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The population of the freshwater prawn Macrobrachium tenellum (Smith, 1871) in four sites in the lower part of the coastal plain of the Ameca River, Mexico is analyzed before drastic anthropogenic modifications of the riverbed occurred. Of the 7,100 individuals of M. tenellum collected between February 2015 and January 2016, 45.7% of which were females (3,250), 4.3% ovigerous females (309), 39.3% males (2,79), and 10.6% undifferentiated (750). Males were significantly larger and heavier than females. In general, the largest individuals were collected at the most distant sites from the coastline (Colomo and San Juan), whereas the smallest ones were captured near the river mouth. The sex ratio (males:females 1:1.3) deviated from the expected 1:1. The length-weight relationship of females, males, and the population in general indicated a negative allometric growth for all three groups. The results of our research may serve as a reference point for future investigations assessing the impact of anthropogenic changes on M. tenellum populations. [ABSTRACT FROM AUTHOR]

Objective: Analyze the projects on aquatic species financed by CONAHCYT through the information provided by the Transparency Units (TU) of the public research centers (PRC) CIBNOR, CICESE and CIAD. Design/Methodology/Approach: The information was requested from the TUs of the centers through the official email of the TUs. The TUs sent the information, and it was organized in spreadsheets for later analysis. For the analysis, only the projects financed by CONAHCYT were considered and the following were selected: the year the project began, the technical manager, the species or species that were the main object of the project, and the amount approved. Results: The projects financed in the timeline established by each center are shown, as well as the amounts approved, the responsible researchers and the species addressed. Native species are the ones that have obtained the most financed projects, although part of the budget has been applied to invasive alien species. The social incidence is perceptible in some of the financed projects, although it has been a characteristic that has been fairly attended. Study limitations/Implications: The research has been limited to the information provided by the TUs of PRCs. If more information exists, it is not available through this route. Findings/Conclusions: The three PRCs propose projects that are mostly on native aquatic species. There has been a decrease in the number of projects funded. The social incidence is barely perceptible in the projects proposed and financed by CONAHCYT. [ABSTRACT FROM AUTHOR]

We analyzed the occurrence of morphotypes in the males of Macrobrachium tenellum (Smith, 1871), a species of potential use in farming, using biometric data and multivariate statistical analysis. Specimens were collected in the Ameca River, Mexico and grown for four months in two rectangular concrete ponds 50 m2 at an initial density of 10 individuals m–2. A biometric analysis was done on all male specimens, identified by the presence of the appendix masculina on the second pair of pleopods. We measured eight dimensions in each of the measured male specimens. Color and spination of the right second cheliped were also determined. We performed a statistical analysis of the data using multivariate analysis, which resulted in the identification of five morphotypes: dark-brown claw (DBrC), brown claw (BrC), cinnamon claw (CC), translucent claw (TC), and small male (SM). The mean of groups of almost all variables showed statistically significant differences except for the ratio Lcl:Lpo. There was no significant difference between groups BrC and DBrC, and spine angles were not significant between groups CC versus TC and BrC. A detailed description of the main macroscopic characteristics that differed between morphotypes is provided, which will allow their identification in future work. Our results will also help in studying social interactions between the male morphotypes. [ABSTRACT FROM AUTHOR]

Macrobrachium tenellum and M. americanum are common freshwater prawns from the Americas' tropical and subtropical Pacific continental side. They have different biological attributes and are currently threatened by human impact on their ecosystems. Both species provide different quality products for human consumption and are intensively exploited without proper management. This study analyzes, discusses, and compares the available information for both species and their current status as a live resource. [ABSTRACT FROM AUTHOR]

We analyzed the reproductive cycle of females of the palaemonid shrimp Macrobrachium tenellum (Smith, 1871) collected in the Ameca River, between the Jalisco and Nayarit states, Mexico. We studied the seasonal occurrence of ovigerous females during the year, their relationship with abiotic factors, and the size of the first sexual maturity. The study included 7,100 specimens of M. tenellum , of which 2,791 (39.3%) were males, 3,559 (50.1%) females, and 750 undifferentiated (10.6%). The sex ratio of the total (male-female) population differed significantly from the expected 1:1 with more females. A total of 309 females carried eggs (8.7% of all collected females). Ovigerous females, which were collected in three of the four sampling sites, were found almost year-round (with the exception of March and December), and their number showed a significant positive correlation with water temperature and rainfall. The size of first maturity (TL 50% ) for all collected females was 55.7 mm total length (TL), ranging from 64.3 mm TL to 42.7 mm TL. The results revealed that the population of M. tenellum in the Ameca River has a continuous reproductive period associated with the rainy season and increasing water temperature. [ABSTRACT FROM AUTHOR]

Dormitator latifrons is an amphidromous fish species distributed on the Pacific coastal region from California to Peru. It has a high potential to be cultured in Mexico. However, there is very little information about its biology, physiology and culture. This research study is a contribution to the hematology and blood chemistry of this native species. Results show hematocrit values of 28%, erythrocytes 2.075x106 mm³, leukocytes 35.035x10³ mm³, mean corpuscular volume 161.547 fL, NBT 0.39, glucose 51.467 mg dL-1, protein 3.936 g dL-1, albumin 1.906 g dL-1, globulin 2.391 g dL-1 and albumin/globulin ratio 0.686. [ABSTRACT FROM AUTHOR]

