Moenkhausia pittieri has been recorded in river systems belonging to the endorheic basin of Lago de Valencia and in systems belonging to the exorheic basin of the Caribbean Sea, all in Venezuela. Although historically found in 11 sub-basins, it is now considered extant in only six sub-basins with no records since the beginning or middle of the 20th Century in the other five sub-basins. The current area of occupancy (AOO) based on known extant occurrences is only 140 km². Although this will be an underestimate of the true AOO, the value is not expected to be greater than 500 km². All sub-basins where the species is still extant are under constant pressure from threats including deforestation, habitat modification and overfishing. There are six locations based on these threats, and they have resulted in continuing declines in the extent of occurrence (EOO), AOO, habitat extent and quality, number of subpopulations, and number of mature individuals. The majority of individuals are now found in subpopulations that are disjunct with no dispersal between them, and are considered too small to be viable in the long term. Therefore, the population is considered to be severely fragmented. This species is assessed as Endangered.

Moenkhausia pittieri was described from a coastal river located in the north of Venezuela that belongs to the basin of the Caribbean Sea in Venezuela, and also from a tributary of Lago de Valencia, of the so-called endorheic basin of Lago de Valencia (Lasso et al. 2003, Rodríguez-Olarte et al. 2009). According to the description of the species (Eigenmann 1920), the holotype (CAS 62059, ex IU 15136), was captured on August 1, 1918, by A. Pearce (see Pearce 1920) and comes from the Río Tiquirito, a tributary of the sub-basin of the Río Tuy, north of the town of El Consejo. According to other information provided by these authors, such as the altitude (2,040 feet = 622 m asl), in this evaluation we place this locality at 10º 17 '17''N and 65º 15' 40''W of the State of Aragua. Most of the paratypes (CAS 62060, ex IU 15136, 27 specimens, come from the same locality as the holotype (CAS 62059) and an additional paratype (CAS 70732, ex IU 15137, one specimen), were also captured by A. Pearce (see Pearce 1920) on July 28, 1918, in the Rio Bue (= Río Güey), in the current city of Maracay. The Río Güey is a tributary of the Lago de Valencia in the Aragua State, which we located for this evaluation at 10º 15 '58''N and 67º 36' 35''W, at an altitude of 447 m asl.

After the initial description of the species, it has been cited from both sites of the type material (Pearce 1920, Eigenmann and Myers 1929, Schultz 1944) or one of them (Luengo 1963, Weitzman and Palmer 1997, Lima et al. 2003, Bertaco et al. 2011), or simply from Venezuela (Frank 1971, Mills and Vevers 1989, Riehl and Baensch 1991).

Other authors indicated it to be in the sub-basin of the Río Tuy (Fernández-Yépez and Martín Salazar 1952) and Lago de Valencia (Mago 1968, 1970, 1978; Román 1985, 1992; López-Rojas and Bonilla 2000; Rodríguez and Rojas-Suárez 2003), or for both systems (Lasso et al. 2003, Rodríguez-Olarte et al. 2009, Bonilla and López-Rojas 2013), without giving more details of precise sites.

However, based only on the citation for the Lago de Valencia from Luengo (1963) and Mago (1968, 1970, 1978) basin, it was believed (erroneously) to be endemic to this sub-basin. In this way, Marrero and Machado-Allison (1990), Rodríguez-Olarte (1995) and Campo and Suarez (1996) cite it as a novelty their discovery in the Río Tuy basin, which, as explained at the beginning of this section, was described for this sub-basin 70 years earlier (Eigenmann 1920). The allocation in the distribution of Moenkhausia pittieri, as endemic (only for one basin), that of Lago de Valencia or Río Tuy by some authors (Luengo 1963; Mago 1968, 1970, 1978; Román 1985; Royero 1992; Lima et al. 2003; Rodríguez and Rojas-Suárez 2003; Pérez et al. 2018; Rodríguez-Olarte et al. 2018; Fricke et al. 2020), is an error or confusion that extends from the 1960s to recent dates.

Some authors have pointed to Moenkhausia pittieri being present in additional river systems to the type localities. In this evaluation, we have considered it appropriate to geographically locate these localities with a good approximation, a detail that is not explicitly provided by the cited authors. Luengo (1963), the reference for the Río San Diego, a tributary of the Río Los Guayos (10º 15 '25' 'N, 67º 56' 56 '' W, 470 m asl), near the city of Valencia (Carabobo state) through two specimens captured in 1950 and in Quebrada La Mesa (= Quebrada Corral de Piedra), a tributary of the Río El Limón (10º 13 '56' 'N, 67º 37' 57 '' W, 540 m asl) to the north-west of Maracay (Aragua state), for 15 specimens captured in 1948 and another 16 captured in 1950, respectively. More recently, since the 1990s, M. pittieri has been identified from the Río Urba (10º 11 '39' 'N, 66º 11' 51 '' W, 30 m asl), by capturing 162 specimens in 1983 (Marrero and Machado-Allison 1990) and from the Quebradas Manantial, Querepe and Caraballo tributaries of the Río Merecure (10º 14 '24''N, 66º 12' 00''W, 30 m asl), for the collection of 57 specimens in 1992 (Rodríguez-Olarte 1995). Both rivers are tributaries of the Río Tuy, in the region of Miranda State known as the Barlovento depression. Subsequently, Solórzano et al. (1997) recorded the species in two tributaries of the El Guapo or El Guamito reservoir, in the Río Guapo sub-basin (10º 06 '19''N, 65º 58' 50''W, 100 m asl), and four specimens were captured in the Río Aragua and an additional specimen, at the confluence of the rivers Guapo and Guayas, both groups of fish in September and October 1997. A year earlier, Campo and Suarez (1996) captured 19 specimens in the Quebrada Cupata (10th 12 '13''N, 66º 26' 07''W, 70 m asl), a tributary of the Río Taguaza, before the construction of a reservoir on that river. Ten years later, Ortaz et al. (2006) recorded a total of 127 specimens in the Taguaza reservoir (10º 10 '45''N, 66º 25' 59''W, 133 m asl), all captured between August and December 2001. This reservoir receives the waters of the micro-basin of the Río Taguaza, which flows into the right bank of the Río Tuy.

In regional assessments on the conservation status of Moenkhausia pittieri, Campo et al. (2008, 2015) indicate the localities cited above. Likewise, in a study on the diversity of fish and the conservation status of species in the Río Tuy sub-basin, González et al. (2015) recorded M. pittieri in the Río El Sapo, a tributary of the right bank Río Tuy (10º 11 '20''N, 66º 10' 39''W, 90 m asl).

In our review of collections from Venezuela (MHNLS, MBUCV, EBRG and MCNG), we found most of the material pointed out by all the authors cited. Likewise, it is very important to mention that in this review we found 21 lots containing 273 specimens captured in localities or sub-basins in addition to those registered in the previously mentioned published works. These are the Río Mesia in 1982 (MBUCV 27654), the Río Güere in 1991 (MBUCV 21246), rivers Panaquire, Yaguapa and Caño Basura (Panaquire region) in 1983, 1992 and 2001 (MBUCV 15651, 19559, MHNLS 9606, 14564), Rio Santa Cruz, tributary of the Rio Taguaza, in 1981 (MBUCV 12520, 12523), all tributaries of the Rio Tuy system. We also find records from Río El Limón in 1948 and 1974 (MBUCV 3027, 8894) and in the Quebrada La Cumaca, a tributary of the Río San Diego and Río Los Guayos in 1990 (MCNG 24625), both river systems belonging to the Lago de Valencia basin. In other fluvial systems currently independent, but possibly associated in the past with the Río Tuy, which belong to the Caribbean Sea basin, we find records of Moenkhausia pittieri. These are the Las Río Islitas, a tributary of the Río Guapo in 1977 and 2004 (MHNLS 2308, 16238), as well as the Río Curiepe in 2004 (MHNLS 17086, 17090), the Río Capaya in 1986 and 2005 (MHNLS 9199, 17737, 18599) and the Caño Urape, a tributary of the Río San José in 2004 (MHNLS 16250).

The review of international collections (in countries other than Venezuela) shows some records with precise coordinates not documented. Thus, there is the collection of 19 specimens in 1938 from the Río Mariara (CAS 54671, ANSP 82632), four specimens in 1966 and three in 1968 from the Río Vigirima, a tributary of the Río Guacara (ANSP 139489, ZMA.PISC 113788, ANSP 112499 ), both tributaries on the north slope of Lago de Valencia.

For a detailed description of the acronyms of the cited collections see Sabaj (2016) and Fricke and Eschmeyer (2020).

In conclusion, a total of 44 lots and 428 specimens are present in these collections in Venezuela, which were captured between 1948 and 2009. To this is added the material deposited in international collections, the types (29 specimens) captured in 1918, and 26 specimens captured between 1938 and 1968.

According to field observations made by one of the authors of this evaluation (I. Mikolji), Moenkhausia pittieri has been captured or observed in at least two localities in the Lago de Valencia basin. In the Río Vigirima, a tributary of the Río Guacara (10º 20 '21''N, 67º 53' 19''W, 556 m asl), four specimens were captured in 2006. Likewise, in the ravine called the Deshuesadero de Los Muertos, a right bank tributary of the Cabriales or Caño Central river system, east of the town of Tocuyito (10º 06 '02''N, 65º 08' 22''W, 500 m asl), high and constant abundances were found (> 120 individuals) during the years 2008 and 2009. This panorama changed abruptly in 2010, as specified in the Threats section.

