Economic analysis of intensive and super-intensive Litopenaeus vannamei shrimp production in a Biofloc Technology system / Análise econômica da produção intensiva e superintensiva de camarão Litopenaeus Vannamei em sistema de bioflocos

In recent decades, new aquaculture technologies have been developed and improved, such as the Biofloc Technology system, which is considered an alternative to the conventional aquaculture model. This study compared the bioeconomic viability of intensive production in nurseries and super-intensive production of shrimp Litopenaeus vannamei bioflocs greenhouses. The investment for implementing the project was US$ 767,190.18 for intensive production and US$ 807,669.16 for super-intensive production. The analyses showed Net Present Value of US$ 363,718.21 and US$ 385,477.42, Equivalent annual value of US$ 59,830.66 and US$ 63,410.00, Net future value of US$ 965,052.69 and US$ 1,022,786.35, Payback Period 4.12 and 4.11, Discounted payback period 5.64 and 5.63, Profitability Index 1.47 and 1.48, Internal Rate of Return 20.49 and 20.55%, and Modified Internal Rate of Return 14.61 and 14.64%. The investment analysis used in this study showed that super-intensive production in a greenhouse is the best investment option. The development of a new scenario simulating the super-intensive production of shrimp in a Biofloc Technology system, considering land use as a premise, made it possible to observe the possibility of obtaining financial gains in scale, both in the reduction of production costs and in the economic performance of the enterprise. However, the financial contribution for the implementation and operation of the project increased substantially.

Nas últimas décadas, novas tecnologias aquícolas têm sido desenvolvidas e aprimoradas, como o sistema de bioflocos, considerado uma alternativa ao modelo convencional aquícola. O presente estudo compara a viabilidade bioeconômica da produção intensiva em viveiros com a da produção superintensiva em estufas do camarão Litopenaeus vannamei em bioflocos. O investimento para implantação do projeto foi de US$ 767.190,18 para produção intensiva e US$ 807.669,16 para superintensiva. As análises apresentaram valor presente líquido de US$ 363.718,21 e US$ 385.477,42, valor anual equivalente de US$ 59.830,66 e US$ 63.410,00, valor futuro líquido de US$ 965.052,69 e US$ 1.022.786,35, período de payback 4,12 e 4,11, payback descontado 5,64 e 5,63, índice de lucratividade 1,47 e 1,48, taxa interna de retorno 20,49 e 20,55% e taxa interna de retorno modificada 14,61 e 14,64%. As análises de investimentos neste estudo mostraram que a produção superintensiva em estufas é a melhor opção. O desenvolvimento de um novo cenário simulando a produção superintensiva de camarões em sistema de bioflocos, considerando o uso da terra como premissa, permitiu observar a possibilidade de ganhos financeiros em escala tanto na redução dos custos de produção quanto no desempenho econômico do empreendimento. No entanto, a contribuição financeira para implantar e operar o projeto aumentou substancialmente.

Common moist diet replacement to promote sustainable Cobia Rachycentron canadum (Linnaeus) near - shore farming in Brazil

Cobia is one of the most promising warm water aquaculture species. In Brazil, cobia farming began in 2008 in the state of Rio de Janeiro from experimental scale facilities to regular near-shore farms based on fresh/frozen fish diets composed mostly of Sardinella sp. Despite the encouraging results achieved in the promotion of sustainable cobia farming, we advocate the replacement of fresh/frozen fish by a practical formulated feed. This experiment evaluated the zootechnical performance and environmental efficiency of moist and practical formulated feeds in early grow-out phases in the cycle of cobia nearshore cage culture. Four hundred and twenty juvenile cobia (151 ± 7 g) were fed with moist feed and practical formulated feed for 56 days. Biometrics were taken every two weeks and diets were analyzed for proximate composition, fatty acid composition and pellet quality. Although growth performance was equivalent between treatments, feed consumption and feed conversion ratios (FCR) were different (p < 0.05) and varied according to water temperature. Cobia fed moist feed exhibited an FCR two times higher than those fed formulated feed. Elevated settling speed and low floatability contributed to higher heterogeneity and lower efficiency of fish fed moist diet. Nitrogen excretion rate was reduced (64 %) and protein efficiency ratio elevated (27 %) within formulated diet groups in comparison to those fed moist diet (79 % and 15 %, respectively). The fatty acid profile of cobia muscle was similar across the groups. With no negative effects of diet substitution on production performance and improvement of environmental efficiency, this approach can be applied and advocated globally and contribute to the responsible intensification of sustainable marine fish culture.(AU)

