WHAT FISH EAT AND WHEN

In this article Dr Mike Ladle looks at what the fish species around the UK feed on. Many of the food sources mentioned are actually present in New Zealand, even the lugworms and sandeels. The interesting thing however, is that they are rarely sighted or used as bait. This is perhaps an exciting opportunity for surfcasters and bait fishermen to exploit. Remember that NZ is six months out of phase with the UK so the life cycles will likely be six months out of step with the information listed below.

In the article Mike has highlighted in bold italics information which may be particularly useful in deciding WHEN and WHERE to use a particular bait.

WHAT FISH EAT

“Returning to the subject of food, it is well worth looking at the yearly cycles of some of the most important bait / food organisms and trying to establish when they are most likely to be available to the fish that eat them.

Firstly there is the ubiquitous lugworm. These plump worms are widely used as bait, probably because they make a good hookful of material that is acceptable to a wide range of fishes. Also, they are comparatively easy to find and dig from shores of sand and muddy sand. Lugworms occur both on the open coast and in sheltered bays and estuaries; the so-called black lug, gullies, and so-forth, are varieties of the same species* and differ because of local conditions. A very similar species, the tail-less lugworm (Arenicolides ecaudata), is found on stony or gravelly ground. Fish which feed on these worms are thus accustomed to finding one or other species in most intertidal areas.

*(Since this chapter was written in the early 1980’s it has been shown that, as many anglers have long believed, the black lug is a totally different species from the common or blow lug (Arenicola marina). In 1993 scientists first described black lug (now called Arenicola defodiens) from specimens collected in South Wales. Black lug are found on moderately exposed sandy shores but do not seem to live in estuaries where blow lug may be abundant. Unlike blow lug they only occur below mid-tide level and live in more or less vertical burrows up to one metre in depth. Many details of their lifestyle are unknown).

The common lugworm, whose little spirals of sand are such a conspicuous feature of our beaches, is normally well protected in the U-shaped feeding burrow, where it lies pumping water down through the little sand-filter, which provides its food. At intervals, the lugworm backs up to the surface to add to its cast. Only rarely can any portion of the worm’s body protrude from its burrow and then only the expendable tip of its `tail’.

Lugworms do, however, leave their burrows and would seem to be particularly vulnerable to fish twice a year. In particular, many worms may come to the surface at their spawning time. The lugworm releases eggs and sperm from within the safety of its burrow between spring tides in late October. At this time deaths following spawning can reduce the numbers of lugworm on a beach by as much as 40% and for a short time, many dead worms may be found on the surface of the sand.

Lugworms also migrate by a form of swimming, which takes place at times not associated with spawning. Swimming worms have been seen in May, when bare stretches of beach may be quickly re-colonised. It seems probable that fish are especially attracted to lugworm beds, both below and between the tidemarks, in May and in October-November. At these times they may even be conditioned to, or preoccupied with, feeding on these worms.

Ragworm larvae survival

The king ragworm, another good big hookful and a very popular bait, has been studied on the aptly named Black Middens, a large area of mudflats near the mouth of the River Tyne in Tyne and Wear. The most striking feature of these and other ragworms is the jaws, which pop out and pinch the angler’s finger as he baits up. They are not, as might be supposed, used for capturing the tiny algae and bits of detritus on which the worms feed. In fact, the pincers are weapons that are often employed to repel other ragworms from the burrow. The manner in which these jaws are used can be clearly seen if two worms are introduced at opposite ends of a piece of glass tubing immersed in a dish of sea water. The king rag lives on mudflats, often close to and under large stones. Several other species of ragworm are used for bait, notably the small red harbour ragworm, which lives on the upper levels of the shore. These red ragworms are always most abundant where freshwater runs over or percolates through the sediment.

King ragworms are dug for use and for sale as bait. The extent to which bait diggers remove large worms on the Black Middens is as high as 75-80 per cent. It takes about a month for a dug out patch to repopulate from surrounding areas. Spawning of king rag takes place in May and large numbers of tiny worms appear on the flats in July and August, having either grown and developed on the shore or migrated from below the tide marks. The worms then live and grow in the mud for two or three years.

Ragworm life cycle

Female worms remain in their winding burrows to spawn, releasing their eggs into the overlying water. In contrast the male worms turn deep green, develop extra-large swimming paddles at spawning time and release their sperm while swarming in the water above the burrows. At this time (in late spring) they will be readily caught and eaten by fish. The male worms swim in a curious manner with the front part of the body. held out stiffly and the back end wriggling, rather like some of the modern, soft plastic, `sand eel’ lures. Some anglers will not use green breeding ragworms for bait because they are thought not to be attractive to fish. We cannot comment on this statement but would be interested in any evidence that breeding worms are distasteful to fish.

