A freshly caught black jewfish with the line in its mouth indicating it was gut hooked
Most fishermen have a fascination with all manner of jewfish and to be honest I must admit I am the same.
I’m not quite sure whether it’s just the thrill of the chase or the size of the prize but one thing is for sure if you’re heading to places like the Northern Territory or Cape York, as we are in May, Black Jewfish (Protonibea diacanthus) are always on the agenda.
The Territory Government in conjunction with the Fisheries Research and Development Corporation have recently conducted a major study into Black Jewfish and quite frankly I was shocked with the results. In fact it made me very despondent to the point where I am not sure that I wish to target them directly.
Black Jewfish inhabit the tropical areas of Northern Australia, across to Asia, China and India.
In 1995 Asia, China and India actively fished for this species accounting for 400,000 tonnes in that year alone. Ten years later the catch was zero as the populations were wiped out.
Local aggregations still exist in the Northern Territory and northern Queensland and today little is known about their life cycle although the recent study referred to certainly has uncovered some interesting facts.
With regard to spawning, it appears that the NT Black Jewfish tend to spawn in December whilst their Cape York counterparts spawn in May. Black Jewfish are sometimes called “croakers” as when they are caught they sometimes make a croaking sound on the deck. It is thought that this sound may be related to the fish’s mating behaviour as is the case with other species.
There also appears to be stunning differences between populations of Black Jewfish.
For instance in NT the average size of a 1 year old fish is 65cm, a 2 year old fish 90cm, a 3 year old fish 100cm and a 4 year old fish 110cm. In Queensland the corresponding lengths for 1 to 4 year old fish would be 40cm, 60cm, 80cm and 85cm respectively perhaps due to overfishing and the removal of larger breeding fish stock.
The Black Jewfish can grow to 45kg but also has a short life span – 12 years. This compares poorly with the southern mulloway that can live to 45 years of age.
Although it is said that the fish like to inhabit reefs, wrecks and holes to a depth of 100m, the NT tests have shown that the areas the fish inhabit don’t necessarily fit this logical pattern as aggregations studied appeared to be located in a trench and a relatively flat and featureless ocean area.
One interesting fact about the Black Jewfish is that they have a tendancy to school up or, more correctly, “aggregate” in large numbers – sometimes in their thousands. This makes them susceptible to overfishing.
Their problem is that, unlike the southern jewfish, they are not elusive and respond to live bait, strip baits and lures and are relatively easy to locate. A little knowledge of deep holes or jewie spots, some strong line and brute strength and an angler with little experience is able to extricate these fish from the depths.
Over fishing these aggregations can cause serious problems for the Black Jewfish – size/age balance and reproductive issues for the populations. Results of the NT study show that there doesn’t appear to be any blending of aggregations and fish lost to populations are not replaced with members of other schools.
Tests also show that the Black Jewfish remain in the same location which also makes them easy targets. Tagged fish were found in the same spot after 500 days of release.
It seems that catching Black Jew is akin to shooting fish in a barrel – you catch one, you should catch more.
Apparently 30% of Black Jewfish caught by recreational fisherman are released which is good news. However the NT study also looked into the survival rates of released fish.
Barotrauma caused by changes in pressure on the fish whilst raising it from the depths is a serious issue for those fishermen keen to release after capture.
In summary, fish pulled in from depths of water greater than 15m had little chance of survival as the impact of barotrama caused “pop-eye”, swim bladder perforation and extended stomachs through their mouths.
Between depths of 10-15m 46% of fish sustained life threatening injuries whilst those caught in depths less than 10m had 100% survival rates.
Another consideration for safely releasing Black Jewfish is the use of circle hooks as these were found to set inside the lip or the mouth of the fish every time unlike the traditional “j” hooks that set in the gut of the fish 40% of the time thus inducing life threatening injuries to the fish.
Ok, so what should you do to make sure the remaining Black Jewfish stocks flourish rather than vanish?
