Influence of color and brightness on ontogenetic shelter preference by the prawn Macrobrachium rosenbergii (Decapoda: Palaemonidae)

The giant river prawn, Macrobrachium rosenbergii (de Man, 1879), is a species of great commercial importance. It is farmed under different conditions that translate to a great range of light environments, which impact their behavior and productivity. We present the first study employing both visual modeling and beha vioral data to evaluate the ontogenetic changes in color preferences of juveniles and adults of M. rosenbergii. We offered ten shelters of different colors to juveniles and adults and registered their preferences. Our results show that shelter preference changed with ontogeny: juveniles chose shelters based on chromaticity (preference for blue), while adults based their decisions on brightness (preference for dark grey). This preference adults show for dark colors is probably associated with light avoidance behavior. We recommend providing blue shelters for juveniles and dark shelters for adults.(AU)

Effect of two diets on the fecundity of ablated and non-ablated female of Macrobrachium amazonicum

Macrobrachium amazonicum is a species of freshwater shrimp of great importance for aquaculture and to know its reproductive potential, through the study of its fertility is necessary. Therefore, this study aimed to evaluate the effect of two different diets on the reproductive performance of the species, whether or not adopting the ablation procedure. The experiment was carried out in a completely randomized design in a 2 x 2 factorial arrangement, with two types of feed (inert and fresh) and two conditions (ablated and non-ablated females), using six replicates per treatment. After 10 days of spawning, the eggs were removed and counted in their entirety. For each female, three spawns were obtained, totaling 72 samples. The fertility rate, the interval between spawning and the weight gain of the females were analyzed. There was no interaction between the studied factors, except for weight gain, in which ablated females that received fresh feed gained up to three times more weight than non-ablated females. Females that received fresh feed obtained higher fertility (1,373.9 eggs) than those that received only inert feed (1,084.1 eggs). The interval between spawns was 1.6 days shorter in ablated females.(AU)

Tuleariocaris neglecta Chace, 1969 (Crustacea: Caridea: Palaemonidae) associated with the sea urchin Astropyga magnifica Clark, 1934 (Echinoidea: Diadematidae) in the Alcatraz Archipelago, southeastern Brazil

The caridean shrimp Tuleariocaris neglecta Chace, 1969, is reported from the Alcatraz Archipelago (24°S, off the coast of southeastern Brazil) in association with the sea urchin Astropyga magnifica Clark, 1934. This finding significantly increases the known range of this species from 20°S to 24°S. An overview of the species in Tuleariocaris with their respective associated host sea urchins is provided.(AU)

Hygienic and sanitary characteristics of dry salted fish marketed in Porto Velho city, Rondônia ­ Brazil / Características higiênico-sanitárias de pescado salgado seco comercializado em Porto Velho, Rondônia ­ Brasil

Handcrafted salted fish is marketed weekly in retail markets and public fairs in the Porto Velho city, Rondônia sate, Brazil. Knowing the microbiological quality of these products is essential for public health, given that such products are not subject to any quality control. The aimed of the study was to evaluate the hygienic-sanitary characteristics and the moisture content of pirarucu and salted and dried shrimp marketed in the Porto Velho city. Twenty samples were collected, 10 pirarucu and 10 shrimp, in February and June 2019. For microbiological analysis, surface plating was performed using acidified potato agar, for molds and yeasts, and PCA agar for halophilic bacterias. Moisture was determined by gravimetry, using an oven at 105° C. Results for molds and yeasts on pirarucu ranged <10 log CFU/g (absent) to 3 log CFU/g. For shrimp, values ranged <10 log CFU/g to 3.57 log CFU/g. For halophilic bacterias, contents ranged <10 log CFU/g to 6.30 log CFU/g in pirarucu samples and <10 log CFU/g to 6.97 log CFU/g in shrimp samples. The variation in moisture content ranged 36.99 to 54.31% for pirarucu, and 40.6 to 56.82% for shrimp. The results obtained may be related to poor hygienic conditions in processing, the lack of hygiene of utensils and places for handling, or even the quality of the raw material used.(AU)

Pescado salgado preparado artesanalmente é semanalmente comercializado em mercados varejistas e feiras públicas na cidade de Porto Velho, Rondônia. Conhecer a qualidade microbiológica desses produtos é essencial para a saúde pública, haja visto, que tais produtos não estão sujeitos a nenhum controle de qualidade. O objetivo do estudo foi avaliar as caracterís-ticas higiênico-sanitárias e o teor de umidade de pirarucus e camarões salgados e secos comercializados em Porto Velho. Foram coletadas 20 amostras, 10 de pirarucu e 10 de camarão, em fevereiro e junho de 2019. Para as análises microbiológicas foi realizado o plaqueamento em superfície usando-se ágar batata acidificado, para bolores e leveduras, e ágar PCA para as bacté-rias halofílicas. A umidade foi determinada por gravimetria, com uso de estufa a 105°C. Os resultados para bolores e leveduras em pirarucu variaram de <10 log UFC/g (ausente) a 3 log UFC/g. Para os camarões os valores variaram de <10 log UFC/g a 3,57 log UFC/g. Para as bactérias halofílicas os teores variaram de <10 log UFC/g a 6,30 log UFC/g nas amostras de pirarucu e de <10 log UFC/g a 6,97 log UFC/g nas amostras de camarão. A variação nos teores de umidade foi de 36,99 a 54,31% para o pirarucu, e de 40,6 a 56,82% para o camarão. Os resultados obtidos podem estar relacionados às más condições higiênicas no processamento, à falta de higiene dos utensílios e dos locais de manipulação, ou ainda, à qualidade da matéria-prima empregada.(AU)

