Cobitis taenia (Linnaeus 1758), Spined loach (Cobitidae)

Author: Ronald Fricke, Germany

1. Description of the habitat/autecology of the species

The spined loach Cobitis taenia lives benthic in slow-flowing and still waters, lagoon and lake habitats and estuaries, on soft substrate. The species is active at night, staying hidden under rocks or burying in the substrate during the day. Spined loach spawns in spring or summer; the eggs are deposited scattered into plant material, attached to rocks or macrophytes in shallow, flowing water (Froese & Pauly, 2005). Maximum total length 13.5 cm.

2. Distribution (past and present)

This species is distributed in Baltic Sea and northeastern North Sea drainages. In the Baltic Sea area, it occurs in tributaries of all parts except for the Gulf of Bothnia, but only in waters of less than 10 per mille salinity. In Finland, the species is restricted to the eastern part of the Gulf of Finland. Cobitis taenia was believed to be more widespread in the past, but found to represent a species complex by Bohlen & Rab (2001), with the nominal species C. taenia mainly restricted to the Baltic Sea drainages. In Sweden this species has in recent surveys turned out to be common in soft, muddy substrates from hypereutrofic to dystrophic lakes (Delling et al, 2002).

3. Importance (sub-regional, Baltic Sea-wide, global)

Due to its genetic diversity, populations in HELCOM area are of global importance. The species is not considered as rare, but is sensitive to human activities. Its decline status is unknown.

4. Status of threat/decline

In the HELCOM area, this species is classified as vulnerable (VU) according to IUCN criteria (HELCOM, 2007). It is listed as endangered (EN) by Germany and Finland, as vulnerable (VU) by Denmark, as least concern (LC) by Sweden, and as not evaluated (NE) by Estonia. The species is included on Annex II of the EU Habitats Directive.

5. Threat/decline factors

It is believed that spined loach is threatened by sand and gravel extraction and by eutrophication and habitat loss since the species needs to bury and breathe in clean sandy substrate. However, the recent findings of spined loach in several different types of habitat (Delling et al., 2002) makes a re-evaluation of threats necessary. It is also possible that there are different types of spined loaches with different habitat requirements.

6. Options for improvement

There is a need for further knowledge on essential habitat requirements of the species and on population structure of the species until any recommendations can be given.

7. References

Bohlen J. & Rab P. 2001.  Species and hybrid richness in spined loaches of the genus Cobitis L. (Teleostei: Cobitidae), with a checklist of European forms and suggestions for their conservation. Journal of Fish Biology, 59a: 75-89.

Froese R. & Pauly D. (eds) 2005. FishBase. Available in: www.fishbase.org, version (11/2005).

HELCOM 2007. HELCOM Red list of threatened and declining species of lampreys and fish of the Baltic Sea. Baltic Sea Environmental Proceedings, No. 109, 40 pp.  Available in: http://www.helcom.fi/stc/files/Publications/Proceedings/bsep109.pdf