Leuciscus leuciscus
(common dace)

The common dace can be considered an invasive species outside its native range because it has the ecological characteristics of recognized successful invaders. It is a feeding generalist (i.e. debris, small invertebrates, etc.) but usually has a high plant content in its diet. In addition it has high fecundity, fast growth rate and is considered tolerant of anthropogenic pressures. It is a long-lived, highly mobile fish due to its pelagic condition. Humans may also facilitate its spread due to its value as a bait species in recreational fishing. It is common in river backwaters and considered a nuisance because it invades salmonid fisheries. It is a common species in aquaculture (FAO, 1997).

Europe and Asia: North, Baltic, White and Barents Sea basins; Caspian basin, in Volga and Ural drainages; Black Sea basin, from Danube to Dnieper drainages; Atlantic basin, in Seine drainage; Mediterranean basin from Rhône to Arc drainages (France). It has a localized distribution in Romania, Scandinavia and in central Finland (Kottelat and Freyhof, 2007).

The common dace is without interest to the aquarium trade, but is considered a valuable species in aquaculture (FAO, 1997) and also has interest as a bait fish and angling species. Therefore, recreational fishing, escapes from aquaculture facilities and interconnection of waterways represent the main pathways of introduction into other locations.

The common dace is a gregarious rheophilous and epipelagic fish species (Billard, 1993). Adults aggregate in dense swarms in winter in the lower reaches of rivers or backwaters and often migrate to spawning streams in autumn and overwinter there. Juveniles spend winter in cavities along the shores. The species inhabits shallow shoreline habitats as juveniles and faster-flowing waters as adults (Kottelat and Freyhof, 2007).

Genetics

Some genetic records were listed with the same values in South Pyrenees, former Yugoslavia and other unspecified localities. Haploid/gametic chromosome number (n) is 25, whereas diploid/zygotic chromosome number (2n) is 50-50 (Sofradzija, 1977; Hafez et al., 1978; Vasil’ev, 1980; Arkhipchuk, 1999). DNA analysis of this species is included in Perea et al. (2010).

Reproductive Biology

Sokolov and Berdicheskii (1989) reported that common dace regularly undertake migration of some tens of kilometres to spawning sites, which are often situated in tributaries.

The species spawns for the first time at 2–3 years and standard length 11–14 cm (Cepkyn, 2002). Common dace usually spawns only once or twice during its life, in March-April when temperatures reach 5–10ºC (Zhukov, 1965). Males form large aggregations, each male defending a small territory. Females spawn only once a year and, in some populations, during a very short period (3-5 days). Females lay sticky eggs into excavations made in gravel. Fecundity is estimated at between 1550 and 22600 eggs (Zhukov, 1965; Movchan and Smirnov, 1981). Larvae feed along shores.

Physiology and Phenology

The water temperature tolerance range is 4-28ºC. The tolerance range for other water parameters has not yet been published.

Longevity

L. leuciscus lives up to 10 years (Kottelat and Freyhof, 2007). Maximum reported age is 16 years (Wüstemann and Kammerad, 1995).

Nutrition

L. leuciscus feeds on plants, small invertebrates and detritus (Kottelat and Freyhof, 2007). Diet composition may vary seasonally (Weatherly, 1987). The gut content of specimens captured in September in the River Dee, UK, is shown below:

Environmental Requirements

Fast-flowing waters.

All piscivorous animals, native or introduced, are potential natural enemies of the common dace.

Predation by Squalius cephalus (Cyprinidae), Lota lota (Lotidae), Perca fluviatilis (Percidae), Oncorhynchus mykiss and Salmo trutta (Salmonidae) has been reported in Germany (Wüstemann and Kammerad, 1995) and by Esox lucius (Esocidae) in the River Frome, UK (Maitland and Campbell, 1992).

Although fish are not the main prey item for many raptors, juveniles and adults of common dace have been found in the gut content of Buteo buteo, Circus aeruginosus,Milvus sp. and Strix aluco in Germany (Wüstemann and Kammerad, 1995). Otherwise, common dace can be a common prey item for specialized piscivorous raptors such as Haliaeetus albicilla and Pandion haliaetus and for other waterbirds (Podiceps sp., Phalacrocorax carbo,Ardea cinerea,Larus sp. and Alcedo atthis (Wüstemann and Kammerad, 1995).

Only one mammalian predator of common dace is reported: Lutra lutra (European otter; Procyonidae). It feeds on both juvenile and adult forms (Wüstemann and Kammerad, 1995).

Animal feed, fodder, forage

• Bait/attractant

General

• Sport (hunting, shooting, fishing, racing)

The similar morphological traits between species of the Leuciscus genus require the aid of specialists to distinguish between them. The combination of morphological and genetic traits may also be necessary to ensure proper identification (particularly in juvenile specimens) and this procedure may also allow detection of hybrids.

The existence of stowaway species mixed with valuable species in ornamental or any other live fish stocks is not uncommon. The live fish trade therefore requires careful inspection by specialists in order to detect undesirable organisms which are often not labelled. In addition, the regular monitoring of current waters allows managers to detect new fish introductions and to know the spread patterns of exotic species once introduced. This information helps resource managers to identify areas at high risk of invasion and to plan local eradication programmes when possible. Electrofishing is a widely recognized method to catch fish without damaging the ecosystem in current waters. Nets are a complementary sampling tool for surveys performed in lakes or reservoirs.

Common dace can be distinguished from congeners in Europe by the following morphological traits: subinferior or subterminal mouth; subequal jaw, upper jaw slightly longer; upper lip tip about level with centre of eye; not projecting snout; articulation of lower jaw distinctly behind anterior margin of eye; horizontal branch of preoperculum shorter than vertical branch; and 40-50 + 1-2 scales on lateral line (Billard, 1993). Rarely longer than 30 cm TL; normally 47-52 scales in lateral line; anal fin concave; caudal fin forked with 19 rays (Wüstemann and Kammerad, 1995).

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Prevention

Education programmes are needed to raise public awareness about the threats of introduced species to ecosystems. Regular monitoring of waters by trained specialists help to detect new invaders and newly invaded areas.

Eradication

Complete eradication is almost impossible, particularly in large areas. Local extirpation of introduced fish species may be performed in areas of high conservation value and, in particular, in small streams where the probability of success increases.

Control

Physical barriers and rotenone are commonly used to control small fish. Regular removal of specimens in small streams may mitigate the effect of exotic species.

Monitoring and Surveillance

Regular electrofishing surveys.

Italy: FAO (Food and Agriculture Organization of the United Nations), Viale delle Terme di Caracalla, 00100 Rome, http://www.fao.org/

04/01/12 Original text by: 

Mònica Utjés Mascó, Department of Animal Biology & Research Institute of Biodiversity (IrBio), Faculty of Biology, University of Barcelona, Avda Diagonal, 643. E-08028 Barcelona, Spain

Alberto Maceda Veiga, Department of Animal Biology & Research Institute of Biodiversity (IrBio), Faculty of Biology, University of Barcelona, Avda Diagonal, 643. E-08028 Barcelona, Spain

The names of reviewers are available from CABI on request