SPANGLED emperor are synonymous with a fishing trip to the north of Western Australia but all too frequently they are not held in high enough regard by anglers who catch them.
Spangled emperor usually make up at least part of the catch for North-West inshore boat anglers and some are adept at targeting them in shallow water where they provide a very good account of themselves.
Spangleds have many and varied common names, both here and in countries to our immediate north. Probably the most commonly used name in WA is nor-west snapper, or nor-wester. Others include tricky snapper - perhaps from the less successful anglers who pursue them. Other less common names include sand snapper and yellow sweetlip.
These excellent emperor deserve to be rated more highly as an eating fish but happily they are not, which means quite a few anglers target something else when out fishing and spangleds become a bycatch.
As with many of the genus Lethrinus, juvenile spangled emperor can be very easily confused with other members of the same group, and even when they reach maturity may still be mistaken for other species. Watch out for the spangled emperor's blue lines on the cheek and blue spots on the scales, whereas the blue-spotted emperor has blue spots on the cheek but no spots on the scales.
The blue-lined emperor has short blue lines radiating from the eye of which some cross the forehead and connect with the opposite eye. However, the blue-lined does not have any blue marks on the scales - rather a dark streak on each one.
I wouldn't mind betting that many of us have confused these three species over the years.
There are differing opinions about the maximum size attained by spangled emperor but various reference books show them as growing to between 4.4kg and 6.5kg. Not huge by any means but still a very nice fish.
The common distribution in WA waters is generally north of the Abrolhos Islands but spangled emperor are occasionally caught farther south, even down as far as Rottnest.
Spangleds are found in Continental Shelf waters where they prefer hard bottom, with the notable exception being deep water sponge habitats. In shallower water they favour hard coral, or rubble bottom and the sand patches adjacent to them. They inhabit depths ranging from two metres to 75 metres.
The array of emperor species all have varying dietary preferences, which is presumably nature's way of ensuring that they don't all compete for the same food. Shellfish are top of the list for spangled emperor, so find bottom which holds tasty shellfish and you should improve your chances of catching a feed.
Generally, adults form small schools consisting of fish of similar size whereas juvenile spangleds form large schools in shallow sheltered areas. However, it should be emphasised that shallow water habitat is certainly not the exclusive domain of small fish.
Breeding and migration
There are still gaps in the known life history of spangled emperor. For example, it's not known whether they are protogynous hermaphrodites - that they function first as females and then as males - though it has been established that other emperors certainly are. In some far northern latitudes spangled emperor may well spawn all year, peaking once, but at the southern end of their range they spawn between May and October. When the eggs are laid they are pelagic and float in the ocean currents, but little is known about the species during its early life. Research has shown that spangleds reach maturity at 38cm, well below the recreational size limit. Interestingly, tagging results showed that some individuals moved up to 60 nautical miles.
Commercial trawling has the capacity to affect spangled emperor stocks in North-West Shelf waters but there is little information available on catch data and trends in this fishery. Off the WA coast, trawlers and trap fishermen are restricted to waters deeper than 50 metres so some spatial management of stocks already exists. However, given the total tonnages being taken by trawlers this needs closer scrutiny.
Recreational fishing can also deplete local stocks but there are no indications of this in current catch data.
Tackle and bait
I have caught most of my spangled emperor while boat fishing, using 15kg mono or 30kg braid on short stroker rods. However, they were generally bycatch when the main target was red emperor or scarlet sea perch.
If targeting spangled emperor I would normally fish in shallow water and without doubt the best gear for them is a six-kilo spin stick or baitcaster outfit. They put up a really good fight on this tackle. I favour the simplest of rigs: two metres of 15-24kg mono trace, with a half or a whole small fish as bait, on either ganged 6/0 Tarpons or a single 7/0 hook with no weight at all. And yes, mulies work.
Trickle the odd piece of bait into the water as berley and cast towards any visible structure, but leave the bait sinking slowly over sand bottom adjacent to the lumps. And think shellfish: if you use some as bait or berley your chances will improve.
Though many spangled emperor are caught bottom bouncing in depths greater than 20 metres, this is not my preferred way to catch these fish. Rather I like to find low coral outcrops and coral rubble bottom where I can anchor in less than 5m and sometimes as shallow as 3m if the country looks promising. Here a weightless bait will tempt spangleds, which can be surprisingly fickle feeders at times.
These strong fish will take jigs quite readily at times, and adding a sweetening piece of bait to a jig is a good way to start just to prove to yourself that jigs really do work. When fishing shallow water don't be frightened to move if you're not doing well. Even if you have caught a couple of fish, still consider moving when they go off the bite because sizable spangleds are often only in small schools.
Don't berley too much if you want to avoid attracting sharks. Finally, don't under-estimate spangled emperor, especially in shallow water over coral or rock. They will stitch you up in seconds in dicey territory if you don't assert authority as soon as they strike. They are a very powerful species - as are all emperors.
References: Kailola, Williams, Stewart, Reichelt, McNee and Grieve Australian Fisheries Resources 1993. Hutchins and Swainston Sea Fishes of Southern Australia 1986.