Sounders and Barramundi Behaviour
Re: What's in Awoonga?
« Reply #11 on: 14.12.05 at 06:37:13 » Barra are the biggest, and the apex predator in the Awoonga system. Barra tend to move as singular fish, not necessarily always following in tight bunches or tight schools, although it can happen at times! Singular, well spaced fish are very distinct on a sounder's display in open water, or they can be cluttered and a bit indistinct in amongst cover such as horizontal timber, or concealed within weeds. The second largest fish species (on average weight) in the system, is actually mullet, but their habits very rarely see them venture into any situation where upon they can be viewed on a sounder's display screen. Mullet are usually visually identified with the naked eye on or near the surface in shallow water, in depths where sounders become useless fish finding tools. Catfish (1 to 3 kg) school in varying sizes from a handful to house sized schools. They are a much smaller fish than that of the common 10-20 kg barra that inhabit Awoonga. Displayed images vary from one sounder to the next because of variations in vertical and horizontal pixel count, depth ranges used; gain settings, transducer type etc. Everything is relative at some point as displayed images are shown as representatives to the size of sounded objects. I have noticed that catfish tend to have a short, sharp display shape, whilst barra have a much longer, and obviously proportional longer arch length to catfish. Bony bream schools are common in sizes similar to that of the average car, although bony bream and other wandering type baitfish species like banded grunter can be quite sparse and more loosely packed at times; hence the reason for cloud like formations and smudges on your display screen. Increasing water temps through summer sees the whole lake system warm to temperatures that at times can feel uncomfortable to fish. (This happens in hot summers in hot periods). Awoonga is situated at the southern end of the 'Tropical' region of Queensland, yet it still experiences, (like now, 38 d/c, 14/Dec/2005) very hot days which reflect strongly and highly influence water temperatures and therefore barra behaviour, (as well as other species)! The deep waters of the lake warm to certain depths which are governed somewhat by the severity of weather; and by the mixing of currents within the lake core. All animals have 'comfort levels', and barra have a certain 'water temperature precinct in which they feel most comfortable in given situations! Barra are not actively on the search for food 24hrs a day, so at times they enjoy a relax in favourable, comforting, soothing water which in this case , Dec 05, is deeper/cooler water which is often adequate with ideal oxygen concentrations and favourable current flows. Tolerable water on the other hand, is any water that can be located in Awoonga. Barra can tolerate high temps, but just like most animals, will search for cooler areas to rest in when required. (Just like people and air cons). Concentrations of micro organisms can lay at varying levels in the depths of Awoonga, and the 30 feet mark in many places in the lake at present time (Summer. 2005) sees the convergence of the thermocline-like image where water of different density meet creating a distinct gathering of life forms. Below the separation line is much cooler, dense water, and above it are warmer water layers of varying stages and the temp increases steadily towards the surface. This is discovered by using testing equipment on 80ft of cable. E.g. the surface temp in an extremely hot period may be 31 d/c, and 15 feet down, 29 d/c, and 30 feet down 26 d/c, and at 33feet, (3 more feet down, below the separation line it quite often drops about 4 or 5 d/c. This is why many barra continually show at similar depths, and also why many other forms of life hold at the same depth. (It’s a comfortable depth, water chemistry and temperature). Every animal has a different tolerance, and therefore they all find their happy medium somewhere in the water column. But in saying all that, comfortable temps and tolerable temps are 2 totally different situations. Many barra are trolled from the depths on 30 ft lures, as well as 10 foot lures in the same locations. Whilst this is happening, 34d/c water temp in shallow water sees wild fishing sessions on hungry and pumped up barra. Big barra trolled in 30 ft, mid lake; whilst barra are also captured casting to the shoreline at the same time, same day.

Most weed is either attached to the bottom in 5 m or less and thriving, attached and dying, or dead and floating. Mid water weed is not what you are sounding!!

