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Aquaculture is undoubtedly a critical sector for satisfying the needs of a growing human population and meeting the Sustainable Development Goals of Agenda 2030 [...]

The effects of the intensification on the performance of the Amazon River prawn hatchery carried out in a simple recirculation system were investigated. Newly hatched larvae were stocked in 120 L tanks at 80, 100, 120 and 140 larvae L−1 in a closed recirculating system. The experiment used a randomized block design with five replicates. An exponential equation was adjusted to express the relationship between the stocking density and productivity (postlarvae L−1). The development, larval quality, survival and postlarval (PL) dry weight did not significantly differ among the treatments (p > 0.05). When 80 larvae were stocked, the productivity (54 ± 11 PL L−1) was lower than those at higher densities (p < 0.05). Stocking 120 and 140 larvae L−1 resulted in higher productivities (75 ± 18 and 80 ± 17 PL L−1, respectively) with a lower use of Artemia nauplii to produce each postlarvae (~1200 Artemia nauplii PL−1). The maximum mean M. amazonicum postlarval production estimated by the exponential model was 93 PL L−1. This means that despite the increase in stocking density, productivity tends to stabilize. The results showed that M. amazonicum tolerates high intensification in recirculating hatchery systems based on a crushed shell bed biofilter, and the intensification optimizes Artemia use.

Over recent years, Macrobrachium amazonicum has become a popular species for shrimp farming due to their fast growth, high survival rates, and marketability. Several studies have focused on the development of new technology for the culture of this species, but many aspects of their nutrition and physiology remain unknown. Thus, the goal of the present study was to obtain transcripts of putative genes encoding digestive enzymes, based on a library of the cDNA from the hepatopancreas of M. amazonicum, sequenced in the Ion TorrentTM platform. We identified fragments of nine genes related to digestive enzymes, acting over proteins, carbohydrates and lipids. Endo and exoproteases were also recorded in the hepatopancreas, indicating adaptation to the digestion of protein-rich foods. Nonetheless, the enzymes involved in the carbohydrate metabolism formed the largest functional group in M. amazonicum, including enzymes related to the digestion of starch, chitin, and cellulose. These findings indicate that the species has a genetic apparatus of a well-adapted omnivorous animal. This information may provide important insights for the selection of ingredients for the formulation of a more appropriate diet to the enzymatic repertoire of M. amazonicum.

The present study evaluated the environmental sustainability of Nile tilapia net-cage farms of different sizes by applying a set of environmental sustainability indicators and exploring benchmarks combined with the indicators. One large-scale (LS), one medium-scale (MS), and two small-scale farms (SSI and SSII) placed in Southeastern Brazil were studied. Data from three batches were obtained from each farm during a production cycle, with durations ranging from 189 to 263 days, totaling twelve sample units for each variable. During fish production, samples of water, sediment, fish, feed, and greenhouse gases were collected and used to calculate the Environmental Sustainability Indicators (ESI). These indicators were grouped into five principles: the use of natural resources; efficiency in the use of resources; release of pollutants and unused by-products; pollutants accumulated on the bottom of the water body; conservation of genetic diversity and biodiversity. Each indicator was converted into a performance scale. Data of ESI obtained from each farm, and a literature review was used to develop a “standard” value, allowing the benchmarking of the environmental sustainability of the farms. The best environmentally sustainable index was obtained in the farm MS (87), followed by farm SSI (85), and the worst was farm SSII (73); farm LS achieved an index of 82. Farm SSI was positively influenced by the use of energy, nitrogen, phosphorus, and carbon, which was on average 17% lower than the other farms, and by the highest efficiency in the use of nitrogen and phosphorus (32.7% and 23.6%, respectively). Farm MS was positively influenced by the lowest phosphorus accumulation and organic matter (1 and 90 kg/t, respectively). Farm SSII was negatively influenced by the high levels of accumulated phosphorus and organic matter (10 and 723 kg/t, respectively). The results showed that environmental sustainability is independent of the farm size. Other factors, such as feed composition, management techniques, and water temperature, were more critical. The use of the benchmarking tool has shown to be a way to better use ESI to assess the sustainability of aquaculture in the absence of defined endpoints for each indicator. This tool provides a reference value for each environmental sustainability indicator, allowing improvements to reach desirable states.

