YOU'LL learn lots about main coarse fish species and how to catch them in summer by reading this article, and by getting stuck into Angler's Mail magazine every week.
LOW WATER STALKING IN SUMMER
When rivers are low and clear in summer, fishing can be difficult, but it is still possible to catch and you can improve your chances in a number of ways.
Roving while keeping concealed and fishing for one fish at a time is one option, and this allows you to cover lots of ground and target fish that are not buried deep in cover, and have their guard down, relatively speaking.
The target fish are often not actively searching for food, but they are alert, and will opportunistically take relatively large food items if you can present them in a natural way.
This form of fishing can be very rewarding, but also very frustrating, because if the fish becomes aware of you, either by sight or through vibration, you will have lost your chance.
If you do manage to get into position to present a suitable bait, for example a freelined slug or breadflake for chub, or a lobworm or piece of meat for barbel, takes can be instantaneous, followed by memorable and sometimes hairy close-range scraps.
The main rules of engagement are to keep low on the horizon, approach from downstream and present the bait as naturally as you can, and if you spook the fish, move on to another swim, but keep a mental note of the spot, as the fish will often be back in the same position when you return.
THERMAL LAYERS EXPLAINED
The process of thermal stratification is most prevalent in the summer, and has a big influence on fish behaviour in waters that are affected.
In calm conditions, when wind-driven mixing is minimal, the surface layers of the water column are heated by the sun, and effectively become separated from the cooler water away from the surface.
The boundary between the two layers, known as the thermocline. The upper layer of water is warm and rich in oxygen, while the lower layer is cool, and over time can become completely devoid of oxygen, and of fish.
In stillwaters of more than a couple of metres in depth it pays to avoid fishing on the bottom in deep water in calm, hot conditions, as it is likely that the lake will have stratified, and the fish will be near to the surface, or in the margins.
GET FISH COMPETING FIRST
If you prefer to stay in one spot rather than rove around, there is another way of catching consistently when rivers are low and clear. This tactic relies upon the opportunist nature of fish.
The trick is to get fish competing for food before you start fishing, and a bed of small food particles such as hemp or micro pellets, or the introduction of loose feed little and often, can both work.
It is important, however, that you don’t introduce a rig or start to catch fish until the fish have built up confidence, and a competitive feeding regime has been established.
It can take anywhere from 30 minutes to several hours to build up competition. Once the fish are feeding competitively, it is often possible to remove several members from the shoal without the others becoming spooked and leaving the area.
The swimming speed of a fish, and the power it can generate is a function of a number of factors including fish size and water temperature.
As a rule of thumb, large fish of a given species can swim faster, and fight harder than small ones. It is also true that the warmer the temperature, the faster a fish can swim, up to a point.
However, coolwater species such as trout and grayling can come in like a wet sack in very hot weather. In general, however, swimming performance improves with increasing temperature.
For hard-fighting species such as carp and barbel it is important to ensure that your tackle strength and knots can cope with this additional power, especially when fishing close to snags.
Summer is often a time of year when, due to water clarity and fish behaviour, there is a tendency to scale down on line strength, but this must be balanced against the increase in power and speed of your target species.
CHANGING OXYGEN LEVELS
In densely vegetated waters there is a daily cycle of oxygen concentration that can affect both fish behaviour and feeding.
Plants are known as primary producers, and they grow using a process called photosynthesis whereby energy from the sun is used to generate food.
Oxygen is a by-product of photosynthesis, so on bright, sunny days when plants are photosynthesising actively, oxygen concentrations rise steadily throughout the day, and are often close to saturation by mid-afternoon.
At night it is a different story. Photosynthesis stops, and so does the release of oxygen into the water.
Plants, along with fish and millions of micro-organisms, use up oxygen during respiration, meaning that the oxygen saturation in the water falls through the night, reaching a minimum just after dawn.
Fish are used to this daily fluctuation in oxygen concentration, and sometimes change their behaviour as a result. In affected waters, fish are often found close to the surface overnight and at dawn, but they don’t always feed strongly.
