Printer Friendly

Freshwater prawns of the genus Macrobrachium (Decapoda: Palaemonidae) from the San Pedro-Mezquital River, Nayarit, Mexico.

The crustaceans of the family Palaemonidae include 36 recognized genera that are distributed in sea, brackish and/or fresh water (Holthuis, 1952). In this family, the genus Macrobrachium Bate (1868) is found, comprising about 246 species that inhabit fresh and/or brackish water environments with a wide geographical distribution in tropical and subtropical regions (De Grave & Fransen, 2011). They are distinguished from other palaemonids genera mainly for presenting the second pair of pereiopods chelate, and often in male longer than entire body (Holthius, 1952). These organisms present a behavior called amphidromy (McDowall, 2007), in which adults live in freshwater and migrate downstream near brackish water to spawn, after larval development, juveniles migrate to freshwater environments (Bauer, 2011). In Mexico, 20 species are reported (Villalobos, 1982; Villalobos-Hiriart et al, 1993; Wicksten & Hendrickx, 2003; Hernandez et al., 2007; Alvarez & Villalobos, 2016); however, the discussion on the presence of some shrimp species on both sides (Atlantic-Pacific), or only on one of the slopes, continues among specialists. According to the region they are known as acocil, chacales, camarones, langostinos, acamayas, cauques, moyas, piguas, popotillos o gambas, are an important resource of the artisanal fishing for the people of each region (Hendrickx, 1995). The San Pedro-Mezquital River originates in the state of Durango and crosses the Sierra Madre Occidental as it passes through much of the state of Nayarit until it ends in the south of the Reserva de la Biosfera Marismas Nacionales Nayarit (DOF, 2010). The singularity of this river, is that it does not have dams in its course by Nayarit, condition that few rivers in Mexico present it. So the species move freely along the river and the basin giving great benefits to the biological diversity that sustains this lotic ecosystem. The presence of freshwater prawns in the state of Nayarit has some reports (Villalobos-Hiriart et al., 1993; Perez-Velazquez et al., 2011); however, the San Pedro-Mezquital River is not registered to date. Therefore, the present study reports for the first time the freshwater prawns of the genus Macrobrachium in several localities of the San Pedro-Mezquital River, Nayarit River, Mexico.

In January, February, May 2009 and from July to September of 2012 several localities of the San PedroMezquital River, Nayarit, were visited between 08:00 AM and 18:00 PM (Fig. 1). The sampling sites of higher altitude and away from the coast were San Blasito with more than 220 m, Piedra Bola 170 m, Cortina 150 m, Naranjo 103 m, Venado 50 m, Ruiz 27 m, San Pedro 16 m and Tuxpan 10 m. In each site was recorded depth and transparency with Secchi disc. As well as temperature, dissolved oxygen, pH and conductivity using a YSI model 85 multiparameter device, YSI model 55 oximeter and Hatch potentiometer. It was estimated the stream flow and velocity in a section near the Venado and San Pedro in March 2009, uses a float (an object such as an orange, ping-pong ball, pine cone, etc.) to measure stream velocity. Calculating flow involves solving an equation that examines the relationship among several variables including stream cross-sectional area, stream length, and water velocity (US EPA, 1997).

The prawns were collected using aquatic net, surber net and minnow seines at each site along the river and rocks, boulders, pebbles, sands, aquatic vegetation, trunks, branches and litter were removed. The specimens were separated and preserved in 70% ethanol, tagged with the collection data and geographic position with a GPS. In the laboratory shrimps were identified at the genus and species level, with the support of Holthuis (1952), Nates & Villalobos (1990) and Hernandez et al. (2007). To determine the relationship of the environmental variables with the richness of species and their abundance the Pearson correlation coefficient was used.

