Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The effective formalin therapeutic concentration (ETC) against Cichlidogyrus spp. infecting tilapia was obtained. Also, the stress and immune response to formalin baths in O. niloticus were achieved. A static bioassay with four concentrations (0.5, 1.0, 1.5, 2.0 mL L-1) of formaldehyde (37% dilution) in water, and one control without this substance was performed. Results evidenced that 1.5 mL L-1 of formalin for 40 min was the ETC to eradicate monogeneans without manifesting macroscopic damage to fishes. Thirty tilapias underexposure with ETC of formalin (FORM Group) were evaluated for stress, utilizing cortisol and glucose determination, and immune response (lysozyme activity and differential counting of organic defense cells). Other 30 tilapias without cichlidogyriasis and with no exposure to formalin were the Control Group. Evaluation times were: three hour pre-treatment (T0), and one hour, three days and three months post-treatment (T1, T2, and T3, respectively). A peak of cortisol (~326 ng mL-1) was observed in tilapias of FORM Group at T1 with significant differences with the control group (P ˂ 0.05). Similarly, glucose concentration reached significant values (~119 mg dL-1) at one hour after the conclusion of treatment (P ˂ 0.05). Those values returned to the basal limit at the last time of the study. The lysozyme activity and white blood cells in differential counting showed no significant differences in the same conditions (P > 0.05). Results confirmed total control of cichlidogyriasis with the ETC of formalin obtained and an evident resistance of tilapia to treatment as stabilization of its physiological stress response was achieved.

In general, aquaculture wastes from traditional aquatic organism cultivation rapidly deteriorate the water quality of the surrounding ecosystems, endangering animals living in the area. The integrated multi-trophic aquaculture (IMTA) system is a bio-mitigation strategy to alleviate the adverse impacts caused by aquafarming pollutants on the environment and aquatic species. This study provides an overview of the IMTA system, explains the interactive processes among the different trophic levels, summarizes the major practices being followed around the temperate coastal waters with a field case study in Japan, and discusses the assessment of IMTA bio-mitigation efficiency through experimental greatly dependent on the customs and market values in the local IMTA practice. Bio-mitigation efficiency acquired in a land-based experiment exhibits its limitation in approach and conducts a comprehensive analysis on the possibility of applying numerical models to evaluate IMTA effectiveness. The selection of a suitable candidate organism is estimating that in the same or different culture conditions with various biomasses of extractive species. However, in open water experiments, it is difficult to evaluate the bio-mitigation effect of extractive species because the initial biomass ratio (IBR) of the extractive to target species is too small. Alternatively, the possibility of applying existing numerical models to assess IMTA is relatively low. In conclusion, an optimally designed large-scale IMTA experiment is required, in which the IBR of the extractive to target species is adequately considered, and a full-scale IMTA model should be further improved with a database of individual-based submodels for IMTA candidate organisms.

Survival was investigated in Penaeus vannamei fed with powdered plants (PP: garlic, echinacea, ginger, and basil) and challenged with white spot syndrome virus (WSSV) and Vibrio parahaemolyticus by ingestion and immersion, respectively. PP was added to commercial feed at a concentration of 1, 2 and 4 g kg-1. The infection with both pathogens was made at the same time. Shrimp fed with PP (4 g kg feed-1) at different frequencies showed higher survival (96.7%) as compared to the positive control group not fed with PP (6.7%). WSSV prevalence in live and dead shrimp was similar in all treatments challenged with both pathogens varying from 33.3 to 55%. PP protects shrimp against WSSV and V. parahaemolyticus. Therefore, further research about the effect of PP is necessary for commercial shrimp farms.

Aquaculture is a fast growth activity in the world, but needs continued improvement in the conduct of management. In this sense, we highlight the Amazon basin, which has important species of fish as Colossoma macropomum with incipient production to meet the demand of the consumer market. Since that problem identified, we applied a Markovian decision process aiming to develop an optimization system to maximize the yield of the C. macropomum aquaculture. Were used mathematical algorithms were simulated with layout scenarios with 5 and 10 ponds, representing different size aquaculture farms. The transition between the growth phases was considered a stochastic process to satisfy the Markov property as per a sequential queuing through growth phases. The main goal was to define the target weight mix for the market and their optimal levels that optimize the production. The highest profitabilities were US$9,608 and 15,385 for 5 and 10 ponds layout scenarios, respectively, with a target weight mix harvest of 0.5 kg and 1 kg; 0.5 kg, 1 kg and 2 kg, respectively. The results showed the number of months for discounted the fixed monthly cost, about the cycle time that lasted of 5, 7 and 11 months, as well as the optimization was defined with the time at the fingerlings stage fixed for 50 days, possible to be improved.

This study aimed to evaluate the effect of manipulating hours of light and water temperature in some important reproductive parameters for Astyanax altiparanae fish farming during winter. The experiment was conducted from July 3rd to August 28th 2013 (57 days), and two groups of 32 couples of fish (G1 and G2) were used. On G1, hours of light and water temperature were not controlled; on G2, otherwise, these variables were manipulated in order to achieve similar conditions to those observed in spring. Every 14 days, eight couples of each group were hormonally induced with carp pituitary gland extract, and eggs were collected after semi-natural spawning. The percentage of females from G2 that spawned was higher than G1 (81.25 vs. 9.38%), the same trend was observed for a number of eggs produced per female (G1: 2,976.57 ± 1,085.71; G2: 8,471.14 ± 860.08). The G2 ovaries presented a higher incidence of primary growth oocytes and post-ovulatory follicles whereas G1 ovaries had more atretic follicles. Economic analysis showed that operational profit from eggs and larvae production on G2 was higher than on G1, as well as the gross margin. In conclusion, the results showed that environmental manipulation might improve reproduction management practices extending eggs and larvae production during the natural non-breeding season. Further studies are necessary to determine more appropriate facilities to be used by farmers in large scale, as well as management protocols to ensure the survival of post-larvae.