1) Fish in waters less than 10m and use circle hooks, not “j” hooks
2) If you catch one or two, use smaller hooks to avoid Black Jewfish or better still move on to another spot
3) Never release fish with extended stomachs through their mouths and never vent the fish’s swim bladder by bursting it with a needle – it will take a good five minutes to reduce and may never recover. Use barbless weighted hooks to release the fish quickly to the bottom. I will write about this method in upcoming weeks.
For me, the discovery of the plight of the Black Jewfish was rather sad - it seems the odds are stacked against them.
I’m not so sure that I would particularly like to target them knowing what I know now.
The barramundi always brings a smile to an angler's face!
Over the next few weeks I will feature posts concerning the life cycles of various Northern Australia fish species.
The major reason for this is that I am a strong believer in the old adage to catch a fish you must first of all think like a fish and know their habits. Some may say the real reason is that our Fishing and Reef Tour Specialists (F&RTS) team are heading off to Weipa in May and a little prior research may come in handy.
Of course, a great pointer to the habits of the fish you are targeting is to take a good look at their life cycle.
This week we’ll discuss the Barramundi or “Lates Calcarifer”.
Well known in the tropical Northern Australia rivers and estauries the Barramundi is said to prefer slow moving or still muddy waters but may also inhabit nearby reefs or islands.
Barramundi are pretty versatile as they are both protandrous and catadromous.
What the??
Ok, protandrous means that the fish changes sex from male to female whilst catadromous refers to its ability to migrate between fresh and salt water. A Barra tends to change from male to female once it has reached a length of 90cm, but only if it lives in saltwater.
Lets take a look at how life begins for a typical Barramundi.
During the months of September and March a female will produce eggs (upwards of 32 million in a season!) in salt water marine bays, river mouths or salty reaches of estuaries. This coincides with the coming and duration of the wet season and in fact most of the spawning occurs during October to December.
Interestingly a male Barramundi will breed at least once if not more times before changing sex. Also there is a theory that some Northern Australia bauxite rich rivers stunt the growth of Barramundi and cause early sex changes amongst the resident populations.
When hatched the baby Barramundi (about 1.5mm in length) move into tidal creeks, mangrove areas or coastal swamps that offer protection. They reach a length of 20mm by the end of their first month.
After the wet season the Barramundi migrate upstream to seek fresh water habitats for their first year where they will attain a length of around 300mm. If accessing fresh water is not an option they will stay in the salt water areas to mature.
Growth spurts for Barramundi largely occur through the wet season and sexual maturity (usually as males) happens after 3 to 5 years. During this time they will reach lengths of 600-800mm.
At about 4 years a small proportion of Barramundi will mature directly as females.
When water flows permit, mature fish make their way back to the estauries and salty areas to spawn amongst the resident population of Barramundi.
It is thought that the older, female fish are able to pass on their survival traits and genetics to the young as they are well adapted to the local conditions.
An adult Barramundi can live to over 30 years of age and weigh in excess of 55kg and grow to over 1.5 metre in length but most caught are between 500-700mm. A one metre fish is thought to be around 8 years old.
Small fish and prawns make up most of their diet and as cannibals they have been known to feast on other Barramundi half their own size.
Tagged fish indicate movement is fairly limited along coastlines however they will travel long distances to spawn in estuaries from freshwater river systems. Once such fish was reported to have travelled over 600km.
I remember some of the earlier trips our crew took part in down in Tathra and Bermagui and the thought recently occurred to me that there is a lot of fun to be had in catching live bait.
Light hand lines, small hooks, little or no weight, a few pumps of the bread and fish scraps’ burley bucket and away you go – slimy and yellowtail heaven!
Throw the line over the boat with a small piece of squid and don’t worry about winding it back on the reel on the way in. Let it drift with the burley trail and once you feel the fish, pull on the line and gently guide it back to the boat. Complete the exercise by lifting the fish over to the live bait tank with minimal or preferably no handling at all thus keeping its scales intact and its chances of survival high.
