Order: Cypriniformes Family: Cyprinidae
Foto: Ari Saura
Description: The bream is one of Finland's largest native cyprinids. It has a deep, narrow body, and a protrusible mouth when feeding from the bottom. The young common bream in particular can easily be confused with the silver bream (Abramis bjoerkna) or blue bream (Abramis ballerus). The silver bream can be distinguished by its smaller scales and more numerous fin rays in the anal fin, and the blue bream by its long anal fin and upturned mouth. The common bream has 26−34, the silver bream 22−26 and the blue bream 35−44 anal fin rays. Whereas the common bream has over 49 scales on its lateral line, the silver bream has fewer than 49.
Origin and distribution: The bream occurs throughout almost the whole of Europe. The northern limit of its range lies north of the Arctic Circle. Finland's most viable stocks are in the lakes of southern and central Finland, and in shallow sea bays. The northernmost lakes with bream lie as far north as the Sodankylä area but, as a common species, the bream does not occur north of the Oulujoki water system. The majority of the northernmost stocks have originated from releases occurring in the course of translocation. Usually the more eutrophicated a lake, the more abundant is its bream stock, though the mean size of individual fish then tends to remain small. As a result of eutrophication, the bream has become more abundant in many lakes, in the Archipelago Sea, in the Gulf of Finland and also in the outer archipelago.
Reproduction: Bream do not reach maturity until an age of 7−11 years and a weight of 250-900 g. Spawning begins in spring when the water temperature has risen to about 15 oC. In many places spawning takes place in cohorts, and may last several weeks. Different spawning groups are frequently named after natural events occurring during the spawn. Eggs stick to the stems, leaves and roots of aquatic plants. Larvae hatch 8−12 days after fertilization, depending on the water temperature.
Food, growth and migrations: Bream larvae feed on zooplankton. Adults feed mainly on molluscs and insect larvae living on bottom silt, but when there is a shortage of food large bream, too, have to feed on zooplankton. The common bream is a long-living and relatively slow-growing species, though the growth rate varies considerably from one place to another. Bream in large shoals in eutrophicated lakes may weigh only 0.5 kg at 15 years, whereas under more favourable conditions they may weigh as much as 1.5−2 kg at the same stage. Bream schools searching for food may move over quite a large area. In the Archipelago Sea, for instance, their feeding migrations extend to the outer archipelago even though the spawning grounds are in estuaries and inner coastal bays. When the water temperature drops, bream gather into winter schools in deep water.
Fishing and catches: Owing to its abundance, large size and good flavour, the bream has long been a highly valued catch species. Bream weighing over 1 kg have a fat content of 4−10% and are equally good whether baked in the oven, smoked or salted. In 2004, the recreational catch exceeded 2 million kg. Nowadays bream are caught mainly with large mesh gillnets, but also with hooks and lines, fish traps, trap nets and long lines.
Vulnerability, threats and management: Finland's bream stocks have been managed by releases and fishing restrictions. The stocks in many lakes originate from fish released 20−120 years ago. Bream have been easy to introduce into new waters through releases of brood fish or juveniles. The best management strategy is to organize fishery. In many severely eutrophicated lakes in southern Finland, dense and poorly growing bream stocks contribute to eutrophication. Together with the roach (Rutilus rutilus), the common bream is one of the most important targets of fishery management aiming to improve water quality. Bream are no longer so highly valued either commercially or for food, and even fast-growing stocks tend to be inefficiently exploited. With intensive fishing, however, the remaining bream will grow larger and their value as a food resource will also increase.