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  1. #121
    Giant Trevally
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    Quote Originally Posted by tackle_buster View Post
    Anyone know if Rocky has had much rain/flow down the fitz
    below minor flooding at laurel bank above the weir from what i can see gaz. maybe around port alma would be ok for a fish
    Finally got one

  2. #122
    Legendary Angler
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    Quote Originally Posted by Douglas View Post
    Some people think they can hear the sounder frequencies working away on their boat. They can't.

    What they're actually hearing is the audible sound of the sharp rise time of the pulse hitting the membrane of the sounder face. Put your hand over the transducer while its operating and you'll see what I'm referring to. A sounder sends out so many of these pulses in a second. Sometimes these pulses are called "pings" if you watch submarine movies.

    Frequencies of 50khz, 83khz, 200 kHz, 300khz, 455 kHz, 800 kHz or 1200 kHz are the frequencies transmitted by the transducer depending on what type of sounder you've got (fish cannot hear these frequencies).

    The rate at which the sounder sends these pulses out depends on the depth of water. If deep water, then it takes longer for the pulse to travel there and back so the longer the sounder needs to "listen" for the echo. That dictates that the rate of pulses being sent out is slower. That rate is called the Pulse Repetition Frequency (PRF). War movie buffs will know it as the ping speed.

    It shows up as a low level "clicking" sound which can be heard by fish and humans. It sounds like the ticking of an electric fence which operates on a similar principle except the fence sends its pulse along the wire while a sounder sends its pulse out into the water.

    It is a low level and low frequency rate between 5 and 30 times per sec. Some sounders allow the operator to "fiddle" with the PRF (or "ping" for the movie watchers) but most change the rates automatically on selection of depth or frequency selected by the operator. There is usually an adjustment for scroll speed to keep up with increased pulse rates when travelling fast. When travelling fast, more pulses are needed per sec to get some detailed echos onto the screen.

    I found out last night that there has been a "underwater duck caller" on the market (and in use) by anglers for some time.

    Apparently this "fish/duck caller" is marketed under the name of Hydrowave. It plays audio sounds into the water of a variety of sounds of fish activities designed to attract fish to the vicinity of the boat.

    Is it a successful "fish caller"? Anybody got one?
    ive seen one hydrowave in operation dont know whether they attract bigger fish but gee they do so with bait ,was sitting talking with this guy and under both our sounders was pretty featureless with no bait .he turned it on and in around 10 minutes there was bait everywhere under us from boney,s to those small gar and tiny feeder fish.
    the world is a lot better place if you just smile

  3. #123
    Yellowfin Tuna
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    Thanks Al. I guess it depends on what sounds are played. As I understand it, sounds can vary from bait gathering to fish feeding. In your example it appears to attract bait rather than simply simulate bait moving around. Actual live bait near the boat would be better than "fake" bait, I guess.

    Couple of people I've spoken to here seemed a bit sheepish in confessing to owning and using one. Don't know why. Its all experimentation. Ya never-never learn if ya never-never experiment.

    I'll have a look at them when I've finished the effects off colours and light underwater.
    Last edited by Douglas; 09-03-2018 at 07:28 AM.

  4. #124
    Yellowfin Tuna
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    Present state of Fitzroy.

    Minor flooding upstream.

    All gates open. River flowing.

    Clarity of water in town reach very poor. See attached photo of a sample from this morning. Dirty water strategy. (concentrate on lateral line + lots of lure action + noise).

    Has a measured turbidity of 410 NTUs which translates to sunlight penetration of about 40mm.

    Barra will be in town reach with gates open.

    20- 30 knt winds and drizzle will make it extremely uncomfortable.

    Conditions downstream only marginally better

    Last edited by Douglas; 09-03-2018 at 02:25 PM.

  5. #125
    Yellowfin Tuna
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    First installment.

    These are simply my thoughts about the subject in an effort to understand better if there are any practical reasons behind observations arrived at by people such as Johnny Mitchell and Ryan Moody through years of experience.

    If there are and somebody can find them, then through sharing of knowledge, others can arrive at their own ways of utilising any shortcuts found.

    Happy to receive to considered input.



  6. #126
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    I think there is other data to be considered.
    Take a look at some underwater videos on youtube.
    Even in fairly murky waters down 20 metres, there is light, colours are drained out, but the outlines and shadings are still very visible.

    We know that colours are removed the deeper you go however I think that once a fish's eyes have adjusted to the light available at a level their perception of visibility increases. Similar to how our eyes adjust to darker environments.

    If a fish descends to a bait it would be harder to see the bait as their eyes will take time to adapt, however I think it would be opposite for a fish rising to a bait.....

    For me, colours on any lure going deeper than 6m is to catch the shopper.
    I find I have greater success with natural bait colours, stark white or black lures, or translucent lures these days.
    Typical example is Squidgies wild prawns in cracked pepper.......would nearly be invisible down 10 feet in the rivers i fish. Similarly Berkley has a colour called casper clear, just the slightest hint of yellow and very fine glitter flecks.....yet they work well for me as far down as 20 metres in not so clear water.

  7. #127
    Legendary Angler
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    Tony !!!!!