Prospection of putative genes for digestive enzymes based on functional genome of the hepatopancreas of Amazon river prawn

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-richfoods. 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.(AU)

Bycatch of Asteroidea from shrimp trawl fishery in the southwestern Atlantic Ocean ­ Brazil

Shrimp trawling is considered a significant negative impact on the marine ecosystem, especially on the benthic community. Sea stars (Echinodermata: Asteroidea) are one of the most affected groups by unintentional catches. This study was performed at the Santana Archipelago, a Marine Protected Area in the northern region of Rio de Janeiro State, between 2008-2009. Sea stars accidentally caught by trawling were collected during open and closed season of the shrimp fisheries (Xiphopenaeus kroyeri) at depths of 5-60 m. A generalized linear zero-inflated model was applied to test for differences in capture between fishing seasons and depths. A total of 158 sea star specimens were captured. These specimens were identified as Asterina stellifera, Astropecten acutiradiatus, Astropecten brasiliensis, Astropecten cingulatus, Luidia alternata alternata, Luidia clathrata, Luidia ludwigi scotti, Luidia senegalensis. The sea stars A. brasiliensis and L. senegalensis are currently considered as vulnerable species in the Brazilian official list of threatened species. The higher capture of sea stars was shown in deepest areas, and there was no significant difference in the number of specimens between seasons. This is the first study about asteroids accidentally captured by shrimp trawling.(AU)

Natural diet of Macrobrachium brasiliense (Crustacea, Decapoda) in a Cerrado stream / Dieta natural de Macrobrachium brasiliense (Crustacea, Decapoda) em um córrego de Cerrado

Knowledge about the diet of a given species is essential to provide information on the growth and maintenance of populations in a natural environment. Macrobrachium brasiliense (Heller, 1862) is a species of freshwater prawn widely distributed in Brazil, being frequent in aquatic environments inserted in the Cerrado biome. The aim of this study was to evaluate the natural diet of a population of M. brasiliense, comparing the consumed food items according to sex, seasonality and body size of individuals. Monthly collections were carried out between September 2018 and August 2019. The individuals collected had their sex identified and the length of the cephalothorax measured. Stomach content was assessed based on the degree of repletion, the method of points and the frequency of occurrence. There was a high frequency of plant material in the stomach contents and a smaller but significant frequency of aquatic insects. There were no significant differences regarding the diet of males and females and between the dry and rainy seasons. It was observed an increase in total insect consumption with the increase in size of males and females of M. brasiliense. A diet preference for Trichoptera was recorded in both sampling periods for males and females. The results obtained confirm an omnivorous diet for the species and suggest that the composition and proportion of items may vary depending on the size of the individuals and the availability of the items in the environment.(AU)

O conhecimento acerca da dieta de uma determinada espécie é essencial para fornecer informações sobre o crescimento e manutenção das populações em ambiente natural. Macrobrachium brasiliense (Heller, 1862) é uma espécie de camarão de água doce com ampla distribuição no Brasil, ocorrendo frequentemente em ambientes aquáticos inseridos no bioma Cerrado. O objetivo deste estudo foi avaliar a dieta natural de uma população de M. brasiliense, comparando os itens alimentares consumidos em função do sexo, sazonalidade e tamanho corporal dos indivíduos. Foram realizadas coletas mensais entre setembro de 2018 a agosto de 2019. Os indivíduos coletados tiveram seu sexo identificado e o comprimento do cefalotórax mensurado. O conteúdo estomacal foi avaliado a partir do grau de repleção, método de pontos e de frequência de ocorrência. Verificou-se elevada frequência de detrito vegetal no conteúdo estomacal e uma frequência menor de insetos aquáticos, porém significativa. Não houve diferenças significativas quanto à dieta de machos e fêmeas e entre as estações seca e chuvosa. Foi observado um aumento do consumo total de insetos com aumento de tamanho de machos e fêmeas de M. brasiliense. Uma preferência de dieta por Trichoptera foi registrada em ambos os períodos de amostragem para machos e fêmeas.Os resultados obtidos confirmam uma dieta onívora para a espécie e sugerem que a composição e a proporção de itens podem variar em função do tamanho dos indivíduos e da disponibilidade dos itens no ambiente.(AU)

Natural diet of Macrobrachium brasiliense (Crustacea, Decapoda) in a Cerrado stream / Dieta natural de Macrobrachium brasiliense (Crustacea, Decapoda) em um córrego de Cerrado