The number of individuals collected in the seven visits to the sampling sites was 802 (Table 1). The prawns were found under branches, trunks, roots or rocks of various sizes and sediments from coarse to fine, as well as in fast and slow current, typical places of the lotic ecosystem, in these decapods (Hendrickx, 1995). The presence of six species of freshwater prawns is reported for the first time in the San Pedro-Mezquital River basin: Macrobrachium americanum (Bate, 1868), M. occidentale (Holthius, 1950), M. digueti (Bouvier, 1895), M. michoacanus (Nates-Rodriguez & VillalobosHiriart, 1990), M. hobbsi (Nates & Villalobos, 1990) and M. tenellum (Smith, 1871) (Table 1). The six species recorded are described:

Macrobrachium americanum (Bate, 1868)

Local common name: cauque, chacal, endoco. Habitat. In the clear waters of the San Pedro-Mezquital River. They are distributed in logs, under rocky areas, inside caves that form the water and in some cases immersed in the vegetation adjacent. We found this species cooccurring with M. occidentale. Material examined: The total length on male and female specimens collected was 222.2 mm max. and 84.13 mm min. Cephalothorax length was 79.60 mm max. and 29.17 mm min.

Macrobrachium occidentale (Holthius, 1950)

Local common name: langostino, cauque. Cooccurring with M. americanum. The total length on male and female specimens collected was 109.63 mm max. and 41.45 mm min. Cephalothorax length was 43.12 mm max. and 15.19 mm min.

Macrobrachium digueti (Bouvier, 1895)

Local common name: langostino. The total length on male and female specimens collected was 81.86 mm max. and 50.56 mm min. Cephalothorax length was 30.08 mm max. and 21.87 mm min.

Macrobrachium michoacanus (Nates & Villalobos, 1990)

Local common name: cauque, langostino. Cooccurring with M. hobbsi and M. tenellum. Material examined: the total length on male and female specimens collected was 74.27 mm max. and 33.88 mm min. Cephalothorax length was 26.49 mm max. and 13.49 mm min.

Macrobrachium hobbsi (Nates & Villalobos, 1990)

Local common name: langostino. They inhabit areas of running water in adjacent vegetation on the river. Cooccurring with M. tenellum and M. michoacanus. Material examined: the total length on male and female specimens collected was 58.41 mm max. and 54.33 mm min. Cephalothorax length was 22.16 mm max. and 18.54 mm min.

Macrobrachium tenellum (Smith, 1871)

Local common name: manopalito, chacalin, manudo, manocarrizo, langostino. Habitat: they inhabit areas of running water in adjacent vegetation on the river; although in a lentic environment, such as pools, they live in stagnant water with large amounts of deposited organic material, with low dissolved oxygen gradients and very variable conditions of temperature and salinity (Guzman & Kensler, 1977). Co-occurring with M. hobbsi and M. michoacanus. Material examined: The total length on male and female specimens collected was 90.41 mm max. and 44.74 mm min. Cephalothorax length was 36.75 mm max. and 17.26 mm min.