According to our bibliographic and collection review, as well as our field observations, Moenkhausia pittieri has been recorded in river systems belonging to the endorheic basin of Lago de Valencia (Güey, El Limón, Mariara, Guacara, Cabriales - Caño Central rivers, San Diego - Los Guayos), as well as in systems belonging to the exorheic basin of the Caribbean Sea, such as the Tuy, Curiepe, Capaya, San José and Guapo rivers.

Originally Moenkhausia pittieri was only known from the type series of specimens (holotype: CAS 62059 and paratypes: CAS 62060, CAS 70732), a total of 29 specimens captured in 1918 (Eigenmann 1920).

There are no population studies throughout its range. Only in some inventories do the authors provide data on the number of specimens captured, which we can take as an indication for population estimates. Luengo (1963), in his study of the fish of the Lago de Valencia basin, cites the Río San Diego through two specimens captured in 1950 and in the Quebrada La Mesa (tributary of the Rio Limón), for 15 specimens captured in 1948 and another 16 captured in 1950, respectively. More recently, since the 1990s, M. pittieri has been identified from the Río Urba, through the capture of 162 specimens in September and December 1983 (Marrero and Machado-Allison 1990) and from the Quebrada Manantial, Querepe and Caraballo tributaries of the Merecure River, for the collection of 57 specimens in August 1992 (Rodríguez-Olarte 1995). Both rivers are tributaries of the Río Tuy. Next, Solórzano et al. (1997) recorded in two tributaries of the El Guapo or El Guamito reservoir, in the Río Guapo sub-basin, four specimens captured in the Río Aragua and an additional specimen, at the confluence of the Guapo and Guayas rivers, both groups of fish in September and October 1997. A year earlier, Campo and Suarez (1996) caught 19 specimens in the Quebrada La Cupata, a tributary of the Río Taguaza, before the construction of a reservoir on that river. Ten years later, Ortaz et al. (2006) registered a total of 127 specimens in the Taguaza reservoir, all captured between August and December 2001. This reservoir receives the waters of the Río Taguaza micro-basin, which flows into the right bank of the Río Tuy. In another tributary of the Río Tuy (Río El Sapo), González et al. (2015a) recorded only one specimen in a sampling carried out in February 2009, the last date of a documented record of Moenkhausia pittieri, with a reference specimen in Venezuela. In total, some 431 specimens are mentioned in the cited works, from 1930 to 2015, where the greatest abundances are found in tributaries of the Río Tuy, such as the Río Urba, (162 specimens: Marrero and Machado-Allison 1990) and the Río Taguaza (146 specimens: Campo and Suarez 1996, Ortaz et al. 2006).

In our review of collections from Venezuela (MHNLS, MBUCV, EBRG and MCNG) and other countries (CAS, ANSP, ZMA), we found to a large extent the material indicated by all the authors cited above. Likewise, it is very important to mention that in this review we found 26 lots that contain 300 specimens captured in localities or sub-basins in addition to those registered in the previously mentioned published works.

In chronological order, we have that in the Lago de Valencia basin,19 specimens were captured in 1938 from the Río Mariara (CAS 54671, ANSP 82632), 15 specimens in 1948 and 28 in 1974 (MBUCV 3027, 8894) in the Río El Limón, four specimens in 1966 and three in 1968 in the Rio Vigirima (ANSP 139489, ZMA.PISC 113788, ANSP 112499), and finally, four specimens in Quebrada La Cumaca, a tributary of the Rio San Diego and Los Guayos, captured in 1990 (MCNG 24625 ).

At the beginning of the 1980s, studies and collections of fish began to be carried out in another river system belonging to the Caribbean Sea basin, the Río Tuy sub-basin, by researchers from at least four different institutions. Thus, in 1981, 11 specimens were captured in the Río Santa Cruz, a tributary of the Río Taguaza (MBUCV 12520, 12523) and in 1982 one specimen was captured in the Río Mesia (MBUCV 27654), while in the neighbouring micro-basin of the Río Güere, 39 specimens were captured in 1991 (MBUCV 21246). Between 1983 and 2004, different samplings were carried out in the lower region of the Río Tuy, called the Barlovento depression (Panaquire region). In 1983 a total of 85 specimens were captured in the Río Panaquire (MBUCV 15651) and 11 in the Río Yaguapa (MBUCV 19559), while in that same river, two specimens were captured in 1992 (MHNLS 9606), and just one specimen in 2004 (MHNLS 16270). Finally, in this region, there are records of four specimens captured in the Caño Basura in 2001 (MHNLS 14564) and only one specimen in 2004 (MHNLS 16332).

Finally, in three other river systems currently independent, but possibly associated in the past with the Río Tuy, which belong to the Caribbean Sea basin, we find records of Moenkhausia pittieri. In this way we observe 10 specimens captured in 1977 in the Río Las Islitas (MHNLS 2308), from the Río Guapo sub-basin, the oldest record from another river system, as well as three specimens captured in 1986 and two specimens in 2004 and one in 2005 from the Río Capaya (MHNLS 9199, 17737, 18599). We also found 52 specimens from the Río Curiepe, captured in 2004 (MHNLS 17086, 17090) and in that same year, a single record of five specimens captured in the Caño Urape, a tributary of the Río San José (MHNLS 16250).

For a detailed description of the acronyms of the cited collections see Sabaj (2016) and Fricke and Eschmeyer (2020).

In conclusion, a total of 44 lots and 428 specimens are present in these collections in Venezuela (partially mentioned in some cited investigations), which were captured between 1948 and 2009. To this is added the material deposited in international collections, the material Type (29 specimens), captured in 1918 and 26 specimens captured between 1938 and 1968.

With the passage of time, a marked decrease in the number of captured specimens of Moenkhausia pittieri is observed in most of the river systems recorded in the collections. This situation, when compared with some regional inventories, shows us the total disappearance or local extinction of subpopulations of this species in some systems, such as in the Lake of Valencia basin. In this regard, according to the information presented in this evaluation, M. pittieri was recorded in six river systems of this basin between 1918 and 1990. In at least two of these systems, we diagnose the local extinction of subpopulations of the species. As shown in its description, part of the type material of M. pittieri was captured in the Río Güey (= Río Bue according to Eigenmann 1920 and Pearce 1920), on July 28, 1918, in the current city of Maracay. Lugo (1990) and Fernández-Badillo and Lugo (1994), after 24 intensive and systematic samplings (every 15 days for one year), found only six of the 17 species recorded by Eigenmann (1920) and Pearce (1920) in that river system, highlighting the disappearance of M. pittieri. In the same way, in the Río El Limón micro-basin, in the present evaluation, we find records of five specimens captured in 1948 and 28 in 1974 (MBUCV 3027, 8894). However, according to Ortaz (1992), he did not record this species in that river after 15 intensive samplings, between August 1985 and January 1987. In the same way, López-Rojas and Bonilla (2000) carried out continuous samplings between November of 1990 and January of 1993 in the rivers Cúpira, San Diego, Vigirima, Guayabita, Güey, El Paya and El Limón, and only found 15 (40%) of the 37 species registered in the basin of Lake Valencia. Although these authors indicate the capture of Moenkhausia pittieri in only two sub-basins, they do not provide any details of the localities or other information. In our review of national collections, we did not find records of specimens captured by the cited authors. A query to one of the authors of this work (A. Bonilla pers. comm.), affirms the capture of specimens in the San Diego and Cúpira rivers, without indicating dates or number of specimens captured. Likewise, after the mention of M pittieri for the El Guapo or El Guamito reservoirs (Solórzano et al. 1997), this species has not been detected again in the Río Guapo sub-basin. In our review of collections, we observed 10 specimens captured in 1977 in the Río Las Islitas (MHNLS 2308), coming from the Río Guapo sub-basin, being the oldest record of another river system; but we did not find records after this date (1997). Nor have we captured specimens in that river, in samplings carried out in 2004, 2005 and 2009, by one of the authors of this evaluation (O. Lasso-Alcalá). The reasons for the extinction of the local subpopulations of Moenkhausa pittieri in these sub-basins are explained in the Threats section.

However, in only the case of the Río Taguaza micro-basin (a tributary of the Río Tuy), an increase in the subpopulation appears to be observed after the construction and commissioning of a reservoir in 1997. In two tributaries of the Río Taguaza, records of the Río Santa Cruz show 11 specimens captured in 1981 (MBUCV 12520, 12523) and 15 years later, Campo and Suarez (1996) indicate the capture of 19 specimens in the Quebrada Cupata. Ten years later, with the reservoir built since 1997, Ortaz et al. (2006) report the capture of 127 specimens. In this regard, it is important to clarify that the effort and sampling number, between the records and compared studies, was very different. The 11 specimens of the MBUCV collection and the 19 specimens cited by Campo and Suarez (1996), are the product of two samplings in two stations, carried out in March 1981 and July 1996, respectively, and the 127 specimens referred to by Ortaz et al. (2006) come from seven samplings, between June and December 2001. Although these last authors do not indicate exact data on the number of specimens captured by sampling, on average there were 18 specimens captured by sampling, a number very similar to that found by Campo and Suarez (1996) of 19 copies. In this way, certain stability is inferred in the population of M. pittieri in this river system, possibly a product of the conservation status of this micro-basin (see section on Conservation Actions).

