Talking to people who consistently catch fish is always enlightening and adds to our store of knowledge. One thing that surfaces time and again is that snapper love current.
No doubt a strong current undermines the edges of channels and drop-offs, uncovering the worms, crabs and shellfish that the fish prey on. So the snapper are more active, and when they are more active they are moving and in a feeding mode. This makes them more likely to encounter your bait and more likely to eat it.
Sounds simple and logical, but it is always surprising that so many people don't know what sort of tide and how much current they are going to find when they head out. It is not something they have given any thought to, but it is so easy to plan ahead.
You can check the upcoming tides in the daily newspaper, or on the internet. I still use my "bible", the OceanFun Tide Times Calendar. It is actually a sun, moon and tide calendar and I also use it to look up moon phases. In Auckland the tides vary from 2.6m to 3.6m and I work on tides of more than 3m as a minimum, preferring to fish on tides of 3.3m or 3.4m.
The same principle will apply in other waters.
For six months of the year the biggest tides of the month will occur around the full moon, with the smallest tides on the new moon. For the other six months it is the reverse.
Although the moon phase is not as important as the tide flow, it does have an effect on fish (and birds and animals). The best fishing days are in the two weeks around the new moon, while the full moon usually sees poor fishing. It is as if somebody has turned off a switch - the fish go into sleep mode, and when you do catch one the gut is usually empty. They are not feeding.
When you get big tides and the new moon you have the best combination. Remember those memorable red-letter days when the fish went crazy on the bite? Chances are the moon and tides were all lined up but you weren't aware of it.
Fish and animals are more active at first light in the morning and last light in the evening. Snapper are wary fish and will not come into the shallows in bright, sunny conditions. But they will in low light, and this is always the best time to fish. When the turn of the tide, a big tide, and a good moon phase all coincide near dawn or dusk you have all your ducks in a row and should do very well.
My preference is for low tide at dawn as the first couple of hours of the incoming work well. Often, just when you think you have it all worked out the fish pull the rug out from under your feet just to remind you who is in charge. But I wouldn't have it any other way.
Generally, though, on any one day you will find that one tide will produce better than the other, so it is a good idea to fish part of the incoming then the outgoing, or vice versa, to cover your options. Another rule of thumb when bottom dunking, as we call fishing the popular channels in 15m to 25m of water, is: The stronger the current the longer the trace.
I know some fishermen who use a 10m trace for all their snapper fishing. It obviously allows the bait more movement, and there is no doubt a moving bait is an advantage. But in slack water a long trace is a handicap, and we shorten the trace to about half a metre. A commercial fisherman told me this, and it does really make a difference. So it is horses for courses.
The other important variable to fishing the channels in currents is to vary the rig. We usually start out with a running rig on one rod and a ledger rig on another outfit. Often it doesn't matter and it comes down to what you prefer, but sometimes one rig will outfish the other. The advantage of a ledger rig is that the sinker is at the bottom and the baits are above it, so you feel the bites a lot better. This is a definite advantage for inexperienced fishermen.
You will also find that where you encounter jack mackerel (yellowtail) or slimy mackerel, you will usually find snapper. Look for schools of baitfish in midwater on your fishfinder and start fishing - either drifting through the area or anchoring.
Also drop a light rod with a sabiki (string of tiny jig flies), adding small chunks of bait to each hook. You should have no trouble catching plenty of mackerel which can be used as cut bait, or in the case of small yellowtails a whole fillet or whole fish.
When a blue mackerel, also called slimy mackerel, comes up on the bait flies you are in the money. These little speedsters are top bait either as a livey for kingfish or as cut bait for snapper. You will invariably catch your biggest snapper on the fresh bait.