Although called a carp, the grass carp looks more like the chub – another member of the carp family (Cyprinidae). It has an elongated, cylindrical body, silvery bronze sheen and large scale pattern.
Only young fish are likely to be taken for chub since grass carp grow rapidly. If in doubt, count the scales along the lateral line – the grass carp has 43-45, the chub 56-61. The fins are all smoothly rounded and the anal and dorsal fins both have eight rays. The large mouth is very wide, giving the head a flattened look.
A native of large rivers in eastern China and Russia, the grass carp was introduced into European waters in the 1970s to control weed growth. Ponds, lakes, canals and drainage channels have been stocked with this species, but to date it has an extremely limited distribution in Britain. It is also unlikely to spread by natural means because its specific breeding requirements are not fully met in Britain.
Dense weed beds are the most likely hiding place for grass carp and, like other species of carp, they bask just under the surface in warm sunny weather, retreating to deeper water in winter.
Grass carp fry feed on plankton such as daphnia, but when they reach a length of 5cm (2in) they feed exclusively on plant material. This is why they make effective weed clearers.
Grass carp spawn in warm weather in the fast reaches of large rivers. The eggs are carried downstream for many miles before hatching. Because of Britain’s temperate climate and the fact that grass carp are located mainly in still and slow-flowing waters, they are unlikely to breed here.
How do you catch them if they only eat plants? Normal carp baits have taken these fish, two of the most successful being tutti-frutti boilies and sweetcorn. In hot weather the carp takes surface baits and has been seen to inspect a bait for several minutes before sucking it powerfully into its cavernous mouth.
You need very strong tackle to land grass carp because they are ferocious fighters. Lines should be 10-15 lb (4.5-6.7kg) b.s., matched to 2-2/2lb (0.9-l.lkg) TC rods.
On the Continent grass carp weighing 80 lb (36kg) are not unusual. A fish of this size is about 1.67m (5Vaft) long. Since they have only recently been introduced into British waters and have the potential to live for up to 30 years, weight limits can only be estimated. However, because of the cold climate a maximum of 35-45 lb (15.7-20.2kg) is likely in Britain.
Although it is a large and powerful fish, the grass carp is particularly susceptible to damage caused by prolonged handling. If you catch one, don’t hold it in a keepnet -return it carefully to the water as soon as possible after unhooking.