Knowledge about the diet of a given species is essential to provide information on the growth and maintenance of populations in a natural environment. Macrobrachium brasiliense (Heller, 1862) is a species of freshwater prawn widely distributed in Brazil, being frequent in aquatic environments inserted in the Cerrado biome. The aim of this study was to evaluate the natural diet of a population of M. brasiliense, comparing the consumed food items according to sex, seasonality and body size of individuals. Monthly collections were carried out between September 2018 and August 2019. The individuals collected had their sex identified and the length of the cephalothorax measured. Stomach content was assessed based on the degree of repletion, the method of points and the frequency of occurrence. There was a high frequency of plant material in the stomach contents and a smaller but significant frequency of aquatic insects. There were no significant differences regarding the diet of males and females and between the dry and rainy seasons. It was observed an increase in total insect consumption with the increase in size of males and females of M. brasiliense. A diet preference for Trichoptera was recorded in both sampling periods for males and females. The results obtained confirm an omnivorous diet for the species and suggest that the composition and proportion of items may vary depending on the size of the individuals and the availability of the items in the environment.

O conhecimento acerca da dieta de uma determinada espécie é essencial para fornecer informações sobre o crescimento e manutenção das populações em ambiente natural. Macrobrachium brasiliense (Heller, 1862) é uma espécie de camarão de água doce com ampla distribuição no Brasil, ocorrendo frequentemente em ambientes aquáticos inseridos no bioma Cerrado. O objetivo deste estudo foi avaliar a dieta natural de uma população de M. brasiliense, comparando os itens alimentares consumidos em função do sexo, sazonalidade e tamanho corporal dos indivíduos. Foram realizadas coletas mensais entre setembro de 2018 a agosto de 2019. Os indivíduos coletados tiveram seu sexo identificado e o comprimento do cefalotórax mensurado. O conteúdo estomacal foi avaliado a partir do grau de repleção, método de pontos e de frequência de ocorrência. Verificou-se elevada frequência de detrito vegetal no conteúdo estomacal e uma frequência menor de insetos aquáticos, porém significativa. Não houve diferenças significativas quanto à dieta de machos e fêmeas e entre as estações seca e chuvosa. Foi observado um aumento do consumo total de insetos com aumento de tamanho de machos e fêmeas de M. brasiliense. Uma preferência de dieta por Trichoptera foi registrada em ambos os períodos de amostragem para machos e fêmeas.Os resultados obtidos confirmam uma dieta onívora para a espécie e sugerem que a composição e a proporção de itens podem variar em função do tamanho dos indivíduos e da disponibilidade dos itens no ambiente.

Food acceptance in different larval stages of Macrobrachium carcinus / Aceitação de alimentos em diferentes estágios larvais de Macrobrachium carcinus

Food acceptance in different larval stages of Macrobrachium carcinus was evaluated by investigating the stage at which the ingestion of inert moist diet food begins and by the incidence of Artemia nauplii and inert moist diet in the digestive tract throughout development. Two experiments were carried out: in the first study, the acceptance of the inert diet was evaluated in 60 larvae of each stage (I to XII) fed ad libitum after two hours of fasting. The inert diet was 100% accepted at zoea stage V. In the second study, newly hatched larva was then kept in larval tanks and fed with Artemia nauplii and inert moist diet simultaneously. Fifteen minutes after feeding, 50 specimens of each larval stage were examined and evaluated for the ingestion of these foods. Larvae at stage I did not feed, while larvae at stage II consumed both live and inert food. From the stage of zoea IX, the exclusive consumption of Artemia nauplii was not verified. These data indicate that feeding M. carcinus in larviculture can be initiated at stage II with inert moist diet and Artemia nauplii, and an exclusive supply of inert moist diet from stage IX can be recommended.

A aceitação alimentar nos diferentes estágios larvais de Macrobrachium carcinus foram avaliadas a partir da investigação da fase em que começa a ingestão de uma dieta inerte úmida e a incidência de náuplios de Artemia e da dieta inerte úmida no trato digestório durante todo o desenvolvimento. Foram realizados dois experimentos: no primeiro, a aceitação da dieta inerte foi avaliada em 60 larvas de cada estágio (I a XII) alimentadas ad libitum após duas horas de jejum. A dieta inerte úmida foi 100% aceita na fase V de zoea. No segundo experimento, larvas recém-eclodidas foram mantidas em tanques larvais e alimentadas com náuplios de Artemia e dieta inerte úmida simultaneamente. Quinze minutos após a alimentação, 50 espécimes de cada estágio larval foram examinados e avaliados em relação à ingestão desses alimentos. Larvas no estágio I não se alimentaram, enquanto larvas no estágio II consumiram alimento vivo e inerte. A partir do estágio de zoea IX o consumo exclusivo de náuplios de Artemia não foi verificado. Esses dados indicam que a alimentação de M. carcinus na larvicultura pode ser iniciada no estágio II, com dieta úmida inerte e náuplios de Artemia, e pode ser recomendado o fornecimento exclusivo de dietas úmidas inertes a partir do estágio IX.

