd few being caught occasionally around the South Island. 

References

The Fishes of New Zealand, volume four. Edited by Clive D Roberts, Andrew L Stewart, and Carl D Struthers. Published in New Zealand in 2015 by Te Papa Press, Wellington, New Zealand.

A Treasury of New Zealand Fishes, by David H Graham. Published September 1953, by A.H. & A.W. Reed, Wellington New Zealand.

Sea Anglers Fishes of New Zealand, by Arthur W. Parrott. Published in 1957.

Collins Guide to the Sea Fishes of New Zealand by Tony Ayling. With 48 colour plates by Jeffrey J. Cox. Published by William Collins Publishers Ltd, 1982.

New Zealand Fishes, identification, Natural History and Fisheries by Larry Paul. Published by Reed Books, Auckland. 1986

Common New Zealand Marine Fishes by Chris Paulin. PublishedMy Canterbury University Press 1998.

Coastal Fishes of New Zealand – An identification guide by Malcolm Francis 

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