Targeting Big Fish on Tidal Estuaries

Craig Worthington shares his experience saltwater flyfishing the flats for snapper...

Upgrading your catch by encouraging bigger fish to bite is a useful tactic on many fishing days. Little fish can be a pain. They’re always stripping your bait or grabbing your lure or fly. There can be so many of them that bigger fish are totally crowded out. Changing up to a bigger or tougher bait, lure, or fly, can slow down the little guys and give the bigger fish a chance to find the hook.

I relearned this valuable lesson quite recently. My wading adventures on the tidal flats of the Bay of Islands had been continuing unabated, but I was beginning to wonder what I should do about the excessive abundance of small fish that I was catching. I needed to find a way of upgrading the size of the fish hitting my flies, without denting my overall catch.

A fishing session on a hitherto unexplored Bay of Island’s flat gave me a few answers. Keen Auckland saltwater fly fisherman and photographer Mark Hoffman drove all the way north for the fishing. He came duly prepared with new neoprene waders and a couple of light fly rods.

We hit the first flat in the warmth of a lovely autumn evening and immediately started catching fish. They were good hard-fighting snapper, but they weren’t big.

The flats were glassy, warm, and a delight to wade across. Small snapper continued to swirl on the surface as they chased shrimps across the top.

We started trading fish-for-fish on unweighted shrimp flies as the sun eased down into the western hills, yet there was only an occasional fish caught that was over 30cm. The action was fast and very entertaining, but we were certainly getting plagued by a lot of small fish.

There were in fact mini snapper bust-ups all around us. Small snapper actively hunted shrimps right across the flat and trapped them against the surface. There would be small explosions, a flurry of red fins, and the sight of small shrimps flicking into the air. It was fascinating to watch.

The trouble was this hot surface action from small snapper was a major red herring. It stole our attention away from trying to figure out where the bigger fish might be. It looked good, but we had to come to the realisation that only small snapper were engaged in this surface feeding activity. Unweighted shrimp flies in this situation were simply going to be too attractive to all those little snapper on top.

So, Mark tied on a bigger, heavier Clouser (a fly with sinking dumbbell eyes attached) and fished this hard on the bottom. Soon after he hooked into a much better fish of over forty centimetres. On his ultra-light 3wt fly rod it put up a great fight. With just one easy fly change Mark had effectively upgraded his catch.

Mark Hoffman changed his fly to a weighted clouser and upgraded his catch almost straight away.

Foolishly, I persisted with the small shrimp fly. Mostly through laziness (my bag and the shore were a long wade away). I continued to connect with sub-legal fish.

I couldn’t complain about the number of strikes, but really needed to catch a plus 35cm fish to prove I could get away from the smaller fish. It was not to be. Within twenty minutes the tide forced us out of the water. It was time to go home. Mark had taken out the pole position and, effectively, shown me the way.

By the time I had a chance to return to the flat (a few days later) that fishing lesson had been fully absorbed. I totally understood what I needed to do. I lengthened my fluorocarbon leader for a better sink rate, tied on a larger, dumbbell weighted, mantis shrimp fly, and fished this sinking fly hard on the bottom.

The mantis shrimp fly was a new fly and one that I had recently created. I had spun it up because I figured that mantis shrimp would be a sought-after prey item in this area and would be very appealing to any larger fish on the flat.

Mantis shrimps prefer the firmer sand and shell substrates that are found on many of New Zealand’s tidal flats. They are well known for coming out of their burrows and scurrying about in warm shallow water as the tide comes in. In terms of being tempting snapper morsels, they are second to none.

The mantis shrimp fly that effectively upgraded the catch.

Imitating a mantis shrimp is the hard part. They are a complex little crustacean, but somewhat dull to look at from above. With short legs and claspers tucked in under their body they don’t have too many distinctive features. I hoped that my rabbit fur, hare fur, and grey chenille offering would reflect this dull appearance and look like a wayward mantis shrimp out for a walk.

One cast across waist-deep water was all it took to wash away any fears that my fly wouldn’t work. As the early morning sun rays cracked across the eastern horizon my first cast of the day was slammed before I had even retrieved two metres of line. A deep bend in the rod and line peeling from the 6wt Sage reel indicated that a better-than-legal snapper had grabbed the fly. I was stoked. Upgrading was well and truly underway!

I went on to have one of the most fantastic days of shallow water saltwater fly fishing that I have ever had anywhere. I caught a dozen snapper from thirty to forty centimetres in water that was only a metre deep and connected with few fish that were under legal size. The new mantis shrimp fly had effectively upgraded my catch with a better class of fish. All while wading waist-deep over an extensive pipi and cockle flat that was nothing but dry sand and firm mud at low tide.

In this shallow water environment, the fish hit the fly hard – like they were truly trying to kill a spiky crustacean – and went on crazy sand-kicking runs. There were some great fights.

The change in fishing tactics produced a better class of fish.

And all the time the little snapper feeding on top were still doing their best to distract me. They were erupting all around, even while I was fighting fish. Three or four of them exploded within a rod’s length of me as they demolished a shrimp meatball on the surface. Some of them were just about swimming through my legs. They had to be ignored. Less than a metre down, on the bottom, were bigger snapper that were doing different things.

So, I went home extremely happy with my morning’s fishing and still a little bit in disbelief as to what I had found. This was another Northland flats fishing experience and another fantastic day. After ten or more trips to some of the local flats, I had now found that good-sized snapper were there for the taking. A slight change in tactics had delivered bigger fish that were well worth pursuing.

The next big question in my mind was: how far could this upgrading go? What size fish would it be possible to catch with a fly rod while wading on a Northland sand flat? And would this fishing continue into winter?

It is going to be a lot of fun finding out.

July 2023 - Craig Worthington
New Zealand Fishing News Magazine.
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