Common moist diet replacement to promote sustainable Cobia Rachycentron canadum (Linnaeus) near - shore farming in Brazil

Cobia is one of the most promising warm water aquaculture species. In Brazil, cobia farming began in 2008 in the state of Rio de Janeiro from experimental scale facilities to regular near-shore farms based on fresh/frozen fish diets composed mostly of Sardinella sp. Despite the encouraging results achieved in the promotion of sustainable cobia farming, we advocate the replacement of fresh/frozen fish by a practical formulated feed. This experiment evaluated the zootechnical performance and environmental efficiency of moist and practical formulated feeds in early grow-out phases in the cycle of cobia nearshore cage culture. Four hundred and twenty juvenile cobia (151 ± 7 g) were fed with moist feed and practical formulated feed for 56 days. Biometrics were taken every two weeks and diets were analyzed for proximate composition, fatty acid composition and pellet quality. Although growth performance was equivalent between treatments, feed consumption and feed conversion ratios (FCR) were different (p < 0.05) and varied according to water temperature. Cobia fed moist feed exhibited an FCR two times higher than those fed formulated feed. Elevated settling speed and low floatability contributed to higher heterogeneity and lower efficiency of fish fed moist diet. Nitrogen excretion rate was reduced (64 %) and protein efficiency ratio elevated (27 %) within formulated diet groups in comparison to those fed moist diet (79 % and 15 %, respectively). The fatty acid profile of cobia muscle was similar across the groups. With no negative effects of diet substitution on production performance and improvement of environmental efficiency, this approach can be applied and advocated globally and contribute to the responsible intensification of sustainable marine fish culture.

Arthrospira platensis filtrada como alimento complementario de juveniles del camarón blanco: efectos sobre crecimiento y sistema inmune / Filtered Arthrospira platensis as a food suplement for juvenile shrimp Litopenaeus vannamei: effects on growth and immune system

De forma general, las microalgas son fuente de alimento indispensable durante las primeras fases de desarrollo de los camarones marinos. Algunas microalgas, como la Arthrospira platensis, son ricas en substancias antioxidantes, y tienen la capacidad de retirar compuestos tóxicos del agua en los sistemas de producción acuícola. De este modo, constituimos un experimento con dos tratamientos triplicados, donde se evaluó la aplicación de biomasa filtrada de microalga A. platensis como suplemento alimenticio para camarón blanco del Pacífico, Litopenaeus vannamei. Se utilizó un sistema de cultivo estático de seis unidades, con volumen útil de 250 litros de agua marina (30 ppt), donde se sembraron 300 camarones m-2 con peso inicial de 0,7±0,2 g. Al final del experimento (42 días) se evaluaron parámetros inmunológicos y de desempeño zootécnico. Los camarones alimentados con A. platensis como como suplemento fueron signicativamente mayores que los camarones del tratamiento control y no presentaron diferencias en la supervivencia. Igualmente, se obtuvieron mejores resultados en los parámetros inmunológicos del tratamiento con inclusión de microalga. De esta forma, al suministrar la microalga como alimento suplementario al camarón L. vannamei, crecimiento y sistema inmunológico se vieron favorecidos.(AU)

