A day in the Fitzroy

[Douglas]

To finish up my thoughts on soft plastics as vibration generators, rember that the theories are constructed in a perfect or ideal underwater world.

We're assuming that there are no other underwater vibrations present. That's the ideal world.

The reality is that the underwater world isn't ideal at all and never will be.

There are many many other sources for the fish lateral lines to pick up apart from our attempts to "make our lures heard" in the cacophony of sounds. Our lures have to stand out to be noticed.

On one of his DVDs, Johnny Mitchell demonstrated what can be heard underwater at night in the Fitzroy mouth with his headphones and Jesus Box submerged beside the boat. Noises everywhere.

I suggested to John later that he should give charter work away and simply sell Jesus Boxes and headphones. Make more money. He countered that it wouldn't be as much fun. Touche'.

Anyway, the lesson is that you've gotta be heard over everything else.

While a plastic lure like the little pink one might work in shallow, clear fresh water with not a lot of background noise (because a barra can use eyes as well as lateral lines to target it), it would be useless in water that had much more background noise and was dirtier.

I'll come back to the subject of "dirtier" water later when I look at colours.

Happy to hear any views others have about this subject.

[Douglas]

Tidying up my understanding of how lateral lines work.

Barramundi lateral lines.doc

[Douglas]

'nother Fitzroy outing on Australia Day.

Barrage gates been open again and tannin water now stretches about 5 km down river.

Did some water clarity measurements with a you-beaut technical turbidity measuring device I bought. Thought I'd literally check out how good/bad the water clarity actually is in the Fitzroy.

With the tannin the clarity looked pretty good to us and we got a turbidity reading which equated to 150mm (6 inches). The light from the sun vanished at a depth of 6 inches.

In normal colour downstream it was 80mm. About 3 inches.

With high optimism off we went.

Had a day with soft plastic vibes at likely spots chasing king threadfin.

Friend of ours was onto a barra (unintentionally) as we pulled up. 99cm, tagged and released.

Evan 99cm.jpg

We got 2 bull sharks which we initially thought were big king by the way they took off with our vibes.

Anyway finished the day with 6 accidental barra of:

75cm, 41cm, 56cm, 81cm, 85cm, 80cm. Mate got treble hook straightened by another one which escaped.

All within town reach (CBD).

Was good to see the 41cm model. Product of late 2016 spawning. Heaps found in floodplain lagoons but not so many in river.

Had another issue with those bl...y folding landing nets (Kato I think)

Mate went to net my 85cm model and it busted straight through the mesh like a hot knife through butter. Ended up with the barra still in the water, me in the boat with rod and line through hole in net with the landing net between us.

Had to delicately pass rod through the net via the hole to continue the fight.

I put something up on here a while ago about those landing nets. Same thing happened to mate when out with someone else. That time fish was bigger than 85cm.

Those Kato folding net frames are OK. Its simply that Tupperware mesh they come with.

Told mate last time to get "real" cord mesh but he persevered with the rubbishy stuff. Even had the retailer give him a new one previously.

Not anymore. Yesterday, mesh was cut off and binned back at the boat ramp and replacement one goes back to shop today. Look for suitable cord mesh to fit frame.

Its easy to see what's wrong with them in respect of barramundi.

Narrow pointed head and big heavy body (barra, not my mate). Enormous amount of pressure generated by the small surface area of the snout with the weight behind it. Similar to the damage caused by ladies stiletto heels when they were in fashion. (Haven't worn mine in years).

Barra goes into net headfirst (cant net from tail end as they go ballistic). When net lifted, barra goes headfirst down into bottom of net AND.......straight through and back into water. Even 8ocm ones.

Be aware.

[gunna]

Better check my net before I head on up.

[Douglas]

When is that Peter? Want to make sure I'm around.

[gunna]

Pm on its way Douglas.

[Douglas]

A conversation with a well known barra fisherman, caused me to rethink my views about lures. I hinted at that in the post/s I did a few weeks ago on soft plastics.

