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This work investigates the effect of adding different sources of organic carbon in biofloc systems on water quality, microorganisms' density and zootechnical performance of juvenile Mugil liza raised in the biofloc system indoors over 45 days. Fish (±7.99 g) were stored at a density of 15 fish per tank and fed a commercial feed of 42% protein. The study was arranged in three treatments according to the carbon source: dextrose—DE, liquid molasses—LM and rice bran—RB, and one control with no bioflocs (clear water—CW), all in triplicate. The treatments had no influence (p > 0.05) on the performance parameters of the animals, survival (over 90%), as well on the productivity (between 0.35 and 0.6 kg/m3). Overall mean of total ammonia was lower (p < 0.05) in the biofloc systems than in clear water (CW). Nitrite average was lower (p < 0.05) in the bioflocs fertilized with LM and RB carbon sources, having a concentration of 1.3 ± 1.9 mg/L and 0.6 ± 0.6 mg/L respectively. RB also had the smallest range in nitrite levels throughout the study, from 0.04 to 2.5 mg/L. The LM and RB provided a greater (p < 0.05) abundance of total adhered and coccus bacteria. Water consumption was higher (p < 0.05) in the CW (1.87 m3 per tank) compared with the biofloc treatments (0.41 and 0.44 m3 per tank). Liquid molasses contributed to maintaining water quality compared with clear water, providing savings of around 80% of water. [ABSTRACT FROM AUTHOR]

Aquaculture has many occupational hazards, including those that are physical, chemical, biological, ergonomic, and mechanical. The risks in aquaculture are inherent, as this activity requires particular practices. The objective of the present study was to show the risks associated with the aquaculture sector and present a critical overview on the Brazilian public policies concerning aquaculture occupational health. Methods include online research involved web searches and electronic databases including Pubmed, Google Scholar, Scielo and government databases. We conducted a careful revision of Brazilian labor laws related to occupational health and safety, rural workers, and aquaculture. The results and conclusion support the idea that aquaculture requires specific and well-established industry programs and policies, especially in developing countries. Aquaculture still lacks scientific research, strategies, laws, and public policies to boost the sector with regard to occupational health and safety. The establishment of a safe workplace in aquaculture in developing countries remains a challenge for all involved in employer-employee relationships. [ABSTRACT FROM AUTHOR]

Weaning is a critical period for production of marine fish juveniles. The objective of this research was to evaluate the effect of co-feeding on survival, growth, and cost of production after the weaning of juveniles of Brazilian flounder Paralichthys orbignyanus. Juvenile flounder (32 days after hatching) were fed on HUFA enriched Artemia and subsequently three periods of co-feeding with dry diets (15, 20, and 25 days) were tested, a control group, where flounder were fed exclusively on Artemia was also followed until the end of the experiment. Juveniles fed on Artemia showed significantly higher (P<0.05) survival (82%), weight (480±157mg) and total length (35.5±5.0mm) than flounder weaned into dry diets, independent of the co-feeding period. Growth was similar (P>0.05) for juveniles fed on dry diets, but a higher survival rate was registered when the co-feeding period was longer. The results obtained demonstrate that flounder fed exclusively on Artemia have a better performance than those weaned into dry diets. However, unitary cost of production is reduced when juveniles are weaned 58 days after hatching. [ABSTRACT FROM AUTHOR]