Molluscs such as mussels, cockles and clams, are widely used as bait. In the north of England the mussel is the favourite. Easily available to the angler in large quantities these bivalves inhabit exposed rocky shores and stony, muddy estuaries. Mussels are usually firmly attached and well protected from fish predators, with the possible exception of wrasse, which have very powerful teeth. Mussels are attacked and eaten, however, notably by starfish, shore crabs, edible crabs and oyster catchers, all of which must leave remains to be eaten by fish. They are rightly regarded as good bait, for cod and flatfish in particular. Probably because the mussels have to be shelled and are a little difficult to hook they are not much used by anglers in our area.

Here in the south, the slipper limpet, an alien snail introduced by man from the West Atlantic, provides an alternative bait to mussel. Slipper limpets are easy to extract from their shells and are a good deal tougher than mussels, but they are, in our experience, not quite so attractive to most fish. These limpets occur in masses with the smaller specimens on top of the pile. Large limpets are all females, having begun their lives as small males and changed sex as they aged.

Crab life cycle

Many anglers, throughout the country, regard crab as the premier bait for a wide variety of the more popular fish species. Green shore crabs are usually the easiest to obtain and enormous numbers of these can be collected in a short time from harbours, estuaries and rocky shores. The ordinary hard-crab is useful as ground bait and makes a first class hook bait for large wrasse but, despite much speculation to the contrary, no one has ever presented evidence of catches to show that they are a good general bait. Usually crabs of all types are collected and used as bait when they are about to moult (peelers) or have just moulted (soft-backs). Crabs grow and moult most frequently when they are young and in warm weather. A convenient way of recognising both peeler and soft-back crabs is to look for pairs. The males can infallibly detect females which are about to shed their shells and carry them about until they moult, at which time mating occurs. On the West Coast this mostly is in August and September. The females do not produce their eggs until the following April-May, though in our part of the country they are also found in winter. Other than pairs, peeler and soft-crabs of the three common species can be found at almost any time of year, but will be most frequent in the warmer months.

Other crustaceans eaten by fish and used as bait by anglers are shrimps and prawns. The daily tidal rhythm of the brown shrimp, which lives on sandy beaches, has already been mentioned. The equivalents of these animals on rocky and weedy shores are several species of prawn. These are all used as bait, particularly in the south and west of the country where fish such a bass, wrasse and pollack take them readily. The two common species of prawn are to be found in rock pools throughout the summer months. The larger of the two (up to three inches in length) migrates offshore in winter and is normally found at lower tidal levels than its smaller counterpart, even in summer. Both of these prawns become very active on the ebb of the spring tides and they also exhibit dusk and dawn periods of swimming during the neaps.

An interesting aspect of prawn behaviour, in relation to the feeding of bass, was related to us by the late Bert Randall of Weymouth. In the course of his life Bert must have spent as many hours watching fish, catching fish and watching other people catch fish as anyone in the country. In his youth he used to tend the small-mesh pots used in this part of the country to catch prawns. Often he would drop a large prawn into the deep clear water where he could see bass swimming. The prawn would sink slowly with its body held stiff and straight and its spear-like rostrum projecting in front. In this state the prawn was rarely attacked by a bass, but as it approached the sea bed it would usually flex its tail and dart for cover. At this instant the bass would react and make its lunge in an attempt to capture its prey. Presumably the fish respond to a combination of form and movement in the way that is often referred to by wet-fly fishermen. Bait presentation can obviously be very important in sea fishing.

Because they are easily obtainable in large quantities from fishmongers and tackle shops, squid and cuttlefish are popular baits. The squids sold are mostly those imported from the Pacific Ocean and, in their dead, frozen state, they are pinkish, leathery and rather tough. Less commonly appreciated is the great abundance and variety of squids and cuttlefishes, which swim in the seas around the British Isles. The living creatures are mostly fast swimming, streamlined, opalescent, translucent animals. The species eaten by fishes include the tiny little-cuttlefish, several species of which are very abundant offshore, near the sea bed. One of these, Sepio1a, is found in enormous numbers just below the low water mark off sandy beaches and is sometimes present in the guts of fish from such beaches.

The larger common cuttlefish (Sepia) is active at night and may be over one foot in length. Its internal shell or cuttlebone (used to supplement the diet of budgerigars) is often cast up with the flotsam and jetsam along the tideline. Cuttlefish live on sandy sea beds, feeding, after dark, on shrimps, which they disturb by projecting jets of water onto the sand and seize by using the two longest tentacles. The cuttlebone is used rather like the ballast tank of a submarine. By varying the amount of fluid in the bone the cuttlefish can control its buoyancy and is able to swim either slowly by rippling the marginal fin or quickly by jet propulsion. These molluscs live for about three years and very cold spells of weather may cause mass deaths. At these times thousands of dead cuttlefish and their bones may be washed up on beaches. Like squid and octopus, cuttlefish are masters of colour change. Although they are normally well camouflaged, cuttlefish blanch when they are scared and develop two enormous eyespots, a pattern which is presumably a last resort in trying to repel large fish. It also suggests that their predators are susceptible to such threats.