That’s not the only way to prepare for a fishing trip and there are many other live bait options depending on where you intend to fish.
One of my favourites on a beach fishing trip is to dig with your feet in the wet sand for pippies. The trick with all live bait exercises is to only use what you need and to let the rest go – so if it’s pippies and you find them everywhere keep them fresh and throw the unused ones back into the water once you’re done.
Then there is beach worming and this can be too much fun on its own! It can be difficult to master but it is enjoyable. We included a beach worming activity into our decathlon one holiday and I must admit we were unsuccessful in extricating one beach worm but it was a bit of a hoot.
I have been known to pull a few worms out of a beach using pliers, a coathanger and several pilchards used as stinkbait. An offering of pippie or fish scraps rounds the kit off. The go is you sweep the receding beach water with your stink bait and look for the tell tale v marks left by the beach worm as it puts its head up to see what’s going on.
From there it’s a battle between you, the surf and the worm as you try and coax it back out of its hole using your pippie or fish scraps as an offering. Once it arches its head you grab it with your pliers in a twisting and pulling motion and you don’t stop lifting until you see the end of the worm.
If you’ve never done this before you will be surprised about how long the worms can be and in particular how slimy they are. When you catch your first beach worm you will be tempted to give the fishing away altogether!
Fishing down the Georges River with my kids when they were young we had a couple of live bait options at our fingertips. I would send the kids out to either catch some small crabs or to dig for squirt worms. That kept them entertained and me with fresh bait for hours!
Wading with scoop nets and flash lights for prawns is also a winner and I have many fond memories of bucket loads of freshly caught prawns being swum in fresh water before being transferred to pots of boiling sea water. Mind you it’s funny you know, I can’t remember any that found themselves used as live bait!
I’m not into catching blackfish yet but I do have a small stream located nearby where I live that is loaded to the hilt with green weed. Once the fresh is out of the river I may even give the blackfishing scene a go and update you with my success or lack thereof.
As the stream is not conducive to just wading into and scooping up the weed, a good trick is to use a handline and throw a one pound sinker into the water and pull it back in. The weed will attach itself to the weight as its dragged along the bottom and all you need to do then is to collect it in a bucket.
Down the Shoalhaven River we always use to pump fresh yabbies from the sand, use them to catch some yellowtail and then use the yellowtail to catch flathead – that was the end of the chain.
With rock fishing fresh crabs, cunjevoi and weed are just about the three best baits you can use although in the past I have used oysters (those I haven’t eaten!) and limpets to some degree of success. Depending on the season sometimes you may find large numbers of squid that can be caught on jigs.
I’ve not used garden worms but I am told that they are also effective baits. An old trick is to wet a hessian bag and leave it covering the soil overnight. Worms will be attracted by the moisture and you should uncover a few once you lift the bag the next morning. This can save a lot of digging and stops you from finding worms cut in half by your shovel.
You can also get your worms by lifting up your compost waste or bin if you have one.
For our inland lakes and streams witchetty grubs, millipedes and even maggots can be used.
I have had first hand experience in catching yabbies out of clay dams out the back of Booroowa with sticks, string and lumps of meat for bait. Once you feel the yabbie you pulled them slowly towards the edge of the dam and then with a swoosh land them on the bank.
Anyway, the fun for me sometimes is more in the hunting, gathering and collecting of various baits than the actual catching of the fish.
But one thing is always certain – you can’t beat fresh bait.
Years ago I was lucky enough to pay a visit to the largest sand island in the world – Fraser Island. Like most tourists at the time we took a bus trip along the beach front and through the heart of the island stopping off at the lakes and the rainforest areas.
There was no doubt that the island itself was picturesque and I was blown away by the rainforest and freshwater stream that spun its way through the middle of it.
But there was one thing that didn’t impress me and that was the amount of plastic that was washed up on the beach front.
Alas it is the same along the Australian coastline particularly in remote beach locations that don’t have the luxury of council sponsored grooming.