A similar number of prawns have been reported towards the northwest of this river, in the peninsula of Baja California (Hernandez et al., 2007), and to the southeast, on the coast of Oaxaca (Villalobos et al., 2010), and the possibility of the presence of other prawns M. acanthochirus (Villalobos-Figueroa, 1967) and M. olfersi (Wiegmann, 1836) in rivers that discharge in the Mexican Pacific (Villalobos, 1982; Villalobos-Hiriart et al., 1992; Hernandez et al., 2007; Villalobos-Hiriart et al., 2010). The highest richness was recorded in Venado with six species, Ruiz and San Pedro recorded five species respectively. This result is similar to that reported by Villalobos-Hiriart et al. (2010) in rivers of Oaxaca, finding most of the species towards the middle and low (coastal plain) of the rivers studied. In addition, these three localities accumulate about 70% of the abundance relative of registered prawns. M. americanum andM. occidentale were found in San Blasito, at an altitude of 220 m and 70 km upstream from Tuxpan, a locality with the closest at Marismas Nacionales, of lower altitude (10 masl), where it was found only to M. tenellum. The difference in species richness between localities may be related to the sampling intensity, since San Blasito and Piedra bola were visited in only one occasion (May 2009), while the rest of the sites were visited in more occasions. Piedra Bola only recorded the presence of a male ofM. americanum. From Tuxpan locality the river changes in geomorphology with predominance of soft substrate consisting mainly of sands and silts, with a minimum slope, and therefore in rainy season tends to present floods, communicating with south of protected natural area Marismas Nacionales, by diverse streams and channels, where M. tenellum was the only prawn present and abundant. M. occidentale was the most frequent shrimp in the river, present in six of the eight localities, followed by M. digueti in five localities and the rest of the species were registered in the localities of the lower part of the river, Venado, Ruiz, San Pedro and Tuxpan. The sex ratio for the total population of shrimp caught was equal to 1:1. The ovigerous females represented only 6.6% of the total of prawns captured, in which M. digueti and M. hobbsi showed the highest number of ovigeras, with 17 females respectively, followed by M. michoacanus (10). Juveniles recorded above 35% of the abundance, indicating an active and continuous recruitment among the shrimp towards the lower part of the river basin, as evidenced by the localities of Ruiz, San Pedro and Tuxpan. The highest localities (>100 m) did not register juveniles, except in Naranjo (103 m) with a single individual. Like juvenile shrimp, ovigera females are almost entirely present in the localities of the lower part of the river basin, in preparation for migration to brackish waters and completing the reproductive cycle, as in these orga nisms (Bauer, 2011). These females were registered mainly in the months of June to September in the localities of the lower part of the river. However, M. occidentale recorded an ovigera female in May in San Blasito, with more than 200 m of altitude. The reproductive period in these organisms is related to the rainy season (New & Valenti, 2000), but change, depending on the region, in this case this event was recorded in spring and summer.

The environmental conditions recorded in the water column of the San Pedro-Mezquital River during the months and sampling sites are the minimum necessary for the presence and adequate development of aquatic fauna of the lotic system. No significant variations were found in the physical and chemical parameters of the water recorded during the study period. The fluctuations of temperature, dissolved oxygen and pH were in favorable ranges to perform the processes of osmo-regulation, thermoregulation and oxygen circulation in the gill chamber. The Table 2 summarizes the values of recorded variables. The temperature was 22.3 and 30.1[degrees]C in the dry season (average: 26.6[degrees]C [+ or -] 1.7) and in the rainy season it ranged from 26.4 to 32.6[degrees]C (average: 28 [+ or -] 2.9[degrees]C). Dissolved oxygen had a mean value above 6.32 mg [L.sup.-1], the minimum concentration required for the life of the aquatic fauna in the river during the sampling dates. Likewise, the pH remained slightly neutral with an average of 7.4 [+ or -] 0.81 in the dry season and 7.2 [+ or -] 0.28 during the months of maximum humidity (rainy season). In terms of conductivity, in May 2009 was around 300 [micro]s [cm.sup.-1] and in the rainy season decreased to an average of 170 [micro]s cm-1. In Venado site the stream flow of 18 m3 s-1 and velocity of 0.6 m s-1 in March 2009 (dry season), while at San Pedro was the same velocity (0.6 m s-1) and stream flow at 22 m3 s-1; it is suggested that in the rainy season the stream velocity should reach 1.6 m s-1 and a stream flow rate of 122 and 123 m3 s-1 respectively. It is characteristic that the runoff that incorporates solids to the channels in rainy season, with the consequent increase of nutrients.

With the recording of environmental and biological variables collected, a correlation analysis was performed and the level of dependence was determined on the presence of prawns and their abundance (Table 3); however, only the correlation between altitude and abundance (-0.446) were significant with a 99% confidence level. Thus, it is confirmed that the presence and abundance of Macrobrachium are found mainly in the coastal plain of this river, as it happens in some rivers of the coast of Oaxaca, Mexico (VillalobosHiriart et al., 2010).

The people of the rural communities in the river, including indigenous communities, actively capture the species of the freshwater shrimps and the various species of prawns are fed, mainly M. americanum, M. tenellum andM. occidentale, during certain times of the year, as in other regions of the Americas (Hendrickx, 1995).

