FISHING is about trial and error. It might sound contradictory but the more experience we gain, the less we seem to know about our quarry.

Imagine for a moment you are out on Victoria's Port Phillip Bay and your target species is King George whiting.

You know the whiting are in the area, your spot is well chosen and you are fishing well, but the whiting are not co-operating.

Then, the tide starts to flow and, as if someone has turned on the lights, the whiting have started to feed.

This is a common occurrence.

It is more pronounced in estuaries where tidal flow is a major influence on the movements of fish.

In bays, the change of tide, either high or low, can be feeding trigger for species such as snapper.

Not all fish are the same; whiting, as already shown, prefer to feed in current.

When the current stops running, chances are the whiting will cease feeding.

Water height can be decisive in the surf, where larger predators will take advantage of rising water to work their way over sandbars and into gutters closer to shore to feed on smaller fish.

For different reasons, gummy sharks also like high water. A rising tide exposes crabs and worms as the waves pound the sand.

Factors that bring fish on the bite in freshwater include natural events such as an insect hatch on a gin-clear mountain stream, or a downpour that causes riverbanks or lakes to rise.

In the case of the latter, the ensuing rise of water inevitably brings trout inshore to graze over the freshly flooded grass for the likes of snails and worms.

Native species are also affected by rising water. Murray cod are at their most willing, in terms of being caught, the day before and on the day of a rise in water levels.

I have read that fish feel a greater change in pressure swimming down a metre of so in the water column than changes in barometric pressure above the water surface.

Maybe so, but in my experience, a falling or rising barometer does affect the feeding habits of some species including trout, Murray cod and snapper.

These examples are all basic fish feeding habits. The only commonality is that while they are applicable most of the time, there is no 100 per cent guarantee.

Feeding habits of fish can be both simple and complex.

There are no hard and fast rules, and the truth of the matter is that while we anglers may think we know what triggers a hot bite, we can't be certain.

Fishing to established patterns based on time of tide when you previously caught fish works most of the time, and the fish go and spoil the party by doing something they are not supposed to.

Bream are a good example of a contrary species. One day they will be easy, the following day it's like fishing for a different species.

As a general observation, bream will more likely be shy and finicky on bright sunny days, and easier to catch when there is cloud to dull the sun.

Like most estuary species, bream often feed better around the change of tide.

In shallow water, bream will move in on the rising tide and be gone before the ebb is half way through, most of the time.

Sometimes though, bream double dip, moving in early on a making tide for a feed, then waiting for the slack water at high tide to start feeding again.

In areas where this species feels relatively safe, such as in a large snag, they may feed at any time of the day or night.

Trout are a little easier to work out, provided you know what they are feeding on. When there is an insect hatch on, you will often see them sipping insects on or just below the surface.

During spring, when the smelt school up to spawn, there is a good chance trout will be feeding on them.

Moreover, when the water rises suddenly and floods the banks, the chances are trout will move in and feed on snails and worms.

Weather is important in trout fishing, particularly on lakes and impoundments, where the worst days, weather-wise, can be best in terms of results.

Overcast days when there is enough wind to ruffle the surface seem to bring them on the bite nearer the surface and closer inshore.

Like most predators, trout are opportunistic feeders, which probably explains why we catch them on synthetic baits such as Powerbait, or on saltwater baits, including pilchard strips.

There are times when you have to experiment. Traditional methods or baits are not working, so it is time to try something different. Most anglers adopt the approach of changing rigs or using alternative baits. Sometimes both.

Steve Cooper can be heard on the Casting Off program on Radio Sport927 between 4.30am and 6.30am on Saturdays.