Fine tuning of your sounder is required for max results. Understand what lives in your area and you’re well on your way to interpreting what is being displayed. Common life forms and objects which become common images on your sounder are things such as: barra, catfish, bony bream, plank tonic and micro organism blooms, (usually mid water) long tom, banded grunters, gar fish, turtles, diving birds, trees, weed banks, logs, rocks, etc
*zoom features help in identifying objects.
*vary sensitivity or gain settings in varying depths for max definition.
*target level or colour line features help you place emphasis on different levels of target density.
If you are searching for less dense items, and closely looking for any changes in density,
lower your target level, and vice versa for harder objects. Run it on normal or an average for everyday use, but be careful to change it back when you are finished fiddling, otherwise future confusion can be had.

What I would like to add to this that may or may not have been touched upon in the most informative topic that I have read in this fishing forum to date; on sounders. It was hard to read every point made by members, but I think a few did get left out that I feel are very important. Apologies if I re-touch on anything.
Firstly,
Pixel count- which is the number of 'dots' which make up the display screen. A high resolution sounder will have a high pixel count and is therefore capable of producing a highly defined image that will make many viewers go "Wow"! A low resolution, low pixel count will nearly always have a sounder interpreter going, "Hmmmm, well, I wonder what that is?" 240 vertical by 240 horizontal pixel counts is an average unit. 360 by 360 is a pretty defined sounder, but 480 by 480 is readily available nowadays and therefore will give you great definition of sounded images.
A colour sounder with 240 by 240 is nowhere near as good as a 480 by 480 black and white unit. A colour 480 by 480, is exceptional for definition and for helping us read into what lays beneath. The varying colours used on screen and represented are used to show different density objects. E.g. Red is mostly used to represent solid and hard return echoes/objects, whilst orange, green, blue, yellow, white etc is used to show less dense objects. The grey line feature on black and white units works the same, although it uses shades of 'grey' to differentiate between different densities. Colour is far easier on the eye to help distinguish density variations.

Depth ranges need to always stay close to actual water depths. If it is 25 m deep, there is no point running the unit on a 60 metre range window. Bring range and depth as close together as possible for best definition. Zoom features help us interpret sounded objects easier especially in instances when fish lay close to the bottom or in extreme deep water when life stays low in the water column, or if you wish to have an expanded view of a small marking on the screen. It is really like a magnifying glass that helps us 'see'.

If you are running 'fish symbols', you are really wasting your time! Use your sounder manually for best results. Most sounders work best if adjusted by the operator and not just from auto modes! Some sounders may run fine in auto, but most need operator assistance to best 'tune' them in for best results.

It is possible to compare sounded image sizes to range windows to help work out the size of the displayed imagery, E.g. A 20 kg barra is say approximately a foot (30 cm) in body depth (or more), and in 20 feet of water, that barra will cover one 20th (1/20) of the water depth and also show on the screen in a range window of 20 feet at a very similar proportional scale. Singular bony bream, gar, or any other small particular baitfish show as distinct tiny markings in a proportion when compared to depth scales and other sounded images like trees or timber, remembering that the average bony bream is maybe about 10 cm long and 6 cm high. Even turtles and diving birds will show up. Small fish will show as a very small mark in a 60 ft depth range window. If trolling in 20 feet on an 80 ft window, even large barra will seem small on the display screen, with tiny fish being almost unnoticeable on the display. Keep your range window close to your working depth for best understanding of images. Bony bream often school in dense balls that could vary from a school of 10 fish to about 1 million fish. I've sounded small baitfish in Awoonga in 90 ft of water that filled the water column from 42 ft below right through to almost touch, and in some places seem to join the bottom. The school was approximately 80 to 90 ft in length. These were only small fish, possibly in that 4 to 8 cm range. Baitfish, catfish, and barra for that matter all can and do move vertically in the water column within a sounder's transducer's cone angle. Images of moving fish appear as lines and squiggles and can be either displayed as a line moving up or down at varying angles. The longer a fish stays beneath your transducer, the longer it gets displayed on your screen. If a 10 cm bony bream followed your boat whilst it stayed beneath your transducer at 50 ft in 80 feet of water, it would be displayed as a straight flat distinct and joined line at the 50 ft mark on your sounder. If it then swam towards the surface while still under the transducer, it would firstly appear as a flat line, then with a distinct angle change heading up towards the surface. Fish often move and change formation, so each pass over an area of eye-catching fish life can be displayed differently each time. If an area is choked with timber or weed, it is highly possible that barra won't show on your screen as the bottom structure can help conceal the barra as they hide within the formation. So, just because you don't see barra on your sounder, doesn't mean they aren't there. And even in deep water when barra are holding near the surface, quite often no barra will show on your sounder as your approaching boat scares the fish off to one side and well away from your transducer! Strikes still come from barra that approach from the side and that have not been spooked by the overhead boat! Food for thought!
All markings on a sounder are comparable to one another. Barra are the biggest and the apex predator in the systems, catfish and smaller barra are on an equal par, and then the downsizing continues with a myriad of bait species. The more we learn the more questions it creates! I hope this helps you somewhat.