In one sentence: plastic is the scourge of the earth.
This was brought home to me yet again this week with the news of a rubbish vortex twice the size of Texas floating somewhere between Hawaii and Japan.
It’s estimated that there is 100 million tonnes of plastic produced each year and over 10% of that ends up in our oceans if not directly by careless fisherman, oil pltforms, cruise ships and beach goers but indirectly through stormwater fallout.
With slight winds, calm waters and clockwise currents discarded rubbish gets caught in the “Trash Vortex”, “Great Eastern Garbage Patch” or the “Asian Trash Trail” and stays there collecting more. Reports of up to 6kg of plastic for every kilogram of naturally occurring plankton are common within the area.
Not quite our ideal flotsam and plastic is said to make up 90% of the world’s floating rubbish.
Sadly not all plastic floats. In fact 70% of plastic sinks to the bottom of the ocean floor.
Tests in the North Sea have found that there 110 pieces of plastic garbage for every square kilometre of sea bed.
Clean up operations for the plastic soup could be put in place tomorrow – if only there was a government or people movement somewhere in the world that would take responsibility for it.
The impact on fish populations is still inconclusive but one thing is for sure the breakdown of plastic in the water into tiny pellets that have the ability to attract man made chemicals which enter the food chain through the fish we eat is obviously not a positive phenomena.
Needless to say, next time you’re on the water make sure you keep your rubbish on board and where possible keep your plastic usage to a bare minimum.
Of course when I was a lad we had a reputation for catching them ugly and drinking them pretty but then again it had nothing to do with the fishing.
You know how it is, you watch the TV shows and they kiss the fish or pose for the camera and they gently let the fish swim away. All good stuff and I agree entirely with the concept of letting fish go.
But there’s a price you pay for all the kindness in releasing your catch and that is that you deprive our fisheries department of vital information about fish movements and their behaviour.
And yet your average fisherman expects that you have to be a Ross Hunter or someone who ventures out to sea every five minutes to be part of the taggng program when nothing could be further from the truth.
In fact the best part about the NSW DPI tagging program is that you can join in all the fun for the cost of a local phone call.
All you need to do is contact the NSW Department of Primary Industries on 1300 550 474 and ask for some tags.
Ok, what next? Well the NSW DPI will send you some tags and also an applicator which is like a hollow needle. This can be attached to a pole with twine and glue and once the tag is placed in the applicator it is ready to thrust into your fish (generally behind the dorsal fin) before releasing.
You will also receive some cards attached to the corresponding tags (they are numbered the same) and here you print all the capture details including the weight and length of the fish, date and time, fight time of capture, condition of the fish upon capture, the species caught and the gps co-ordinates of where it was captured (if known) and of course your own details.
But don’t go sticking tags into every fish you catch! Tags are specifically for pelagics (surface fish) like tuna, mackerels, billfish, mahi mahi, cobia, barracuda or sharks or carangids like kingfish, amberjack, samsonfish or rainbow runners.
It’s a fun and rewarding process to be involved in and if you are lucky enough to snare and tag a fish that is recaptured NSWDPI will contact you and provide you with the updated details on that fish that you let go a few years back! Wow, how’s that for nostalgia and pride to receive feedback on a fish that you had a hand in both catching and releasing years ago.
I must admit that at times it is difficult in estimating the size (hint – look at how it stacks up against the size of your boat in the water) and weight – well all I can say is look at your crew and guess from there. Seriously, perhaps the most important measure is the length as the weight can generally be extrapolated by the experts.
Make sure your catch is capable of swimming away comfortably – if it’s a marlin hold its bill under the water and slowly motor away. Once you see it light up again it’s safe to release.
Tagging instead of bagging lends a new dimension to fishing fun and I highly recommend that you involve yourself in this worthwhile program.
The NSWDPI tagging program has been running for over 30 years and a copy of an historic report outlining a summary of the tagging and recaptures between 1973 and 2005 can be obtained at no cost at;