Food acceptance in different larval stages of Macrobrachium carcinus / Aceitação de alimentos em diferentes estágios larvais de Macrobrachium carcinus

Food acceptance in different larval stages of Macrobrachium carcinus was evaluated by investigating the stage at which the ingestion of inert moist diet food begins and by the incidence of Artemia nauplii and inert moist diet in the digestive tract throughout development. Two experiments were carried out: in the first study, the acceptance of the inert diet was evaluated in 60 larvae of each stage (I to XII) fed ad libitum after two hours of fasting. The inert diet was 100% accepted at zoea stage V. In the second study, newly hatched larva was then kept in larval tanks and fed with Artemia nauplii and inert moist diet simultaneously. Fifteen minutes after feeding, 50 specimens of each larval stage were examined and evaluated for the ingestion of these foods. Larvae at stage I did not feed, while larvae at stage II consumed both live and inert food. From the stage of zoea IX, the exclusive consumption of Artemia nauplii was not verified. These data indicate that feeding M. carcinus in larviculture can be initiated at stage II with inert moist diet and Artemia nauplii, and an exclusive supply of inert moist diet from stage IX can be recommended.(AU)

A aceitação alimentar nos diferentes estágios larvais de Macrobrachium carcinus foram avaliadas a partir da investigação da fase em que começa a ingestão de uma dieta inerte úmida e a incidência de náuplios de Artemia e da dieta inerte úmida no trato digestório durante todo o desenvolvimento. Foram realizados dois experimentos: no primeiro, a aceitação da dieta inerte foi avaliada em 60 larvas de cada estágio (I a XII) alimentadas ad libitum após duas horas de jejum. A dieta inerte úmida foi 100% aceita na fase V de zoea. No segundo experimento, larvas recém-eclodidas foram mantidas em tanques larvais e alimentadas com náuplios de Artemia e dieta inerte úmida simultaneamente. Quinze minutos após a alimentação, 50 espécimes de cada estágio larval foram examinados e avaliados em relação à ingestão desses alimentos. Larvas no estágio I não se alimentaram, enquanto larvas no estágio II consumiram alimento vivo e inerte. A partir do estágio de zoea IX o consumo exclusivo de náuplios de Artemia não foi verificado. Esses dados indicam que a alimentação de M. carcinus na larvicultura pode ser iniciada no estágio II, com dieta úmida inerte e náuplios de Artemia, e pode ser recomendado o fornecimento exclusivo de dietas úmidas inertes a partir do estágio IX.(AU)

Economic-fishing analysis of the prawn cryphiops Caementarius (Molina, 1782) in the Majes-Camaná river Arequipa-Perú (2019) / Análise econômico-pesqueira do camarão Cryphiops caementarius (Molina, 1782) no rio Majes-Camaná Arequipa-Perú (2019)

The prawn (Cryphiops caementarius) is the only resource in the Peruvian coastal rivers that supports a commercial fishery. Bioeconomic-fishing aspects are reported based on data (fishing, costs and income derived from fishing) acquired in situ monthly in four altitudinal strata (every 200 meters above sea level - masl) of the Majes-Camaná river during 2019. The catch per unit of effort (CPUE) was expressed in kg h-¹, monthly income was estimated based on the average catch values, number of tasks and price of the resource. To evaluate the profitability of the activity of an average fisherman (by stratum), a cash flow based on income and expenses was executed under situations with a constant future, using economic profitability indicators such as the Net Present Value (NPV), Internal Rate of Return (IRR), Benefit-Cost ratio (B/C) and Discounted Payback Period (DPB). There was a predominance of the diving method, the catches (kg) and the fishing yield increased throughout the fishing period (April-December) with a maximum value of 4.8 kg h-¹ (December - high strata). Investment costs per fisherman were low, roughly 1,000 soles. The sale price increases with altitude, decreasing over the course of the year depending on the availability of the resource; the monthly income per fisherman varied from 964 soles (April - low stratum) to 6,760 soles (December - high stratum). The economic simulation model showed that the income exceeded the costs of the fishing activity from the first year of activity in all the altitudinal strata, the economic profitability indicators showed high profitability for the activity.

O camarão (Cryphiops caementarius) é o único recurso hidrobiológico dos rios da costa sul do Peru que sustenta uma importante pesca comercial. Os aspectos econômico-pesqueiros foram reportados a partir de dados (pesca, custos e receitas provenientes da pesca) adquiridos mensalmente in situ em quatro estratos altitudinais (a cada 200 m acima do nível do mar - mamsl) do rio Majes-Camaná - Arequipa durante 2019. A captura por unidade de esforço (CPUE) foi expressa em kg h-¹; a renda mensal foi estimada a partir dos valores médios de captura, número de operações e preço do recurso. Para avaliar a rentabilidade da atividade de um pescador médio (por estrato), foi executado um fluxo de caixa com base nas receitas e despesas em cenários futuros constantes, utilizando indicadores de rentabilidade econômica, como o valor presente líquido (VPL), taxa interna de retorno (TIR), relação custo-benefício (B/C) e período de reembolso descontado (PCR). Foi registado o predomínio do método de mergulho; as capturas (kg) e o rendimento pesqueiro aumentaram ao longo do período de pesca (abril-dezembro) com um valor máximo de 4,8 kg h-¹ (dezembro - estratos altos). Os custos de investimento por pescador foram baixos, aproximadamente 1.000 Novos sóis. O preço de venda aumentou com a altitude, reduzindo ao longo do ano dependendo da disponibilidade do recurso; a renda mensal por pescador variou de 964 Novos sóis (abril - estrato baixo) a 6.760 Novos sóis (dezembro - estrato alto). O modelo de simulação econômica mostrou que a receita superou os custos da atividade pesqueira desde o primeiro ano de atividade em todos os estratos altitudinais; os indicadores de rentabilidade econômica mostraram alta rentabilidade para a atividade.

