The Digestive Habits of Carp

Picture shows digestive habits of a carp

The digestive habits of carp affects how they feed at different times of the year!

Many anglers have seen carp test baits by taking them into their mouth and blowing them back out. The carp is an intelligent fish and has a memory. It knows what’s good and what’s not edible. Carp may test the food’s nutritional content, its taste or to determine if it has gone off. It may reject bait because it remembers that a particular substance or smell was accompanied by a hook or barb.

What Tastes Good to a Carp?

Carp grow rapidly in areas where the water is warm and rich in food. They can reach 0.9kg (2lb) in a year and continue to grow at that rate indefinitely. Asian carp can eat up to 40% of their body weight daily. Grass carp can eat their weight in weeds each day. In Britain, many of the waters are too cold to encourage maximum growth.

Like all creatures, carp have daily nutritional requirements for vitamins, minerals, proteins, amino acids, carbohydrates, oil and fibre. Carp can smell amino acids emitted by bloodworms, crayfish, and aquatic plants. Green-lipped mussel extract, kelp extract, liver powder and molasses contain sucrose and amino acids, which the carp has learned to recognise as having nutritional value. Some anglers use peanuts. While peanuts contain lipids, sugars and amino acids, these do not mimic the natural foods carp like.

Carp find many different items tasteful. They love boilies, bread crust, meat baits, maize, fruity flavours (items containing vitamin C), stilton cheese, white fishmeal, full fat soya flour, lactalbumin, rennet casein, robin red, hemp and seaweed extract. The best items are those that either emit favourable smells or contain ingredients which mimic them. Carp will also eat flavoured imitation baits. When boilies fail to attract them, artificial corn will usually work. Zoom Carp Snacks have been used successfully by many anglers. The snacks come in honey, vanilla, strawberry and chocolate flavours.

How do Carp Digest their Food?

To explain why certain baits are attractive to carp, we need to understand something about its digestive system. Inside the carp’s mouth, the buccal cavity is lined with a folded membrane with tough ridges. The mucosa is covered in microscopic projections called papillae and is richly provided by mucus goblet cells and taste buds. The palatal taste organ on the top of the mouth traps the food against the bottom of the mouth. Non-food items are expelled through the gills. Larger items are spat out. Approximately 97% of what the carp takes in is ejected. At the back of the mouth are the pharyngeal teeth. These are aligned in three rows on each side of the mouth, with three teeth in the innermost row and one tooth each in the two outer rows. The teeth are positioned below a tough calcified pad. Food is ground between it and the pharyngeal teeth. The duct which carries the ground up food to the intestine and receptive sack is called the oesophagus. It is lined with tastebuds to taste the fragmented food prior to ingestion. A dense bed of cilia and goblet cells aid the passage of the selected food material through this area.

Unlike many other animals, carp do not have a stomach. Digestion takes place in the intestine, which is twice the length of its body. Different enzymes are secreted by the pancreas along the intestine. Trypsin and chymotrypsin are used to break down protein. The system works best if it is able to process a steady supply of food. This is why carp are constantly rooting around for something to eat. Anglers should take advantage of this by feeding them small amounts of food on a regular basis.

Carp cannot digest all foods efficiently. They might eat bread and sweet corn, but it is difficult for them to digest them. Fibre, especially grass and alfalfa meal, is important as it allows the intestine to grip the food and keep it moving. Worms, insect larvae and fresh vegetable matter are only partly digested and serve as roughage to keep the intestine active and healthy. Carp will also ingest silt and other indigestible detritus to bulk out their diet.

Some Suggestions about Bait

Okay. Now we know what carp will eat and what they will reject. Most likely it will be an easily digestible flavoured food. BUT there are exceptions to every rule. What works one place at one time of the year will not necessarily work at another during a different season. Anglers often use easily digested food/ingredients in bait during the winter. This is because the carp don't move much due to the cold conditions. In the summer months, when fish are more active, anglers should use more protein in their baits. Older carp, however, require less protein.