These guys whose barramundi catching abilities are fact, have formed conclusions based on years of experience.

It would be foolish in the extreme to dismiss those conclusions.

When I drilled down a bit further with the conversation, it was obvious that what this fisherman was having trouble explaining was why these conclusion (although correct) had come about.

During the explanations, it became apparent that the reasons didn't stack up despite the correct conclusions/outcomes.

Then came a warning bell mention of infrared eyes. Barramundi do not have infrared eyes.

At that point I thought " Could this guy be right for the wrong reasons?"

There must be technical reasons to support the conclusions that had been arrived at.

So off I went digging further into the supportable technical aspects about effectiveness of lures eg action, colour, dirty/clean water, devices used by fish to detect food etc.

Its been a journey of enlightenment and its not finished yet.

One big eye-opener for me has been the effect of the distribution of light and colour in water.

I found quite a few articles about the subject. Some by people like Greg Vinall who I'd consider to be the go-to person on colour absorption and light scattering in water.

Other articles were simply cherry-picked from even more articles and were short on explanation.

Both types of info were based on what happens in crystal clear water (usually oceanic).

Unfortunately, none of the articles were relevant to fishing in dirty water and THAT'S where barra fishing happens.

With no info available, I've had to do my own "citizen science" research which has included buying some test equipment suitable for nailing down some specific things about dirty water.

Am I learning? You betcha.

At the end of the post on soft plastics, I said I'd do hard body lures which is what I'm doing.

I also had the opportunity to see an interview with Dave Killea (previously Killalures). Highly informative with a couple of nuggets on lure action thrown in with Dave Killea's casual style.

Anyway, I've nearly finished gathering the info and the next job is to put it in easy to understand words.

[Douglas]

Opening day here resulted in a 125cm and a 107cm barra (that I know about anyway. Could be more).

Town reach/CBD is the current go-to place.

Mate went down yesterday in rain for 85cm (on $3 soft vibe), and 80cm, 78cm and 70cm on 100mm drop-bear squidgy.

I went on Thursday to Marmor for a 21cm barra. A significant catch as it threw more light on the spawning events late last year and subsequent recruitment.

At 21cm it also equalled the only mangrove jack I've ever caught and even that was by accident. It attacked a 65mm squidgy (1/3 its size).

A 100mm model also attacked the lure but couldn't get its mouth around the tail. Aggressive little buggers.

[Douglas]

Went back to 12 Mile on Mon to check out reports of an even smaller range size of barra recruits than the 3 that had already been determined. Those 3 range sizes (100mm, 150mm and 200mm) indicated 3 spawning events in summer '17/'18 which was unusual.

Sure enough another range size of 50 - 60 mm was found making 4 spawnings!

Anyway, that's Bill Sawynok's reaction to the results.

He got 26 little barra in his standard 20 castnet survey with 22 of them in the 50 - 60mm range. Lots more than usually found at 12 Mile with the standard survey (usually around 6 in 20 throws).

22 indicated a very successful spawning event using 12 Mile as the standard estuary reference.

We went there with Bill's castnet, my rod/reel to check out growth of Dec 2016 spawning. (6 @ 460 - 520mm range indicated growth as expected).

This time we also had a BRUV along (Baited Remote Underwater Video-camera) and deployed it. Haven't seen video results yet.

Little fellas were hiding in the shallowest and weediest sections of the saltpan creek.

Some pix attached.

Also measured water turbidity (clarity) @ 19 which translates into being able to see 320mm into water. Clarity has dropped from about 1 metre due to ingress of salt water on big tides.

The recent big tide was how the little barra got in 12 Mile away from the predators in Port Alma area. Those 500mm barra already in there will give them a touch-up though.

Bit wary when going to 12 Mile now as the big croc at the junction with Inkerman Ck hasn't been seen for a month or so in case he's decided to come up 12 Mile in search of some fresh water.

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[al49]

yes you might get a nice surprise and drop something in your dacks if the old lizard sticks his nose out in front of the net there