Economic-fishing analysis of the prawn cryphiops Caementarius (Molina, 1782) in the Majes-Camaná river Arequipa-Perú (2019) / Análise econômico-pesqueira do camarão Cryphiops caementarius (Molina, 1782) no rio Majes-Camaná Arequipa-Perú (2019)

The prawn (Cryphiops caementarius) is the only resource in the Peruvian coastal rivers that supports a commercial fishery. Bioeconomic-fishing aspects are reported based on data (fishing, costs and income derived from fishing) acquired in situ monthly in four altitudinal strata (every 200 meters above sea level - masl) of the Majes-Camaná river during 2019. The catch per unit of effort (CPUE) was expressed in kg h-¹, monthly income was estimated based on the average catch values, number of tasks and price of the resource. To evaluate the profitability of the activity of an average fisherman (by stratum), a cash flow based on income and expenses was executed under situations with a constant future, using economic profitability indicators such as the Net Present Value (NPV), Internal Rate of Return (IRR), Benefit-Cost ratio (B/C) and Discounted Payback Period (DPB). There was a predominance of the diving method, the catches (kg) and the fishing yield increased throughout the fishing period (April-December) with a maximum value of 4.8 kg h-¹ (December - high strata). Investment costs per fisherman were low, roughly 1,000 soles. The sale price increases with altitude, decreasing over the course of the year depending on the availability of the resource; the monthly income per fisherman varied from 964 soles (April - low stratum) to 6,760 soles (December - high stratum). The economic simulation model showed that the income exceeded the costs of the fishing activity from the first year of activity in all the altitudinal strata, the economic profitability indicators showed high profitability for the activity.(AU)

O camarão (Cryphiops caementarius) é o único recurso hidrobiológico dos rios da costa sul do Peru que sustenta uma importante pesca comercial. Os aspectos econômico-pesqueiros foram reportados a partir de dados (pesca, custos e receitas provenientes da pesca) adquiridos mensalmente in situ em quatro estratos altitudinais (a cada 200 m acima do nível do mar - mamsl) do rio Majes-Camaná - Arequipa durante 2019. A captura por unidade de esforço (CPUE) foi expressa em kg h-¹; a renda mensal foi estimada a partir dos valores médios de captura, número de operações e preço do recurso. Para avaliar a rentabilidade da atividade de um pescador médio (por estrato), foi executado um fluxo de caixa com base nas receitas e despesas em cenários futuros constantes, utilizando indicadores de rentabilidade econômica, como o valor presente líquido (VPL), taxa interna de retorno (TIR), relação custo-benefício (B/C) e período de reembolso descontado (PCR). Foi registado o predomínio do método de mergulho; as capturas (kg) e o rendimento pesqueiro aumentaram ao longo do período de pesca (abril-dezembro) com um valor máximo de 4,8 kg h-¹ (dezembro - estratos altos). Os custos de investimento por pescador foram baixos, aproximadamente 1.000 Novos sóis. O preço de venda aumentou com a altitude, reduzindo ao longo do ano dependendo da disponibilidade do recurso; a renda mensal por pescador variou de 964 Novos sóis (abril - estrato baixo) a 6.760 Novos sóis (dezembro - estrato alto). O modelo de simulação econômica mostrou que a receita superou os custos da atividade pesqueira desde o primeiro ano de atividade em todos os estratos altitudinais; os indicadores de rentabilidade econômica mostraram alta rentabilidade para a atividade.(AU)

Natural diet of Macrobrachium brasiliense (Crustacea, Decapoda) in a Cerrado stream

ABSTRACT Knowledge about the diet of a given species is essential to provide information on the growth and maintenance of populations in a natural environment. Macrobrachium brasiliense (Heller, 1862) is a species of freshwater prawn widely distributed in Brazil, being frequent in aquatic environments inserted in the Cerrado biome. The aim of this study was to evaluate the natural diet of a population of M. brasiliense, comparing the consumed food items according to sex, seasonality and body size of individuals. Monthly collections were carried out between September 2018 and August 2019. The individuals collected had their sex identified and the length of the cephalothorax measured. Stomach content was assessed based on the degree of repletion, the method of points and the frequency of occurrence. There was a high frequency of plant material in the stomach contents and a smaller but significant frequency of aquatic insects. There were no significant differences regarding the diet of males and females and between the dry and rainy seasons. It was observed an increase in total insect consumption with the increase in size of males and females of M. brasiliense. A diet preference for Trichoptera was recorded in both sampling periods for males and females. The results obtained confirm an omnivorous diet for the species and suggest that the composition and proportion of items may vary depending on the size of the individuals and the availability of the items in the environment.

