Water quality and growth of juvenile specimens in giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879) cultures applied in recirculation and biofloc systems

Biofloc research commenced in the late 1970s, with the white shrimp Litopenaeus vannamei and the Nile tilapia Oreochromis niloticus the most commonly studied species. The present study evaluated M. rosenbergii cultures in recirculation and biofloc systems by comparing the water quality and productive performance of juveniles in both systems. The study was based on a simple randomized experimental design with a recirculation and biofloc treatment, each conducted in triplicate. The initial length and weight of the organisms was 1.04 cm and 0.31 g (recirculation) and 1 cm and 0.30 g (biofloc), respectively, while the bioassay, which lasted nine weeks, was undertaken in a salinity of 5 ppm with a natural photoperiod (12:12). The present study monitored basic variables corresponding to the water, survival, growth (in weight), and the composition of the plankton.The basic variables of the water (temperature, salinity, and pH) were kept within the recommended range for the culture. Of the plankton observed in the biofloc, nematodes, rotifers, cyanobacteria, ciliates, heliozoa, and dinoflagellates predominated. The organisms grown in the recirculation system reached 5.35 cm in length and 1.28 g in weight, while those grown in the biofloc reached 5.18 cm and 2 g, with significant differences in individual weight observed. Survival in the recirculation and biofloc systems was 73% and 60%, respectively, with significant differences observed. It is concluded that, although the survival rate was higher in the recirculation system, the weight of individual organisms was higher in the biofloc treatment

Analysis of sizes and state of ovarian maturity in yellowfin tuna (Thunnus albacares) captured in the Gulf of Mexico

The yellowfin tuna Thunnus albacares is the second most important fishery in Mexico, due to its production costs and commercial value”  The species is fished on both coast of the country, with the Pacific Ocean presenting productions lightly higher than that of the Gulf of Mexico where, in spite of the above statement, tuna catches have recently shown a downward trend. For this reason, analysis is required of the size and stage of ovarian maturity and it is necessary to determine whether capture size is the primary reason behind the decline in the yellowfin tuna fishery Three tuna fishing trips were conducted in the Gulf of Mexico in order to gather data pertaining to fork length (Lf) and gonads Histological sections were obtained from the latter for analysis and determination of maturity stage. The results showed that males were predominant (40%) among the individuals for which the sex could be differentiated in the catches of T. albacares. The Lf values in the catch, were between 75 and 162 cm. However, variations in this parameter were found between sexes. The relationship between length and weight showed that the males are larger than the females, however, the equationgiven by the parameters of a=0.9406 and b= 3.4504, demonstrated growth of positive allometric type in both sexes. There was progressive development in the state of ovarian maturity over the months of capture. Chromatin nuclear (CN) was the most frequent phase within primary ovarian development (November, February, March), stages were present, although these did not present a direct relationship to fork length

Population Analysis of The Snapper Lutjanus Griseus, Based on The Artisanal Fisheries of The Tamiahua Coast, Veracruz

Artisanal fishery in the Gulf of Mexico is mainly undertaken for subsistence and is, thus, of great socioeconomic importance, with Lutjanidae one of the most important families caught in the region. However, there is scarce fisheries knowledge in the Gulf of Mexico and, in light of pressure from the fishing community, research into the population dynamics of these species is of vital importance for the management or conservation of coastal resources. This study aims to contribute information for the analysis of the population of Lutjanus griseus (Linnaeus, 1758), a common species on the Tamiahua coast, in the state of Veracruz. Samples and biometric data (weight, sex, total length and maturity) were recorded by the fishing community on this coast. The monthly population structure was constructed using fish size. Data from 987 individuals, the size of which oscillated from 15 to 80 cm, were registered over the course of a year. The sex ratio was 1:1, while the maximum calculated age was 10 years. Von Bertalanffy and Gompertz growth models reported a maximum age and growth of L∞=182.46 K= 0.05 and to = -1.71. The best fit was achieved by means of the Gompertz model, as based on the Akaike criteria and the biological interpretation of the parameters. Reported data and the models used in this study suggest that the minimum catch size should be 40 cm and that the fishery should either cease activities in the months of the reproductive peak or that quotas should be among the fishing cooperatives on the coast of Tamiahua

HEMATOLOGICAL VALUES IN THE LEATHERBACK SEA TURTLE DERMOCHELYS CORIACEA FOUND AT BARRA DELA CRUZ BEACH, OAXACA, MÉXICO

In the months of December and January of the nesting 2013 season 2014 were copies of leatherback turtles (Dermochelys coriacea) on the beach bar de la Cruz, Oaxaca to determine the correlation between the biometric measures curved carapace length and values of hematological, between these and the curved carapace width and Hematological values and the State of deterioration of each female. Were punctures in breast cervical dorsal half of spawning, when females were completely immobile [1]; 8 females, four altered blood samples were obtained (presence of barnacles, fungi and barnacle) and four not altered. We found seven blood cells in all turtles, varying according to the alteration. In not altered turtles were 10 783 erythrocytes values; 2 043 heterophile; 6 576 monocytes; 5 802 basophils; 2 010 azurophilic; trombocito 9 090 and lymphocyte 1 148, while in the altered: 2 622 erythrocytes; 1 077 heterophile; 1 557 monocytes; basophil 3 080; 1 927 azurophilic; thrombocytes 309 5 and 1 773 lymphocyte. Through the analysis of linear correlation was determined that organisms which presented alterations had fewer blood cells, which had no physical changes were greater number of blood cells and there is no correlation between the curved carapace width and the number of blood cells