Petestop, I’m relying on you guys to fill in some of the gaps in what I write, especially when it comes to local knowledge. Your observations are very pertinent and appreciated. Please helpout with some of the local subtleties which I obviously can’t write about with any authority. Chip in with any additional info where needed.
Part 1: Finding structure
Part 2: Mapping structure and building a mental 3D picture
Part 3: Finding the fish on structure
Part 4: Interpreting fish and their behaviour from your sounder
The structure I have drawn is a simple one because it’s easier to illustrate the principles. One of my intentions with this series of articles is to help people to think about their fishing. If I take people fishing, I don’t just want to catch them fish. I want to help them catch more fish for themselves.
Many of the structures that I fish are larger and more complex than the ones I have drawn. Some of them have several crests along their length and if the structure is cut by a depression with crests either side, even if there is a larger crest, you’ll get fish on this secondary location. Some of the structures have other structures nearby and sometimes the gap between two nearby structures can be very productive too. Some of the best structures I fish regularly are those situated right on the edge of the dropoff. They may rise to 100ft from the surface, with the shallow side being 250ft and the deep side being 1000ft or more. These are especially attractive for XXL fish of various sorts, especially when the current is running in from the deep side, even at an oblique angle. Here there are big dogtooth, amberjack and sharks (we get LOTS of sharks on jigs).
Tenggiri do indeed seem to orient on tall structure, but like any preditor, find the bait and you’ll find the bigger fish. The key to fishing structure is to understand what types of bait you have, where it will be, what the prefered prey species of your quarry is and what sort of attack method is prefered by the species you seek. You’ve touched on it yourself.
Where I fish, tenggiri prey predominantly on rainbow runners which are very common. They are present in huge schools of 2kg fish. Tenggiri feed on these, not small bait. Tenggiri are very well equipped to deal with large prey since their teeth are like razors and the jaws are designed for slicing, not grabbing and holding. They are also very streamlined for high speed. This in itself tells you tenggiri will not be hiding behind a rock waiting to grab a passing bait fish and bolt back to their hole. Groupers do this, not tenggiri. Find the rainbow runner, which are uptide of the structure, usually close to the surface. Look for the larger arches below the school and these will be tenggiri. They cruise below their quarry, launch a high speed sprint attack from below and cut their prey in half with their jaws. The tenggiri may overrun it’s quarry on the strike by 20ft, ending up flying like a missile into the air, two halfs of a rainbow runner dropping away on each side. This is a very spectacular method of feeding. The tenggiri will rise and fall with their prey. If the bait is deep, the tenggiri are still below them, so you need a method that goes deep, like jigging. If the rainbow runners are on the surface, the tenggiri will be high in the water column and trolling rapala’s works great.
I’m going to break with common tactics here and tell you that when I find such a situation, with bait shallow and tenggiri within 50ft of the surface, I troll DEAD SLOW with rapalas and with metal headed “hex” heads with coloured feathers. I troll at tickover speed. I can see the rapala metal bib flashing in the sunlight and I troll them up close right in the prop wash, perhaps 20 to 30ft behind the boat. The “hex” heads are run from the outriggers pretty close too and they just sort of slide along - no splash, no bubble trail, just the odd glint from the silver surface of the metal head. I believe that the boat appears to a tenggiri as the main school of bait fish, tightly packed. In the wake are a few stragglers. Sick fish that can’t keep up and they wallow and flash as they swim erratically trying to keep up with the main school (the boat). It’s this flash that triggers the strike and I don’t have to troll fast, because even though the tenggiri is tremendously fast, it’s attacking at high speed from below, not chasing down it’s prey in a flat out sprint. We often get strikes on the outrigger where the first thing you see is the tenggiri launching out of the water as it takes your bait. It flies through the air in a graceful arch, plunges back into the water and only then does the outrigger clip pop open and the reel start to scream. I have been observed by other boats to reverse faster on a big tenggiri hooked on light gear than I actually troll forwards!
If you watch the sounder during multiple passes of the structure, you’ll see the bait schools change shape. Spread out and with individual small fish visible in the school, no preditors. Tightly packed and visible as a single dense red cloud and you can be sure they are being hassled by something, even if you can’t see bigger fish on the sounder.
I’m going to break with traditional thinking again and tell you that if you can find a bait ball upcurrent of the structure and it’s being hammered - bait flying everywhere, tuna jumping, tenggiri flying every which way, maybe a shark or two, or even a Marlin slashing through the whole lot eating anything and everything, expect to find snapper, grouper and other traditionally bottom hugging species underneath the action, up high in the water column, mopping up the scraps. You can get snapper to come right up to the surface in some circumstances. You might even get the odd one on a rapala, but the killing method is - soft plastic baits on jig heads dropped down the water column on free spool!
Contrast the feeding methods of tenggiri with that of a grouper. Big mouth. Grasping rearward facing fang teeth. Large fins and a barrel shaped body. Clearly not a pelagic speedster. Also he’s eating bait he can swallow whole. Depending upon how big the grouper you expect, they generally won’t be tackling 2kg rainbow runners and the rainbow runners don’t often go that close up to the structure. A grouper has all the features of an ambush preditor. Even his colouration is designed to blend in with the rocks he hides in. Don’t expect him to come to you. You have to go to him and employ methods suitable for grouper. Where I anchor the boat behind Peucang Island for the night is a shallow reef edge. The top of the reef is barely submerged at low tide. At high tide it’s maybe 4 ft deep. At the edge, it drops off into 20ft of water. If the tide is dropping, you can catch grouper after grouper after grouper on soft plastics on light jig heads, but you have to fish the plastics sink and draw. Let the weighted jig sink into any holes or edges on the reef. Once you get the feel of it and learn to live a bit dangerously on the retrieve, you can literally catch a fish a cast. Fish with poppers or swimming minnows that just swim along over their heads, no fish! Fish an unweighted plastic that doesn’t get down into the holes, no fish!
As I said, I don’t do a great deal of bottom fishing, but we do a ton of downrigger trolling, jigging and freelining live baits. Your observations have given me a nice lead in to the next topic of fish behaviour interpreted from the sounder and how best to catch the fish you see. A knowledge of the species you seek will also help you both interpret what you see on the sounder and catch your intended quarry.
As soon as I get my pictures back from Jakarta I’ll post some real shots here.
Part 5: Trolling structure
Part 6: Jigging structure
bluenose - Just Fish 
U4 - 2006
Thomas 