RESUMO O conhecimento acerca da dieta de uma determinada espécie é essencial para fornecer informações sobre o crescimento e manutenção das populações em ambiente natural. Macrobrachium brasiliense (Heller, 1862) é uma espécie de camarão de água doce com ampla distribuição no Brasil, ocorrendo frequentemente em ambientes aquáticos inseridos no bioma Cerrado. O objetivo deste estudo foi avaliar a dieta natural de uma população de M. brasiliense, comparando os itens alimentares consumidos em função do sexo, sazonalidade e tamanho corporal dos indivíduos. Foram realizadas coletas mensais entre setembro de 2018 a agosto de 2019. Os indivíduos coletados tiveram seu sexo identificado e o comprimento do cefalotórax mensurado. O conteúdo estomacal foi avaliado a partir do grau de repleção, método de pontos e de frequência de ocorrência. Verificou-se elevada frequência de detrito vegetal no conteúdo estomacal e uma frequência menor de insetos aquáticos, porém significativa. Não houve diferenças significativas quanto à dieta de machos e fêmeas e entre as estações seca e chuvosa. Foi observado um aumento do consumo total de insetos com aumento de tamanho de machos e fêmeas de M. brasiliense. Uma preferência de dieta por Trichoptera foi registrada em ambos os períodos de amostragem para machos e fêmeas.Os resultados obtidos confirmam uma dieta onívora para a espécie e sugerem que a composição e a proporção de itens podem variar em função do tamanho dos indivíduos e da disponibilidade dos itens no ambiente.

Diets for Macrobrachium acanthurus breeders: Sperm evaluation / Dietas para reprodutores de Macrobrachium acanthurus: avaliação espermática

The application of biotechnology in animal reproduction has enabled the production of young forms in both quantity and quality. Increasing the number of viable gametes produced by reproducers, among other factors, through an ideal diet, can ensure higher production. Therefore, the aim of this study was to determine the influence of three diets on the sperm survival of Macrobrachium acanthurus. To this end, 24 M. acanthurus males were used, distributed randomly and equally among treatments. Their diets were composed of 100% fresh food (fish and squid muscle - 14% protein), 100% dry feed (commercial feed - 50% protein) and a mixture of these diets containing 30% protein. Spermatophores were extracted through electrical stimulation every 15 days, and the controls consisted of spermatophores obtained directly from nature. No significant difference between diets was observed comparing shrimp and spermatophore weights. The 100% fresh diet provided the best sperm survival performance.

A aplicação de biotecnologias na reprodução animal tem possibilitado produzir formas jovens em quantidade e qualidade. O aumento da quantidade de gametas viáveis produzidos pelos reprodutores, mediante uma dieta ideal, entre outros fatores, pode garantir uma maior produção. Assim, o objetivo deste trabalho foi determinar o efeito de três dietas quanto à sobrevivência espermática de Macrobrachium acanthurus. Para tanto, 24 machos de M. acanthurus foram utilizados, sendo distribuídos ao acaso e de forma igual entre os tratamentos. As dietas foram compostas por 100% de alimento fresco (músculo de peixe e lula - 14% de proteína), 100% de alimento seco (ração comercial - 50% de proteína) e uma mescla dessas dietas contendo 30% de proteína. Os espermatóforos foram extraídos por eletroestimulação a cada 15 dias, sendo o controle aqueles obtidos diretamente da natureza. Não houve diferença significativa entre as dietas quando comparado os pesos dos camarões e dos espermatóforos. A alimentação 100% fresca proporcionou o melhor desempenho para a sobrevivência espermática.

Diets for Macrobrachium acanthurus breeders: Sperm evaluation / Dietas para reprodutores de Macrobrachium acanthurus: avaliação espermática

The application of biotechnology in animal reproduction has enabled the production of young forms in both quantity and quality. Increasing the number of viable gametes produced by reproducers, among other factors, through an ideal diet, can ensure higher production. Therefore, the aim of this study was to determine the influence of three diets on the sperm survival of Macrobrachium acanthurus. To this end, 24 M. acanthurus males were used, distributed randomly and equally among treatments. Their diets were composed of 100% fresh food (fish and squid muscle - 14% protein), 100% dry feed (commercial feed - 50% protein) and a mixture of these diets containing 30% protein. Spermatophores were extracted through electrical stimulation every 15 days, and the controls consisted of spermatophores obtained directly from nature. No significant difference between diets was observed comparing shrimp and spermatophore weights. The 100% fresh diet provided the best sperm survival performance.(AU)

A aplicação de biotecnologias na reprodução animal tem possibilitado produzir formas jovens em quantidade e qualidade. O aumento da quantidade de gametas viáveis produzidos pelos reprodutores, mediante uma dieta ideal, entre outros fatores, pode garantir uma maior produção. Assim, o objetivo deste trabalho foi determinar o efeito de três dietas quanto à sobrevivência espermática de Macrobrachium acanthurus. Para tanto, 24 machos de M. acanthurus foram utilizados, sendo distribuídos ao acaso e de forma igual entre os tratamentos. As dietas foram compostas por 100% de alimento fresco (músculo de peixe e lula - 14% de proteína), 100% de alimento seco (ração comercial - 50% de proteína) e uma mescla dessas dietas contendo 30% de proteína. Os espermatóforos foram extraídos por eletroestimulação a cada 15 dias, sendo o controle aqueles obtidos diretamente da natureza. Não houve diferença significativa entre as dietas quando comparado os pesos dos camarões e dos espermatóforos. A alimentação 100% fresca proporcionou o melhor desempenho para a sobrevivência espermática.(AU)

