Target species

Some fish species present in the VCO of high value represent the Project target. Among them stands the Marble trout, a species endemic of Northern Italy; in the Ticino River Basin (as elsewhere) its population is threatened by multiple factors. The construction of dams and weirs on rivers prevents the natural migration of adults, making it impossible for the population to complete the reproductive cycle. Add to that the pressure of fishing on species, favored by a minimum capture measure that does not seem to be sufficiently cautionary (35 cm). The marble trout is also threatened genetically, as it can interbreed with brown trout (Salmo trutta), used in the Piedmont region for repopulation activity until 2010 (the year of adoption of the Regional Law 37/2006).

There are also other native fish species of the Ticino River basin and Lake Maggiore less affected by the pressure of fishing, but threatened of extinction due to the gradual deterioration in the quality and availability of water, the presence of invasive alien species and the existence of artificial barriers, such as Sculpin, Italian Riffle Dace, Pigo and Savetta.

Finally, another critically endangered aquatic species is the Crayfish, native decapod whose survival is threatened by many factors. Competition with alien decapod crustaceans is considered one of the main threats to the native shrimp of our waterways and in the VCO waters are currently at least two exotic species: red swamp crayfish (Procambarus clarkii) and Spinycheek crayfish (Orconectes limosus). The introduction of these species has led to the spread of the dangerous “crayfish plague”, an epidemic disease caused by the water mold Aphanomyces astaci, of American origin, which since its accidental entry into Europe over 100 years ago (in 1860) it caused a real decimation of our crayfish populations. The native freshwater crayfish, finally, is particularly sensitive to environmental degradation and to certain pollutants, in particular to some metal ions (copper, zinc and chromium) and to some pesticides used in agriculture.

Marble trout

  • SCIENTIFIC NAME: Salmo marmoratus

  • TAXONOMY: Order Salmoniformes, Family Salmonidae

  • ORIGIN: the marble trout is an endemic Salmonid of the Po river basin. The distribution areal is constituted by rivers of the south-alpine valleys

  • MORPHOLOGY: it has a tapered body with a very large mouth, in a median position, provided with a robust and well-developed dentition. The adipose fin typical of Salmonids is present. Species of large size, can reach lengths greater than the meter and a weight of more than 20 kg. The livery is grey-yellow on the back and sides, with the characteristic marble pattern, consisting of irregular sinuous lines of grey, brown or greenish color. The belly is yellowish or whitish. The dorsal and caudal fins are dark-grey, while the pectoral, ventral, and anus are light grey with yellowish shades.

  • SIZE: It is a species attaining a very large body size (up to 110 cm).

  • HABITAT: it populates the foothills of the waterways, characterized by high flows and clear waters, fresh, well oxygenated, with sustained or moderate current and with pebbles and gravel bottoms. It prefers areas rich in shelters and deep holes where to hide. It is often associated with the grayling, the sculpin and the brown trout (due to the frequent immissions of the latter). In the upper plain, it shares its habitat with several species of ciprinidi. It also lives in the area of the spring and in the fontaniles of the Po Valley.

  • DIET: it is an ichthyophaga that in the first 2-3 years of life its mainly eats invertebrates (insect larvae, crustaceans, oligochaetes and often also adult insects). With the advancing age begins to preying fish, especially sculpins, minnow and small trout.

  • REPRODUCTION: sexual maturity is reached in the third year of age. Between November and December the females go up the minor tributaries in search of pebbles, with shallow waters where to dig  holes with rapid movements of the tail in which to lay the eggs, which once fertilized are covered with gravel. Each female lays about 2,300 eggs per kg of body weight.

  • CONSERVATION STATUS: the last census of fish fauna in the hydrographic network of VCO District (2010) highlighted the presence of the marble trout along the R. Toce and its tributaries, as well in the S. San Bernardino. Distribution and population structure are however not homogeneous indicating unstable populations which are locally under significant threats. The species is in steep decline due to the destruction and fragmentation of its habitat, fishing pressure and introduction of the brown trout for angling purposes.

  • PROTECTION: in the national context (IUCN Red List of Italian Vertebrates): CRCRitically Endangered. In the European context it is included in annex II To Directive 92/43/EEC. At world level it is recognized by the IUCN as a species “LCLeast Concern.


  • SCIENTIFIC NAME: Chondrostoma soetta

  • TAXONOMY: Order Cypriniformes, Family Cyprinidae

  • ORIGIN: its areal comprehends almost all the Northern Italy, although in strong depletion.

  • MORPHOLOGY: it has a fusiform body, relatively developed in height, and with a typical rectangular-shaped mouth, slightly curved downwards, located in a clearly inferior position. The dorsal and the anal fins have a concave back edge. The livery is grey, with a dark grey or grey-brown back and the lighter sides, while the belly is white. The dorsal and caudal fins are grey, the pectoral, ventral and the anal are yellowish or pale orange. It has no sexual dimorphism.

