Tags Fish Guide

Western Blue Groper

Tags Fish Guide
BLUE groper are a very powerful fish – you just have to look at one to see that. They are solid slabs of things, with a heavy body that seems to extend right back to the tail. Blue groper are a serious angling proposition and present an exciting fishing challenge to anglers that chase big fish off our rocky southern coastline.

In the minds of dedicated anglers, our south coast conjures up images of dark blue holes and gutters pressed hard against the rocky coastline, and lurking within them monster blues. But the reefy and boulder strewn country that they like so much is not easy to prise a big blue groper from. Only good strong tackle and a fair slice of dedication will ultimately achieve the goal.  Given the nature of the coastline that blue groper inhabit it is appropriate to remind anglers at this point that fishing off the south coast’s granite boulders is one of the most dangerous fishing activities to participate in. Several anglers have lost their lives fishing off the rocks in recent years. It is advised that anglers observe all the rock fishing safety rules. Always wear appropriate footwear, flotation vests and, of course, never fish alone.

Blue groper are best recognised by their prominent fleshy lips and peg-like teeth. Smaller specimens are generally found inshore and are greyish brown in colour, to match their surrounding habitat. As they mature and grow their colour changes through olive green to a glorious blue as they grow larger and move offshore.

Sea Fishes of Southern Australia records a western blue groper of 39.5kg – now that’s a big fish. But more commonly, blue groper between six and 10 kilos are encountered by anglers fishing accessible areas of our coastline, with enough 10kg-plus specimens around to reward dedicated anglers who are prepared to travel to more remote fishing locations.

They can be found from the South Australian border up as far as the Abrolhos Islands, but tend to be more abundant in remote and lightly fished areas in the south of WA. Juveniles up to 10cm in length inhabit seagrass meadows and shallow protected inshore waters. Larger adults are found over reefy country farther offshore, in depths of up to 60 metres.  It is also worth noting that blue groper do not exist in dense populations and finding more than two or three from a particular location would be unusual.

Breeding and migration
We know very little about the biology of western blue groper other than, like its cousin the eastern blue groper, it is a protogynous hermaphrodite. This means all juveniles are females, and it is known that the eastern blue groper undergoes sexual transition from female to male once it reaches around 50cm in length. However, because the eastern blue groper only attains one metre in length (18 kilos), whereas the western variety grows to a whopping 1.75 metres (40 kilos), it is thought that sexual transition and maturity may occur at a greater size with the western blue groper.

Spawning is thought to occur in summer into early autumn, but as yet research is not completed in this area. It would also appear the western blue groper is much longer lived than was previously thought and specimens of 70-90cm ranged in age from 22 to 45 years. The oldest fish observed was an amazing 69-years-old.

The western blue groper is a benthic carnivore consuming a wide variety of prey items including small fish, crustaceans, molluscs, cephalopods and sea urchins.

Over-fishing presents the biggest threat to blue groper, and this includes both recreational and commercial activities.   They are very inquisitive and considered to present an easy spearfishing target, which makes them vulnerable to localised stock depletion.  In addition, the demersal longline and gill net fishery catches significant quantities of blue groper. For example, in 2003/04 over 32 tonnes of blue groper were taken from the southern part of WA in this fishery alone.

Tackle and bait
This is no species to trifle with. Successful rock hopping blue groper anglers use heavy mono, up to 24kg, on stout beach rods or heavy spinning rods. On most occasions only a high drag setting will stop a decent blue groper taking you into the reef.  A heavy leader, or trace, of up to 37kg may at times be needed to minimise bust-offs in really difficult country. However, this will need to be balanced against better bait presentation when using lower breaking strains.  Terminal gear should include a good heavy-duty swivel and either a strong single hook or a two hook paternoster rig. Generally, given the nature of the underwater terrain, a spoon sinker is the best bet.  It is rare that you will get the conditions and location that will let you present your bait with no weight attached. But if you can, give it a go. It is a really good way to fish, especially if you have a berley trail going as your bait should follow the general direction of the berley.  Probably the most consistently successful bait is rock crab, which can generally be found around good blue groper locations for obvious reasons. Octopus and squid baits will do the trick, but nothing beats a red rock crab.

Fishing methods
First find a safe place to fish from the rocks that offers good broken reef and boulder country within reasonable casting range. If it boasts a nice deep hole as well then all the better.  Cast your bait into some of the most likely looking spots until you find a fish. Remember these fish generally travel alone so you will need to either seek them out or berley them in to you.  You don’t have the luxury of letting a decent blue groper take line and you will need to be prepared to go hard from the beginning in order to be in with a chance of landing one.  Oh, and don’t leave your bait in the water and your rod unattended for obvious reasons.  Fish safe.

References: Sea Fishes of Southern Australia by Barry Hutchins and Roger Swainston.  Murdoch University Centre for Fish and Fisheries Research – Peter Coulson.
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