Animal performance and welfare of giant freshwater prawn (Macrobrachium rosenbergii) subjected to feed restriction

Behavior activities of giant freshwater prawn Macrobrachium rosenbergii juvenile, their performance, and acquired lesions when under temporary feed restrictions were analyzed. Five animals/experimental units (10 prawns/m2 ) were employed for treatments DFL ­ daily feed supply in the light phase; DFD ­ daily feed supply in the dark phase; AFL ­ alternating feed supply in the light phase; and AFD ­ alternating feed supply in the dark phase, for a 24-hour period, with four replications each. Prawns were fed a pellet diet, twice a day, with 10% of their biomass/day. Specimens were monitored during 60 consecutive days, with behavior recording daily and weighed every 10 days, with assessment of lesions and/or amputated limbs at the end of the experimental period. Types of behavior comprised exploring, grooming, inactivity, crawling, swimming, excavation, burrowing, agonism, and feed ingestion by scan sampling, with instantaneous registration every 60 s, in 15-min windows, before and after feed, in light and dark phases. Feed restricted in alternate days during light and dark phases did not interfere in growth or survival of the specimens, with increase in apparent feed intake and less feed conversion ratio and specific growth rate. Agonistic behavior was higher in specimens with feed restrictions, with an increase in the number of lesions and amputations. The above demonstrates welfare decrease in farmed M. rosenbergii and depreciation in the quality of the final product.(AU)

Reproductive aspects of the prawn Macrobrachium amazonicum in a continental population living downstream of a hydroelectric dam / Aspectos reprodutivos do camarão dulcícola Macrobrachium amazonicum em uma população vivendo a jusante da barragem de uma usina hidrelétrica

The migratory behavior of females of the freshwater prawn Macrobrachium amazonicum(Heller, 1862) can indicate a strategy that optimizes the population establishment. With this idea in mind, we evaluated the reproductive biology of M. amazonicum, hypothesizing that females were evenly distributed downstream of Hydroelectric Dam. Specimens were collected monthly for one year, from six sites of Rio Grande river. The specimens were sexed and measured (carapace length; CL). A total of 14,697 adults were captured, 2,864 males (AM), 11,082 non-breeding females (AF) and 751 breeding females (BF). The smallest BF had 3.8 mm CL. The distribution of demographic groups was assessed by a Principal Component Analysis (PCA), which explained 95.16% of the distribution over the collection sites. Breeding females were more abundant in the sites closest to the dam. This result can be explained by rainfall, which varied significantly throughout the year. As the breeding females migrated upstream toward the dam and were more abundant there, our hypothesis of homogeneous distribution was rejected. This behavior probably optimizes larval dispersion. The reproduction was continuous with peaks in the period preceding the maximum rainfall.

O comportamento migratório das fêmeas de Macrobrachium amazonicum (Heller, 1862) pode revelar estratégias para otimizar o estabelecimento da população. Com essa ideia em mente, avaliamos a biologia reprodutiva de M. amazonicum, hipotetizando que as fêmeas estavam uniformemente distribuídas a jusante da Usina Hidrelétrica. Os espécimes foram coletados mensalmente durante um ano, em seis localidades do Rio Grande, identificados quanto ao sexo e tiveram mensurado o comprimento da carapaça (CL). Foram capturados 14.697 camarões adultos, sendo 2.864 machos (AM), 11.082 fêmeas não-ovígeras (AF) e 751 fêmeas embrionadas (BF). A menor fêmea BF possuía 3,8 mm CL. A distribuição dos grupos demográficos foi avaliada por uma Análise de Componentes Principais (PCA), a qual explicou 95,16% da distribuição ao longo dos pontos de coleta (BF mais próximas da barragem). Tal explicação provavelmente foi relacionada com a precipitação, a qual variou significativamente ao longo do ano. Nossa hipótese de distribuição homogênea foi rejeitada, uma vez que as fêmeas ovígeras sobem o rio até as proximidades da barragem, provavelmente para otimizar a dispersão das larvas. A reprodução foi contínua com picos em períodos que antecedem os valores máximos de precipitação.