  • SIZE: it is a medium size species, which reaches 40 cm in length and 1 kg of weight.

  • HABITAT: the habitat of this gregarious species is the middle and downstream stretches of the major rivers or oligo- or mesotrophic lakes. It presents a highly migrating behavior both in lake and fluvial environments. The knowledge regarding its biology is incomplete.

  • DIET: it feeds mainly on epilitic algae (in addition to macrobenthos) that is able to graze thanks to the conformation of the mouth. The diet also includes organic debris and benthic invertebrates, especially gastropod molluscs.

  • REPRODUCTION: sexual maturity is attained for both sexes at 3-4 years; the period of scrubs goes from April to May. In This period the breeders migrate in groups to the areas of reproduction located in the small streams, where the deposition takes place in fresh and current waters, on gravelly seabed, near the shores. Each female is able to lay several thousand of eggs.

  • CONSERVATION STATUS: It’s distribution has always been limited to larger lowland rivers, and with lownatural frequency in Piedmont, but over the past two decades this presence was strongly reduced,even in the R. Ticino basin. During the last census of subalpine lake’ fish community (Lombardy Region,2015), the species was absent in L. Maggiore while during the last census of fish fauna in thehydrographic network of VCO District (2010) it has been capture in the R. Ticino upstream the lake. It’s signaled in the L. Mergozzo (SPA IT1140013). In Italy the species is inserted in the RED LIST as “Endangered”. C. soetta is one of the inland water fish species that was mostly damaged by the dam construction and otherbarriers along the river routes, preventing free movement along the rivers necessary to reach the bestbreeding areas. Other factors that represent a high threat to the species are the artificialisation of the river habitats and the gravel extraction for constructions, that lead to a decrease of the breeding areas available.


    National (IUCN Red List of Italian Vertebrates): ENENdangered

    Global (IUCN): EN – ENdangered

    Species inserted in annex II of the Directive 92/43/EEC.

    Species included in annex III of the Berne Convention


  • SCIENTIFIC NAME: Rutilus pigus

  • TAXONOMY: Order Cypriniformes, Family Ciprinidae

  • ORIGIN: endemic of the Padanian basin, it is present in northern Italy, from Piedmont to Veneto, with populations settled both in the great Subalpine Lakes – excluded Lake Garda and Iseo – and in the left tributaries of the Po. It was also placed in some basins of central Italy.

  • MORPHOLOGY: the body is fusiform, with a small head and a mouth in an inferior-median position. The livery is bronzing-golden on the sides with a dark back; the edge of the scales is black, making a characteristic dark lattice pattern appear on the body. The Eye is silvery or bronzing. The pectoral and anal fins are orange in color, more intense during the reproduction; the dorsal and caudal fins are dark grey. During the reproductive period the males are covered on the muzzle and on the back of evident bridal tubercles.

  • SIZE: medium size species, can reach a length of 50 cm.

  • HABITAT: it populates the lakes and the stretches with greater depth and moderate current of the rivers, preferring the clear waters and the areas rich of vegetation. In the great pre-alpine lakes it frequents the coastal areas, with rocky and steep sides covered with algae, in winter it moves in depth. The Youth stages form groups often interspersed with individuals of alborella, while the adults often live with the savetta’s one.

  • DIET: the main component of the diet is the filamentous algae, especially in juvenile specimens. The diet is however omnivorous and also includes benthic macroinvertebrates and, in particular, gastropods and insect larvae.

  • REPRODUCTION: sexual maturity is reached by males at 2 years of age and females at 2-3 years of age; the deposition takes place between April and May on the vegetation and on the stones of the bottom in shallow coastal waters. Each female lays from 35,000 to 60,000 eggs per kg of weight.

  • CONSERVATION STATUS: In Italy the populations of pigo have been in strong contraction for some decades. One of the causes is certainly represented by dams and other transverse barriers, which in the river environments prevent individuals close to reproduction from reaching the depths suitable for spawning; also the sport fishing carried out during the reproductive period near the barriers could be responsible for the significant demographic decrease of various populations. Among other factors that may have caused the decline of the Italian populations, at least in the catchment area of Ticino, it is also necessary to include the introduction of the gardon (R. rutilus), an exotic species of Danubian origin, able not only to hybridize with the pigo but also to occupy the same trophic niche.