DOI: 10.3856/vol46-issue3-fulltext-13

Received: 1 March 2017; Accepted: 20 January 2018

ACKNOWLEDGMENTS

We thank the people of the communities in the San Pedro-Mezquital River, Nayarit, who were always attentive to support us during the sampling. To Universidad de Guadalajara for the support of logistical and economic resources of the Project "Adecuacion de la Manifestacion de Impacto Ambiental Modalidad Regional (MIA-R) del Proyecto Hidroelectrico Las Cruces, en el estado de Nayarit de acuerdo con los lineamientos actuales de la Secretaria de Medio Ambiente y Recursos Naturales".

REFERENCES

Alvarez, F. & J.L. Villalobos. 2016. Freshwater decapod diversity and conservation in Mexico. In: T. Kawai & N. Cumberlidge (eds.). A global overview of the conservation of freshwater decapod crustaceans. Springer, Cham, Switzerland, pp. 237-266.

Bauer, R.T. 2011. Amphidromy and migration of freshwater shrimps. I. Costs, benefits, evolutionary origins and an unusual case of amphidromy. In: A. Asakura (ed.). New frontiers in crustacean biology. Proceedings of the TCS summer meeting, Tokyo, 2024 September 2009. Brill NV, Leiden, pp. 145-156.

De Grave, S. & C.H.J.M. Fransen. 2011. Carideorum Catalogus: the recent species of the Dendrobranchiate, Stenopodidean, Procarididean and Caridean shrimps (Crustacea: Decapoda). Zool. Meded., 85: 195-588.

Diario Oficial de la Federacion (DOF). 2010. Decreto por el que se declara como area natural protegida, con el caracter de reserva de la biosfera, la region conocida como Marismas Nacionales Nayarit, localizada en los municipios de Acaponeta, Rosamorada, Santiago Ixcuintla, Tecuala y Tuxpan en el Estado de Nayarit. Diario Oficial de la Federacion. 12 de mayo de 2010. Distrito Federal, Mexico. [http://dof.gob.mx/nota_ detalle.php?codigo=5294348&fecha=03/04/2013]. Reviewed: 10 January 2017.

Guzman, A.M. & C. Kensler. 1977. Posibilidades del cultivo del langostino Macrobrachium en el area de la ciudad de Lazaro Cardenas, Mich. y zonas de influencia. An. Inst. Cienc. Mar Limnol., Univ. Nac. Auton. Mexico, 19 pp.

Hendrickx, M.E. 1995. Camarones. In: W. Fischer, F. Krupp, W. Schneider, C. Sommer, K.E. Carpenter & V.H. Niem (eds.). Guia FAO para la identificacion de especies para los fines de la pesca. Pacifico centrooriental. Plantas e invertebrados. FAO, Roma, pp. 418537.

Hernandez, L., G. Murugan, G. Ruis-Campos & A. Maeda-Martinez. 2007. Freshwater shrimp of the genus Macrobrachium (Decapoda: Palaemonidae) from the Baja California Peninsula, Mexico. J. Crustacean Biol., 27: 351-369.

Holthuis, L.B. 1952. A general revision of the Palaemonidae (Crustacea Decapoda Natantia) of Americas. II. The subfamily Palaemoninae. Allan Hancock Foundation, Publ. Occas. Pap., 396 pp.

McDowall, R. 2007. On amphidromy, a distinct form of diadromy in aquatic organisms. Fish Fish., 8: 1-13.

Perez-Velazquez, P.A., S. Hernandez-Ventura, P. UlloaRamirez, J.L. Patino-Valencia & J. Tovar-Avila. 2011. La pesca del langostino (Macrobrachium tenellum) en la Laguna de Mexcaltitan, Nayarit, una alternativa economica regional. Cienc. Pesq., 19: 13-20.

Nates-Rodriguez, J.C. & J.L. Villalobos-Hiriart. 1990. Dos especies nuevas de camarones de agua dulce del genero Macrobrachium Bate (Crustacea, Decapoda, Palaemonidae), de la vertiente occidental de Mexico. An. Inst. Biol. Ser. Zool., 61: 1-11.