As all coastal environments, the Patos Lagoon Estuary (PLE) is an important habitat for the early stages of the life cycle of many marine organisms. Little is known, however, about how larvae respond to the estuarine dynamics because this study is complex. An actual way to investigate fish eggs and larvae dispersion is to use "Individual-Based Models" (IBM). Here, an IBM is used to study the wind influence on the transport of fish eggs and larvae of Micropogonias furnieri in the PLE. Circulation patterns were generated and extracted from TELEMAC-3D hydrodynamic model and simulated in an IBM. Results demonstrated that the transport of M. furnieri larvae to the PLE is maximized during periods of southerly winds. During northerly winds, on the other hand, larvae are advected off the estuary. This study revealed that the wind-driven estuarine dynamics mainly modulate the transport variability of eggs and larvae and it could have consequences for M. furnieri’s recruitment.

During two sampling trips carried out over the continental platform of Gulf of Tehuantepec, a total of 101 Lolliguncula panamensis Berry, 1911 were caught. Thirty mature specimens (19 females and 11 males) were found to have unusually short arms. Dorsal mantle length, arm's length, and body weight were measured from the fresh specimens. Evidence of regeneration was observed at different points along arms; these may have been the result of partial autonomies. In the injured arms, the surface of the arm's tip was wholly covered with skin. Fracture planes were found in our histological sections; the autotomized arms exhibited constricted muscle fibers in the longitudinal sections indicative of wound closing. The arms of the specimens observed were very similar to the regenerating arms of other squids. This study represents the first to report arms regeneration and hectocotylus in this squid wild-caught. These results suggest that Lolliguncula panamensis exhibit partial autotomy, and the ability to regenerate the arms. Additionally, each of the eight arms can do so, presumably during defensive interaction or mating.

The pustulose ark, Anadara tuberculosa, is considered as an emblematic species of the east Pacific mangrove ecosystem. The decline of its populations is of increasing preoccupation, in particular in Peru. The use of hatchery-produced larvae for stock enhancement or aquaculture is attractive but raises strong criticisms from an ecological point of view, as it could conduce to loss of genetic diversity in wild populations and favor the disease spreading from hatcheries to the environment. In this works, spat production through traditional aquaculture/biotechnology technologies was associated with pathogen molecular diagnostics and with genetic diversity estimation to produce specific pathogen-free (SPF) larvae from genetically characterized populations. All PCR and nested-PCR diagnostics of common bivalve pathogens, such as Bonamia, Martelia, Perkinsus and OsHV1, led to negative results for healthy or moribund adults and spat samples. Microbiological and molecular analyses realized during mortalities led to identifying a pathogenic Pseudomonas strain present on culture tank walls, in moribund spats and adults´ blood. Population genetic variation was assessed by mitochondrial COI gene sequences which showed 36.7% haplotype diversity. This study with hatchery production, pathology and genetic components for an overexploited native bivalve represents an original model for successful mollusk stock enhancement or/and innovative aquaculture programs.

This work aimed to determine the optimum stocking density of Penaeus vannamei, cultured in a photo-heterotrophic intensive circular system inlined grow-out ponds with minimal water replacement. Five intensive density levels (100, 300, 500, 700 and 900 ind m-3) were considered. The water quality measured for the 98 days grow-out period was within the adequate range for P. vannamei. TAN, nitrate and total phosphorus water quality were significantly higher (P < 0.05) at the higher density. Growth rates and survival decreased as density increased after 300 org m-3. Based on the results of this study, it was found that shrimp grows adequately in high biomass density (99.21 kg tank-1) and density of 500 ind m-3 in an intensive photo-heterotrophic system with a maximum harvest weight of 10 g.

Shrimp production has been affected by disease outbreaks caused by Vibrio sp. bacteria. Using a polyculture system has been proposed as preventive management, but until now, the mode of action by which the organisms in polyculture obtain some benefits was unknown. Some studies indicate that these benefits are related to the immune system in the skin mucus. The present study aimed to determine the antibacterial potential of skin mucus in two tilapia varieties, Oreochromis sp. (marine adapted) and O. niloticus (freshwater), against Vibrio bacteria that affect the shrimp Penaeus vannamei. Skin mucus extracts were obtained from both varieties of tilapia during spring and winter. The extracts were: acidic, aqueous and two organics. In total, 16 extracts were obtained. During the winter season, no antibacterial activity was detected; however, in the spring, the acidic extract from the marine-adapted tilapia inhibited V. parahaemolyticus. Additionally, V. harveyi was inhibited by the acidic and organic extracts from both varieties. The aim of this study was confirmed: tilapia skin mucus has antibacterial activity against Vibrio bacteria, which depends on the tilapia variety, bacterial strain, season and the concentration of colony forming units. SDS-PAGE revealed a protease of 96 kD present in all extracts, even in those without antibacterial activity.