Tackle and Tactics
Mike Ladle


Information Page.

Seeing is believing.

“Fish don’t take lures in this area because the water’s too dirty!”

“A big, smelly bait’s the thing to attract them when the water’s dark or highly coloured!”

“Our new plug has a built-in rattle which drives the fish wild!”

“A few drops of concentrated Snibbo on your two-week-old squid bait is guaranteed to increase catches!”

“With out a doubt the best colour for attracting pollack/coalfish/ling/cod in 50 fathoms of water is black/red/chartreuse/you-name-it!”

These and many similar statements are part and parcel of anglers’ bar-side conversations and often stem from advertising guff. How can we, as anglers, decide whether such comments are likely to be true?

Is there any means of knowing what a fish can see, smell, feel or sense in any other way? Of course our natural inclination is to ‘try it out’ but all fishing is a patchy business and few of us are able to devote enough time or catch enough fish to give a straight answer to whether, where or when one bait or lure works better than another. Worse still, it is only too easy to get the wrong end of the stick and decide that we have “cracked it” just because a shoal of cod or bass swam by shortly after we had attached a new ‘item’ to the end of our line.

Scientists have devoted a lot of time to finding out how fish see, feel and smell in the watery world in which they live. An understanding of just what our adversaries are capable of can be very useful when we are trying to make decisions what to do.

Most of the published studies, however interesting they may be, are written in obscure and expensive journals. Worse still, the language in which they are written is rich in jargon and difficult to decipher. Nowadays the internet provides access to some of this material but frequently this makes it even more confusing and even worse is wrongly interpreted.

Let’s try to unravel the sensory world of fishes and present a simple picture of how they detect our offerings and how they decide whether to accept or reject our presentations.

Firstly, how is it possible to find out what a fish senses? The most direct approach is to take a look at the eye, nose, skin etc. under the microscope and see whether the structures are anything like our own. After all, our entire impression of the world is coloured by our own ability to see the tints of the rainbow or distinguish the small of roast beef from last week’s rotten lugworm.

The next method is to stimulate the fish’s eye, mouth or lateral line and then try to record any change in the electrical signals reaching the brain. By using modern equipment we can do just this.

Lastly and perhaps most difficult of all, we can offer the fish a choice of foods and see which ones it prefers. Much more instructive, in this respect, is the use of conditioning. The basic idea is that we train a fish to respond in some way (for example to go to one end of the tank and anticipate food) when it is presented with a particular colour, sound or scent.

All of these methods tell us something about fish senses and by combining them we can learn a good deal. Let’s look first at vision. What can a fish see? Most fish have eyes of a type similar to our own and even in the murky depths they use them to good effect.

The available information ranges from size, shape, pattern and texture to colour and brightness. We can assume that fish which carry brightly coloured “flags” (sticklebacks, cuckoo wrasse, tub gurnard) are able to see the patterns and possibly the colours.

Since most inshore waters are pretty murky much of the light falling on the surface has been absorbed by the time depths of about 25 meters (80ft) (usually much less) are reached. So bright colours can only be seen in shallow, well lit conditions.

In gin clear tropical waters the commonest colours seen on fish are often the bright blue of the background lighting and the contrasting shades of yellow and orange-yellow. In dirty freshwater, or coastal seas, the corresponding colours are green-brown and red shades.

It is well known that the eyes of many animals have two types of light sensitive cells, the rods which are used for black and white (night time) vision and the cones which pick up colours. All fish have rods and many have three or more types of colour crunching cones. In general those fish which live near the surface have excellent colour vision and sharp eyes; mid-water fish tend to have a wider range of colour vision combined with adaptations for seeing contrasts in dim light. Bottom living and night hunting species have eyes which are adapted only for picking out silhouettes in the gloom.

When it comes to colour vision apparently the colour sensitive cones in the retinas of some fish move to the surface in daytime so that the fish see colour better in bright (day) light than at night. Also, fish that hunt in the bright conditions near the sea’s surface (such as mackerel and bass) tend to have a fast ‘shutter speed’ which helps them to detect prey. Striped bass, which are very like our own bass but bigger, can detect a wide range of colours and are supposed to be most sensitive to chartreuse (don’t ask me why) and have a fast ‘shutter speed’. In contrast the eyes of weakfish (that feed in a similar way but in the dark) work best at night. It is suggested by Horodysky (who did the research) that chartreuse lures are most visible (but I would hazard a guess - not necessarily most attractive) to the bass. I suspect that the least of a predators problems is simply seeing your lure at distance.

The eyes of fish have to be able to focus light under water so they have powerful lenses shaped like glass marbles. Unlike our own eyes the shape of the lens can not be changed so the fish focus by moving it back and forward. The spherical lens prevents the fish from closing down its pupil (the hole through which light enters the eye) so in bright light they have to mask the sensitive retina by cloaking it with pigment. Yellow filters in the lens or other parts of the eye may help to sharpen up the image. Generally mid-water predators like bass or mackerel see more clearly then bottom feeders.

Studies of behaviour show that many fish can distinguish shapes as well as colours. The upper contour of a shape is an important feature and projecting lumps and spikes (e.g. fins) help in recognition. When we design our lures careful thought should be given to their purpose, to the conditions under which they will be used and above all to the capabilities of the fish which they are designed to deceive. In general we will not go far wrong if the lure is designed to resemble the natural prey items of our quarry but in some circumstances the best colour may not conform to this plan. A prime example of selecting a lure to catch the fishes eye would be the choice of a jet black or red plug, spoon or rubber eel for use in deep (dark) water. Predators often home in on the silhouetted profile of their victims.

Ultra-violet light does not travel far through water so as a rule ultra-violet perception is not an important part of fish perception. However, it has been shown that certain damsel fish that, to our eyes, look as though they have black and white stripes actually have a UV reflecting patch on the dorsal fin. This patch is more visible to the young damselfish schoolmates than to more distant predators

For the present I suggest that the best approach is to try and use lures that are shaped, coloured and behave more or less like the natural prey items of the day. Most important of all is to use a lure which will get to where the fish are (right distance, right depth and fish without too much snagging). You’ll never get it just right so however hard you try let's hope that your lure may be just different enough to stand out in a crowd but not different enough to deter that twenty pound bass.

If you have any comments or questions about fish, methods, tactics or 'what have you.'get in touch with me by sending an E-MAIL to - docladle@hotmail.com

Bass eye.

note the big fixed pupil - good for seeing in poor light.'

Mackerel eye.

These eyes have a fast 'shutter speed'.  The eyes of mackerel are specially streamlined to avoid drag.'