Microalgae is an important food source during the early stages of marine shrimps. Some microalgae such as Arthrospira platensis, are rich in antioxidant substances and also have the capacity to remove toxics compounds from the water in aquaculture systems. The trial consisted in two treatements by triplicate, where the inclusion of filtered microalgae A. platensis as feed supplementation during production of juvenile Litopenaeus vannamei, was assessed. The experimental desing was based on a static system with six 250-L tanks with marine wáter (30 PSU), stocked 105 shirmps (300 shrimp m-2) with an average wheight of 0,7 ±0,2 g. At the end of the fed trial (42 days), the zootechnical and immunological parameters of shrimps were evaluated. Significatives differences among the treatments were found for both parameters. Shrimps that received supplementation of microalgae A. platensis showed higher growth and better response of the immune system. Thus, these results allow to conclude that the supplementation of filtered microalgae A. platensis improve growth and immunological parameters of white shrimp L. vannamei.(AU)

Arthrospira platensis filtrada como alimento complementario de juveniles del camarón blanco: efectos sobre crecimiento y sistema inmune / Filtered Arthrospira platensis as a food suplement for juvenile shrimp Litopenaeus vannamei: effects on growth and immune system

De forma general, las microalgas son fuente de alimento indispensable durante las primeras fases de desarrollo de los camarones marinos. Algunas microalgas, como la Arthrospira platensis, son ricas en substancias antioxidantes, y tienen la capacidad de retirar compuestos tóxicos del agua en los sistemas de producción acuícola. De este modo, constituimos un experimento con dos tratamientos triplicados, donde se evaluó la aplicación de biomasa filtrada de microalga A. platensis como suplemento alimenticio para camarón blanco del Pacífico, Litopenaeus vannamei. Se utilizó un sistema de cultivo estático de seis unidades, con volumen útil de 250 litros de agua marina (30 ppt), donde se sembraron 300 camarones m-2 con peso inicial de 0,7±0,2 g. Al final del experimento (42 días) se evaluaron parámetros inmunológicos y de desempeño zootécnico. Los camarones alimentados con A. platensis como como suplemento fueron signicativamente mayores que los camarones del tratamiento control y no presentaron diferencias en la supervivencia. Igualmente, se obtuvieron mejores resultados en los parámetros inmunológicos del tratamiento con inclusión de microalga. De esta forma, al suministrar la microalga como alimento suplementario al camarón L. vannamei, crecimiento y sistema inmunológico se vieron favorecidos.

Microalgae is an important food source during the early stages of marine shrimps. Some microalgae such as Arthrospira platensis, are rich in antioxidant substances and also have the capacity to remove toxics compounds from the water in aquaculture systems. The trial consisted in two treatements by triplicate, where the inclusion of filtered microalgae A. platensis as feed supplementation during production of juvenile Litopenaeus vannamei, was assessed. The experimental desing was based on a static system with six 250-L tanks with marine wáter (30 PSU), stocked 105 shirmps (300 shrimp m-2) with an average wheight of 0,7 ±0,2 g. At the end of the fed trial (42 days), the zootechnical and immunological parameters of shrimps were evaluated. Significatives differences among the treatments were found for both parameters. Shrimps that received supplementation of microalgae A. platensis showed higher growth and better response of the immune system. Thus, these results allow to conclude that the supplementation of filtered microalgae A. platensis improve growth and immunological parameters of white shrimp L. vannamei.

Use of Polymerase Chain Reaction for Bivalve Pathogen Surveillance in the Yellow Clam Mesodesma mactroides.

The yellow clam Mesodesma mactroides is a valuable shellfish occurring from the southeastern coast of Brazil to the northern coast of Argentina. Populations of yellow clams are disappearing from their entire range, and the cause is still unknown. The objective of this paper was to search for World Organisation for Animal Health (OIE)-listed pathogens and their relatives in the genera Marteilia, Bonamia, and Perkinsus as well as Mikrocytos mackini and the virus OsHV-1 µ var the yellow clam population in southern Brazil using molecular techniques and classic histology protocols. A total of 180 clams were manually collected in the intertidal region at six sampling points covering the entire coast of Rio Grande do Sul State (length, 622 km) in 2013. Tissue samples were tested by OIE-recommended single-step conventional polymerase chain reaction assays. The screening showed no evidence of the specific sequences of the protistan parasites and viral pathogens at any site within the six zones under study. We recommend continuous monitoring of the mollusks in the region. Received July 3, 2015; accepted February 3, 2016.