    National (IUCN Red List of Italian Vertebrates): ENENdangered

    Global (IUCN): LC Least Concern

    Species included in annex II of the Directive 92/43/EEC

    Species included in annex III of the Berne Convention

Italian riffle dace

  • SCIENTIFIC NAME: Telestes muticellus

  • TAXONOMY: Order Cypriniformes, Family Cyprinidae

  • ORIGIN: autochthonous species. Recently, molecular analyses have highlighted the existence of a significant genetic distance between the populations of minnow in the north, central and southern Italy, which must actually consider their validity as a valid species

  • MORPHOLOGY: the body is fusiform and elongated, with a relatively small head and slightly sub-terminal mouth. The color of the back varies from the greenish-black, to the grey-brown, to the greenish-grey. On the hips there is a characteristic and well evident black longitudinal band, below which is visible the lateral line, with pores edged with yellow-orange. The coloration of the hips and belly is white with silver reflections. The dorsal and caudal fins are grey, while the pectoral, ventral and the anus are yellow-orange. The males in reproduction show more bright colors and are covered with bridal tubercles on the head.

  • SIZE: it is a species of medium-small size, which normally reaches the maximum lengths of 18-20 cm.

  • HABITAT: species fond of the running water, clear and rich in oxygen, the Italian riffle dace shares with the grayling the foothills of the waterways, where it prefers the lateral zones, with moderate current near the shores, with gravelly seabed. It is abundant in the creeks of the hill and in the plain streams where the current speed is not excessive. It is also found in the littoral region of the great pre-alpine lakes at the outlet of the rivers. It characterizes the area of the Cyprinidae Reofili, where it is associated with the Insubrian barbel, the minnow and the chab.

  • DIET: the diet is omnivorous, and comprises mainly macrobenthonic organisms and epilethic algae; during the summer the Italian riffle dace also feeds on terrestrial insects (mainly Diptera) that are hunted top water.

  • REPRODUCTION: sexual maturity is reached at 2-3 years of age in both sexes. The reproductive period is between April and July. The spawning takes place at night on gravelly or pebble bottoms, in low water with fast current. Each female can lay down a few thousand of eggs.

  • CONSERVATION STATUS: the species is threatened by the various forms of water body pollution and habitat alteration. The artificializations of riverbeds, excessive water levies and gravel levies are strongly impeding on the reproductive substrates of this species and the processes of longitudinal fragmentation (bridle and barrier) prevent the species to ascent to spawning areas.


    National (IUCN Red List of Italian Vertebrates): LCLeast Concern

    Global (IUCN): LCLeast Concern

    Species included in annex III of the Berne Convention


  • SCIENTIFIC NAME: Cottus gobio

  • TAXONOMY: Order Scorpeniformes, Family Cottidae

  • ORIGIN: native. The bullhead is widely distributed in Europe, from the Pyrenees to the Ural and from Scandinavia to northern-central Italy, excluding the southernmost regions. In Italy populates the torrential waters of the entire Alpine arc, the resurgences of the Padanian Plain at the north of the Po and some apenninic waterways.

  • MORPHOLOGY: the body, devoid of scales, is fusiform, with a large and flattened head and a wide mouth. The pectoral fins are very developed and the anal one is quite long. The background livery varies from brown-grey to greenish-brown with large irregular dark spots on the back and sides, sometimes confluent to form wide transverse bands. The Belly is white. The dorsal, pectoral and caudal fins are clear with specular dark spots arranged in regular rows, not evident or absent in the ventral and the anal fins. During the reproductive period the males show a darker livery.

  • SIZE: it is a small size species, which normally does not exceed the maximum length of 15 cm.

  • HABITAT: it prefers clear and fresh waters, well oxygenated, with substrates of pebbles and boulders. It mainly colonizes the streams, where it is associated with the brown trout and the minnow; It is also present in the foothills of the main waterways, in the initial stretches of the resurgences of the high plains and in the great pre-alpine lakes. Occasionally it can be found also in the Alpine lakes. Typically benthonic species, active predominantly during the night, during the day hides under the stones or among the aquatic vegetation; it has territorial customs.

  • DIET: it mainly feeds of aquatic invertebrates, which hunts on the bottom: insect larvae (Diptera, Tricoptera, Efemeropterans and Plecottera), Crustaceans and Anelliidae (Irudinei and Oligochaetes). Occasionally, the bullhead can also capture small fishes.

  • REPRODUCTION: the sexual maturity is reached at 1-2 years in the mountain environments; they breed in late spring, laying eggs in shallow waters with rocky bottom. The scrub period begins towards the end of February and can extend until the middle of May. The male prepares a cavity under boulders or other submerged objects; Attracted by the courtment of the male, the female enters the nest and, in reversed position, lays the eggs making them adhere to the vault of the shelter. More females can lay their eggs in one nest and each can produce 200-585 eggs. The male defends the eggs energetically until hatching, which occurs 3-4 weeks after fertilization.