Aquaculture in Brazil probably started in the 17th century, during the Dutch occupation of the northeastern region. Currently, this activity can be divided into five main sectors, defined by tradition and type of cultured organism: freshwater fish, marine shrimp, mollusks, freshwater prawns and frogs. Production in 2019 was estimated at 800,000 tonnes, representing a gross revenue of US$ 1 billion. Freshwater fish is predominantly produced, followed by marine shrimp. The main farmed species are Nile tilapia (Oreochromis niloticus), tambaqui (Colossoma macropomum) and the Pacific white leg shrimp (Litopenaeus vannamei). Other species have great local socio-economic importance. The bulk of production comes from small farms: more than 80 % have less than 2 ha. Brazil has more than 200 thousand freshwater fish farms, about 3000 marine shrimp farms, and about 100 aquaculture research institutions. A large domestic market is available for edible fish and shellfish, ornamentals, baitfish and hatchery-reared juveniles for biomitigation purposes. The challenge is to develop truly sustainable production systems to support a perennial industry. New technologies, including digital devices and simple disruptive innovations, can increase productivity and support the shift to a circular economy, bioeconomics and sustainability supported by science-based innovations and knowledge.

The Covid-19 pandemic has uncovered the foremost struggles of the twenty first century: social-economic inequality, global value chains, national security, and the environmental crisis. None of these seems novel, as many staged fiction dystopias have been predicting and warning mankind about the negative impacts of unsustainable consumption behaviors by displaying scenarios of exponential human population and economy growth. Several scientific tools for assessing sustainability have been developed to cover social, economic, and environmental aspects, however, most of them are simply used either separately or without a solid conceptual model supporting an epistemological construct to allow for deeper and scientific-based discussions on sustainability. This work presents a perspective about possible scenarios of the world's sustainability, based on a straightforward integrated framework for its quantification. The three capitals of sustainability, summarized as environmental sustainability, productivity and happiness are combined, based on the input-state-output model, and further plotted on a 3-axis graph. Eight different combinations of the three capitals show eight potential future worlds. The least desirable scenario, named “Ineffective,” depicts an environmentally unsustainable, unhappy and poor world, whereas “Paradise” is the utopia to be pursued: happy, environmentally sustainable and productive. Societies' decisions on taking action after quantitatively measuring and monitoring sustainability will be determinant in placing the world on a more developed and sustainable path, and the model proposed in this work can be useful in promoting discussions in this direction.

Seaweed culture is generally referred to as a sustainable production system. Nevertheless, this concept is biased by an environmental approach only, neglecting the economic and social dimensions of sustainability. The objective of this study was to assess the sustainability of the seaweed Hypnea pseudomusciformis cultivation and its use as human food consumption. We developed a pilot farming with the Association of Algae Producers of Flecheiras and Guajiru, in the municipality of Trairi, Northeastern Brazil. We applied a set of indicators to access environmental, social, and economic dimensions of sustainability. The environmental indicators showed highly efficient use of energy, nitrogen and phosphorus, which increased in the algae biomass during culture by 383%, 894%, and 1860%, respectively. Besides, H. pseudomusciformis culture absorbs carbon, does not pollute, and shows low risk to the local biodiversity because of it is a native species. Social indicators revealed that 51% of all investment stays in the local community, and the income distribution is equal among workers. The farm presented a high labor demand, which is socially inclusive. The H. pseudomusciformis farm was highly profitable, with an internal rate of return of 119%, recovery of invested capital in 1.2 years and positive externalities, generating 262.00 US$.t−1 as additional income. The farm showed high performance in the environmental, economic, and social dimensions of sustainability. Thus, this activity may be a sustainable manner to produce high-quality human food and raw materials for industry. The results obtained in the present study provide secure information for farmers, investors, and policymakers, which may encourage small and medium farmers to start seaweed farming in tropical Atlantic Southwestern coast.