Analysis of the marine shrimp farm production chain in Rio Grande do Sul state / Análise da cadeia produtiva da cultura de camarão marinho no sul do Brasil

This study aims to identify, describe, and analyze the main links of the marine shrimp culture production chain in the extreme south of Brazil, specifically in the Rio Grande and São José do Norte municipalities, Rio Grande do Sul state. The research was carried out through prior bibliographic, in loco research and the application of interviews and questionnaires to identify the entire local productive process from the inputs needed for production to the arrival at the final consumer. The results indicate that the production chain requires actions in the process until the products final commercialization. Even as a growing market in Brazil, more investments, better support from the Government for the installation of new farmers, a reduction of bureaucracy in public agencies, training of actors involved in production, and some other points identified in this study can help decision makers, inherent to the activity, to establish sustainable production strategies aimed at lasting and full development of local shrimp production.(AU)

Este estudo tem como objetivo identificar, descrever e analisar os principais elos da cadeia produtiva do camarão marinho no extremo sul do Brasil, especificamente nas cidades de Rio Grande e São José do Norte, estado do Rio Grande do Sul. A pesquisa foi realizada por meio de uma revisão bibliográfica prévia, pesquisa in loco e aplicação de entrevistas e questionários para identificar todo o processo produtivo local a partir dos insumos necessários para a produção até a chegada ao consumidor final. Os resultados indicam que a cadeia produtiva requer ações desde o processo até a comercialização final do produto. Mesmo com um mercado em crescimento no Brasil, mais investimentos, mais apoiodo Governo para a instalação de novos agricultores, a redução da burocracia em órgãos públicos, o treinamento de atores envolvidos na produção, e alguns outros pontos identificados neste estudo podem ajudar os tomadores de decisão, inerente à atividade, a estabelecerem estratégias de produção sustentáveis que visam um desenvolvimento da produção local de camarão duradouro e completo.(AU)

Analysis of the marine shrimp farm production chain in Rio Grande do Sul state / Análise da cadeia produtiva da cultura de camarão marinho no sul do Brasil

This study aims to identify, describe, and analyze the main links of the marine shrimp culture production chain in the extreme south of Brazil, specifically in the Rio Grande and São José do Norte municipalities, Rio Grande do Sul state. The research was carried out through prior bibliographic, in loco research and the application of interviews and questionnaires to identify the entire local productive process from the inputs needed for production to the arrival at the final consumer. The results indicate that the production chain requires actions in the process until the product’s final commercialization. Even as a growing market in Brazil, more investments, better support from the Government for the installation of new farmers, a reduction of bureaucracy in public agencies, training of actors involved in production, and some other points identified in this study can help decision makers, inherent to the activity, to establish sustainable production strategies aimed at lasting and full development of local shrimp production.

Este estudo tem como objetivo identificar, descrever e analisar os principais elos da cadeia produtiva do camarão marinho no extremo sul do Brasil, especificamente nas cidades de Rio Grande e São José do Norte, estado do Rio Grande do Sul. A pesquisa foi realizada por meio de uma revisão bibliográfica prévia, pesquisa in loco e aplicação de entrevistas e questionários para identificar todo o processo produtivo local a partir dos insumos necessários para a produção até a chegada ao consumidor final. Os resultados indicam que a cadeia produtiva requer ações desde o processo até a comercialização final do produto. Mesmo com um mercado em crescimento no Brasil, mais investimentos, mais apoiodo Governo para a instalação de novos agricultores, a redução da burocracia em órgãos públicos, o treinamento de atores envolvidos na produção, e alguns outros pontos identificados neste estudo podem ajudar os tomadores de decisão, inerente à atividade, a estabelecerem estratégias de produção sustentáveis que visam um desenvolvimento da produção local de camarão duradouro e completo.