Apparent stability in Moenkhausia pittieri subpopulations can also be inferred with field observations made by one of the authors of the present evaluation (I. Mikolji) and other colleagues, in at least three sites in the Lago de Valencia basin. Thus, in the Rio Vigirima (10º 20 '21''N, 67º 53' 19''W, 556 m asl) a tributary of the Rio Guacara, its presence was observed in June 1998 (Mujica and Pugliesse 1999), as well as four specimens were captured in 2006, and their presence was observed again in June 2009 (E. Mujica pers. com.). This could be a case of population stability with low abundance, if we consider the four specimens captured in 1966 and three in 1968 from the Rio Vigirma, which we cite from the review of international collections (ANSP 139489, ZMA.PISC 113788, ANSP 112499). We have another case similar to the previous one, with the field observations of the presence of M. pittieri in the Quebrada La Cumaca (10º 15 '25' 'N, 67º 56' 56 '' W, 470 m asl), a tributary of the Río San Diego (sub-basin of the Río Los Guayos), dating from May 2010 (E. Mujica pers. Com.). It is important to remember that in this river system, two specimens were captured in 1950 (Luengo 1963) and four specimens in 1990 (MCNG 24625). Likewise, in the Quebrada El Deshuesadero de los Muertos, a right bank of the Cabriales-Caño Central river system, east of the town of Tocuyito (10º 06 '02''N, 65º 08' 22''W, 500 m asl), the first author of this evaluation (I. Mikolji), found high and constant abundances (> 120 specimens) during the years 2008 and 2009 (Mikolji 2018). This panorama changed abruptly in 2010, with the local extinction of this population, as specified in the threats section.

Finally, as there are no current published studies evaluating the status of their populations, it is estimated that their trend is decreasing according to the data from the bibliographic review, the analysis of records in collections, and field observations. Thus, it is also believed that in general, the populations of Moenkhausia pittieri have decreased, given the serious threats and strong degradation of the ecosystem where it lives (See threats). This situation makes sense, as in some river systems, populations of this species have disappeared, as reported in this assessment.

According to unpublished information provided to the authors of this evaluation, from ornamental fish breeders, this species can live up to a maximum of 4 years in captivity, so we estimate a maximum of 3 years or less in the wild. This indicates at least three or four generations in 10 years.

There are no records of the species since the beginning and middle of the 20th century, in the locations where we declared it extinct. Next, in the locations where their populations have declined 80%, but their populations are not being exploited, there are no records since 1990. Finally, in the Tuy River Basin, in addition to the fact that there are no records in the last 20 years, their populations they are heavily exploited for the ornamental fish market, for which we estimate a decline of 50%.

Moenkhausia pittieri inhabits coastal rivers in northern Venezuela, its central region, and the so-called Caribbean Sea Basin. Likewise, it inhabits (or inhabited) river systems that drain into the Lago de Valencia, from the so-called endorheic basin of Lago de Valencia (Lasso et al. 2003, Rodríguez-Olarte et al. 2009).

The Lago de Valencia basin, with a surface area of 3,140 km² and a perimeter of 127 km (Blanco et al. 2015), is located in the western region of the Cordillera de la Costa (CCR) of Venezuela, between the Serranías del Litoral and del Interior. It is currently the only endorheic-type basin in the country, where all its tributaries flow directly into the Lago de Valencia, which does not have any connection with the sea. The rivers whose sources are located in the Serranía de Litoral (northern region of the basin), with a maximum height of 2,429 m asl in the Pico Codazzi Natural Monument, run from north to south, and most of them are associated with large cities and other populated centers, such as the capitals of the states Aragua (Maracay) and Carabobo (Valencia). The following river systems run in Carabobo state from north-west to north-east: Río Los Guayos (Río San Diego), Caño Dividive, Caño El Nepe, Río Guacara, Río El Ereigue, Río Cura and Río Mariara; while in Aragua state (north-east) are the Río El Limón, three artificial industrial wastewater channels (Corpo Industria, Papelera and Sudamtex), Río Güey, Río Maracay, Río Turmero and Río Aragua. Likewise, the river systems that originate in the south of the basin, from south-west to south-east, are the Río Cabriales or Caño Central, Caño La Negra and Río Güigüe in Carabobo state and the Río Magdaleno, Río Tocorón and Caño Aparo in Aragua state (Apmann 1979, MARNR-JICA 2001, Pérez et al. 2018).

In this basin, the river systems where Moenkhausia pittieri has been recorded show a variation in their basic hydrographic characteristics. In general, tributaries have little flow, which is maintained by the contribution of point sources of urban and industrial wastewater; however, at the headwaters level, flows fluctuate with the dry and rainy climatic periods, so the values are variable. The Río Güey sub-basin has a length of 14 km, a surface area of 38 km² and a flow of 0.550 to 1.564 m³/s. The Río El Limón and its tributary, the Quebrada La Mesa has a length of 21 km, a surface area of 85 km² and a flow of 0.182 to 1.893 m³/s. The Río San Diego, including its final portion called Río Los Guayos, has a length of 26 km, a surface area of 150 km² and a flow of 0.999 to 3.619 m³/s. For its part, the Río Cabriales, which is part of the sub-basin also called Caño Central, has a length of 40 km, a surface area of 232 km² and a flow from 0.837 to 4.560 m³/s. Finally, the Río Mariara has a length of 10 km, a surface area of 40 km² and a flow of 0.018 to 0.162 m³/s, while it and the Río Vigirima, belonging to the Río Guacara sub-basin, have a length of 26 km, a surface area of 148 km² and a flow of 0.045 to 0.614 m³/s (MARNR-JICA 2001, Abarca and Rodríguez 2005, Pérez et al. 2018).

In the Caribbean Sea basin, the sub-basins of the Rios Tuy, Curiepe, Capaya, San José and Guapo, where Moenkhausia pittieri has been recorded, have their sources in the Cordillera de la Costa Central (CCR) (Serranías del Litoral y del Interior). The Río Tuy rises at 2,429 m asl in the Pico Codazzi Natural Monument, the Río Curiepe rises on the south flank in Cerro Carrizal, Fila Palmital (800 m asl), the Río Capaya rises in the Las Perdices Row (1,120 m asl), the Río San José at 1,064 m asl in the La Cuchilla Row and the Río Guapo at 1,087 m asl in the La Bandera Row, Sierra del Bachiller, respectively.

The Río Tuy has a length of 240 km, an area of 6,600 km² and a flow of 82 m³/s and empties into the Caribbean Sea, while the Río Guapo has a length of 60 km, an area of 475 km², a flow of 2.2 m³/s and flows into the Laguna de Tacarigua, east of the Río Tuy. For their part, the Curiepe and Capaya Rivers have a route of 32 and 74 km, a surface area of 174 and 349 kkm² and a flow of 1-3 and 3.2 m³/s respectively. Finally, the Río San José is a small sub-basin neighbouring the Río Guapo, with a length of 46 km and a small flow that does not exceed 2 m³/s, currently flowing into a series of artificial channels north of the town of Río Chico (COPLANARH 1969, Zinck 1982, Solorzano et al. 1997, Rodríguez-Olarte et al. 2018). It is important to mention that the final sections (last kilometres) and mouths of these five rivers were modified in the 1940s and 1950s, with which previously the Río Capaya was a tributary of the left bank of the Río Tuy, and possibly the Río San José was a tributary of the Río Guapo. This has important connotations of fragmentation and isolation of Moenkhausia pittieri populations to be considered in the classification of its threat category.

It is important to note that according to the bibliographic review (Eigenmann 1920, Pearce 1920) of national collections (MHNLS, MBUCV, EBRG and MCNG), international (CAS, ANSP and ZMA), as well as field observations, the altitudinal interval where Moenkhausia pittieri inhabits is located between the middle (622 m asl) and low (30 m asl) sectors of the basins. However, this interval is somewhat different in each of the river systems where the species lives or inhabited. In the Lago de Valencia basin, we recorded it between 556 in the Río Vigirima and the mouth of the Río El Limón in the lake at 417 m asl. In the Río Tuy sub-basin, it presents the greatest variation, between the 622 m asl of its Type locality in the Río El Consejo and the 35 m asl in the Panaquire region (Ríos Urba, Yaguapa and Panaquire). In the sub-basin of the Río Guapo we recorded it between 100 m asl, in the sector of the first reservoir built in that basin and the Río Las Islitas (30 m asl), a tributary of the Río Guapo. In the other coastal fluvial systems, M. pittieri lives mainly in the lower sectors of the Río Curiepe (45 m asl), the Río Capaya (38 m asl) and the Caño Urape, a tributary of the Río San José (30 m asl). For a detailed description of the acronyms of the cited collections see Sabaj (2016) and Fricke and Eschmeyer (2020).

