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Fly fishing for smallmouth yellowfish

Where to go for them

Many anglers don’t know the difference between the large and the smallmouth especially when they are around 300 mm especially beginners to the sport of fly fishing. Especially as some smallmouth yellowfish don’t have the very thick lips that most possess. They have two pairs of barbells though and eyes that are able to see below and to the sides. They occur higher than the largemouth yellowfish in smaller tributaries. They prefer clear flowing water of bigger rivers with sandy rocky bottoms. The Smallmouth (barbus aeneus) breeds in spring to early summer after the first good rains of the season. It is said that they migrate upstream to spawn on suitable gravel beds. Eggs hatch in 3-8 days and after a further 5 days begin feeding on microscopic organisms. The Vaal /Orange catchment is the major area but is also found in Gouritz, Kei, Fish, Limpopo and Zimbabwe and other areas. They mature at 200 mm. Females at 240 mm. They are omnivorous but gets more piscivorous when large. The Vaal River and Orange River have many great spots to catch them in large numbers. Our largest during October this year in the beginning of the season was a 12 pound fish by Hardus in the Lower Orange river where we operate our wilderness raft excursions. We expect very large specimens during our November excursions. The heavy floods of the beginning of this year 2010 have now cleared sand and silt over gravel beds and there should be more spawning areas than the 10 previous years .Already I have witnessed exceptional spawning by Mudfish along the Orange river.

How to fish for them

What is important is to remember the preferred habitat and to “match the hatch” . Also bear in mind that they prefer fast flowing water of around 1-1 ½ meters between interspersed rocks with some aquatic vegetation along the edges. Between large rocks and behind drop offs. 

See our video on “How to catch Yellowfish volume 1-5”.Or buy our DVD on Yellowfish.

What tackle t use

5/6 weight rod, floating line and tippet of 2-6 kilograms depending on the size of the fish and the ease of catch periods. I go for the large smallmouths and prefer the 6-9 weight rods as I don’t want to lose the largemouths that also from time to time take my large flies while catching for Smallmouths. Never go lighter than a 5/6 to minimise break offs.

Fly patterns

Dragon fly nymphs, wide range of caddis patterns, daddy long legs, TVN, stonefly nymphs, beetles, adult dragonflies etc. See fly section.

The fight

I have Nothing to say about the fight than that it is a few times harder than any trout. It is a very powerful fish and when catching a 4 kilogrammer in the stream it sometimes feels like you have hooked into a rock or got stuck. It then takes a few seconds to determine whether you have hooked into a fish or whether you got stuck. No feeling in the world can beat a good day’s smallmouth yellowfish action in a wide long rapid. Even better to do it where there’s no other people around in perfect surroundings. And even better if you sleep right next to the water and do some night casting in bright moonlight as well. That’s in summer when the water is warm and they are prolific in the fast water.

In winter it gets extremely tricky and very small flies with very slow actions will produce a fish ..or maybe two during June / July. Not really the time to target them. Just after the spawn is good .

Records

SA record I believe is 7.84 kilograms on conventional tackle. Large fish on fly as far as I’m concerned are over 4 kilos with everything over 5 kilos exceptional catches. 

Fly fishing for Largemouth Yellowfish

The Largemouth Yellowfish or Barbus Kimberleyensis is the largest scale bearing fish in Southern Africa and indeed in South Africa. It has a larger mouth than other yellowfish that terminates in thin lips. It has two pairs of smallish thin barbells with dorso –lateral eye placement. One of the differences between it and the smallmouth yellowfish is that you cannot see the eyes from below and more visible from the top. In other words they are good hunters of prey upwards. Their colours vary from silver to yellow but the younger fish of 300 mm are very silver in colour. It is said that the SA record is 22,2 kilograms. The females grow larger than the males and gets older. A very sensitive and scarce species but probably the most valuable sports angling species in Africa with the Perch, Tiger and Goliath tiger – to date. Of course the mudfish, catfish are two species together with the Clanwilliam yellowfish and other yellowfish and a few other fish species have not reached their full potential with fishermen though...may be a good thing!. It is my opinion that anglers up until now have not been able to land the larger Largemouth yellowfish specimens, even on conventional tackle. We specialise in monster catfish and the most brutal takes ever while catching catfish with 50 pound line and 80 pound leaders have been largemouth yellowfish. There is just no way a fly rod of 12 weight will land a 20 kilogramer in our rivers. Well let me say the chances are slim. Everything in our powers should be done to eradicate the conventional anglers that are successful with this species and kill every fish they catch. I know angler along the Vaal River that have only been fishing for this species and will catch as much as 15 Largemouths and above 5-10 kilograms on every outing and eat and sell them. At least small effort are made to research these fish over the last few years but almost nothing have been done as far as I’m concerned. The telemetry program on the Vaal have revealed nothing as far as I m concerned to really assist with the conservation of this specie.

