Salinity is an important factor influencing growth and survival of aquatic organisms such as Artemia, a valuable aquaculture species. This study evaluated the effects of salinity on A. franciscana populations from different water bodies in Mexico?s Pacific Coast. With this purpose, five autochthonous bisexual Artemia populations were tested to assess their survival and growth values against salinities of 40, 60, 80, 100 and 120g/l, under laboratory conditions (25±2°C; pH 8-10; constant light and aeration). The organisms were fed with 100mL of rice bran and 2L of Tetraselmis suecica (500 000cel/ml). The culture experiments were made in 200L plastic tanks, and survival and growth final values were obtained after 21 culture days. Survival and growth curves were determined by a regression analysis (R2). The significant differences between salinities were determined by ANOVA test (p < 0.05). The best survival and growth rates were found at salinities of 100-120g/l. When the Mexican Artemia populations were cultivated at 40g/l of salinity, 100% mortality was observed in the juvenile stage. This study determined that survival and growth values of A. franciscana populations increased with salinity. The five A. franciscana populations presented significant differences in their survival rate under various salinity regimes. The studied populations experienced high mortality at salinities under 60g/l and over 200g/l, and especially during the metanauplius stage. The present study confirms that growth rates in Mexican A. franciscana populations from Pacific Coast habitats are not inversely proportional to salinity. These A. franciscana populations should be cultured at 100-120g/l of salinity to obtain better survival and growth rates. This data is useful to improve culture systems in aquaculture biomass production systems. Rev. Biol. Trop. 59 (1): 199-206. Epub 2011 March 01.

A preliminary biometric and ecologic database for the brine shrimp Artemia from Mexico and Chile is presented. The area abounds in small and seasonal ponds and large inland lakes, the latter mainly located in Mexico, although relatively large and isolated lakes are found in complex hydrological settings in pre-high plateau areas of Chile. This paper summarizes research efforts aimed at the localization, characterization, and evaluation of the aquaculture potential of Artemia populations in Mexico and Chile, which exhibit great habitat diversity (ponds, salterns, coastal lagoons, sea arms, coastal and inland lakes), contrasting weather conditions and different levels of isolation and human intervention. This study covered locations between 29° north latitude (Baja California, Mexico) to 50° south latitude (Puerto Natales, Chile). Biological characteristics considered are species name, reproductive mode, cyst diameter, chorion thickness, and nauplius length, whereas ecological data include pond size, pH, salinity, temperature, and water ionic composition. Artemia franciscana is the only species found in Mexico, it exists together with A. persimilis in Chile, though separated geographically. Ecological differences in habitat exist between both regions but also within countries, a pattern particularly clear with regard to water composition. Surprisingly, a Mexican (Cuatro Ciénegas, A. franciscana) and a Chilean location (Torres del Paine, A. persimilis) share habitat characteristics, at least for the period when data were collected. The discriminat analysis for cyst diameter and nauplius length shows that Artemia from only one location match in cyst diameter with those from San Francisco Bay (SFB) (Point Lobos), and one (Marquez) is far apart from SFB and all the others. The Chilean locations (Pampilla, Cejar, Cahuil, Llamara, Yape) share cyst diameter, but tend to differ from SFB. The remaining Mexican locations (Juchitan, Ohuira, Yavaros) are well separated from all the others. With regard to nauplii length, populations tend to distribute in a relatively random manner, being Marquez the location differing the most in cyst diameter from SFB. This database will contribute to the knowledge of radiation centers and serves as a baseline for further biogeographic studies, population characterization, management, and monitoring of Artemia biodiversity. Likewise, the impact of colonization and translocations for aquaculture purposes can be better assessed with a baseline for reference. Mexico and Chile exemplify the need to increase and further integrate regional information to tackle fundamental problems underlying practical utilization of Artemia.

Tilapia (Oreochromis niloticus) is one of the most important species in aquaculture, so the optimization of its culture by using sustainable strategies is fundamental. The aim of this study was to evaluate the effects of incorporating natural pigments (carrot and beetroot meal) as carbon sources in a biofloc system on the growth, immune response, and oxidative stress of O. niloticus. The experiment comprised four treatments: clear water as control (CT), biofloc with molasses (TBM), biofloc with carrot meal (TBC), and biofloc with beetroot meal (TBB). Results showed that biofloc helped to maintain optimal water quality and high survival rates, but specifically, TBC treatment achieved the highest growth rates and feed conversion ratio, along with elevated leukocyte counts, indicating improved health and immunity. Gene expression analysis revealed enhanced antioxidant activity (sod, gpx) and modulated immune responses (tnf-α, il-1β), particularly under thermal stress. Carrot meal emerged as an effective carbon source in biofloc systems, promoting growth, immune resilience, and oxidative stress resistance in tilapia, while beetroot meal improved pigmentation. These findings highlight the potential of natural pigments to enhance aquaculture sustainability and productivity.