Regarding the use of the habitat and ecosystem, it appears Moenkhausia pittieri has a preference for freshwater lotic systems, since all the 483 known specimens of the species registered in collections come from watercourses in the basins of Lago de Valencia and Mar Caribe. Even the specimens cited for the Taguaza and El Guapo (or Guamito) reservoirs by Campo and Suarez (1996) and Solorzano et al. (1997), were captured in the Quebrada Cupata and the Aragua, Guayas and Guapo rivers, tributaries of these reservoirs. Only the study by Ortaz et al. (2006), indicate the capture of 127 specimens in the Rio Taguaza reservoir (Subbasin of the RíoTuy), the product of seven samplings, between June and December 2001.

It is a bit complex to classify the types of waters (sensu Sioli 1975) of the coastal river systems where Moenkhausia pittieri inhabits. This is due to the physical characteristics of the soils through which these rivers flow and, to the state of conservation and the anthropogenic impacts present in the sub-basins (see Threats section). Due to this situation, the physical and chemical characteristics of the waters can vary both in geographical (spatial) and temporal terms, between the climatic periods of rain and drought and the hydrological periods of high waters and low waters. In this way we can find white and clear waters (sensu Sioli 1975) in the systems where this species inhabits.

As mentioned in the previous paragraph, the physical and chemical characteristics of the waters of the water courses where Moenkhausia pittieri lives are variable. As an example we cite the parameters of some river systems in some of the basins where it has been recorded. In the Lago de Valencia basin, the Río Vigirima system (a tributary of the Río Guacara), presents normal average values of temperature (21.5° C), dissolved oxygen (9.47 mg / l) and pH (7, 57) and conductivity (78.89 μS / cm), for these typical undisturbed mountain streams (Obispo 2015). In the Río Cúpira (La Cumaca), a tributary of the San Diego and Los Guayos rivers, temperature values between 20.00 and 23.50°C, 6.03 and 8.00 pH, 46.00 to 65 have been recorded, 00 μS / cm of Conductivity and 6.62 and 9.07 mg / l of dissolved oxygen (Storaci et al. 2013)

In the sub-basin of the Río Tuy, highly affected by anthropic activities (see Threats section), it is difficult to find works that indicate physicochemical variables of the water bodies not affected by these activities. In this way, Mogollón et al. (1993), present an overview of this issue by sectors of this river system, with data collected from 32 sampling stations between 1979 and 1990, during the rainy and dry climatic seasons. In the south-west sector of the sub-basin, where the systems with presence of Moenkahusia pittieri are located (Rios Taguaza, Urba, Yaguapa, Panaquire, El Sapo, Merecure, Caño Basura and others) in rivers with less or low anthropogenic influence, these authors found average values of temperature (26 °C), pH (7.2), conductivity (130 m mhos) and dissolved oxygen (8.5 mg / l).

It is important to mention that although Moenkahusia pittieri is registered in coastal fluvial systems, it has not been registered in the mouths (estuarine ecosystems) of the Tuy, Capaya, Curiepe, San José and Guapo rivers. Rodenas and López-Rojas (1993) found 34 species with marine and estuarine ecological habits, and 18 freshwater, where M. pittieri does not appear to be found at the mouth of the latter river system in the estuary of the Laguna de Tacarigua. In this sense, we can classify it as a primary freshwater species, with low tolerance to salinity (Myers 1938, McDowall 1988, Castro-Aguirre et al. 1999).

The absence of Moenkahusia pittieri in other coastal fluvial systems of the north of Venezuela (Caribbean Sea basin), neighbouring the Lago de Valencia basin, and the Tuy and Guapo rivers basins, draws our attention. Among these, to the east, are the sub-basins of the Río Unare, Aragua-Neverí and Manzanares, which have an ichthyological richness of 121, 40 and 56 species respectively, and which have been studied since the 1960s, and do not include Moenkahusia pittieri in its ichthyofauna (Mago 1965, Fernández-Yépez 1970, Aguilera and Carvajal 1976, Herrera and López 1997, Marín 2000, Pérez et al. 2003, Ruíz et al. 2005, Rodríguez-Olarte et al. 2009, Salazar et al. 2018, Salazar and Arcia-Barreto 2020). To the west of the Lago de Valencia basin, there are the sub-basins of the Yaracuy, Aroa and Tocuyo rivers, which have also been heavily inventoried, with a current richness of 144, 120 and 123 species respectively, and neither has registered M. pittieri (Fernández-Yépez 1972; Rodríguez-Olarte et al. 2006, 2007, 2009, 2015, 2018).

On the aspects of biology, such as feeding and reproduction of Moenkahusia pittieri, not much is known. With regard to their diet, the only data found are provided by three studies. Eigenmann (1920), in the description of the species, indicates that remains of insects were found in the alimentary canal of some specimens examined from the Río Tiquirito. Marrero and Machado-Allison (1990), point out that the alien material (wasps, ants, termites, etc.) that enters the rivers of the Panaquire region, is consumed mainly by M. pittieri, highlighting the importance of the conservation of riparian forests for the survival of the species. Contrary to this, Ortaz et al. (2006) indicate that terrestrial insects only constituted a small part of the feeding of this species in the Río Taguaza reservoir (sub-basin of the Río Tuy), during the period from June to December 2001. In this population, zooplankton, mainly crustaceans of the Class Cladocera and Copepoda, constituted an average of 81% of the Frequency of Appearance (FA) and 99% of the numerical frequency (NF) of the diet of M. pittieri. However, these proportions in the consumption of organisms varied according to the climatic period, where zooplankton predominated in the rainy period (99% FN). In the dry period, zooplankton consumption decreased to 90% FN, adding benthic organisms such as diptera of the Chironomidae and Ceratopogonidae families, coleopterans, hemiptera and ostracods, occupying 8% of FN and alien material of terrestrial origin, made up of arthropods (arachnids, dipterans and hymenopterans) and plant material (remains of leaves and small seeds), with 2% of the NF. Additionally, these authors point out that in a few specimens they observed filamentous chlorophylls and pennales diatoms.

Regarding the reproduction in the natural environment of Moenkhausia pittieri, there is no information on important basic aspects, such as minimum reproductive size, fertility, Gonadosomatic Index and reproductive period. However, this species is relatively easily bred in captivity by experts. According to the information supplied (M. Marinho pers. comm.), From an adult pair (up to 60 mm standard length) of this species, 10 to 12 induced reproductions per year and litters of 50 to 60 fry per reproductive event can be obtained. According to Marinho (2017), some of the physicochemical parameters of water to achieve reproduction are a temperature of 25 °C, 6.8 pH and 1 ° of Hardness (Hardness 1 dGH: German degree, dH, deutsche Härte). This last author studied its larval development in captivity, highlighting four stages and 12 events in its growth. The first, called yolk-sac stage, between the first and second day of life, in the 3.2 to 3.4 mm notochord length (NL) larvae, the formation of pectoral bud and the black pigmented eye occurs. In the second stage (pre-flexion larval stage), which occurs between three and eight days of age, in the larvae between 3.4 and 4.5 mm NL, the formation of the mouth, the inflation of the gas bladder occurs and the absorption of the yolk-sac. The third stage (flexion larval stage), occurs between days 19 and 46 of life and 5.3 to 8.9 mm of SL, where the formation of all the appendices is observed, with the radii of the caudal, dorsal and anal fins, including the development of the adipose fin in the larvae. In the fourth stage (post-flexion larval stage), the formation of pelvic bud, the pelvic-fin rays and Uppermost pectoral-fin rays occurs, between 9.6 and 11.8 mm SL, at 49 and 58 days, respectively. Finally, it is important to mention that cannibalism is common among larvae of this species, when they are bred in captivity and the breeding pairs can live up to five years (M. Marinho pers. comm.).

Moenkhausia pittieri have been bred in ornamental fish farms near the Lake of Valencia for about 15 years. In many occasions they have multiplied in small abandoned or unused manmade ornamental fish lagoons filled with Vallisneria sp. aquatic plants. They have also been found thriving in artificial lagoons filled with groundwater which are used to grow out Colossoma macropomum for human consumption. Therefore, it seems that the species is easily bred in captivity if favorable conditions are present.

An important feature in the information that is known about this species is that studies on its genetic aspects, such as chromosomal number and somatic karyotypes, have been approached since the 1960s by different authors (Post 1965; Gyldenholm and Scheel 1971; Arefjev 1989, 1990). However, it is worth noting that in recent decades these studies have not been carried out with modern techniques, despite its international importance as an ornamental species. Only a partial sequence (mitocohondrial gene 12S rRNA), unpublished, from a specimen of unknown locality, probably from the ornamental fish trade, was found in the GenBank system.

