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FISH GUIDE · Freshwater

French nase: identification, habitat and fishing guide

Parachondrostoma toxostoma

A river fish with a conical snout and curved downward-facing mouth.

Catalogue names : French nase. Forms and names may vary between habitats.

Editorial review : · This species guide is not permission to fish. Read the precautions below and check the current rules for your location before targeting a species. Some species or populations are protected.

Geographical distribution

The retained scope includes the native Rhône and Garonne drainages cited by DORIS. That source still uses Chondrostoma toxostoma; its older Iberian extensions are not generalised to taxa now distinguished separately. This selection of drainages is not exhaustive.

  • Native range : Rhône
  • Native range : Garonne

Documented areas, not an exhaustive list. Presence in a region does not imply presence in every water body or permission to fish.

Distribution sources

Identification

Horseshoe-shaped mouth, sharp horny lips and generally pale fins.

Parachondrostoma toxostoma is the retained canonical name; DORIS uses Chondrostoma toxostoma while noting the other combination. Nase has a stronger snout and more pronounced orange-red fins.

The Gers federation also compares toxostome with dace and chub: examine the anal fin, concave in toxostome and dace but convex in chub. Its fishing paragraph names only the latter two for natural-bait, pole and fly fishing: those methods are not attributed to toxostome.

In the conclusion of his 2016 report, Théo-Paul Hans states that the genomes of the fish caught still needed analysis to validate identity and introgression. Contact with nase therefore does not prove a hybrid; the report cites the Verdon as an example of coexistence with no introgression then demonstrated.

Habitat

Clear, oxygenated rivers over gravel, pebbles or rock.

Mineral bottoms and flowing waters form the documented habitat. Spawning areas are often gravel in small tributaries.

Diet

Diatoms and filamentous algae attached to the substrate, supplemented by small invertebrates.

Behaviour

A shoaling fish that feeds over pebbly bottoms in flowing water.

Schooling and feeding from the substrate do not validate feeder fishing or a plant-based recipe; no nase method is transferred.

Indicative biological size

15–25 cm according to the Lot fishing federation species account.

Fishing context and precautions

Gard, 2022: light-line fishing on the Claysse, bait drifting downstream. Check local rules.

A distinctive feature

Its horny lips allow it to take food attached to stones.

The Doubs federation’s 2016 report stresses that coexistence with nase does not automatically produce genetic introgression. Its field identifications still required genetic checking; a photograph does not establish a hybrid.

Sources and review

Each reference includes its access date. Overall editorial review: . Local conditions and regulations may change.

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