In many ways the asp is a very large, very aggressive east European chub. Its average weight is 10-12 lb (4.5-5.4kg) but fish of over 30 lb (13.5kg) are sometimes taken. It reaches this large size because of its predatory nature and carnivorous diet.
The asp roams the upper layers of the water, hunting out small shoals of fish and attacking them noisily from dusk through to dawn. Nothing living around the waterside is safe – frogs, water voles and even ducklings have been known to disappear down the throat of this voracious feeder.
To cope with food items of this size, the asp -not surprisingly – has a huge mouth. This extends back to the eye. The lower jaw is longer, with a thickened tip which fits into a notch in the upper jaw. The body is slender, with a keel behind the vent. Mature fish develop a hump behind the head. The asp’s body is blue-grey with a dark green back and white belly. Apart from the dorsal and tail fins, which are grey, its fins have a reddish tinge. The scales are small -there are 65-74 along the lateral line. The asp is a large, graceful fish that would excite a lot of anglers if it were present in Britain. Sadly, it isn’t.
Finding the asp
The asp lives in the eastern edges of Europe – from eastern Holland and Germany, through parts of Scandinavia and across Europe to Siberia and the Black and Caspian Seas. It is typically found in the middle reaches of lowland rivers.
Adults live as solitary predators and love to inhabit lagoons, old backwaters and the slack areas above dams and weirs. Some, particularly those living in the Caspian and Black Sea areas, become migratory — feeding in the brackish estuaries and breeding upstream in fresh water.
Spawning takes place between April and June, depending on water temperature. Shoals of asp move upstream to find fast water over a stone or gravel bottom. The sticky eggs are deposited and fertilized between the stones, where they hatch after 10-15 days. The young fry drift downstream into slow flowing sheltered areas, feeding at first on tiny insects and crustaceans.
As early as 10-12 weeks after hatching the young fry are eating other young fish. This accounts for their extremely rapid growth – after only a year young asp can weigh well over 1lb (0.45kg). Sexual maturity is reached in four to five years, when the fish weigh about 8 lb (3.5kg).
The asp is considered to be good eating, and is an important commercial fish in parts of eastern Europe where it is caught with nets, traps and longlines. Sadly, due to overfishing, it is becoming scarce throughout much of its natural range.