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Feeding flatties.

Is it worth casting a long way? The answer to this question must surely be, yes - sometimes. The main benefits of a good casting capability are most likely to be seen when trying to target a bait on a particular species, like plaice.

Because these fish almost always swim over 'soft' ground in search of their prey, which is mostly molluscs such as small clams, mussels, cockles and the like, the shore angler will usually find himself propelling his chosen bait over areas of nice, relatively clean sea bed. The haunts of flatties tend to be more or less snag-free so there is no problem about using fine lines and appropriate shock leaders. The fish are powerful muscular creatures but since they are only about the size of a freshwater chub, hefty tackle should not be necessary.

A long cast is often most likely to produce the biggest specimens because of the well established connection between depth of water and size of plaice. Over gently shelving shorelines the deepest water is almost always furthest from the water’s edge and that is where the flatty expert will seek his match winner or frying pan filler.

Of course, the fact that small plaice tend to spend their time in shallower water than their elders and betters does not mean that they stay at one level all the time. Between the tide marks the water may change from zero to 40 feet deep in the space of only six hours and if the fish are to find their preferred depth of water (assuming that they have one) they must move in and out with the ebb and flow.

Some years ago Dr Gibson, a scientist of the Scottish Marine Biological Association, spent many hours “plaice watching”. Gibson’s idea was to find out how these popular flatfish behaved in relation to the rising and falling of the sea. He anchored his small rubber dinghy in shallow water so that it could be easily moved to any fixed point. To make it easier to observe by cutting down surface reflection the fish were viewed through a large “glass bottomed” bucket.

By watching individual fish and making careful notes of how they moved and the direction in which they were headed it was possible to build up a picture of general patterns of behaviour. The swimming movements of the plaice were of two types firstly there were the ‘longer’ periods of activity, lasting for more than a second. These seemed to be designed simply for getting from A to B as quickly as possible. Secondly, there were the short bursts lasting for only a fraction of a second which a fish used when it was actively searching for food.

The limitations of visibility meant that observations were confined to shallow water (up to seven or eight feet) and to young/smallish fish but there is no reason to think that the big fish behave differently. As you might expect the fish moved up the shore on the flood tide. This upward movement took place for quite a short period, when the water had reached about three or four feet deep, which was about two hours after low water.

During this inshore movement most of the swimming was of the brief, food-searching type. On the ebb, again roughly two hours before low water, the fish shifted back down the shore. This time the movements were much more purposeful and involved little feeding activity.

This recalls some experiences that I had when fishing for flounders many years ago. I took to laying my baits in the waters edge in, literally, a couple of centimetres of water (when there were no gulls about). In this case the flounders (good sized ones) often took the bait within minutes when the depth had perhaps doubled or trebled and was only just enough (despite their shape) to cover the flatties backs.

While on the subject of flatfish and scientific studies it may be worth taking a look at some other observations on their food and feeding. Unfortunately most of the work was carried out in North America or New Zealand so the species were different from those which we fish for. However, the principals are exactly the same and I shall translate the results to our familiar plaice, dab, sole, flounder etc.

The first thing to notice is that despite their apparent similarity flatfish species are not randomly scattered on the sea bed. Fish eaters like the brill and turbot are normally to be found on areas of coarse sediment where tidal currents are stronger and the prey (fish) are most vulnerable to their lurking attacks. Dabs will be found over sand where shrimps and beach fleas are common, plaice will concentrate in areas which are rich in bivalves, such as mussels, cockles and clams, while flounders will often hunt for crabs, worms and molluscs in estuaries where mud is the main type of sediment. Although there is a certain amount of overlap in the diets of the different kinds of fish, each is an expert when it comes to its own preferred food.

Sometimes pollution, silting, dredging or spoil dumping has the effect of changing large areas of the sea bed into an absolutely uniform, desert-like plain. Such areas often provide a very monotonous diet of only one or two species of worms for the resident flatties. In areas where China clay is dumped off the Cornish coasts the clay covered sea bed has proved to be an important nursery area for dabs. Perhaps significantly (to mackerel, garfish, bass and anglers), whitebait were seen to avoid the milky water.

Some experiments with small plaice (by Ansell and Gibson) showed another (not very convincing) reason why these fish might like sand. The flatties were exposed to four predators cod, pollack, swimming crabs and shrimps (yes they will eat little flatties) either in the open or where they could bury themselves in the sand. Only the pollack were baffled by the burying behaviour – the others just dug them up and ate them. However, perhaps more surprisingly, predation rates were greater IN THE DARK than in the light for all the predators EXCEPT THE POLLACK.

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