The main reason why we should do everything in our powers to prevent the poaching and killing  and even catching these species is that they take 5 years to grow only 300 mm and matures at 6 and 8 years respectively when the anal fin turns slight orange. Females the longest.  

Where to go for them

The Vaal Orange catchment but they are not to be found in the higher altitudes of Lesotho and the Cape as well as in dams. Recently some very large fish are being caught in our dams by carp anglers. Most of these are also not returned alive. Deep channels in rivers behind boulders right into the rapids. Especially the shoulder or backwater. They are very active after the first small fish in the season starts breeding such as the mudfish. It is then good to fish for them between the thousands of small fry that are jumping around on the surface. They prefer cleaner water and therefore anglers seem to be more successful on fly in the beginning of summer before the water starts to colour form the first rain water. The cleaner waters of the Wilge, the Vaal, Orange, Riet rivers have been good. The Wilge River have produced the largest fish and most good sized fish during September/ October. The main reason for this is that these areas are controlled by farmers and poaching is strictly controlled and forbidden for long stretches of good habitat. The Lower Orange river produced the most fish we caught in relation to smallmouth yellowfish in the same area. Largemouth yellowfish of good sizes will be caught in the beginning of next summer I predict. The good spots are closely guarded secrets however and rightly so! As far as I’m concerned there is no area as good as the Lower Orange for Large specimens due to the same reasons the catfish grow so large over there.

How to fish for them

As they are predators they eat mice, rats, reptiles such as lizards, large insects that fall into the water, such as bugs, grasshoppers, scorpions, crabs, small fish, frogs,  small birds etc. They are also quite omnivorous as all the conventional anglers records show. They take mielie pips, fish heads, fish fillets as well as etc as well.

So in essence the angler need to mimic the prey at the right habitat like with all other fish that are targeted. Slowly drifting and casting to right underneath trees where birds normally sit on overhanging branches, Casting a fly to above a boulder and allow it to drift into the eddy behind the rock. Along rocks sticking out of the water, in the back water of pools and even below rapids. No noise should be made and you basically have one cats per spot. Crab patterns work right onto the bank. The most underutilised areas .The crab can literally be dropped onto the bank and slowly pulled into the water .

What tackle to use

Anything smaller than a 7 weight is pushing it although 5/6 weights are used mostly as anglers targeting Smallmouth’s hook into them by accident. Of course it is easier to catch with a 5/6 all day than a 9 weight but a 9 is my preferred weight together with a 10 weight. They are predators that take insects when small but heavy piscivorous above 300 mm it is said. Floating to intermediate and at times sinking line for strong flowing waters . I don’t go lighter than 6 kilos with my tippet. 

Fly patterns

Mice patterns crab patterns, streamers, deceivers, zonkers, pups, peddars dragon, Dahlbergs divers, Basic bugs, frogs and large nymphs 

The fight

Well its statistics show that it almost always go 12 rounds.....and still win on a knock out. Lots of times they win the fight on a rod break off during the strike. Other times by pulling the rod out of the anglers hands during the take. Sometimes they snap the leaders or the fly and sometimes they just spit out the fly. Lots of times though they tend to “miss” the fly with the first take with a very large splash. It is not a known fact what happens during these misses. It could be that it is just so developed that it can in a fraction of a second feel that the content of the fly is not the real McCoy or the prey item. 