Compostos nitrogenados sobre o consumo alimentar de camarão-rosa Farfantepenaeus brasiliensis / Nitrogen compounds on food consumption of pink-shrimp Farfantepenaeus brasiliensis

Os experimentos foram realizados para investigar os efeitos da amônia, nitrito e nitrato no consumo alimentar de juvenis de Farfantepenaeus brasiliensis. Os camarões com peso médio de 4g foram aclimatados durante 28 dias em diferentes concentrações crônicas de amônia, nitrito e nitrato. Após o período de exposição de 28 dias, 20 camarões por tratamento foram individualizados em unidades experimentais de 3 L, a fim de ser analisado o consumo de ração em função da quantidade de alimento oferecido e as sobras durante um período de 24 horas. O consumo alimentar apresentou alterações significativas (P<0,05) para os camarões expostos às concentrações de nitrito e nitrato testadas, enquanto para o tratamento com amônia, os camarões não apresentaram alterações no consumo alimentar (P>0,05). Foi verificado que o nitrito e o nitrato afetam o consumo alimentar de F. brasiliensis. Contudo, a possibilidade de que isso ocorra durante longos períodos, afetando negativamente o cultivo de espécies em cativeiro, reforçam a necessidade do manejo da qualidade de água.

The experiments were carried out to investigate the effects of ammonia, nitrite and nitrate on food consumption of juvenile F. brasiliensis. The juvenile shrimp were acclimated for 28 days with different cronic concentrations of ammonia, nitrite and nitrate. After the acclimation period, 20 shrimps per treatment were individualized in 3 L experimental units in order to analyze their feed intake through the amount of feed offered and leftover for a period of 24 hours. The food consumption presented significant alteration (P<0.05) for the nitrite and nitrate concentrations tested, meanwhile on ammonia treatment, shrimp presented no alteration on food intake (P>0.05). According to the results obtained, nitrite and nitrate affected F. brasiliensis food consumption. However, the possibility of this to happen over long periods, can damage the species in captivity, reinforced the necessity of regular water quality management.

Production of live bait-shrimp (Farfantepenaeus paulensis) in cages at varying stocking densities / Produção de isca-viva de camarão (Farfantepenaeus paulensis) em gaiolas com diferentes densidades de estocagem

In Brazils southern and southeastern coast, sport fisheries have a large demand for live bait-shrimp that is usually not met by local fishermen. The production of 4-5 g shrimp in cages may therefore provide a promising alternative to fill this gap. Unfortunately, studies defining adequate management guidelines for the production of live bait-shrimp in cages are not yet available. In this study, the influence of stocking density on the survival, growth and food conversion ratio (FCR) of the shrimp Farfantepenaeus paulensis reared in cages was evaluated. The trial lasted 42 days and assessed three stocking densities (50, 100 and 200/m2) of F. paulensis juveniles (mean initial weight of 1.04 g). Final survival and weight of shrimp reared at 50, 100 and 200/m2 were 94.1, 94.6 and 59.2%, and 6.0, 5.0 and 4.3 g, respectively. Survival and final weight of shrimp were negatively related to density. FCR was not significantly different between treatments but tended to increase at higher densities. The present results indicate that the production of F. paulensis in cages is feasible at all densities tested, but as rearing 200/m² will produce a larger number of bait-sized juveniles. This stocking density may be recommended when a rearing site presenting optimal environmental conditions is available. The production of live bait-shrimp in cages may become an interesting source of income for

