Renewing Towards the Future

Evaluation of the algae Solieria filiformis (Rhodophyta, Solieriaceae), as a biofilter in an Aquaculture Recirculation System

In this study an evaluation of growth, efficiency of nutrient uptake (NH3, NO2 and NO3), and uptake kinetics was carried out in an experimental biofilter based on an economically important red algae such as Solieria filiformis; this experimental biofilter was included in an aquaculture recirculation system (ARS). The objective of this research was to solve the problem of excessive nutrient loading at the entrance of raw water to the RAS, which in such concentrations, the nutrients or also called secondary metabolites or excretion by microorganisms are detrimental to the welfare of the organisms in culture. These aquaculture recirculation systems are mechanisms used in the rearing of commercially important aquatic animals, such as mostly fish and crustaceans, however, it is possible to culture a wide variety of organisms. The main characteristic of these systems is the great advantage that they have in terms of water use for culture, the organisms that are in culture need water with high quality standards, since in most situations they are used for human consumption and to a lesser extent for research. In that sense, water recirculation gives them a better option, using filters and bio-filters as a mechanism to clean dirt and pathogens allowing their installation in smaller areas unlike conventional crops that use large amounts of water without a previous and subsequent water treatment, discarding the water to adjacent water bodies with high organic loads harmful to society and the ecosystem.


Crocodile population studies

In this study an evaluation of the Crocodylus moreletii and Crocodylus acutus populations was carried out in order to know their status in their natural habitat. Commonly, C. moreletti is known as the swamp crocodile and C. acutus as the American crocodile. The swamp crocodile has a total length of up to 3.5 m and is distributed along the Gulf of Mexico to the Yucatan Peninsula, Guatemala and Belize, while the American crocodile has a total length of up to 6.5 m and is distributed from the southeast of the United States to Central and South America, and in Mexico it extends along the Pacific coast and Quintana Roo. Both species share distribution in some areas and are in the category as subject to special protection in Mexico. The objective of the study was to determine the population status of both species according to their abundance, relative density, population structure by size class and sex ratio, distribution, and habitat quality. Population ecology is extremely important to know the status of both species and to design specific management and conservation programs.