  8. #128
    Yellowfin Tuna
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    From Bill Sawynok

    Barramundi recruitment in the Fitzroy this year is certainly very interesting. In a year when the environmental conditions don’t support strong recruitment that is what we are seeing in the 12 Mile. At this stage the fish there are from at least 5 different spawning events and more likely 6 (see arrows on graph) ranging from Sep-Jan. This is the strongest recruitment there since 2010. I will need to get more data to see if that is reflected in the river but recruits elsewhere have been low in numbers (more in line with environmental conditions).

    This is likely the result of a significant increase in the numbers of spawners and it looks like spawning has occurred over a longer period. Conditions were good for an extended spawning period. The increase in spawners is largely the result of the introduction of the NFZ along with a high level of release of large fish by recreational fishers.

    Also for the first time we are doing targeted recruitment surveys for King Threadfin in the Port Alma area with some interesting results. Based on anecdotal information it appears that Threadfin recruitment is also strong but we won’t know where that sits on the scale for a number of years. For the first time we are getting recruits in the Gladstone area and these are likely to be migrants from the Fitzroy.

    Understanding recruitment is important in forecasting where stocks are headed in the future so that the river can be managed to provide the best return to the community.



    Bill




  9. #129
    Yellowfin Tuna
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    Instalment 2


  10. #130
    Yellowfin Tuna
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    Remember that this exercise is about barramundi and dirty water.

    Even in fairly murky waters down 20 metres, there is light, colours are drained out, but the outlines and shadings are still very visible.


    I guess it depends on what you mean by fairly murky waters. If you can see light (no matter how little) at 20m (or even 5 or 10 metres) then you are not in murky waters.

    In the examples I showed about dirty waters with turbidity levels ranging from 30 to 410 NTUs, there is NO light 20m down.

    In the clearest water mentioned above (30 NTU), the colours are gone by 50cm and ALL light is gone by 1 metre. In the twilight zone from .5m to 1m, the amount of light is steadily reducing to none at 1m.

    In the flood waters I measured here the other day at 410 NTU, light penetration was all over rover at 40mm. Yet a 1.5m barra was caught in the same water in the town reach. Good eyesight?

    Barramundi eye cells change from a mixture of cones (colour nerves in eye) and rods (monochrome nerves in eye) and the colours are replaced by shades of grey that fade to black at 1m as the fish changes from cones to rods. The ratio of rods to cones is higher for barramundi eyes than it is for human eyes.

    Barramundi have the trick eyes (tapedum lucidum or “old red/pink eye” as they’re known) which reflect what dim light they manage to get back through the retina to give a second image. Its passed via the optic nerve to the nerve and superimposed on the first image. The effect is a bit more light but the resultant image is slightly blurred.

    We know that colours are removed the deeper you go however I think that once a fish's eyes have adjusted to the light available at a level their perception of visibility increases. Similar to how our eyes adjust to darker environments.

    Agree totally BUT only in the twilight zone as far as any light manages to penetrate. In this case only up to 1 metre. After 1 metre in water of 30 NTU turbidity, there is no light. Everything is black.

    For me, colours on any lure going deeper than 6m is to catch the shopper.

    They also catch anglers with very shallow divers.

    Agree with that to a certain extent.
    In the case of barramundi in poor visibility estuary waters its true. If water is much clearer, then barramundi will still see in monochrome (shades of grey) to a greater depth.

    THAT’S when contrast between whatever the colours translate to in grey (different colours end up different shades of grey). There’s also what contrast occurs between the lure’s resultant greys and the water colour.

    Typical example is Squidgies wild prawns in cracked pepper.......would nearly be invisible down 10 feet in the rivers i fish. Similarly Berkley has a colour called casper clear, just the slightest hint of yellow and very fine glitter flecks.....yet they work well for me as far down as 20 metres in not so clear water.

    Don’t think that barramundi only use 1 food detection system to the exclusion of others. They are the complete package and use all senses at the same time. To them, its either get a feed or starve. They’ll be using lateral lines and hearing as well simultaneously.

    If you want to get a better handle on what you are grappling with in respect of fishing and how light and turbidity work together, get yourself a turbidity tube. $60 - $80 and you then know exactly what you are dealing with.

    No more guessing or vague references to “not so clear water” or “fairly murky water”. You’ll also see for yourself very quickly how the underwater colour world works.

    Water of 30 NTU turbidity where I fish will be exactly the same as 30 NTU water where you fish. Apples with apples.

    I spent many trips to collect different samples, painting up washers into quadrants with the 7 colours of the wheel, measuring turbidity, measuring depth at which those painted washers disappeared. Different measurements were obtained from all the different turbidity readings.

    Then repeated the whole lot again for fluorescent coloured washers. Again with different results to those washers with normal paint and yet again with different turbidity readings.

    By now you would have the latest instalment which would have covered some of those things. What is coming in the next instalment is fluorescence and that’s when underwater colour interpretation goes to a new level.

    The key points to take away so far is turbidity and barramundi's special "grey light" eyes.
    Last edited by Douglas; 20-03-2018 at 09:59 AM.

 

 
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