No litoral sul e sudeste do Brasil, a forte demanda da pesca esportiva por camarões vivos para serem utilizados como isca não é atendida pela pesca artesanal. O cultivo de juvenis de camarão (peso de 4-5 g) em gaiolas pode, portanto, ser uma alternativa interessante para atender a este mercado. Infelizmente, estratégias de manejo adequadas à produção de camarões em gaiolas ainda não foram devidamente estabelecidas. Neste estudo avaliou-se a influência da densidade de estocagem sobre a sobrevivência, crescimento e taxa de conversão alimentar (TCA) do camarão-rosa Farfantepenaeus paulensis cultivado em gaiolas. O experimento durou 42 dias e considerou três densidades de estocagem (50, 100 e 200/m2) de juvenis com peso médio inicial de 1,04 g. Ao final do período, as médias de sobrevivência e peso dos camarões cultivados a 50, 100 e 200/m2 foram 94,1; 94,6 e 59,2%, e 6,0; 5,0 e 4,3 g, respectivamente. A sobrevivência e o peso final se correlacionaram negativamente à densidade. A TCA, porém, não se diferenciou significativamente entre os tratamentos, mas apresentou tendência de aumento nas densidades mais altas. Os resultados indicam que a produção de isca-vivas de F. paulensis em gaiolas é tecnicamente viável em todas as densidades testadas. Entretanto, como o cultivo de 200 camarões/m² resulta na produção de um maior número de juvenis, esta densidade de estocagem pode ser recomen

Production of live bait-shrimp (Farfantepenaeus paulensis) in cages at varying stocking densities / Produção de isca-viva de camarão (Farfantepenaeus paulensis) em gaiolas com diferentes densidades de estocagem

In Brazils southern and southeastern coast, sport fisheries have a large demand for live bait-shrimp that is usually not met by local fishermen. The production of 4-5 g shrimp in cages may therefore provide a promising alternative to fill this gap. Unfortunately, studies defining adequate management guidelines for the production of live bait-shrimp in cages are not yet available. In this study, the influence of stocking density on the survival, growth and food conversion ratio (FCR) of the shrimp Farfantepenaeus paulensis reared in cages was evaluated. The trial lasted 42 days and assessed three stocking densities (50, 100 and 200/m2) of F. paulensis juveniles (mean initial weight of 1.04 g). Final survival and weight of shrimp reared at 50, 100 and 200/m2 were 94.1, 94.6 and 59.2%, and 6.0, 5.0 and 4.3 g, respectively. Survival and final weight of shrimp were negatively related to density. FCR was not significantly different between treatments but tended to increase at higher densities. The present results indicate that the production of F. paulensis in cages is feasible at all densities tested, but as rearing 200/m² will produce a larger number of bait-sized juveniles. This stocking density may be recommended when a rearing site presenting optimal environmental conditions is available. The production of live bait-shrimp in cages may become an interesting source of income for

No litoral sul e sudeste do Brasil, a forte demanda da pesca esportiva por camarões vivos para serem utilizados como isca não é atendida pela pesca artesanal. O cultivo de juvenis de camarão (peso de 4-5 g) em gaiolas pode, portanto, ser uma alternativa interessante para atender a este mercado. Infelizmente, estratégias de manejo adequadas à produção de camarões em gaiolas ainda não foram devidamente estabelecidas. Neste estudo avaliou-se a influência da densidade de estocagem sobre a sobrevivência, crescimento e taxa de conversão alimentar (TCA) do camarão-rosa Farfantepenaeus paulensis cultivado em gaiolas. O experimento durou 42 dias e considerou três densidades de estocagem (50, 100 e 200/m2) de juvenis com peso médio inicial de 1,04 g. Ao final do período, as médias de sobrevivência e peso dos camarões cultivados a 50, 100 e 200/m2 foram 94,1; 94,6 e 59,2%, e 6,0; 5,0 e 4,3 g, respectivamente. A sobrevivência e o peso final se correlacionaram negativamente à densidade. A TCA, porém, não se diferenciou significativamente entre os tratamentos, mas apresentou tendência de aumento nas densidades mais altas. Os resultados indicam que a produção de isca-vivas de F. paulensis em gaiolas é tecnicamente viável em todas as densidades testadas. Entretanto, como o cultivo de 200 camarões/m² resulta na produção de um maior número de juvenis, esta densidade de estocagem pode ser recomen