Records

No IGFA line class records. The largest on fly on picture is around 10 kilograms. I shall be silent on our largest sizes and the location for the mean time.

Water temperature and fishing 2 micro.

Importance of understanding water temperature in fishing from an academicals point of view.

Just as temperature and its fluctuation is important for fish and aquatic invertebrates so is temperature naturally important for the angler. Why ? Well firstly because anything that causes the fish to stop biting concerns us so we need to know at least the basics of thermal stress. Too large fluctuations too soon up or down will immediately cause the fish to stop biting and even cause death as we all know. The fish deaths after big hail storms on very warm water are normally the clearest example of this. The following article (extracts from a scientific paper ) will show how complex water temperature is in the aquatic environment and that the angler should apply his mind accordingly.

Spatial and temporal variation in water temperature in our rivers.

I have briefly touched on the factors influencing water temperatures earlier. (Hydrological, Climatic, Structural and regional.)

One must take into consideration daily and annual or seasonal fluctuations. Temperatures are normally lowest in early morning hours and warmest in the mid to late afternoons. This also shifts with the seasons. From winter to summer naturally. Of course large deep rivers , small heavily canopied streams have the least diel ranges in water temperature while on the other hand shallow streams exposed to direct solar radiation and braided rivers have the largest dial range of water temperature.

Seasonal  temperatures will naturally have warmer temperatures in summer and lowest in winter. Then there is the inter annual variations like wet cold seasons or dry warm seasons etc . So the averages will thus differ. 

“If spatial and temporal variations is combined three broad spatio-temporal scales may be defined (Gunderson et al.1995 cited by Rivers-More et al.2004);namely,

micro-scale  (operating at areas  ‹10m² (site or reach) and over a time period of hours (diel)]; 

meso-scale operating between 10m² to 10km²n (longitudinal) over a time period of days (seasonal)]; and 

macro –scale [operating at  areas ›10km (regional) and over a time period of years (inter –annual)].”Helen Dalas. University of Cape Town.

Of course studies recently ranged from thermal pollution by dams and powers stations to global warming . Detailed studies on the thermal characteristics of all our rivers are not well documented or shall I say water temperatures are not routinely monitored in South Africa.

When studying water temperatures they normally record either at different period of the day or measure hourly temperatures. Ecologically it makes better sense (latter) due to the fact that it allows for measurements of extremes that will have the greater significance.

Modelling water temperature 

Water temperature model Studies are categorised so far into three broad categories namely, regression, stochastic and deterministic models .(Cassie 2006)

Regression models include linear (Stefan and Preud’homme 1993), multiple or logistic models (Mohseni 1998).

Simple linear models predict water temperatures asa function  of air temperature (weekly or monthly) where multiple regression models include other factors such as discharge time lag etc, while logistic models account for ground water and evaporative cooling (Mohseni and Stefan 1999)

Stohastic and deterministic models are said to be more realistic as they require only air temperature as the input where deterministic models use all relevant meteorological data to calculate energy components. (Stefan and Sinokrot 1993).S o duration curves and degree curves are common outputs to compare cumulative warmth at a site within a season (Essig 1998, Rivers –Moore 2005).

Anthropogenic factors modifying water temperature.

Direct effects of change in water temperatures will direct and include thermal discharge, or indirect including land use charge, agricultural irrigation return flow, flow modification, (river  regulation), inter-basin water transfer, modification to riparian vegetation, and global warming. The effect these have on South African rivers are not known as far as I’m concerned.

Effects of temperature changes on physical and chemical characteristics of water.

Temperatures have great effect on water including solubility, oxygen and other gasses, chemical reaction rates and toxicity and microbial activity (Dallas and Day 2004)

High temperatures reduce solubility of dissolved oxygen decreasing its concentration and thus its availability to aquatic organisms and when temperatures increase the vulnerability to toxins intensifies (cyanide, zinc, phenol, and xylene.)

The effect then on aquatic organisms and ecosystems.