  • CONSERVATION STATUS: the bullhead is very sensitive to the alterations of the environmental quality, and in particular to the artificializations of the riverbed; it is also damaged by excessive water levies, water pollution and predation exerted on youth stages by alien species (as in the case of trout placed in a massive way in favor of sport fishing); in some localities its meats are much appreciated, and it is the object of fishing by illegal methods. This has caused numerous local extinctions, so much so that the areal is in strong contraction. The populations that have been more damaged by the anthropic activities are those of the spring environments while in the mountain areas still live the numerically more substantial populations.


    National (IUCN Red List of Italian Vertebrates): LCLeast Concern

    Global (IUCN): LCLeast Concern

    Species included in annex II of the Habitat Directive 92/43/EEC

White-clawed crayfish

  • SCIENTIFIC NAME: Austropotamobius pallipes complex

  • TAXONOMY: Order Decapoda, Family Astacidae

    Today the systematic framework is still controversial and on the basis of the indications provided both by morphological characters and by the most recent genetic surveys, the genus Austropotamobius is considered divided into two species called A. torrentium, present in the Danube Basin and the Balkans, and A. pallipes complex, distributed in Western Europe, from Portugal to Switzerland and to Dalmatia and from England to France to Liguria. The Latter is considered as a “complex species” as it is further subdivided into A. pallipes and A. italicus. The presence and distribution of the genus Austropotamobius in Italy was recently investigated by genetic investigations that highlighted the presence of A. pallipes in the northwestern area of the peninsula and of A. italicus in the rest of the peninsula (excluding Puglia and islands).

  • ORIGIN: native.

  • MORPHOLOGY: small crustacean belonging to the family of the Astacidae, the white-clawed crayfish is one of the only two native species in Italy, both attributable to the species “complex” Austropotamobius pallipes. It is a crustacean deal with the body formed by 20 segments grouped in three main regions: the head and the thorax, fused into a single section called cephalothorax, and the abdomen. The body is covered by an exoskeleton formed by chitin and calcium salts which is periodically abandoned in the moulting phase to allow its growth. The body, sturdy but at the same time flexible enough, can reach the 11-12 cm of length and the 90 g of weight with the male larger than the female. The cephalothorax ends forward with a spur, called a rostrum, which on both sides carries the pedunculated eyes. In the thoracic region there are 8 pairs of articulated appendices: 3 pairs of massillipedi or masticatory legs and 5 pairs of pereiopods or ambulacral legs. The first periopode carries a well-developed claw. The abdominal limbs, called pleopods, are poorly developed in males in which the first two pairs are modified in copulatory organs (gonopods); in the female are used to retain the eggs during the incubation period. The sixth pair of abdominal appendices (uropods) defines, along with the lamellar appendix (Telson) with which the abdomen ends, the caudal fan that functions as a back-propulsion natatory fin.

  • SIZE: 12 cm

  • HABITAT: it lives in puddles or small streams of hill up to about 800 meters of altitude. It is a solitary animal, with more accentuated territorial tendencies in the males especially during the reproductive period. For the rest of the time they ignore each other even if not infrequently, during the period of the wetsuit, there are episodes of cannibalism. The range of sites suitable to be a refuge for rest periods is very wide: submerged trunks and strains, benches of macrophite, litter of leaves and branches, rocky gorges, etc. When it is possible however it digs burrows along the shores of the water body.

  • DIET: is very varied and can be made up of vegetal substances (seeds, macrofite) or animals (arthropods, rotting animals).

  • REPRODUCTION: sexual maturity is usually reached during the third year. Mating takes place in The autumn months; the males “court” the females in a rather violent way, also reaching to mutilate or even kill the female reticent to the overthrow on the back for the frontal coupling. After the male leaves the female to look for other partners. The fertilized eggs adhere to the abdominal appendices (pleopods) of the female that will protect the young born for a few months (until the following spring). After abandoning his mother, young shrimps face a difficult period; the first months of life are the most problematic and they record the highest mortality rates. Average longevity is 10-15 years, with peaks of up to 20 years.

  • CONSERVATION STATUS: In Italy the species is inserted in the RED LIST (2013) as “Endangered”. The white-clawed crayfish areal in the last years has greatly shrunk, even in the VCO District, as the last available data showed. The distribution of native crayfish in the Province of VCO was the subject of a monitoring campaign conducted from June to October 2009, within an INTERREG Project. The results showed a distribution quite unsatisfactory and fragmented with native species found in few river water bodies and with the alien species found instead in lake environments. The sampling stations with presence of autochthonous crayfish was only 6 of 48 (about 12%) but they generally have stable andbalanced populations, that can be used as sources of reintroduction stocks. The picture attached showsthe number of subjects captured with the above mentioned census.


    Global (IUCN): ENENdangered (Füreder et al., 2010)

    Species included in annex II of the Habitat Directive 92/43/EEC.