Reproductive aspects of the prawn Macrobrachium amazonicum in a continental population living downstream of a hydroelectric dam / Aspectos reprodutivos do camarão dulcícola Macrobrachium amazonicum em uma população vivendo a jusante da barragem de uma usina hidrelétrica

The migratory behavior of females of the freshwater prawn Macrobrachium amazonicum(Heller, 1862) can indicate a strategy that optimizes the population establishment. With this idea in mind, we evaluated the reproductive biology of M. amazonicum, hypothesizing that females were evenly distributed downstream of Hydroelectric Dam. Specimens were collected monthly for one year, from six sites of Rio Grande river. The specimens were sexed and measured (carapace length; CL). A total of 14,697 adults were captured, 2,864 males (AM), 11,082 non-breeding females (AF) and 751 breeding females (BF). The smallest BF had 3.8 mm CL. The distribution of demographic groups was assessed by a Principal Component Analysis (PCA), which explained 95.16% of the distribution over the collection sites. Breeding females were more abundant in the sites closest to the dam. This result can be explained by rainfall, which varied significantly throughout the year. As the breeding females migrated upstream toward the dam and were more abundant there, our hypothesis of homogeneous distribution was rejected. This behavior probably optimizes larval dispersion. The reproduction was continuous with peaks in the period preceding the maximum rainfall.(AU)

O comportamento migratório das fêmeas de Macrobrachium amazonicum (Heller, 1862) pode revelar estratégias para otimizar o estabelecimento da população. Com essa ideia em mente, avaliamos a biologia reprodutiva de M. amazonicum, hipotetizando que as fêmeas estavam uniformemente distribuídas a jusante da Usina Hidrelétrica. Os espécimes foram coletados mensalmente durante um ano, em seis localidades do Rio Grande, identificados quanto ao sexo e tiveram mensurado o comprimento da carapaça (CL). Foram capturados 14.697 camarões adultos, sendo 2.864 machos (AM), 11.082 fêmeas não-ovígeras (AF) e 751 fêmeas embrionadas (BF). A menor fêmea BF possuía 3,8 mm CL. A distribuição dos grupos demográficos foi avaliada por uma Análise de Componentes Principais (PCA), a qual explicou 95,16% da distribuição ao longo dos pontos de coleta (BF mais próximas da barragem). Tal explicação provavelmente foi relacionada com a precipitação, a qual variou significativamente ao longo do ano. Nossa hipótese de distribuição homogênea foi rejeitada, uma vez que as fêmeas ovígeras sobem o rio até as proximidades da barragem, provavelmente para otimizar a dispersão das larvas. A reprodução foi contínua com picos em períodos que antecedem os valores máximos de precipitação.(AU)

Sexual and reproductive traits of the pearl oyster shrimp Pontonia margarita (Decapoda: Palemonidae), symbiotically inhabiting the mantle cavity of the rugose pen shell Pinna rugosa (Bivalvia: Pinnidae)

Symbiosis between decapods and mollusks provides a unique opportunity to examine some of the evolutionary strategies employed by marine invertebrates. We describe the sexual and reproductive traits of the pearl oyster shrimp, Pontonia margarita Verril, 1869, found symbiotically inhabiting the mantle cavity of the rugose pen shell, Pinna rugosa Sowerby, 1835. Solitary males and females (ovigerous and non-ovigerous) and heterosexual pairs (with ovigerous and non-ovigerous females) were found in a total of 47 rugose pen shells collected from a sandy area with seagrass meadows on the southeastern coast of the Gulf of California, Mexico. The body length (BL) of female P. margarita was correlated with the shell volume of their rugose pen shell host. The sex ratio was female-biased (0.85M:1F). Female P. margarita were larger than their male counterparts in terms of BL, cephalothorax length (CL), and the maximum chelae length of the second pereopod (MCL). The CL and MCL were more strongly correlated for males (r = 0.70, p = 0.01). The number and volume of eggs per ovigerous female varied from 95 to 1,571 and from 5.46 ± 0.48 to 8.85 ± 0.97 mm3, respectively. Our results indicate polygamous behavior and social monogamy among P. margarita, and a short-term pairing system for their association with P. rugosa.

Sexual and reproductive traits of the pearl oyster shrimp Pontonia margarita (Decapoda: Palemonidae), symbiotically inhabiting the mantle cavity of the rugose pen shell Pinna rugosa (Bivalvia: Pinnidae)

Symbiosis between decapods and mollusks provides a unique opportunity to examine some of the evolutionary strategies employed by marine invertebrates. We describe the sexual and reproductive traits of the pearl oyster shrimp, Pontonia margarita Verril, 1869, found symbiotically inhabiting the mantle cavity of the rugose pen shell, Pinna rugosa Sowerby, 1835. Solitary males and females (ovigerous and non-ovigerous) and heterosexual pairs (with ovigerous and non-ovigerous females) were found in a total of 47 rugose pen shells collected from a sandy area with seagrass meadows on the southeastern coast of the Gulf of California, Mexico. The body length (BL) of female P. margarita was correlated with the shell volume of their rugose pen shell host. The sex ratio was female-biased (0.85M:1F). Female P. margarita were larger than their male counterparts in terms of BL, cephalothorax length (CL), and the maximum chelae length of the second pereopod (MCL). The CL and MCL were more strongly correlated for males (r = 0.70, p = 0.01). The number and volume of eggs per ovigerous female varied from 95 to 1,571 and from 5.46 ± 0.48 to 8.85 ± 0.97 mm3, respectively. Our results indicate polygamous behavior and social monogamy among P. margarita, and a short-term pairing system for their association with P. rugosa.(AU)