An energy budget allows an understanding about the way in which the energy ingested is distributed among the various functions. In this study, the energy ingested by Zoeae, Decapodids and Juveniles of M. amazonicum allocated to growth, metabolism, nitrogen excretion, feces, and exuviae was measured. Also the main organic substrates oxydized were determined. Feces produced was estimated by the difference between the energy ingested and the energy assimilated plus excreted. Metabolism was assessed based on the oxygen consumption. Ammonia excretion was measured using a spectrophotometer. The oxygen consumed/nitrogen excreted ratio was determined to obtain the substrate oxidized. The energy of the organisms, food and exuviae was determined by wet combustion. Ingestion, body energy content and energy channeled into metabolism and excretion increased during ontogeny and differed between some stages. About 4% of the ingested energy was lost as exuviae. Zoea II showed low assimilation, and ∼46 % of the energy ingested was lost as feces. In Zoea III the accumulation of energy in the biomass predominates (∼45 %) but in Decapodids II and III the use of energy to maintain metabolism predominates (∼88 %). Proteins were the main substrate oxidized. Except in Zoea III, the energy used for metabolism varied from twice to twelve times the energy channeled to growth. This differential may be associated with an uneven pattern in the use of nutrients, growth and behavior. Zoea VI to Decapodid 3 showed a higher relationship in respiration /growth, which may indicate that Artemia nauplii are not suitable for feeding in these stages. The energy budget showed that most energy is channeled to feces (Zoea II) or to metabolism in the early stages. Therefore, the efficiency is low and there is a great potential to channel energy lost in metabolic processes to accumulate in biomass and accelerate larval development by changes in management.

The present study analyzed the inputs, outputs, and accumulation of carbon in ecological compartments of earthen ponds for the grow-out of Amazon river prawn (Macrobrachium amazonicum) and tambaqui fish (Colossoma macropomum) reared in monoculture and integrated multi-trophic aquaculture (IMTA) systems, using recycled hypereutrophic water. A completely randomized experiment was designed with four treatments and three replications: PM- monoculture with 30 prawn m−2, FM- monoculture with 3 fish m−2, IMTA- fish-prawn polyculture with 30 prawn m−2 and 3 fish m−2 reared free-swimming, POLY-CAGE- fish-prawn IMTA with 30 prawn m−2 reared free-swimming and 40 fish m−3 in net-cages. Animals, rain, water, feed, soil, gases, total suspended solids, settleable solids, and accumulated sludge were collected throughout the experiment to determine their total organic and total inorganic carbon contents and to calculate the carbon budget. Results showed that much of the carbon accumulated as solid organic material (∼55 – 84%) and animal biomass (∼4 – 18%). The remaining carbon was discharged to receiving water bodies in the outlet water during harvesting (∼6 – 8%) or emitted as carbon dioxide (CO2) and methane (CH4) (∼1 – 5%). Feed management appeared to influence the major biological processes in the aquatic carbon cycle, such as photosynthesis and aerobic decomposition. All systems showed absorption of atmospheric CO2 (∼529 – 782 kg C-CO2 ha−1) that was higher than the emissions (∼35 – 93 kg C-CO2 ha−1) and CH4 (∼14 – 123 kg C-CH4 ha−1). Furthermore, all of the culture processes in the present study removed ∼1,000 to 2,000 kg Total Carbon ha−1 from the inlet water, and thus, these systems can provide important ecosystem services. The high accumulation of carbon in the settleable solids (∼69% of outputs) and the adequate water quality maintained in the IMTA demonstrate the resilience of this grow-out system to high allochthonous inputs of organic matter as feed. An increased prawn density or the addition of a mud-feeder species to the culture may enhance the incorporation of carbon from settleable solids into harvested biomass, improving the efficiency of the systems.