The native fish Dormitator latifrons, also known as chame, popoyote, puyeque and Pacific fat sleeper, grows in brackish environments in estuaries of the American Pacific coast, from Baja California (Mexico) to Perú. It is consumed regionally, and its characteristics under culture conditions are currently being evaluated. This study compared the proximate composition and fatty acid profile of wild and cultured specimens of D. latifrons to determine the effect of feeding them a commercial diet for tilapia under culture conditions. The protein content of the muscle of wild fish was higher than that of cultured fish, but the total lipid content was lower. The levels of fatty acids C18:1n9 and C18:2n6 were significantly higher (P < 0.05) in cultured fish, while the levels of C20:5n3 (EPA) and C22:6n3 (DHA) were significantly higher (P < 0.05) in wild fish. The n3/n6 ratio was higher in wild fish. These results show that D. latifrons is a species that can be readily cultured and that quickly gets used to formula feed. However, given the fatty acid composition of this species, it is necessary to control the quality of oil in the diet. [ABSTRACT FROM AUTHOR]

Growth and moulting cycle of the crab, Callinectes arcuatus were studied. Specimens were divided into four experimental groups, depending on size. A group of eyestalk-ablated crabs was also included. The smallest crabs had the largest increase in size on a percentage basis. The average growth of the crabs after moulting, as well as the soft crab condition, are reported and discussed. [ABSTRACT FROM AUTHOR]

In order to provide information on the current knowledge about the native fish Dormitator latifrons and identify the gaps that must be filled to achieve correct resource management, a scientometric study was carried out using different scientific databases. A total of 103 publications were registered between the years 1972 and 2021. Results indicate that the species has been addressed since 2001 with less than one publication per year, with 2008 being the year with the highest number of publications (10). The main topics addressed were ecology, physiology, and parasitology of fish. The available knowledge generated about the species is concentrated in 68 journals, with Mexico as the most productive country, followed by USA and Ecuador, and the most productive research centers about this fish were Mexico's Instituto Politécnico Nacional and Universidad de Guadalajara. A total of 285 authors were detected contributing knowledge to the species, with Violante-González in the top with ten publications. The co-authorship co-occurrence maps suggest there is no solid collaborative relationship between the scientific community and that the information generated is insufficient for conserving and exploiting this fish. It is essential to increase the study of thematic areas that allow their comprehensive management in the medium term; topics like reproduction in captivity, aquaculture, and nutrition must be addressed in the future to assure a sustainable use of this resource. [ABSTRACT FROM AUTHOR]

The freshwater prawn Macrobrachium acanthurus represents a valuable resource for fishermen's communities in Mexico, although the information of its culture conditions and nutrition is still scarce. Prebiotics are defined as non-digestible components that are metabolized by specific health-promoting bacteria in the host's digestive system, improving the health status and growth performance of cultured aquatic organisms. Fructooligosaccharides (FOS) and mannan oligosaccharides (MOS) are among the most used prebiotics in aquaculture. The present work aimed to determine the effects of dietary FOS and MOS in the growth performance, immune responses, and sexual maturity of juvenile freshwater prawn Macrobrachium acanthurus. Juveniles (0.06 ± 0.001 g) were fed with diets supplemented with a 3 g kg-1 diet of commercial FOS and MOS for 80 days. At the end of the feeding trial, the following indices were calculated: weight gain, specific growth rate, and feed conversion efficiency, as well as superoxide dismutase and lysozyme activities in hepatopancreas tissue. The growth performance, survival, juveniles' protein contents did no show significant differences among the groups. No differences were detected in superoxide dismutase and lysozyme activities among experimental groups. Around day 60 of the feeding trial, the females fed with the prebiotics maturated, and by the end of the trial, several of them were carrying eggs. It seems that prebiotics might have a role in sexual maturation, but further research is necessary to establish if prebiotics influences the early maturation of M. acanthurus. [ABSTRACT FROM AUTHOR]

The objective of this work was to assess the acceptance of live and inert food by Macrobrachium tenellum during the early larval stages. The larvae were obtained by collecting wild ovigerous females in the Ameca River in the State of Jalisco, Mexico. Eight treatments (diets) were used to feed the larvae: D1, control (fasting); D2, micro-pulverized food (Purina®); D3, living, newly hatched nauplii of Artemia franciscana (INVE®, Salt Lake City, Utah, USA); D4, commercial paste containing microalgae (Instant Algae Rotifer Diet®); D5, water extracted from a biofloc system; D6, cooked egg yolk; D7, newly hatched and frozen nauplii of A. franciscana (INVE®, Salt Lake City, Utah, USA); D8, nutritional supplement for shrimp larvae (Epifeed LH1®). Treatments D2, D5, D6 and D8 showed traces of food in the digestive system. The larvae did not consume D3 and D7 treatments. The diets that had more acceptance were micro-pulverized food, a nutritional supplement for shrimp larvae Epifeed® LH1, cooked egg yolk, and biofloc water. [ABSTRACT FROM AUTHOR]