Here are some tips on how, why and where to target bass and the odd golden perch in deep water in the impoundments through the cooler months.
We realised around 20 years ago that from Autumn to August the bass, especially in Lake Glenbawn, went deep – well over 10m at times. To target them we had to use lead-core line, trolling sinkers and downriggers.
In recent years, especially with the advancement of sounder technology, these methods are no longer required and most anglers have switched to vertically jigging or slow-rolling techniques.
The fish hold at these very deep depths, 10m to even 40m, for various different reasons.
One key is water temperature.
During the warmer months the dam water is usually in two layers, warm on top and cold underneath. The thermocline temperature break divides the warmer epilimnion on top from the colder, oxygen-poor hypolimnion below. The fish often hang around the thermocline.
With good oxygen levels and cooler water, the fish are at their comfort levels and food is never far away.
As Winter approaches, the top layer cools down enough so there is little temperature difference from top to bottom and the dam water ‘turns over’ and mixes. The fish can then range from top to bottom of the water column.
But in the depths there are always good food sources for the fish to forage on. Microscopic copepods and rotifers can be seen easily on the sonar as large black clouds, often with the bass sitting under them.
A near-full Lake Glenbawn has a lot of cover and good structure in these 10m-40m depths.
We are all used to fishing by casting to visible cover. This makes unseen targets difficult to fish for the average fisher.
A lot of people might not realise the difference between structure and cover.
Cover is some physical object separate from the actual bottom contour. It is often misnamed ‘structure’.
Structure is the actual bottom contour – humps, drops, and gullies. I think of structure as the highways and trails the fish use to travel from one area to another and consider cover as the rest spots or motels, if you like.
When it’s transition time for the bass to move around a dam, in particular early Spring and Autumn, I try to find these stop-over spots and keep them in my memory bank, or at least in my GPS!
Generally once you find these sweet spots in the structure you should keep them to yourself because they tend to produce over and over, year after year.
The best way to find the deep structure is to search through old maps or pictures taken of places when the dams were low or before they were built.
Or you can use your sonar to log the areas you think are good and then scrutinise the logs later.
Lowrance has a log sonar viewer available as a free download to inspect sonar data stored on memory cards in very good detail.
I have recently been using the Lowrance structure mapping facility at Glenbawn and St Clair and it is absolutely awesome. It can be used anytime and you can send the files to other Lowrance users. You can access this through Insight Genesis at www.lowrance.com
When I’m out on the water looking for these deep sweet spots, I zig-zag a route while looking very closely at the sounder and use my StructureScan to cover a lot of area quickly. If I notice some cover or schools of bait, I drop a marker buoy and keep moving until I find another spot and drop another buoy and so on, until I have covered a fair amount of the area’s bottom structure.
Eventually you can see a good trail and can get some idea of the bottom structure. Quite often it can be a feeder creek or the old riverbed.
The next step in fishing for these deep and quite often suspended bass is to set your sounder on manual and set the target depth window to give you a better sounding of these fish. And you should also then be able to see your lure on the screen at the level of the fish.
Deciding what colour lure to use is vital.
You must understand that colour vision is extremely important to the life of a fish. Fish rely on colour vision for food selection, for signals on mating behaviour, for shelter and self-defence.
Scientific research has proven that bass have excellent colour vision. They can distinguish all colours of the spectrum from violet to red.
They can even distinguish between closely related colours and even between shades of the same colour.
The bass’s eyes can receive information regarding colour and movement and are its dominant sense for seeking food.
Because of its anatomy, a fish’s eye can receive five times more light than a human’s, thus allowing it to distinguish shape, movement, size and colours that the human eye cannot.
They can do this under varying water clarity and lighting conditions.
Lure colour selection can be very critical for this deep fishing as it will depend on water clarity and light penetration.
I have been using a Spike-It Color Clector to help choose which colours fish see best at a given depth and water clarity.
Fluorescent colours have a wider visibility span than conventional colours, according to the device. I mainly use the selection column for clear water, which is Glenbawn during Winter.
For example, if I lower the Clector probe in about 15m of clear water and the fish are at 11m, the meter shows a reading of 27. That equates in the fluoro colour range to orange-yellow and in normal colours to watermelon to pumpkinseed.
On this day the bass were caught using watermelon plastics early in the day and as the sun climbed higher, pumpkinseed performed better.
If you are catching fish on a particular colour for a period of time and the fish suddenly quit biting, some changes in the water clarity or light penetration may have affected the fishes’ ability to see that particular colour. And if they can’t see it, they can’t strike at it.
This can happen especially late in the afternoon if you are fishing along west-facing banks because the light can change from intensely bright to quite dim within a few minutes as the sun disappears.
These deep schooling fish can be very hard to get to bite but persistence and a finesse approach are sometimes all that is required.
During periods of active feeding, such as in low light, rain and wind, the fish generally move shallower and away from cover. In times of high atmospheric pressure or very still conditions, the bass move deeper and hold tighter to cover.
Most bass in recent weeks have been coming from this deep structure and this usually continues through Winter.
Lately the bass have been taking small plastics rigged on light jigs and the occasional ice jig. Trolling very deep lures will be rewarding over some of the deep cover in 15m, where sunken treetops are down around the lure’s swimming depth.
The other day at Glenbawn, Peter from the Kiosk gave me some lures to try, the Smak Blitz Baga and the Golden Child, which get down around 6m. I used them longlining with about 100m of 12lb fluorocarbon out.
The longlining technique involves casting one of these extra deep-divers and then using the electric of main motor to power away from the static lure while paying out line, The sinking belly of fluorocarbon line helps to make the lure swim even deeper than it normally would and you can then retrieve it through fish you have located on deep structure.
For those who dislike trolling or who are in tournaments where trolling is banned, this method has proven successful here and in the US where it was developed.
There is one downside to this deep fishing in dams, especially for bass and golden perch, and that is they will most likely suffer from barotrauma.
This is caused from the swim bladder expanding rapidly as the fish ascends and if released there is a definite chance that the fish will die, as it cannot stabilise or deflate its swim bladder and so it will float or go ‘belly – up’ and die.
There are two ways this can be avoided, firstly, when the fish is brought to the surface out of say, 14ms, try to release it as quickly as possible, and try not to handle it too much because all its internals are very stretched and can easily be damaged. Quickly release it into a similar depth to where you caught it, or deeper. Do not release it in water shallower than the depth it was caught in, in this case 14m.
The second method of releasing the deep caught fish is to vent its swim bladder with a fairly large diameter catheter, until the swim bladder contracts. This method should be used only if you intend to keep your fish in a livewell, as in a competition, so it can be later released.
Good structure and cover: Bass holding at around 18m among trees; the bottom is 25m-35m deep.
Deep fishing in dams requires various finesse plastics in a variety of colours. The author’s Color Clector probe nominated watermelon as the colour most likely to be visible to the fish. Gulp grubs, whole and cut down, and a trimmed Turtleback Worm. The author likes the Nitro jig head, top because it stands hook up when fished on the bottom.
Bass holding tight to cover in good structure.
Pete from the Glenbawn Kiosk deep jigging on a beautiful Autumn afternoon.
Mark Taylor caught these Glenbawn bass finessing cut-down Gulps in 25m. The fish were suspended around 18m.
Around for several decades in the US, the Color Clector has a photosensitive probe on a cable. It’s meant to measure light penetration at a given depth, assigning it a number. The angler checks off the corresponding number on the front graph what colours can be seen best by the fish. In this case the reading in clear water was 27 and watermelon was the prime lure colour.
This sounder shot shows a jig working along the bottom.