If you have ever had one of those frustrating nights when there seemed to be lots of activity but no takes, only for the bites to start as the activity seemed to be subsiding, fluctuating oxygen concentrations were probably the cause.
DON’T OVERDO THE FREEBIES
There is little doubt that most species of fish feed more in summer, and much of their annual growth in length occurs in the warmer months. As a result, you can get away with using much more feed in summer, as more species are active, and appetites are larger.
That said, for short sessions you could be reducing your chances if you overdo feeding. The more bait there is in the water, the lower the chances of a fish selecting your hook bait. Heavy baiting inevitably lowers your odds of success on a short session.
If you already know where the fish are, either because you can see them or from past experience, it often pays to fish for one at a time, either with a single bait or a small, tight patch of bait.
With this style of fishing it helps if you can introduce your bait without spooking the fish, and freelined baits or rigs lowered into the margins can be deadly.
A baitdropper is a great way of positioning a tight patch of food stealthily with a rig in the middle, and if there are fish in the area you can expect action very quickly.
You may need to move to find a new spot after each fish, but with this kind of fishing multiple catches are possible, even on short sessions.
PREDATORS HUNT BY DAY
In mid-summer the nights are short, and digestion rates are high, so some species normally associated with darkness will feed in the day.
Eels and catfish will hunt fish prey actively on hot summer afternoons in certain circumstances. Big eels are predominantly nocturnal, but they are also opportunists, and are known to feed in daylight to take advantage of seasonal abundances of food.
Minnows are a favourite food of large river eels, and when minnows congregate to spawn, eels are known to home in on this feeding opportunity, even on bright, sunny days.
Catfish are energised by high water temperatures, and hunt fish in the warm surface layers of the lake, even in the heat of mid-afternoon.
With prey fish shoaled up in the oxygen rich water close to the surface, cats can strike from beneath, often engulfing more than one small fish at a time in their cavernous mouths.
RETURNING FISH SAFELY
Fish fight particularly hard in summer and expend a lot of energy during the fight.
Fish use red muscle fibres during normal day-to-day swimming, requiring a supply of oxygen-rich blood.
For more energetic swimming, such as to avoid a predator, jump a waterfall or when hooked by an angler, fish can employ white muscle fibres, which provide power and speed, and function without the need for oxygen.
When using white muscle, glycogen stored in their muscles is converted to lactic acid, and once all the glycogen has been used up the fish effectively runs out of power.
The process of removing the lactic acid and restoring the glycogen reserves requires oxygen and time, and the fish must find somewhere safe to rest.
For this reason it is important that when fish are returned to the water after a fight they are held for a few moments in clean, oxygenated water, until they have the strength to swim off under their own steam.
A fish released too soon can get its head stuck in weed or silt, where it will be deprived of oxygen and could die. Holding the fish upright for a few seconds before release reduces the risk of it getting stuck, and increases the chances that the fish will be able to free itself.
Prebaiting is a useful tool in summer, providing it is used correctly.
It is particularly useful in very big waters with low stock densities, because it increases the frequency with which fish visit particular areas. But to make the most of it you need to try to predict how the fish will respond.
It works best over a period of several days or even weeks, and if bait can be introduced at the same time every day.
Where natural feeding spells are typically at dawn and dusk, bait introduced at mid-morning may not be found until the evening.
By choosing a suitable time, and introducing bait on a daily basis, fish will build up a pattern of behaviour that ensures they are in the area anticipating the arrival of their daily feed.
It needn’t involve huge quantities of bait. A pint of micro-pellets or maggots sprinkled over gravel in the margins can have fish rooting around for hours, and done regularly will ensure fish visit frequently.
You will be able to tell by the appearance of the gravel whether fish have been in and fed, and you may even be able to watch the fish feeding.
A single bait introduced into the right area when the prebaiting has been carried out stands a good chance of picking up a fish.
For great summer advice and tips, plus latest where to fish venue recommendations and catch news, read Angler’s Mail magazine every week.