Additionally, the ecological aspects of Moenkhausia pittieri have not been studied. In the Lago de Valencia basin, this species shared its habitat, and in some localities it still does, with some of the 37 native species known for this basin (Luengo 1963, López-Rojas and Bonilla 2000, Lasso et al. 2003). In the Güey River, Eigenmann (1920) and Pearse (1920) recorded 17 species living with M. pittieri. Unfortunately, as Lugo (1990) and Fernández-Badillo and Lugo (1994) point out, after 24 intensive and systematic samplings (every 15 days during 1989), they only found six (35%) of the 17 species recorded by Eigenmann (1920) and Pearce (1920) in that river system, highlighting the disappearance of M. pittieri. A similar situation occurred in the Río El Limón sub-basin, where this species was also recorded. Until at least 1974, according to the records examined for this evaluation (MBUCV 8894), this species lived together with about 16 species (Luengo 1963). However, only 11 years later, Ortaz 1992) after 15 intensive samplings, between August 1985 and January 1987, did not record this species in that river, since it only found 10 (62%) of the 16 species indicated by Luengo (1963). Later, López-Rojas and Bonilla (2000) carried out continuous samplings between November 1990 and January 1993 in the Cúpira, San Diego, Vigirima, Guayabita, Güey, El Paya and El Limón rivers, and only found 15 (40%) of the 37 species recorded in the Lago de Valencia basin. These authors point to the capture of Moenkhausia pittieri in only two sub-basins, although they do not provide any details of the localities or other information. In our review of national collections, we did not find records of specimens captured by the cited authors.

Likewise, in the sub-basin of the Río Tuy, Moenkhausia pittieri shares its habitat with some of the 60 species that have been recorded for this river system (Rodríguez-Olarte et al. 2009, González et al. 2015). The Tuy drainage, in the Central Caribbean province, represents the third hotspot of the Caribbean drainage of Venezuela (60 sp., 17 (28%) endemic), however, this diversity no longer seems exceptional if grouped with the adjacent Lago de Valencia and Unare drainages (Rodríguez-Olarte et al. 2009). In the type locality (Río Tiquirito), Eigenmann (1920) and Pearse (1920), recorded 13 species coexisting with M. pittieri. Today, there is no information on whether the species still survives in that river. In other tributaries of the Río Tuy basin, Marrero and Machado-Allison (1990) recorded Moenkhausia pittieri along with some 16 species in the Río Urba, Rodríguez-Olarte (1995) found it with another 20 species in tributaries of the Río Merecure and Campo and Suarez (1996), captured it with 12 other species in tributaries of the Río Taguaza. In other sub-basins, Solorzano et al. (1997), indicate it along with 22 species, in the middle and upper Rio Guapo. Finally, there are no published inventories of the San José, Capaya and Curiepe Rivers, however, according to our review of national collections (MHNLS, MBUCV, EBRG), in total we have found it inhabiting at least 47 species of these sub-basins and in detail together with 19 species in the Río Curiepe, 34 species in the Río Capaya and 20 species in the Río San José.

Historically, the North Central Coastal region, where the Central Coast Mountain Range (CCR) is located and the exorheic hydrographic sub-basins of the rivers (from east to west) Aroa, Yaracuy, Tuy, Capaya, Curiepe, Guapo and several other smaller basins (Caribbean Sea Basin) and the endorheic basin of Lago de Valencia, has been the most densely populated in Venezuela, since 43% of the country's population (approximately 12.5 million inhabitants), are settled in this region (Martínez et al. 2020). Due to this, one of the greatest impacts on natural regions, their basins and their biodiversity is concentrated here, which consists of a long list, from the alteration of habitat due to deforestation, erosion and sedimentation due to poor agricultural practices, the pollution of water from agrochemicals, domestic and industrial effluents, construction of development of large cities and urban planning, packaging and channelling of water courses to convert them into effluent systems of cities, construction of reservoirs, extraction of water from basins for agricultural use, industrial and urban, non-metallic mining for the extraction of sand from the main canal and river banks, canalizations and diversions of the rivers for the construction of roads, introduction of species and climate change.

Deforestation or reduction of forest cover due to poor agricultural practices in the period 1988 to 2010, in the Cordillera de la Costa Central (CCR), has been very strong, intensifying in the last 10 years. The montane evergreen forests in the states of Carabobo Aragua, Capital District, Miranda (in the CCR) have been reduced between 50 and 30%, and are categorized as  Critically Endangered (CR), with the possible total elimination or almost total, if the trends of surface reduction are maintained in the next 30 years (Oliveira-Miranda et al. 2010). A similar situation occurs with the highest cloud forests, whose reduction observed between 1988 and 2010 of 32%, has been categorized as Endangered (EN) and Critically Endangered (CR). Finally, the situation worsens with the lower montane forests (semi-deciduous or deciduous), where the reduction ranges between 60% in the capital district (central region) and 80% in the state of Aragua, which is why these forests were classified as Critically Endangered ( CR) (Oliveira-Miranda et al. 2010).

As for water pollution, the Río Tuy basin is one of the most affected and deteriorated in Venezuela (Mogollón et al. 1987, 1993; Álvarez et al. 2007; Ramos et al. 2014), since it is the main collector of agricultural, urban and industrial waste or effluent discharges from the main populated centres of the country located in the states of Aragua, Capital District and Miranda, where 43% of the population of Venezuela lives (about 12.5 million inhabitants), having as main tributaries the Guaire, Guarenas and Guatire Rivers (Río Grande or Caucagua), among others (Delpretti 1989, MARNR 1992). In this regard, very low values of dissolved oxygen (2 - 4 mg / l) and high of conductivity (770 - 1,270 mhos) have been observed, in periods of drought and in areas of the highest human activity of the sub-basin. Likewise, the contamination, shown by the environmental parameters and heavy metals in the sub-basin of the Río Tuy, has been very high and always increasing. Acosta et al. (2002) record abnormal values (very high or very low) of temperature (> 28ºC), dissolved oxygen (<5.6ml / l), total nitrogen (> 55µmol / l), total phosphorus (> 17µmol / l ) and heavy metals in its surface sediments such as copper (> 18µg / g), cadmium (> 3µg / g), chromium (> 5µg / g), lead (> 0.9µg / g) and nickel (> 11µg / g), indicating its progressive increase over a period of 14 years. In the same way, Meléndez et al. (2017), recorded very high concentrations of Na (161.0 mg / l), K (10.6 mg / l), Ca (106.6 mg / l), Mg (53 , 6 mg / l), Cl- (345.3 mg / l), SO4- (172.6 mg / l) and NO3 (13.8 mg / l) and very high temperature values (33.6 ºC), conductivity (1853 µS / cm) and alkalinity (375.8 mg / l of HCO3), associated with alarming levels of contamination in its channel but also in some of its main tributaries, this as a consequence of industrial, domestic and agricultural activities that develop in the sub-basin.

The contamination of the waters of the rivers of the Lago de Valencia basin is much worse than the case described above (González and Matos 2012, Blanco et al. 2015, Córdova and González 2015, González et al. 2015bc, Romero 2017, González et al. 2019). The reason for its deterioration is that it is an endorheic basin, where around 15% of the population of Venezuela lives and whose final receptor, the Lake of Valencia, receives the discharges of agricultural runoff and raw effluents from large cities and towns with the most important industrial manufacturing activity in the country (Lewis 1983; Cressa et al. 1993; Mogollón and Bifano 1993, 2000; García-Miragaya and Sosa 1994; Mogollón et al. 1995, 1996; Infante 1997; López et al. 2000; MARNR-JICA 2001; Sarmiento et al. 2003; Graterol et al. 2006; Pérez 2008; De La Hoz and Gotilla 2009; Xu and Jaffé 2009; Marcano 2010; Burbano 2011; Álvarez et al. 2012; González et al. 2013; Palma et al. 2013; Suárez et al. 2013; Suárez 2014; Martínez 2015; Obispo 2015; Rosales and García 2015; Arjona et al. 2018; Pérez et al. 2018; Govin et al. 2019). With regard to the quality of the water, several of the tributaries of Lago de Valencia meet the symptoms described in the urban river syndrome, a problem that requires urgent attention (Rodríguez-Olarte et al. 2017). The situation is aggravated by the fact that urban effluent treatment plants are not operational and their discharges are transferred to other basins and reservoirs where drinking water is sourced for the human population (Blanco et al. 2015, Páez-Pumar 2017, González et al. 2019).