Marine biotechnology is an emerging field in Brazil and includes the exploration of marine microbial products, aquaculture, omics, isolation of biologically active compounds, identification of biosynthetic gene clusters from symbiotic microorganisms, investigation of invertebrate diseases caused by potentially pathogenic marine microbes, and development of antifouling compounds. Furthermore, the field also encompasses description of new biological niches, current threats, preservation strategies as well as its biotechnological potential. Finally, it is important to depict some of the major approaches and tools being employed to such end. To address the challenges of marine biotechnology, the Brazilian government, through the Ministry of Science, Technology, Innovation, and Communication, has established the National Research Network in Marine Biotechnology (BiotecMar) (www.biotecmar.sage.coppe.ufrj.br). Its main objective is to harness marine biodiversity and develop the marine bioeconomy through innovative research.

ABSTRACT The Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), uses filter feeding and visual predation to catch prey. In filter feeding, the mucus secreted in their gill rakers traps planktonic organisms. In visual predation, the fish spot and capture food, eating it directly. At different ontogenetic stages, the Nile tilapia may impact the zooplankton community differently, since it changes how it captures its prey. The objective in this study was to verify which zooplankton groups contribute to the diet of O. niloticus at the post-larval stage, and if the way they capture food may determine prey size. We evaluated the diet of Nile tilapia kept in ponds for four months. We randomly removed one fish per pond every month. Stomach contents and gills of fish were extracted, fixed in formaldehyde and then analyzed with an optical microscope and stereomicroscope with a micrometric ocular in order to measure the zooplankton and the gill rakers. Fish increased consumption of rotifers, and decreased the consumption of microcrustaceans considerably up to zero in the last month. The gill raker size, nevertheless, increased as tilapia grew. Therefore, negative correlations were found between raker size and size of ingested zooplankton, showing that the size of ingested prey decreases throughout this cichlid's life. Juveniles filter feed on rotifers, and actively prey on microcrustaceans. As adults, fish stop preying visually and the mucus secreted by the gill rakers trap only small individuals. Juvenile Nile tilapia filter feed and visually prey on zooplankton. However, when adults, filter-feeding plays a more important role in the way the zooplankton community is affected. The increase in the size of the Nile tilapia's gill raker does not determine the consumption of larger zooplankton prey, and the presence of mucus in these structures plays a major role for the capture of zooplankton during the cichlid's adult stage.

Diverse reproductive strategies may be adopted by different species of Macrobrachium prawns, and even among different populations of the same species. The present study evaluated the influence of differences in the reproductive strategies of two geographically isolated populations of Macrobachium amazonicum, upon female fecundity, reproductive output and the chemical content of prawns and eggs. One prawn population from Pará only completes its life cycle in brackish water, whereas another from Mato Grosso do Sul only inhabits freshwater. Pará female prawns exhibited a larger average size and weight and produced more eggs than females from Mato Grosso do Sul. However, the Mato Grosso do Sul population produced eggs that were larger in volume than those of females from the other population. Furthermore, eggs produced by Pará prawns were composed primarily of water (56%), whereas those produced in Mato Grosso do Sul were composed mostly of organic matter (80%). This difference in the eggs' chemical compositions did not apply to the chemical compositions of the females, as individuals from both sites were composed primarily of water. Mato Grosso do Sul females invested a higher amount of energy in brood formation (14% of their wet weight) than individuals from Pará (only 10%). It is possible that M. amazonicum populations show a higher degree of plasticity in their reproductive activity due to habitat conditions and genetic differences. Although the brackish population produces larger individuals, and exhibits higher fecundity, the freshwater population exhibited a higher reproductive investment. These results suggest a high reproductive capacity to adapt to different environmental conditions for this species, which should be considered in the context of aquaculture activities.