Different amounts of bait may be required to catch carp depending on the depth of the water. In two feet of water, an angler should consider using smaller bait and a hook with a micro barb. The shallow water should be baited with a few handfuls of hemp or chopped up boilies, and the fishing done in the edge. When the carp sense the bait, they will return to the shallows to eat it, increasing their chances of being caught. Water depth is a crucial factor in the colder months. An average depth of 6-8 feet is ideal for winter fishing. Trickle the bait into the water on a regular basis. During the warmer months, the carp will be feeding more cautiously. They will eat a large amount of the bait, but most will get away without being caught.

Don’t bait up heavily initially. On some waters carp don’t respond well to large quantities of bait raining down on them. In busier waters, however, spodding can actually pull the fish into your swim. If you plan to be in the swim for a few days and you feel that the carp will move into your area during that time, you should consider using a marker float and a spod.

Incorporate some buoyancy into your hookbait, either by designing your own or by using a cork insert. The hookbait is more likely to be swallowed by the carp, making it harder to get rid of and easier for the hook to take hold.

One reason your particular bait may not attract carp is that a newer, more appealing commercial bait is being used by other anglers. It will be worth your while to switch to this bait. If you can’t or don’t want to switch baits, you can try adding hookbait enhancers to your hookbait or lead. These flavoured, water soluble solutions make everything more attractive to carp.

Make sure that your bait contains sufficient quantities of the foods that carp like. If you use hemp pellets, they should dissolve easily in about 10 minutes. Particles and pieces of the pellet should float up and away from the pile and a slick of oil should be produced. Quality hemp pellets will contain whole and crushed hemp seed, which carp love. After 20-30 minutes, the pellets should have dissolved completely and created a feeding spot that carp would find difficult to ignore.

Scientific References for Carp Fishing Article:

“Chilly.” February 2007. Ask the Experts. Mainline Baits.

URL: http://www.mainline-baits.com/askexperts/nov06/questions1.php. [Accessed March 8 2007].

Fareham, Gaz. .” February 2007. Hookbait Workshop: A Balancing Act. Mainline Baits.

URL: http://www.mainline-baits.com/articles/GazBalancingAct.php. [Accessed March 8 2007].

Hayes, Matt. No date given. Ask Matt Hayes,

URL: http://www.anglersnet.co.uk/authors/matt13.htm. [Accessed Feb 27 2007].

“Roman.” February 2007. Ask the Experts. Mainline Baits.

URL: http://www.mainline-baits.com/askexperts/oct06/questions3.php. [Accessed March 8 2007].

Roocroft, Tony. 2006 Carp. Digestion in a Stomachless Fish. Pond Keeping Answers.

URL: http://www.pond-doctor.co.uk/longdigestion.html. [Accessed March 7 2007].

--------------. 2006. Koi Food and Feeding Koi for Results All Year Round.

URL: http://www.pond-doctor.co.uk/directoryfood.htm. [Accessed March 8 2007].

--------------. 2006. Understanding the Koi's Digestive System and How It Works. Pond Keeping Answers. URL: http://www.pond-doctor.co.uk/longunderstandingkoidigestion.html. [Accessed March 6 2007].

“Spug.” February 2007. Ask the Experts. Mainline Baits.

URL: http://www.mainline-baits.com/askexperts/oct06/questions4.php. [Accessed March 8 2007].

Towey, Dean. February 22, 2007. Olfaction or Fiction?

URL: http://www.northwestcarp.co.uk/Carp-Articles/General-Carp-Articles/Olfaction_or_Fiction.html.

[Accessed Feb 25 2007].

Related Carping Articles

Do Carp Have Good taste, smell & Sight?

The Effects of UK Weather for Carp Movements & Feeding Patterns

Carp Spawning Do they still eat our baits?

Different Carp Bait for Catching Big Carp

Locate Big Carp from Visual Features in the Lake

Catch the Biggest Carp from the Margin Shallows