As examples of the contamination of this basin we cite the data of the physicochemical parameters of two rivers where we have diagnosed that Moenkhausia piitieri has disappeared. According to the MARNR-JICA report (2001), in the Río El Limón between 1997 and 2000, conductivity values were recorded (170 - 491 µmho / cm), total solids (200 - 476 mg / l), dissolved solids total (109 - 282 mg / l), pH (6.8 - 8.0), organic matter determined by Biochemical Oxygen Demand (BOD5: 10 - 54 mg / l), Chemical Oxygen Demand (COD: 37 - 76 mg / l ), nutrients such as phosphorus total (0.6 - 2.2 mg / l), nitrogen total (1.7 - 14 mg / l), nitrite (0.01 - 0.66 mg / l), nitrate (0.08 - 0.40 mg / l), chloride (5 - 35 mg / l), sulfate (7 - 41 mg / l), bacteriological contamination indicated by the very high load of total coliforms (160,000 - 3,000,000 MPN / 100 ml), faecal coliforms (160,000 - 3,000,000 MPN / 100 ml), and other inorganic pollutants derived from industry and urban use, such as detergents (0.71 mg / l), oils and fats (2 mg / l), total hydrocarbons (0.3 mg / l). For its part, in the Río Güey, the situation is more serious, since high values of high sediment load and erosion of the soils determined by conductivity (630 - 950 µmho / cm) have been registered, Total solids (696 - 1068 mg / l), Total dissolved solids (416 - 608 mg / l), pH (6.6 - 9.2) elevated organic matter determined by Biochemical Oxygen Demand (BOD5: 250 - 460 mg / l), Chemical Oxygen Demand (COD: 612 - 857 mg / l), nutrients such as Fostoro total (2.7 - 6.2 mg / l), total nitrogen (4.8 - 28 mg / l), nitrite (0.05 - 0.04 mg / l), nitrate (0.18 - 0.37 mg / l), chloride (23 - 119 mg / l), sulphate (27 - 290 mg / l), metals such as iron (0.732 - 1.618 mg / l), copper (0.050 - 0.086 mg / l), zinc (0.210 - 4.820 mg / l), manganese (0.020 - 0.112 mg / l), nickel (<0.050 - 0.367 mg / l), chromium (<0.090 - 0.250 mg / l), lead (<0.200 - 0.06 mg / l), cadmium ( <0.015 - 0.020 mg / l), bacteriological contamination indicated by the very high load of total coliforms (5,000,000 - 90,000,000 MPN / 100 ml), faecal coliforms (5,000,000 - 90,000,000 NMP / 100 ml), and other inorganic pollutants derived from industry and their urban use, such as detergents (1.75 - 6.20 mg / l), phenols (0.04 - 0.98 mg / l), oils and fats (21 - 135 mg / l) and total hydrocarbons (7 - 64 mg / l) (MARNR-JICA 2001). All these values mentioned above stand out for being extremely high for normal or natural conditions of water courses or their presence is abnormal (not natural). The lower values of the parameters found in the Río Limón may be due to the greater dilution due to its greater flow (0.182 to 1.893 m³/ s) with respect to that of the Río Güey (0.550 to 1.564 m³/ s), and to its greater quantity of tributaries (about nine streams) found in an Area Under Special Administration Regime (Henri Pittier National Park).

The previous contamination situation is aggravated due to the withdrawal of water from the basins, for domestic, industrial and agricultural use. Below we mention a couple of examples, which can be extrapolated to the entire basin of Lago de Valencia. In the Río El Limón sub-basin, Abarca and Rodríguez (2005) point out the collection of water for urban use, in all the upper sectors, its nine tributaries, as well as in the main river course located in the vicinity of the National Park Henri Pittier. The water systems and intakes are of the artisanal type (small deviation canals from the riverbed) or engineering works (dikes and small dams) that together cause a very high subtraction of the flow for this sub-basin. Of the 642 l / s measured for the nine tributaries of the Río El Limón, it is calculated that 448 l / s (70% of the flow) is extracted by these intakes (Abarca and Rodríguez 2005). This, together with other causes already explained, such as water pollution and others detailed below (climate change), could have been the trigger for the local extinction of Moenkhausia pittieri in this river system. Likewise, an uncontaminated or altered tributary of the Río Cabriales (Quebrada el Deshuesadero de los Muertos), studied by one of the authors of this evaluation in 2008 and 2009 (Mikolji 2018), was completely dried for agricultural use in 2010, with the consequent local extinction of an important population of M. pittieri.

In general terms, the rivers that are born in the different orographic systems located in the north of Venezuela present a state of conservation that goes from fair to bad, and especially those that drain towards the Caribbean Sea, except for the upper basins of the rivers of the coastal mountain range. (Blanco et al. 2015; Rodríguez-Olarte et al. 2018, 2019; Martínez 2020). However, in the high sectors of these sub-basins the ichthyological diversity is very low.

As explained in the Habitat and Ecology section, the construction of reservoirs or dams seems to be beneficial for Moenkhausia piitieri, according to the results found by Ortaz et al. (2006), supported by the high abundance of the species (127 specimens) in the Taguaza reservoir. In the sub-basin of the Río Tuy, there are at least six other reservoirs, including El Lagartijo, Taguacita, La Mariposa, La Pereza, Agua Fría and Santa Elena that add up to about 1,432 ha. However, the presence of reservoirs can be detrimental downstream of river systems, since they reduce water flow, modify the hydrological regime of the basins and produce large debits in runoff, tending to concentrate only in short periods of time during the period of greatest annual rainfall. In turn, this reduction in flow results in a higher concentration of organic and inorganic chemical pollutants. Likewise, the reservoirs cause the interruption of the migratory reproductive cycle of the fish species adapted to the lotic ecosystems of flowing waters (Winemiller et al. 1996, Zapata and Usma 2013), or the genetic exchange between the subpopulations of the low and middle regions and high watersheds. Likewise, due to the construction of dams that causes the change or conversion of a lotic ecosystem (river) or running waters, to a lentic ecosystem or stagnant waters, the local extinction of subpopulations of some species has also been documented. They inhabit mountain rivers. In the sub-basin of the Río Tuy (Caribbean basin) Lasso-Álcalá O. M.(2013) indicates the local extinction of Trichomycterus mondolfi (Trichomycteridae) and Cordilancystrus nephelion (Loricaridae), in the Río Mesia-Guere system, after construction and commissioning of the Santa Elena Reservoir in 1999.

Another threat that may have influenced the survival of Moenkhausia pittieri is the modification of the natural course of rivers, through their channelling. According to Rodríguez-Olarte et al. (2018) and Monente (2018), in the region of the Barlovento depression where the basins of the Curiepe, Capaya, Tuy, San José and Guapo rivers are located, during the 1940s and 1950s, major engineering works were carried out to divert the mouths of these rivers. In this way, the Río Curiepe, which today flows into the city of Higuerote, previously empties further north, into the estuarine system of Laguna La Reina. For its part, the Río Guapo was a tributary of the Río San José and it is possible that they were connected to the Río Tuy, on its right bank, as well as the Río Capaya, which is known to flow into the latter on its left bank. This would explain the shared distribution of M. pittieri in these currently separate river systems. However, these works caused a geographic and genetic isolation between the subpopulations of the species of the rivers Tuy, Capaya, Curiepe, Guapo, San José, which has never been evaluated.

In the basin of the Lago de Valencia, extensive works have also been carried out to create a complex system of canalization and diversion of different natural water courses, construction of reservoirs and dikes, and other artificial channels have been built for the connection of basins and sub-basins, with the objective of managing and diverting water to the lake, reservoirs or treatment plants, as well as natural water contaminated with urban, industrial and agricultural effluents. Among these ecosystem and habitat alterations we can cite the Caño Central, which receives the waters of the Río Cabriales through a diversion of this river, as well as the waters of the El Paíto river system, diverted to the Central Caño in 1978, so that its waters will not pollute those of the Río Pao, a tributary of the Pao - Cachinche reservoir (Río Orinoco basin). There are also artificial channels created on other previously natural water courses such as the Mozanga Channel, which channels the Caño Los Dividive, the El Tigre Channel built on the Río Guacara and the Río Güey, which for the most part is channelled through the city of Maracay in the North-South direction. Two other sub-basins have been interconnected by a system of dikes and canals. Among these is the Río Turmero, which through the Turmero Dam, as well as an adductor canal, supplies water to the Taiguaiguay reservoir, and in the rainy season, it continues along its natural course until it flows into the Lago de Valencia. On the other hand, the Río Aragua is the longest and largest in the basin, whose waters are diverted at two points: a) In the La Curia Dam, through an adductor canal to feed the Suata reservoir; b) Downstream it is controlled by the Aragua Dam, where it joins the Río Turmero. Both rivers feed the Taiguaiguay reservoir, through the Turmero-Aragua Adductor Channel. At the Taiguaiguay reservoir, the Caño Aparo was built, which is a spillway channel for the reservoir, to drain its waters into the Lago de Valencia (MARNR-JICA 2001).

On the other hand, there are at least three large artificial canals, built on natural drains that collected rainwater from some regions north of Lake Valencia, such as the Corpoindustria Canal, the Papelera Canal and the Sudamtex Canal, which today are large industrial companies that discharge effluents directly to Lake Valencia (MARNR-JICA 2001). Finally, there is a project to channel the Río Cúpira and the El Chivo Quebrada, both tributaries of the Río San Diego-Los Guayos (Aguilera et al 2015), systems from which viable populations of Moenkhausia pittieri have been recorded in the Quebrada la Cumaca and the Rio Cúpira itself. The effect of these canalization and damming works of the rivers in this basin on the populations of Moenkhausia pittieri has not been evaluated either.

In general terms, according to Rodríguez-Olarte et al. (2018), the Río Tuy sub-basin and many of its tributaries have a situation of generalized and extreme impoverishment. The sub-basin has a Very Poor conservation class (CC4), but its situation is more complex than in other coastal rivers in the country, mainly due to the intensity of the impacts and the extension and variety of disturbances, all this in a dynamic matrix of centres. urban areas, agricultural fields, protected areas in mountains, special management areas, fragments of forests in some sectors and a high biological diversity with significant endemism. These same authors also point out a very poor conservation class for the Río Capaya sub-basin, while it is poor for the Curiepe, San José and Guapo river sub-basins. Likewise, if we do an exercise with the methodology applied by these authors, most of the river systems of the Lago de Valencia basin would be classified in a Very Poor (CC4) or Poor (CC3) state of conservation.

Another threat detected for Moenkhausia pittieri is overfishing, as a result of its demand as an ornamental species since at least the 1960s. This is due to the fact that the largest uncontrolled exploitations of the subpopulations of this species have occurred in the sub-basins of the Tuy and Guapo rivers (Campo et al. 2008, 2015) and with certainty in the sub-basins of the other rivers of the Barlovento el Curiepe, Capaya and San José region. It is estimated that the exported quantities ranged between 3,000 and 6,000 specimens per year.