New, M.B. & W.C. Valenti. 2000. Freshwater prawn culture: the farming of Macrobrachium rosenbergii. Blackwell Science, Oxford, 443 pp.

United States Environmental Protection Agency (US EPA). 1997. Volunteer stream monitoring: a methods manual. EPA 841-B-97-003. [http://www.epa.gov/ owow/monitoring/-volunteer/stream/]. Reviewed: 4 July 2015.

Villalobos-Figueroa, A. 1967. Estudio de palemonidos de Mexico I. Macrobrachium acanthochirus una nueva especie del SE de Mexico. An. Inst. Biol. Univ. Nal. Auton. Mexico, 25(1/2): 167-174.

Villalobos-Figueroa, A. 1982. Decapoda. In: S.H. Hurlbert & A. Villalobos-Figueroa (eds.). Aquatic biota of Mexico, Central America and the West Indies. San Diego State University, San Diego, 559 pp.

Villalobos-Hiriart, J.L., A.C. Diaz-Barriga & E. LiraFernandez, 1992. Carcinologia. In: L. HuidobroCampos, H. Espinoza-Perez & J.L. Villalobos-Hiriart (eds.). Estudios especificos de fauna de la zona del embalse del Proyecto Hidroelectrico de Aguamilpa, Nayarit. Informe Final, CFEIB/UNAM, 181 pp.

Villalobos-Hiriart, J.L., A.C. Diaz-Barriga & E. LiraFernandez. 1993. Los crustaceos de agua dulce de Mexico. In: R. Gio-Argaez & E. Lopez-Ochoterena (eds.). Diversidad biologica en Mexico. Rev. Soc. Mex. Hist. Nat., 64: 267-290.

Villalobos-Hiriart, J.L. F. Alvarez, C. Hernandez, G. de la Lanza-Espino & I.D. Gonzalez-Mora. 2010. Crustaceos decapodos de las cuencas Copalita, Zimatan y Coyula, en Oaxaca, Mexico. Rev. Mex. Biodivers., 81: S99S111.

Wicksten, M.K. & M.E. Hendrickx. 2003. An updated checklist of benthic marine and brackish water shrimps (Decapoda: Penaeoidea, Stenopodidea, Caridea) from the Eastern Tropical Pacific. In: M.E. Hendrickx (ed.). Contributions to the study of east Pacific crustaceans. Instituto de Ciencias del Mar y Limnologia, UNAM, pp. 49-76.

Ernesto Lopez-Uriarte (1), Elva Guadalupe Robles-Jarero (1), Manuel Alejandro- Vargas Ceballos (2), Fernando Vega-Villasante (2)

(1) Laboratorio de Ecosistemas Marinos y Acuicultura, Departamento de Ecologia Centro Universitario de Ciencias Biologicas y Agropecuarias, Jalisco, Mexico

(2) Laboratorio de Acuicultura Experimental, Centro de Investigaciones Costeras Universidad de Guadalajara, Jalisco, Mexico

Corresponding author: Ernesto Lopez (ernesto.luriarte@academicos.udg.mx)

Caption: Figure 1. Map of sampling sites in the San Pedro-Mezquital River, Nayarit, Mexico.
Table 1. Freshwater prawns of the genus Macrobrachium in the San
Pedro-Mezquital River. [male] = male, [female] = female, [female]o =
ovigerous female.

