This month, we continue to expose of the basics of successful lure fishing with an examination of one of its core principles.

As touched on last month, ‘matching the hatch’ is one of lure fishing’s accepted rules, and owes its origins to fly fishing for trout. Many of the insects trout eat begin life as aquatic nymphs, crawling on streambeds. As they mature, these nymphs swim to the surface, crack open their little shells and hatch into flying adults. It’s during this transitional phase that they’re at their most vulnerable, and likely to be included on the trout’s menu.

The fact that specific environmental triggers such as water temperature, day length or wind direction can flick a switch that sees literally millions of insects hitting the surface over a short period (sometimes an hour or less) makes these hatches intense events. Fish are hard-wired to cash in on these such protein bounties. When they do, they can become frustratingly single-minded in their pursuit of the main course, often swimming past tucker they’d otherwise savour to slurp down the emerging insects.

This behaviour is referred to as ‘selective feeding’ and it’s not confined to trout waters, as any angler who’s been on an Australian bass river or bream estuary during a big termite hatch will attest! Similarly, those who chase pelagic species such as Australian salmon, yellowtail kingfish and the various tunas may also have come across incidences of this single-minded behaviour, be it salmon and silver trevally locked onto krill, or keg-sized yellowfin tuna blasting sauries. Incredibly, these marine hunters can become just as fixatedly fussy about their diet as any mayfly-educated trout or termite-sipping bass!

Amongst the hardest of all fish to fool are smaller pelagic species such as salmon, kingies, skipjack (striped tuna), kawa kawa (mackerel tuna) and longtails (northern bluefin tuna) feeding on clouds of minuscule baitfish fry. These semi-transparent piscatorial matchsticks are nick-named ‘eyes’ by the anglers who regularly chase their finned tormentors, in recognition of the fact that those pin-head sized black eyes are actually their most visible feature.

Pelagics gorging on ‘eyes’ drive anglers to distraction. Attempts to match the hatch lead to the selection of smaller and smaller offerings, until your diminutive offering simply becomes lost in the multitudes… one of many millions, with a statistical chance of getting eaten that’s every bit as slim as its profile!

Oddly, tying on a big popper or some other dramatically different piece of hardware can occasionally turn things around. So can choosing a slightly over-sized match (pun intended!) with exaggerated features, such as larger-than-life eyes. But you can still expect to make lots of casts most days.

As a rule of thumb, the smaller the prey items responsible for inducing selective feeding, the harder it is to fool predators into eating something else. Also, the smaller and more prolific the food source, the less effective it is to exactly match the hatch by imitating just one prey item. Sometimes, the best way to match the hatch is to imitate a group of prey items, or even to choose some aspects of the prey you suspect might be capable of inducing an ‘attack response trigger’ and enlarging (literally!) upon those elements.

This phenomenon of exaggeration is clearly demonstrated when lake fishing for trout (especially rainbows) feeding on daphnia or ‘water fleas’ (tiny arthropod crustaceans that graze on algae). Daphnia occur in huge numbers, often forming distinct feed layers that moves up and down with varying light intensity and can be dense enough to return signals on a good depth sounder.

When trout feed heavily on daphnia their stomachs become distended with a green sludge made up of tens of thousands of partially digested organisms. Each daphnia is about the size of a pinhead. Not only would it be next to impossible to create a lure or fly that perfectly imitated a single daphnia, it would also be unproductive, because of the one-in-a-million principle already discussed.

Interestingly, lake trollers often score quite well on daphnia-feeding trout by specifically targeting the exact depth at which the feed layer lies and using lures that match the green hue of a mass of daphnia. Exactly why or how this approach works when the lures involved are hundreds, if not thousands, of times larger than a single daphnia is a good question, but one that seems unimportant when an energetic rainbow jumps on!

On one day, matching the hatch may mean precisely that: imitating as closely as possible the size, action, colour and swimming depth of a certain prey item. Yet, on another day, it could mean throwing the rulebook out the window and trying something distinctly left-field. The great thing is that there’s no single, correct answer. Your theory is as valid as the next angler’s… at least until tested!