**4. Results**

On the Caribbean slope, Guatemala has other rivers with conditions completely different as Dulce, Motagua, and Sarstún Rivers, that with another they end on this slope. River Dulce is the main effluent of important aquifers on Sierra de las Minas and Cerro San Gil, as well as highlands from Alta Verapaz, all these rivers produce the Río Polochic that end on Izabal Lake

The Motagua River is the longest of the country. However, due to their origin (closed to Guatemala City) and magnitude, induces an excessive carry of solid wastes mainly plastics and nondegradable material that reach the Caribbean Sea and produce marine pollution [10]. Finally on the Pacific Slope, some main rivers are María Linda, Los Esclavos, La Paz, Achiguate, Coyolate, and Naranjo are located and drainage on the Departments of Escuintla, Rethauleu, Santa Rosa, Jutiapa, Sichitepéquez, San Marcos Quetzaltenango y Sololá [7] (**Figure 1**).

Two structured sampling trips were made on the Atlantic Slopes (Gulf of Mexico and Caribbean), and in Pacific Slope, different trips were made (**Figure 2**). In these trips, the crustaceans were collected using nets and hand. At that time, the GPS and physical and chemical water data were recorded using a GPS Garmin and YSI Oxygen Dissolved recording. In each place, the animals were preserved in ethanol to posterior lab identification. Also, in each

**Figure 2.** Location of sampling sites around the three main slopes Gulf of Mexico, Caribbean Sea and Pacific Ocean.

with connection with the sea in the Amatique Bay [8].

**3. Materials and methods**

172 Biological Resources of Water

Guatemala has three main basins and several economical decapod species associated to these. The first basin analyzed was Caribbean where it was possible to find the following species *Macrobrachium carcinus* (**Figure 3A**), *Macrobrachium acanthurus* (**Figure 3B**), *Macrobrachium olfersii*, *Macrobrachium hobbsi*, *Macrobrachium heterochirus*, and one introduced species *Macrobrachium rosenbergii*; In general, all these species have a good acceptation in the market and in some cases their acceptation had reached high levels, for example *Macrobrachium carcinus* ("La pigua" in Spanish) in the Departments of Quiche, Alta Verapaz, Izabal, and Petén, the populations recently shown an important decrease in the fisheries, due to the over exploitation, pollution of rivers and reservoirs, and therefore, the barriers as dams in rivers that limited their migrations. In contrast, the exotic species *M. rosenbergii* is more frequently in the market and fisheries at least in the harbor fishery of Río Dulce, just now is evaluated if this last species have an impact on native species in several rivers of region. Also, in this region, there are several populations that have an abbreviated larval development and recently was described *Macrobrachium cemai* (**Figure 3C**), that is, used as food by the autochthonous community of Qek'chi in Cerro San Gil, Puerto Barrios, and Izabal. Therefore, there are another small decapods that lack economical value as *Palaemon pandaliformis*, *Palaemonetes octaviae*, and some atyids as *Atya scabra* and *Potimirim glabra* (**Figure 3D**).

In this basin, the crayfish species of *Procambarus* spp. (**Figure 3E**) was recorder and in some rivers there are freshwater crabs of family Trichodactylidae (**Figure 3F**) and Pseudothelphusidae (**Figure 3G**) and the local populations especially the indigenous communities as Qek' chi used by self-consumption and these species are hard to be found in the markets and fisheries, but the families use the children to search these species and by this way, they contribute with food to family.

The second basin is the Gulf of Mexico, the rivers and aquatic reservoirs drainage on the Usumacinta River and the main species are *Macrobrachium carcinus*, *Macrobrachium acanthurus,* and *Macrobrachium heterochirus*, but in this case due to few important markets to sale these products in general are to self-consumption. On this basin, we have recorded two populations with abbreviated larval development but in general few people know their existence and only indigenous populations used this biological resources together crayfish (*Procambarus* spp.) and freshwater crabs of family of Pseudothelphusidae.

In contrast on the Pacific slope in Guatemala, the biological aquatic resources are more diverse in small areas because the mountain chain is a barrier to limit their distribution. But in this area, the species of freshwater prawns are *Macrobrachium tenellum*, *Macrobrachium americanum*, *Macrobrachium occidentale*, and *Macrobrachium digueti,* all these with high commercial value and are easy found in the markets or the people just sale in their houses. The water pollution on rivers or dams are sometimes especially those sites close to cities where few control of waste water exists, the data of oxygen registered was lower in these sites, and the animals were absent, in contrast with those sites so far from human effects. The *Macrobrachium* species are a good indicator of the water quality because there are species as *M. heterochirus* where the oxygen requirements are higher in comparison with another species.

**Figure 3.** Freshwater decapods species in Guatemala. (A) *Macrobrachium carcinus*; (B) *Macrobrachium acanthurus*; (C) *Macrobrachium cemai*; (D) *Potimirim glabra*; (E) *Procambarus* spp.; (F) *Trichodactylidae*; (G) *Pseudothelphusidae*; (H) *Macrobrachium rosenbergii*.
