Southland Reel Life November 2017

Southland smelt – the key to healthy lowland trout fisheries

From about November through to January each year, the common smelt makes its way from the ocean into the tidal reaches of our rivers and streams.

These small and smelly bait fish move into our rivers to spawn on sandy bars or in shallow areas near creek mouths.

Above right: Small feathered smelt imitations are perfect for targeting smelting trout.

During their migration upstream, smelt become available to a myriad of predators, the likes of eels, herons, flounder and of course, trout!  

Some anglers will see smelt as small undesirable fish (relative to whitebait), good only as bait.

However, it's highly likely that these fish are actually the foundation of our lowland trout fisheries because they're such important prey items for trout.

Smelt are very important for the productivity of our trout fisheries and lowland river ecosystems because they provide a massive amount of calorie and protein-rich food for trout as well as native fish and birds.  

Baitfish trout guts Oct 2010For example, there's much more sustenance in a smelt compared to a small mayfly nymph or aquatic snail.

Left: Smelt and other bait fish are very important food items for lowland river trout.

Additionally, smelt are not only important for fishery productivity, but also angler enjoyment.

Many Southland anglers enjoy targeting smelting trout.

Trout will often take feathered lures or soft baits with great enthusiasm when they are actively foraging for the small fish.

If you want to experience fishing for smelting trout, the lower Aparima River near Gummies Bush is a perfect place, along with the lower Oreti River below the Iron Bridge (Invercargill-Riverton Highway).

A careful approach is required when targeting smelting trout because these fish are often foraging in very shallow water close to the bank.

They are able to ‘feel’ the footsteps of anglers approaching the river over noisy gravel. 

Stream bugs

For many people, stream bugs, living under rocks in the river, may not be all that interesting.

However, we trout fishers know that stream bugs are very important trout food and as such, stream bugs are of great interest to us.

Stream bugs are not only useful as trout food, but also as indicators of stream health.

Certain bugs are less tolerant of pollution than others and so, if there are lots of pollution-sensitive bugs in the water we can infer that water quality is good.

Check out this link to Cawthron scientist Robin Holmes who has done a great job of explaining how freshwater scientists can use stream bugs and the MCI (Macroinvertebrate Community Index) to assess stream health, and determine whether there's suitable food to sustain trout populations. 

Cohen Stewart, Southland Fish & Game Officer

Back to Reel Life