gents,
we do a lot of jig fishing on trawler wrecks off the townsville coast. this is what a good wreck stacked in fish (they are big GTs in the water column above the wreck) looks like. our furuno fcv 585 (and many other colour sounders) will show larger fish as dark 'red blobs'.
ignore the bottom zoom column on the left it is just confusing given the wreck and bait.
the middle column shows the history of the entire water column, you can see we've actually gone over the wreck that lies in 150ft of water. the wreck is about 20ft high from the seabed and has a big stack of bait and nannygai on it from 100-130ft from the surface - use the scale and numbers. above this are the GTs (with some cobia and spanish macs, but predominantly GTs - particularly the fish highest in the water column).
the right hand column is the instantaneous "a-scope". it is, as the name suggests the feedback from the instantaneous sounder pulse. not many of my mates utilise this function but I find it invaluable for up to date information. and is very important for determining fish size. big red echoes es are the larger fish. in the picture in this column, you can count 6 red echoes, and these are bit GTs (we know because you can look over the side and see them, and if you throw pilchard cubes over, the echoes rise to the surface until you are nearly hand feeding 30-50kg GTs!).
We have come off the down current end of the wreck where the wreck is still 20 or so foot high, but the bait and fish on the actual wreck have reduced - they prefer the pressure point on the upcurrent side and the upwelling on top - current brings food.
apologies for not taking a photo of the gps at the same time.....
hope this is of use
cheers
martin