Shrimp farming as an alternative to artisanal fishermen communities: the Case of Patos Lagoon, Brazil

The shrimp Farfantepenaeus paulensis is considered a suitable species for culture in the Patos Lagoon estuary, southern Brazil, where its catch has been decreasing in the last few years. Considering the potential of estuarine areas for shrimp farming, the application of low-cost structures to culture shrimp, such as the pen enclosures, is being proposed as an alternative source of income for artisanal fishermen and farmers living near Patos Lagoon. From an economical standpoint, these alternative systems present several advantages over the traditional pond-based culture systems since land, water pumping and artificial aerations are not required, high natural productivity is available and inexpensive materials are employed in the construction of grow-out structures. This paper reviews the farming of F. paulensis in the pen enclosures as an alternative to the artisanal fishing communities of the Patos Lagoon estuary. Particular emphases are placed on the development of culture systems, social and environmental impacts, constraints and perspectives.

O camarão-rosa Farfantepenaeus paulensis é considerado uma espécie com potencial para criação no estuário da Lagoa dos Patos, RS, onde o volume desembarcado deste recurso vem decrescendo nos últimos anos. A criação deste camarão em cercados está sendo proposta como uma fonte de renda alternativa para os pescadores artesanais e agricultores que habitam o entorno deste estuário. Do ponto de vista econômico, estes sistemas alternativos de criação apresentam vantagens sobre os sistemas tradicionais em viveiros de terra: não se necessita ter posse da terra, nem equipamentos de bombeamento d'água ou aeração. Além disso, materiais relativamente baratos são utilizados na construção das estruturas de engorda e há uma grande disponibilidade de alimento natural. Esta revisão apresenta alguns aspectos da criação de F. paulensis em cercados como uma alternativa às comunidades de pescadores. Maior ênfase será dada no desenvolvimento dos sistemas de criação, manejo, impactos sociais e ambientais, dificuldades e possibilidades.

The effect of temperature, salinity and nitrogen products on food consumption of pink shrimp Farfantepenaeus paulensis

Studies were carried out to investigate the effect of temperature, salinity, ammonia, nitrite and nitrate on food consumption of pink shrimp Farfantepenaeus paulensis. Juveniles (0.2 - 0.4 g) were acclimated for 15 days in seawater with different temperatures, salinities and concentrations of ammonia, nitrite and nitrate. After the acclimation period, 20 shrimps per treatment were individualized in order to have their ration intake analyzed through the amount of ration offered and left over within a 24-hour period. Mean food consumption presented significant alterations (P<0.05) for the tested temperatures and nitrite concentrations, whereas for the salinity, ammonia and nitrate treatments, shrimp presented no alteration on food intake (P>0.05). According to the results obtained, temperature and nitrite affected F. paulensis food consumption. On the other hand, variables as salinity, ammonia and nitrate did not affect shrimp appetite. However, the possibility of this to happen over long periods, prejudicing the species culture in captivity, reinforced the necessity of regular water quality management

Toxicidade aguda da amônia no processo produtivo de pós-larvas de Penaeus paulensis Pérez-Farfante, 1967 / Acute toxicity of ammonia in the productivity process of postlarvae of Penaeus paulensis Pérez-Farfante, 1967

Larval shrimp Penaeus paulensis showed a tendency to decrease in ammonia tolerance as the larva metamorphosed from nauplius to postlarvae stage. The 24-h LC50 were 4.04, 1.70, 2.72, and 1.42mg/l NH3-N on nauplii, zoea, mysis and postlarvae, respectively. The zoea stage and the initial postlarvae substages were very susceptible to ammonia. The 96-h LC50 values on zoea and postlarvae were 0.69 mg/l and 0.32 mg/l, against 0.80 mg/l NH3-N on mysis. The eggs of Penaeus paulensis were affected by ammnia, which provoked a progressive decrease in the hatching rate and induced morphological deformities in hatched nauplii. A "safe level" of ammonia was estimated at 0.032 mg/l NH3-N on the basis of 24-h LC50 for eggs