On the other hand, the sub-basins of the rivers that drain into the Caribbean Sea and the basin of Lago de Valencia in Venezuela represent another great threat to Moenkhausia pittieri. These basins present the greatest amount of introduced species in Venezuela, with at least 10 and seven species of exotic origin, as well as 22 and 24 of transferred origin, respectively, in each basin (Luengo 1963; Mago 1968; Lasso-Alcalá 2001, 2003, 2013). To this must be added around 80 exotic ornamental species, of which 40% were bred in captivity, at least in the Lake of Valencia basin, to supply the national market, and their establishment in natural bodies of water and their impact on the ecosystem and native species is unknown (Lasso-Alcalá 2001, 2003, 2013). Among the introduced species we must highlight at least two cases of great importance, due to their long history and impact on the aquatic ecosystem and on the native fauna. In the Lake Valencia basin, since the 1970s, and in the Río Tuy sub-basin since the 1990s, the Black or Mozambican Tilapia Oreochromis mossambicus has been recorded among other exotic species (Pereira et al. 1983; Bisbal 2000; Lasso-Alcalá 2001, 2003, 2013; González et al. 2015a). Given the biological and ecological characteristics of this species of Cichlidae, such as piscivorous predatory habits, moderate fecundity but with strong parental care of eggs and young (territorialism) and rapid population growth, among others, the ecological consequences that these species may have of introduced fish are unpredictable (Lasso-Alcalá et al. 2014). Some of these consequences are interspecific competition, displacement, extinction of native species, changes in the specific composition and trophic structure and loss of biodiversity in the ecosystem, for which it has been classified as one of the 100 most harmful exotic species in the world. Similarly, the river mojarra Caquetaia kraussii, another species of Cichlidae, this time of native origin (native to the Lago de Maracaibo basin), was introduced (transferred) to the Lago de Valencia basin at the end of the decade of 1960 and possibly in the Río Tuy sub-basin in the 1970s (Infante and LaBar 1977; Pereira et al. 1983; Marrero and Machado-Allison 1990; Royero and Lasso 1992; Señaris and Lasso 1993; Rodríguez-Olarte 1995; Lasso-Alcalá 2001, 2003). This species with the same biological characteristics as the previous one, as well as the same consequences, has been mentioned as the cause of the decline of several native species of the Lago de Valencia basin, among them Moenkhausia pittieri (Royero and Lasso 1992; Fernández-Badillo and Lugo 1994; López-Rojas and Bonilla-Rivero 2000; Campo et al. 2008, 2015)

When it comes to climate change or global change, it is difficult to accurately determine the level of threat to aquatic fauna and particularly fish species at risk. There are very few studies on the potential effect of climate change on ecosystems and their biodiversity, although it has been shown that some appear more vulnerable than others (Villamizar et al. 2018). The evidence makes it possible to foresee an alarming situation for diverse ecosystems, which is why studies are required to determine the adaptation and resilience capacity of each of the protected ecosystems. However, according to Paredes-Trejo et al. (2020), these rainfall changes have implications on the seasonal water regime of the rivers, since they could trigger complex impacts on river ecosystems and their ichthyofauna. On the other hand, due to the now exaggeratedly reduced flow of the rivers, during the dry season, fish are more vulnerable to overfishing and exposure to pesticides and pollutants in general (Winemiller et al. 1996). Likewise, climate variability (induced or not by global warming) can change the water regime of rivers (at least temporarily), putting the integrity and functioning of ecosystems at risk and causing their detriment. Consequently, the occurrence of years characterized by a severe water deficit or a water surplus in conjunction with the overexploitation of hydrobiological resources and river pollution can reduce their conservation status (Silva et al. 2016). Furthermore, it is foreseeable to assume that habitats and biota in watersheds that are experiencing excess or deficit rainfall may not evolve fast enough to adapt to the change in precipitation (Paredes-Trejo et al. 2020). In conclusion, these authors propose that if this situation continues, they consider it necessary to establish special protection figures over those most affected regions identified as 'hotspots', which guarantee the conservation of hydrographic basins threatened by climate variability, induced or not by global warming.

With regard to water surpluses or catastrophic events of extraordinary rainfall, there are two examples in sub-basins where Moenkhausi pittieri has become extinct. The first one that we can cite is that of the Río El Limón. Extraordinary rainfall, of the order of 180 mm, and concentrated in less than six hours in this sub-basin, north of Maracay, was accompanied by a torrential avalanche (mass movements) of great magnitude (2 million m³ of soil, sand, silt, clay, rocks and forest), with catastrophic consequences that do not seem to have had equivalent up to that moment in the country's history, due to the amount of victims and material losses caused in this basin on the afternoon of September 6, 1987 (Audemar and Singer 2002). As already mentioned in this assessment, we recorded this species in this river in 1948 and 1974 (MBUCV 3027, 8894). However, according to Ortaz (1992), this species was not recorded in that river after 15 intensive samplings, between August 1985 and January 1987. Thus, the climatic event (torrential rains) and geological (avalanche), in addition to other habitat alterations in that river system of the Lago de Valencia basin, such as the extraction of 70% of its flow for urban use (Abarca and Rodríguez 2005), may be the cause of the disappearance or local extinction of M. pittieri in the Río El Limón system

Likewise, the extraordinary torrential rains that occurred in December 1999 (1,910 mm in just 15 days), in the mountain range of the Central Coast of Venezuela, generated a catastrophe with more than 15,000 missing people and 75,000 victims, as well as 3,500 million USD of losses, the destruction of more than 15,000 homes and other infrastructure (Genatios and Lafuente 2003). Among these infrastructures, these rains caused the El Guapo reservoir dam to collapse, in the Río Guapo sub-basin (where Moenkhuasia pittieri lived), due to the maximum flow observed (310 m³/ s) at the dam site, well above the maximum design flow (101.8 m³/ s) (Liendo 2000, Mendez 2017). In 40 minutes, approximately a volume of water was released in the astonishing order of 120 hm³ (= 1.2 x 10¹¹ L), which produced a flood wave, whose peak was estimated to be around 12 m (Córdova and González 2006). This caused considerable damage to the entire sub-basin and its biodiversity, an issue that was never evaluated (Campo et al. 2008, 2015). As mentioned in the section on distribution and population, Solórzano et al. (1997) recorded Moenkahusia pittieri in two tributaries of the El Guapo or El Guamito reservoirs, in the Río Guapo sub-basin, four specimens captured in the Río Aragua and one additional specimen, at the confluence of the Guapo and Guayas rivers, both groups of fish in September and October 1997. Likewise, after this mention, this species has not been detected again in the Río Guapo sub-basin. In our review of collections, 10 specimens were observed captured in 1977 in the Río Las Islitas (MHNLS 2308), but we did not find records after 1997. Nor have specimens been captured in that river, in samplings carried out in 2004, 2005 and 2009, by one of the authors of this evaluation (O. Lasso-Alcalá). As can be seen, this catastrophic event, induced or not by climate change or global change, which occurred in 1999, may have locally extinguished Moenkahusia pittieri, also in the Río Guapo sub-basin.

Given the morphology, with a tall and slender body, with naturally prolonged fins in the males and a striking pattern of bright coloration and with iridescent and iridescent tones, Moenkhausia pittieri has been a species of ornamental importance since at least the 1960s (Frank 1971, Mills and Vevers 1989, Riehl and Baensch 1991).

Other works by national authors have recognized its importance as an ornamental species (Rengifo 1989, Marrero and Machado-Allison 1990, Román 1992, Royero 1992, Lasso 2006, Campo et al. 2008, López-Rojas and Bonilla 2000, Campo et al. 2015, González et al. 2015a, Rodríguez-Olarte et al. 2018), with a strong demand in the international market. In the 1980s, it was exported from Venezuela with a wholesale value that ranged from 0.25 to 0.50 USD per specimen (Rengifo 1989).

Unpublished information collected for this evaluation indicates that in 2004 and 2005, the highest value per specimen of Moenkhausia pittieri exported from Venezuela, on average, was around 0.35 USD. Today (2020) its retail value per copy in the market is between 3 USD in the USA and in the United Kingdom up to 5 USD in Germany.

In Venezuela, the largest exploitations of the populations of this species have occurred in the Barlovento depression region (sub-basins of the Ríos Tuy, Curiepe, Capaya, Guapo and San José), although also extensively bred subpopulations (artificial lagoons), from the Lago de Valencia basin. About 2,000 specimens per year were exported in 2007 and 2008. These exports were exported from Valencia, Venezuela to the Japanese City of Kuroko for the aquarium trade.

There are no specific measures for the protection of Moenkahusia pittieri.