Squid generally live further from the sea bed than cuttlefish and consequently they are even more streamlined and very active. The internal shell of squids is reduced to a sliver of plastic-like stiffening material. The large squid (Loligo forbesi) is common around Britain and may grow to two-and-a-half feet long. Occasionally we have caught these squids in winter when fishing at night for conger from our local beaches. Many of the abortive runs that occur, when using fish baits from the shore and from boats, may be due to the attentions of squid or cuttlefish. Squid feed on crustaceans, smaller squids and fish. These molluscs bite off the heads of prey fish in a characteristic manner and this may assist in the recognition of squid-bitten baits.

Large numbers of Loligo are netted some miles off the Yorkshire coast, but smaller species, rarely more than six inches in length, are even more numerous. The latter closely resemble the Californian squids used as bait and they are known to be particularly abundant over deep water in winter and spring.

A favourite bait in the south-west of England is the `sand eel’. One of the most abundant species is Raitt’s sand eel (Ammodytes marinus) a so-called lesser sand eel. Scientist P. Winslade used a photographic method to record the activity of these sand eels in tanks. In this way he was able to show that in summer, when the sea is richest in tiny, planktonic copepods which are the main food of the eels, the latter show a strong daily rhythm. They emerge from the sand at dawn, to swim and feed only in the hours of daylight, burrowing back into the sand at dusk.

Sandeel habits

Quite a lot of light is required for the full daytime activity to develop. In more than a few fathoms of water in winter it is normally too gloomy for this to occur. The main feeding period of this sand eel is in April to July, after which, fat from their rich feeding, they tend to stay buried, as their eggs mature, prior to spawning in late winter. Spawning takes place later further north. The other common species of lesser sand eel (Ammodytes tobianus) has both spring and autumn spawning races. Fishes such as turbot, brill and blonde ray, which feed largely on sand eels, are mostly day-active and probably follow behaviour patterns similar to those of the sand eels.

Because all the food / bait organisms mentioned are very abundant but normally well able to take care of themselves, they are likely to be most successful as bait when injury, spawning or other migrations, storm disturbance or tidal movements make them easily available to fish. In effect, any large concentration of a particular food item is a sort of natural ground bait. Often these concentrations are on a scale vastly greater than any that the angler could consider providing. To take advantage of such events they MUST be recognised or, preferably, anticipated. A classic example of such an event is the tidal rhythm of washout of the maggots of the seaweed fly.

Seaweed flies

The seaweed fly (Coelopa frigida) is one of five species of black, bristly flies which buzz about in clouds on the seashore to the consternation of holidaymakers. Their larvae, about the size of housefly maggots, live in the piles of rotting seaweed cast up near the high water mark of spring tides. These flies came into the news in 1953-4, when a veritable plague occurred on the coasts of southern England. The adult flies are irresistibly attracted to cleaning fluids. Factories where carbon tetrachloride or chloroform were used as solvents were inundated with the insects.

The flies normally breed throughout the year and occur on beaches from the English Channel to the Shetlands. Several other types of flies and a number of beetles are also found in rotting weed. Like most other insects, the seaweed fly goes through the stages of egg, larva, pupa and adult. The maggots and pupae have little breathing tubes at the back end. The life cycle takes about three weeks to complete with the maggots growing quickly in the heat generated by the decaying weed. The numbers of flies are governed chiefly by the quantity of rotting weed available as food. Adult flies normally stay in the weed unless they are disturbed by the rising tide, when they congregate and fly in swarms along the beach.

maggots 2

At the top of the spring tides the maggots of these flies are often washed into and onto the surface of the sea where, because they are lighter than the seawater, they float in masses, providing an irresistible attraction to fish such as sand smelts, mullet and bass.

This seaweed fly food source is not restricted to Britain. For example, vast amounts of kelp (between ten thousand and one million tons per year) are washed ashore on the beaches of California and act as a food source for flies and other insects in the way already described. The number of flies is astronomical, with up to twenty million on each mile of beach. These flies have a ten-day life cycle in the summer months.

seaweed fly distribution

Other creatures that feed on weed and, in turn, attract and are eaten by fish, include beach hoppers which live just above the water line and isopods or marine woodlice just below it.

We have now discussed the activities and behaviour of some of the most popular baits. If it is possible to match angling methods and fishing times to such patterns, then catches should improve. This has been the basis of our approach and, at least in some cases, it has been very successful”.

Hopefully this gets you thinking about other baits that you could potentially use to catch fish, especially seen as much of it is relatively easy to gather. Let us know how you get on!

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