Roach Rutilus rutilus ; Linnaeus, 1758. Family: Cyprinidae
The roach (Rutilus rutilus) is a species of the carp (Cyprinidae) family. Silver in colour with large scales, a deep body and forward facing mouth, red eyes, and reddish pectoral, pelvic and anal fins.
The roach spawns in shallow areas in spring. The many small eggs are sticky and cling to mosses or other submerged vegetation. The recruitment of young fish varies widely between years, particularly in rivers, and this can give rise to strong and weak year classes in the adult populations, or if several years of poor recruitment occur together, a dearth of adult fish. Recruitment in small ponds may be consistently high, leading to stunted populations. It is long-lived in some waters - indeed, a sample from the River Tay examined by Marine Scotland Science Freshwater Laboratory in 1971/1972 included many fish of 15 to 18 years old (and up to 21). In general, the maximum length of the roach in Scotland is between 20 and 40 cm.
Diet and Behaviour
Roach juveniles feed on zooplankton and other small invertebrates, and larger fish typically feed on larger invertebrates and filamentous algae. However, other items can be taken. Roach from the Perth harbour area examined in 1971/1972 had been mainly feeding on spilt barley. At all life stages the roach is a strongly shoaling fish.
Habitat and Distribution in Scotland
Widespread in many of the lowland still waters and rivers of central and southern Scotland. It can be abundant, even in waters of mediocre water quality. Although many of the Scottish populations are the result of introductions in the 20th century, some populations, such as that in Loch Lomond, were present in the 18th century when the first national descriptions of freshwater fish distribution were published. It is not known whether such populations were established naturally (for example, by transfer of eggs on birds' feet), or are the results of early undocumented introductions.
Roach as a Sport Fish
The roach is a popular target for coarse fishers. Nearly all are returned live to the water. Although edible, it is not a popular food fish in Scotland, or other parts of the UK.