Species          San Blasito             Piedra Bola
                 22[degrees]23'16.4"N    22[degrees]19'56.4"N
                 105[degrees]01'52.4"w   105[degrees]02'56.9"W

M. americanum    1[male]:                1[male]
                 1[female]
M. digueti

M. michoacanus

M. occidentale   3[male]:
                 4[female]:
                 1[female]o
M. hobbsi

M. tenellum

Macrobrachium
juveniles

Species          Cotina                  Naranjo
                 22[degrees]05'57.4"N    22[degrees]02'28.09"N
                 104[degrees]56'39.6"W   104[degrees]56'2.17"W

M. americanum                            4[male]:
                                         1[female]
M. digueti       1[male]                 3[male]:
                                         2[female]

M. michoacanus                           5[male]

M. occidentale   2[male]:                9[male]:
                 2[female]o              2[female]

M. hobbsi                                1[male]

M. tenellum

Macrobrachium                            1
juveniles

Species          Venado                  Ruiz
                 21[degrees]56'47.6"N    21[degrees]57'04.6"N
                 105[degrees]04'23.1"W   105[degrees]10'44.7"W

M. americanum    6[male]:
                 2[female]
M. digueti       9[male]:                9[male]:
                 5[female]:2o            2[female]:
                                         1[female]o
M. michoacanus   17[male]:               4[male]
                 1[female]:
                 10[female]o
M. occidentale   14[male]                4[female]o

M. hobbsi        3[male]:                4[male]:
                 2[female]:              2[female]
                 2[female]o
M. tenellum      13[male]:               1[male]:
                                         1[female]o

Macrobrachium    10[female]              177
juveniles

Species          San Pedro               Tuxpan
                 21[degrees]57'03.6"N    21[degrees]56'36.3"N
                 105[degrees]10'44.7"W   105[degrees]17'06.2"W

M. americanum

M. digueti       8[male]:
                 12[female]:
                 15[female]o
M. michoacanus   15[male]:
                 7[female]

M. occidentale   5[male]

M. hobbsi        8[male]:
                 13[female]:
                 15[female]o
M. tenellum      55[male]:               80[male]:
                 57[female]              42[female]:
                                         1[female]o
Macrobrachium    26                      74
juveniles

Species          Abundance

M. americanum    2.01

M. digueti       8.66

M. michoacanus   7.41

M. occidentale   5.77

M. hobbsi        6.28

M. tenellum      34.55

Macrobrachium    36.06
juveniles

Table 2. Summary of water parameters and substrate type in 2009 and
2012 of the San Pedro-Mezquital River, depth (min- max in m),
temperature (T[degrees]C), dissolved oxygen (DO), pH, conductivity
(C), Secchi transparency (sT) and altitude (m). Substrate type Rock:
r, boulder: b, pebbles: p, coarse sand: cs, medium sand: ms, fine
sand: fs, limes: l, clays: cl, roots: rt, submerged vegetation: sv,
emerged vegetation: ev.

Date        Locality      Depth     T[degrees]C   DO         pH
                          (m)                     (mg [L.
                                                  sup.-1])

            Cortina       0.3-2     22.3          7.5        7.9
January     Naranjo       0.2-3     24.6          6.8        7.6
2009        Venado        0.7       24.9          4.85       7.4

            Ruiz          0.5       24.8          4.23       7.8

            San Pedro     0.6       24.7          3.98       7.2

            Naranjo       --        32.2          7.1        --
March       Venado        0.2-1     26.6          7.9        --
2009        Ruiz          0.2-0.5   28.2          8.4        --
            San Pedro     0.2-1     29.6          8.1        --
            Tuxpan        0.2-1     30.1          7.7        --

May         San Blasito   0.5-1     23.7          9.3        7.2

2009        Piedra Bola   0.2-3     27.5          9.2        7.3
            Cortina                 29.9          4.56       8.18
June        Naranjo                 28.1          4.37       7.57
2009        Venado                  29.9          4.55       8.02
            San Pedro               32.1          6.14       8.05
            Tuxpan                  32.6          5.8        7.7
September   Cortina                 26.4          5.20       7.54
2009        Naranjo                 26.5          3.99       7.68
            Venado                  26.7          5.0        7.72
            San Pedro               27.1          6.55       7.7
            Tuxpan                  27.5          4.2        7.45
July        Cortina                 27.0          4.5        6.6
2012        Naranjo                 29.1          6.65       6.69
            Venado                  26.4          7.9        6.73
            Ruiz                    27.2          6.2        6.8
            San Pedro               28.2          7.9        6.7
            Tuxpan                  27.8          5.8        6.0
August      Cortina                 30.0          5.7        8.4
2012        Naranjo                 30.3          5.4        9.6
            Venado                  30.5          7.2        7.84
            Ruiz                    27.3          6.2        6.61
            San Pedro               30.4          8.2        8.13
            Tuxpan                  28.0          7.9        7.3
September   Naranjo                 29.1          6.5        6.7
2012        Venado                  26.4          7.9        6.73
            Ruiz                    27.2          6.5        6.79
            San Pedro               28.2          7.9        6.7
            Tuxpan                  28.2          5.8        6.0

