The Macrobrachium genus in Mexico is represented by two big groups: the first one, where the larval stages are extended, and the second one, has an abbreviated larval development. There are three main slopes in Mexico or exorheic basins and several endorheic basins such as lakes and inner lagoons. The species with extended larval stage are M. carcinus, M. heterochirus, M. acanthurus, M. olfersii, M. hobbsi, and M. faustinum in the Atlantic and Caribbean slope, while in the Pacific slope, these species are M. americanum, M. occidentale, M. digueti, M. michoacanus, M. acanthochirus, and M. tenellum. These species have important fishery activities on different basins because they live from oasis in desert to main rivers in the bigger basins. However, there are some rivers that have an extended region on their upstream such as Usumacinta, Grijalva, Papaloapan, and Coatzacoalcos basins that in general are considered as hydrological regions. Just in these extended regions, there are more caves in freshwater, springs, and primary or secondary streams, which are covered by short area rivers, and in these places, there are the following species: M. totonacum, M. tuxtlaense, M. oaxacae, M. cosolapaense, M. oaxacae, M. jacatepecense, M. mazatecum, and M. vicconi, while in the cave are M. villalobosi, M. acherontium, and M. sbordonii. However, for these species, the uses are more for the local groups mainly indigenous cultures such as Mayan, Lacandon, Zapotecs and Mixtecs, and others, and their commercial use is only in the local region depending on where these species are distributed.
Part of the book: River Basin Management
Guatemala is a mega diversity country because it has several ecosystems and the physiography has a high diversity. However, the local population uses this biodiversity as a natural resource of food mainly. The country had three main drainage slopes for their rivers and aquatic reservoirs with several basins (the Gulf of Mexico, the Caribbean Sea, and the Pacific Sea). In these slopes, crayfish, freshwater prawns, and crabs compose the aquatic biological resources. Several fieldtrips were performed around these slopes in order to identify the species which were used as natural aquatic resources and verify if the diversity supports the food needs of the local population. Our findings were that the country has at least four crayfish species of genus Procambarus spp., those living in the high and middle altitude areas. Five freshwater prawn species with abbreviated larval development of genus Macrobrachium, that is, Macrobrachium cemai were also found. The bigger species of Macrobrachium was also identified on the three slopes as Macrobrachium americanum, Macrobrachium tenellum, Macrobrachium occidentale, and Macrobrachium digueti on the Pacific slope, while on the Gulf of Mexico and the Caribbean Sea, Macrobrachium carcinus, Macrobrachium acanthurus, Macrobrachium heterochirus, Macrobrachium olfersii, and Macrobrachium hobbsi were recorded, and therefore, the nonnative species Macrobrachium rosenbergii; with respect to other shrimps, Palaemon pandaliformis, Palaemonetes octaviae, and atyids as Atya scabra and Potimirim glabra were found. According to the freshwater crabs, the Pseudothelphusidae family is the best to represent in comparison with Trichodactylidae where only one population was recorded. Also, we register the uses of these species around the main markets in the country and we found two main ways: the first one is for the bigger species of freshwater prawns and crabs that are offered very expensive in kilogram and are almost offered in restaurants as exclusive dishes. The second one is more for the local consumption, and many families of fishery species that include crayfishes, freshwater prawns with abbreviated larval development, and smaller crabs, and so on, are sometimes found in the markets, with the prices being cheaper and can be bought only by the local people. Our findings show that Guatemala has an enormous potential in the crustaceans decapods for use as natural aquatic resources as protein sources at low cost, especially for the families with low economical level.
Part of the book: Biological Resources of Water
Morphological relief analysis allows the identification of geomorphological forms and cartographic-environmental studies make extensive use of the medium (1:50,000) and large scale (1:250,000), where the topographical contrast is evident. However, at a detailed scale (<1:20,000) and for territories where the contrast of relief does not exceed 10 m in height, the morphological analyses must be adapted accordingly, because they contribute information to altimetry studies and to the topographic configuration of units. Thus, through visual interpretation and manipulation of high-resolution topographical LiDAR data from Cozumel Island, a relief analysis is presented at a detailed scale for the purpose of recognizing the geomorphological units of karst origin, using altimetry and slope cartography, digital models of elevation, and shading that permits the identification of 109 new exokarstic doline and uvala formations.
Part of the book: Trends in Geomatics
The freshwater prawns of genus Macrobrachium with abbreviated larval development have been reported from a diversity of freshwater habitats (caves, springs and primary streams from so-long basins). Here we analysed 360 sites around the Mesoamerican region (Mexico, Guatemala and Belize). At each site, we measured temperature, salinity oxygen dissolved, pH, altitude and water flow velocity values. We documented the riparian vegetation and occurrence and abundance of Macrobrachium populations. All these values were analysed by multi-dimensional scaling and principal components analysis in order to identify key features of the environmental data that determine the habitat types and habitat diversity. The results show that there are Macrobrachium populations in 70 sites inhabiting two main habitats: Lotic and Lentic; and each one have fours subhabitat types. All are defined by altitude range and water velocity that involve the temperature and oxygen variables. In some specific areas, the karstic values on salinity and pH defined some groups. Within the lentic habitats, we identified the following subhabitats: (1) temperate streams, (2) neutral streams, (3) high dissolved oxygen, (4) multifactorial; and for lotic habitats, we identified: (5) water high carbonate, (6) moderate dissolved oxygen, (7) low dissolved oxygen, and (8) high altitude streams. All these subhabitats are located on the drainage basin to the Atlantic Sea, including places from 50 to 850 meters above sea levels and have specifically ranges from temperature, water velocity, pH and salinity for some cases. Also, the geological analysis from the basins where the Macrobrachium inhabit is located showed that the geological faults align with these habitat subdivisions. In this chapter, we discuss the environmental heterogeneity, morphological plasticity and their relationship to physiographic regions across the species ranges.
Part of the book: Crustacea