Depth Sounder Thoughts

Yes, I do agree that you can hear a 'tick ' from many transducers, but the sonar frequency itself that is sent to into the depths and returns to the bottom is supposed to be inaudible to fish and to humans. That 'TICK" you mention I think is possibly the minute pulse that the sounder's transducer emits when the frequency alone is heading or returning from the bottom,(not the frequency itself), definitely not a sound that could be heard 300 feet down in average sea conditions when a boat is slapping the surface from wave movement. That tick is very quiet compared to other sounds such as outboards, crunching gearboxes, anchors hitting the bottom, chain rattling on the rocks/reef below. Some lures rattle louder than a transducer's 'tick' and they still catch fish. I think the issue here is the frequencies used and whether these intermittent pulses can be heard or 'felt' via lateral lines etc. As we know, fish can have mood swings, weather, tides; water temp etc all can have an effect on the activities of fish. Some days, fish are so hungry that we can catch the same fish twice. (Many stories like that) My friend caught the same 8 kg saltwater barra 15 mins after I released it, obviously not showing any ill effects from the ordeal, even after the fish was on deck for 1 minute and photographed 3 times. Some other days we can see fish and not even get a 'look' or a 'follow' from one, backing the theories that not always are fish hungry. Many commercial fishermen, me included have witnessed mass schools of fish such as red emperor, red jew, even coral trout, cobia etc, all raise from the gloomy depths in say 30-40 metres to just metres below the boat, (transducer) to savagely feed on a fisherman's offering. All this can be seen clearly on the sounder as the schooling ball of fish rises toward the surface to 'black out' the sounder screen. These fish rise so close to the boat that they can be viewed with the naked eye as they hammer all forms of bait/lure offered. I'm talking many hundreds of kilos, even tonnes of hungry fish. So with the negative stories about sounders scaring fish off, it may be possible that a fish's mood can determine whether or not it will be irritated by certain circumstances. Very interesting topic, and most certainly in the year 2005 and onwards, we do need to be very careful to avoid anything that may have a negative impact on fish. Fish are not as silly as we sometimes think, patches of fish can be very easily spooked or simply 'put off' by very simple fishing and boating tactics. Evolution (I use that word loosely) has seen fish become very vigilant, and to survive, many species have adapted and changed over time. They have LEARNT to compete against us, hence the reason we have to alter our approaches and styles to stay the successor in the person/fish relationship. LOOK, LISTEN, WATCH & ABSORB YOUR SURROUNDINGS! The answers are there for those who think, and if you are still worried about sounder's spooking fish; turn it off when you are fishing or when you are happy to say you are anchored correctly. This also allows you to focus on your fishing and hopefully catch more fish. The process of elimination is a good way to teach you. "Trial and error", as they say!
Lowrance x 85, moderate ticking noise,,,,,Garmin 250C Colour unit; ticks so loud people think it’s a sprinkler runnin'! I can hear it myself while underwater on the bottom in 12 feet of water while my boat is 40 metres away. I can also hear my mate’s favourite barra lure rattling very loud while I'm underwater at the same distance. It rattles at a similar volume to the transducer. Could the transducer tick help stimulate barra bites?!?!?!?!!??! I can offer many instances of great fishing with the loud ticker still tickin'!

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