Temperatures outside of an organisms optimal temperature  range affects growth rate, behaviour, metabolism,  reproduction, feeding habits, geographical distribution, community structure, movements and migrations, diseases and pollution. (Vannote and Sweeney, 1980 ) called it the “optimal thermal regime”. Quite logical stuff well defined you might say. Some organisms have a good tolerance level in extreme cold temperatures and some in extreme hot temperatures but within these two broad examples there are thousands of organisms living in a narrower temperature range within.

Physiological and behavioural effects 

A 10° C increase in temperature level results in a doubling of organism’s metabolic rate (Hellawell1986) and causes stress due to increased respiration and oxygen demand. Metabolic rate increases drastically. Parasites increase drastically and predator prey relationships are altered radically. Hus fish have temperature thresholds at below which they stop feeding or slow feeding. Fish will move to cooler water if the water temperature increases to close to their threshold and visa versa.

Reproduction, development.

It is common sense that water temperature affects breeding, egg incubation periods, hatching success and duration and it is frequently during reproductive stages that organisms are very sensitive to temperature fluctuations. Fish spawning are known to be triggered by temperature, photoperiod, water level and flooding, intra-specific interactions and the presence of spawning substrates . The spawning periods are almost always during the warmer months when water temperatures are warm. One of the main reasons is that the food is most abundant. In South Africa the water temperatures of 18-19° C seems to be the most favourable for our indigenous fish species. It is also when the growth of aquatic insects are at its peak. Water temperature is also the most important factor in the growth rate of our fish species.

Some temperature/spawn studies on some of our species are;

The Clanwilliam yellowfish (Barbus Capensis) spawn in gravel beds in relative shallow water after upstream migrations between Sep and Dec. Temperatures at spawning beds were between 19.1° and 23.1° Celsius. Lower temperatures the next year however between 16.6° and 17.5° was the water temperature at the spawning sites due to late cold weather. No spawning thus occurred. 19° was thus proposed as a thermal threshold.

Labeo umbratus migrate upstream and spawn on flood plains even in heavy flood summer months such as the previous flood season in the Vaal Orange catchment. Larvae hatched at 22° C (Mulder 1971). 

Oreochromus Mossambicus spawn in late November when minimum temperatures get to 18 ° and raising. (James & Bruton1992) 

Barbus trevelyani (border barb) also will spawn at 18° celcius. (Bok and Heart 1982)

Both labeobarbus kimberleyensis (largemouth yellowfish, labeobarbus aeneus (smallmouth yellowfish), labeo umbratus (moggel), labeo Capensis (Orange River mudfish) and barbus natalensis spawn between 18 and 23° Celcius. Most of them when fresh water enters the system or the water rise they migrate to suitable habitat. The Labeo species prefer flood plains or the gravel that are exposed during the dry months. Thus very critically influenced by the water level control by dams.

Algae.

Water temperature greatly influence the geographical distribution of a specie. Algal species diversity increases from 0°-25°  and decreases › 30°, while biomass increases at 0°-30° and decrease  ›30°. Algal classes shift in dominance from diatoms(‹ 20°) to green algae 15°-30°) to blue green-algae (›30°) (DeNicola 1996). So the greater changes in communities occurs ›25 and less below 25°.  

Lethal temperature effects on aquatic organisms.

Lethal effects on aquatic organisms are affected by.

1-Rate of temperature change ( up or down)

2- Acclimatisation. (Previous temperature history of organism)

3-Duration of exposure (acute vs. chronic)

4-Life history stage of the organisms

5-Physiological state of the organism (effects of other stresses.

6- Adaptive strategies.

There are also sub lethal effects like for instance on reproduction, spawning, egg incubation and hatchability, development and growth, survival of fry etc.

Ref; Helen Dalas (University of Cape town)

Summary.

The fishermen should thus not only keep track of the water temperature over a week period but for the duration of the season/s, and try and obtain a average, minimum and maximum during winter, summer, the minimum daily and daily maximum as well as the temperature range in the area he/she is fishing in. We should also know the threshold of our species and the organisms they feed on and have a good knowledge of the structure of the waters we fish in. A sort of mental underwater picture of the habitat and most favourable spots at various thermal regimes including a good knowledge of the waters above and below in rivers we catch in.