A small part of the river systems where this species inhabits is protected by some conservation and management figures called Areas Under the Special Administration Regime (ABRAE). In the Cordillera de La Costa Central (basin of the Lago de Valencia and sub-basins of the rivers Tuy, Capaya, Curiepe, Guapo and San José) there are at least seven National Parks such as San Esteban (445 km²), Henri Pittier (1,078 km²) , Macarao (150 km²), El Ávila (851.92 km²), Guatopo (1,224.64 km²), Laguna de Tacarigua (391 km²), Natural Monuments such as Pico Codazzi (118.5 km²), and Protective Zones of the Cities of Caracas, of the Upper and Middle Basin of the Río Pao (1,510 km²), the Critical Areas with Priority Treatment Pico Jengibre (Lago de Valencia Basin - 3,035 km²), and the Riberas del Lago de Valencia and Peninsula Environmental Protection and Recovery Areas from La Cabrera and from different reservoirs including El Guapo or El Guamito (Oliveira-Miranda et al. 2010). Of all the ABRAE series listed, the Guatopo National Park would be protecting the subpopulations of Moenkahusia pittieri registered in the Río Taguaza system and its reservoir and at least the tributaries on the left bank of the Río Cuira and the San Esteban National Park would be protecting the subpopulations registered in the upper sectors of the Guacara (Vigirima), San Diego - Los Guayos (La Cumaca and Cúpira) rivers. Additionally, the Laguna de Tacarigua National Park would be protecting the populations of this species that may be present in the sector of the mouth of the Río Guapo, but their presence has not been detected in that region (Weibezahn 1949, Rodenas and López-Rojas 1993). Finally, the subpopulation present in the El Guapo or Guamito reservoir would be protected by the protective zone of this artificial body of water.

However, the functionality of these areas is very limited and the effects on the vegetation cover due to illegal agricultural practices can be easily observed on satellite images (Google Earth). The effectiveness of the decrees on protected areas on M. pittieri is not very high, as evidenced in the reports on their frequent capture and uncontrolled use as an ornamental species (Campo et al. 2008, 2015). In the same order of ideas, the rest of the ABRAE listed above only cover the highest sectors of the sub-basins, which are the regions where M. pittieri does not inhabit, with which 60% or more of the areas and registered populations of this species does not have any protection figure.

The above situation is common in all hydrographic basins in Venezuela, where, beyond the number and diversity of protected areas, their effectiveness is highly questioned, due in part to all the environmental and conservation problems (threats) mentioned in the previous section. On the other hand, and just as an example, in the western region of Venezuela, Rodríguez-Olarte et al. (2011) indicate that existing protected areas should be modified and expanded. This is due to the fact that most of the protected areas show a low effectiveness for the conservation of fish species, mainly because they are very small or because they include only fragments of tributaries or basins, or because they were located in mountain areas, where diversity species was minimal. This situation can be extrapolated to the protected areas of the central-north and eastern region of Venezuela. In the case of the protected areas of the region of the Lago de Valencia basin, whose springs are found both in the Serranía del Litoral and in the Interior of the Cordillera de la Costa Central, although the national parks have an extended coverage of those little basins; the final sections and the mouths are not protected and are heavily intervened (Rodríguez-Olarte et al. 2018).

Regarding the figures of protective zones, reality shows that in these zones different activities are developed that make them conceptually incompatible with protected areas (García and Silva 2014). In this sense, it is the most restrictive figures, such as the National Parks, which have guaranteed the best protection for the watersheds (Naveda and Yerena 2010); However, these figures of limitation of land use have not achieved the levels of protection and conservation for which they were created (Medina 2010, Naveda and Yerena 2010, Oliveira-Miranda et al. 2010).

Regarding Lago de Valencia, we conclude that it is an important continental wetland that is not fulfilling its functions due to the aforementioned degree of deterioration and anthropic intervention (González-Boscán 2003, González et al. 2015bc). If its situation is reversed and the quality of its waters can be recovered, it must be the object of a more restrictive environmental protection figure and become the ecological corridor to connect the biota of the entire basin, thus being able to develop an integrated management from the sources of the rivers to the lake (González et al. 2015bc). In the specific case of tropical lakes such as Valencia, the recommendations of Lewis (2002) should be taken into account, who points out that an effective management program should focus on the interception of nutrients, the protection of the aquatic habitats from invasive species, and minimization of hydrological changes in the rivers to which the lake is connected. In the absence of protective management, a body of water will greatly diminish its usefulness for water supply, production of commercially useful species, and recreation as has been the case to date.

Evaluations carried out in the Laguna de Tacarigua NP, located in the adjacent sub-basin of the Río Guapo, showed that this marine-coastal protected natural area is vulnerable to environmental impacts in its middle and upper basins, which represented a problem to solve through ecological corridors (González et al. 2015c). From these evaluations came the proposal for the Serranía del Bachiller National Park in 1995, which intended to unite the Guatopo and Laguna de Tacarigua national parks, including part of the Barlovento Agricultural Exploitation Zone, protecting the basins of the Cuira, Guapo, Aragüita, Batatal, Cúpira and smaller basins, developing an integrated management from the springs to the lagoon and its marine interface (Naveda and Yerena 2010, González et al. 2015c).

It is important to mention here that the exploitation and trade of Moenkhausia pittieri as an ornamental species, would be regulated by the guidelines established in the Technical Regulation of Management called Resolution MAC-DGSPA / 52, of 03-10-92 (Republic of Venezuela 1992), which prohibits the capture and commercialization of native species of the basins of Lake Valencia and Lake Maracaibo as ornamental fish, as well as the introduction of live specimens in areas other than their capture sites and any alteration of their habitat. However, despite the existence of this regulation, its exploitation and commercialization in this basin has continued without any type of control.

Finally, it is important to mention that Moenkahusia pittieri was regionally evaluated and classified in the Vulnerable A2ce category; B1ab (iii) (Campo et al. 2008) and later as Vulnerable B1ab (iii, iv) (Campo et al. 2015).

Given the diverse and serious threats to Moenkhausia pittieri and its ecosystem, it is extremely difficult to present specific and punctual recommendations or propose actions in favour of the conservation of this species and the environment where it lives.

As already stated in this section, protected areas in Venezuela (ABRAE for its acronym in Spanish) are insufficient in number and functionality, either because they are very small, or because they are located in regions where most of the species are not found (high areas of the basins). Another problem detected is that they only cover a small part of the species' distribution area and that they lack all the infrastructure to exercise adequate surveillance and control, which is why these "protected areas" do not work and are heavily affected by anthropic alterations. In this way, three actions are recommended: 1) create new areas and protection figures (in areas of public and private properties) in the lower regions of the basins; 2) expand existing protected areas; 3) Provide the staff (eg: park rangers) in charge of the custody of protected areas (eg: National Parks Institute - Inparques), with current training, infrastructure, equipment, supplies and adequate living conditions to be able to exercise greater surveillance and control, as well as to provide adequate environmental education to the residents near the protected areas; 4) Encourage, with the residents of the protected areas, sustainable economic activities for the protection and conservation of these areas, such as ecotourism and sport fishing. Likewise, in protected areas and other non-protected areas, which have already been impacted by anthropic activities, such as agriculture, it is recommended to establish more sustainable agricultural practices programs, such as the so-called “organic crops”, including shade coffee (Coffea arabica) in the middle and upper regions of the basins, or cocoa (Theobroma cacao), in the low and humid regions. Reforestation plans with native species should also be established for the recovery of degraded forest areas in the watersheds. These plans can be established with the help of private initiatives and international aid, as well as recovering and reactivating national reforestation plans, which the Venezuelan state had in the past (more than 20 years ago) and gave good results.

Other actions include exercising greater vigilance and control over the large-scale extraction of these species for commercial (consumer) fishing and ornamental fishing. Almost all the captures of the species exploited by these two types of fishing are exported to international markets (commercial fishing: Asia, ornamental fishing: from Venezuela to Colombia, and from this country to North America, Asia and Europe), yielding very little benefit to local communities, to the detriment of fish populations and their ecosystem. To correct this, the closures and quotas already established by regulations, norms and laws in force must be respected, as well as revising and adapting these regulations to the new conditions of pressure from international markets. Greater importance should be given to the study, establishment and dissemination of a more sustainable or subsistence fishing. Support and financing should also be given to fish farming programs, as well as to implement training in the fish farming area at the level of rural communities, to promote crops with indigenous species of already developed technology, as well as support research to generate technological packages with other native species not studied, but that have the appropriate characteristics for cultivation (promising species). These cultivation programs with native species should not only be destined to the generation of protein for the consumption of local populations, or the cultivation of species with ornamental value, but also to the repopulation of natural ecosystems, where these species have disappeared or their populations are in a state of high threat and / or risk of extinction. The promotion of crops with introduced species (exotic or transferred) should be avoided, educating the communities about the disadvantages of these species, as well as the dangers they pose to the native fauna and the ecosystem.

All these actions must be implemented with an adequate environmental and conservation education plan at different levels, starting with children and young people in primary and secondary education from educational centres, close to the distribution areas of the priority species to be conserved. These education and conservation projects must also involve the adult population of the closest local communities, in order for them to take ownership of the care and rational use of species and the conservation of ecosystems (basins), sowing a sense of belonging. and ecological awareness.

For all these activities, international financial support is needed, as well as their accompaniment. This is extremely necessary in a country with a unique fish megadiversity, which is currently mired in a terrible political, economic and social situation, unprecedented in its history and extremely complex to explain and detail here. This harsh reality has contributed in the last 20 years to an ecosystem deterioration of enormous proportions, to the detriment of an extraordinary biodiversity.