Date        Locality      C           sT     Alti-   Substate
                          ([micro]s   (m)    tude    and vegetation
                          [cm.sup            (m)
                          .-1])

            Cortina       --          0.3    150     r, b , p, cs, sv
January     Naranjo       --          0.20   103     b, p, cs, rt
2009        Venado                           50      b, p, cs, ms,
                                                     sv, rt
            Ruiz                             27      b, p, cs, ms,
                                                     sv, rt
            San Pedro                        16      b, p, cs, ms,
                                                     ev, sv
            Naranjo       339.5       0.25   103
March       Venado        300.5       0.20   50
2009        Ruiz          299.7       0.15   27
            San Pedro     313.6       0.20   16
            Tuxpan        337.5       0.10   10      ms, fs, l, cl,
                                                     rt, ev
May         San Blasito   358.8       0.5    220     r, b , p, cs,
                                                     sv, rt
2009        Piedra Bola   333.9       0.5    170     r, b , p, cs, sv
            Cortina       229         0.10   150
June        Naranjo       238         0.8    103
2009        Venado        228                50
            San Pedro     274         0.8    16
            Tuxpan        306         0.8    10
September   Cortina       88.7        0.10   150
2009        Naranjo       94.8        --     103
            Venado        99.2        0.8    50
            San Pedro     85.0        0.8    16
            Tuxpan        77.2        0.10   10
July        Cortina                   0.4    150
2012        Naranjo                   0.5    103

            Venado                    0.5    50
            Ruiz                      0.4    27
            San Pedro                 0.3    16
            Tuxpan                    0.1    10
August      Cortina                   0.1    150

2012        Naranjo                   0.08   103
            Venado                    0.05   50
            Ruiz                      0.05   27
            San Pedro                 0.05   16
            Tuxpan                    0.05   10

September   Naranjo                   0.1    103
2012        Venado                    0.1    50
            Ruiz                      0.08   27
            San Pedro                 0.05   16
            Tuxpan                    0.1    10

Table 3. Pearson correlation coefficient between environmental
variables and species recorded in the San Pedro-Mezquital River.

Parameter                  No        P-value     No          P-value
                           species               organisms

Temperature ([degrees]C)   0.007     >0.05       0.028       >0.05
Dissolved oxigen (mg       -0.113    >0.05       0.112       >0.05
[L.sup.-1])
pH                         0.164     >0.05       0.054       >0.05
Secchi transparency (m)    0.060     >0.05       -0.052      >0.05
Depth (m)                  0.141     >0.05       -0.176      >0.05
Conductivity ([micro]s     -0.024    >0.05       -0.046      >0.05
[cm.sup.-1])
Altitude (m)               -0.013    >0.05       -0.449      <0.01
COPYRIGHT 2018 Pontificia Universidad Catolica de Valparaiso, Escuela de Ciencias del Mar
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2018 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Short Communication
Author:Lopez-Uriarte, Ernesto; Robles-Jarero, Elva Guadalupe; Alejandro-Vargas Ceballos, Manuel; Vega-Villa
Publication:Latin American Journal of Aquatic Research
Date:Jul 1, 2018
Words:4086
Previous Article:Assessment of median lethal concentration (CL50) of pollutants on Macrobrachium tenellum juveniles.
Next Article:Fly larvae (Musca domestica) as a protein alternative in the feeding of Macrobrachium tenellum.
Topics:

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters