Smelt (Osmerus eperlanus)
Order: Osmeriformes Family: Osmeridae
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Foto: Jussi Pennanen |
Description: The smelt is a small cold-water fish with an adipose fin and a maximum length of about 32 cm. It smells like fresh cucumber and has a large mouth with many teeth.
Origin and distribution: The smelt occur in northern waters, sea and lakes alike, round the northern hemisphere. The species is divided into two subspecies, of which O. e. eperlanus is found in the Baltic Sea, in coastal areas of the North Sea, in the White Sea, and in the northeastern Atlantic. Originally the smelt probably was a marine species that reached the Finnish waters at the time of the Baltic Ice Lake and invaded the emerging and isolating lakes in several occasions. As a result, smelt in Finland is represented by two forms: a normal-sized and a small-sized landlocked form. The landlocked form lives typically in the big lakes of southern and central Finland up to the watershed of the River Oulujoki. The most northerly populations are north of the city of Rovaniemi. The normal-sized form of smelt inhabits the entire Finnish coastal area. Smelt were occasionally translocated from the end of the 19th century until the 1970s, however, most stocks are native.
Reproduction: In the spring, soon after ice break-up, smelt migrate in large schools into rivers or shallow coastal waters to spawn. In inland waters, they spawn in shallow lakeshores or migrate to rapids and streams. Small-sized landlocked smelt reach maturity at an age of 1−2 years and marine smelt at 2−3 years. The eggs, which are yellow and about 1 mm in diameter, stick to bottom stones and mosses. The larvae hatch in May or June at a length of about 5 mm.
Diet, growth and migrations: After their first summer, smelt are usually 4−6 cm long, and after their second summer about 8−12 cm long. After the first or second year, growth slows down. Marine smelt grow faster and also reach a larger size than the landlocked smelt. The largest individuals caught in the sea area have been 31−32 cm long. Smelt larvae feed exclusively on zooplankton. Juvenile smelt start to feed on zoobenthos and fish larvae as well. After spawning smelt return to deeper water.
Fishing and catches: Smelt catch by professional fishermen from the sea area was 227 metric tons in 2007, and it was taken mainly from the Gulf of Bothnia. Fishing for lake-dwelling smelt during spawning run with hoop nets has a long tradition, and it still happens every spring in many places. Smelt are considered a delicacy and are caught also with seine, gillnets and trap nets. Ice-fishing for smelt has also been practised along the coast.
Vulnerability, threats and management: Smelt is a least concern species in Finland. Unlike salmonids, the smelt benefits from eutrophication to some extent, as it is not so demanding in terms of water quality as e.g. the vendace. In some waters, stocks have been depleted by pollution and construction of rivers.
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