Ronaldo Cavalli | FURG - Universidade Federal do Rio Grande (original) (raw)
Papers by Ronaldo Cavalli
Revista Brasileira de Reprodução Animal, 2009
O presente artigo apresenta um breve histórico e a situação atual da piscicultura marinha no Bras... more O presente artigo apresenta um breve histórico e a situação atual da piscicultura marinha no Brasil. Ênfase será dada à biologia e ao estado da arte do cultivo do beijupirá (Rachycentron canadum), espécie nativa do litoral brasileiro que, nos últimos anos, vem sendo alvo de uma série de estudos e iniciativas de cultivo. As principais dificuldades e as perspectivas de desenvolvimento desta nova atividade no Brasil são discutidos.
Revista Brasileira de Engenharia de Pesca, Jul 20, 2020
This study assessed the gonadal development of cobia (Rachycentron canadum) reared in floating ca... more This study assessed the gonadal development of cobia (Rachycentron canadum) reared in floating cages off the coast of Pernambuco, northeastern Brazil, in order to verify the possibility that these fish would breed under these conditions. From the 132 individuals sampled between January and September 2011, total length (TL) varied between 26.2 and 61.0 cm, and the total weight (TW), between 121 and 2,436 g. The male to female ratio was 1:1 and the mean gonadosomatic index (IGS) of the females varied between 0.37 and 1.38; the highest value being classified as final maturation. For males, mean IGS ranged from 0.25 to 0.62. The distribution of TL and TW among males and females was not significantly different. Immature, maturing and fully mature males were collected. Conversely, the relatively short rearing period of nine months did not allow the sampling of fully mature females. Nevertheless, the present results indicate the possibility that cagereared cobia may produce offspring. The development of cobia farming in open waters off Pernambuco should therefore consider strategies to minimize or avoid the escape of eggs and/or larvae to the natural environment.
Zootecnica e Nutrizione Animale, 1990
Boletim Do Instituto De Pesca, 2009
Food Chemistry, Dec 1, 2011
An alkaline peptidase was purified from the viscera of the silver mojarra (Diapterus rhombeus) in... more An alkaline peptidase was purified from the viscera of the silver mojarra (Diapterus rhombeus) in a threestep process: heat treatment, ammonium sulphate fractionation and molecular exclusion chromatography (Sephadex Ò G-75), with final specific activity 86-fold higher than the enzyme extract and yield of 22.1%. The purified enzyme had an estimated molecular mass of 26.5 kDa and NH 2-terminal amino acid sequence IVGGYECTMHSEAHE. Higher enzyme activity was observed at pH 8.5 and between 50 and 55°C. The enzyme was completely inactivated after 30 min at 55°C and it was significantly more stable at alkaline pH. K m , K cat and K cat Á K À1 m values, using BApNA as substrate, were 0.266 mM, 0.93 s À1 and 3.48 mM À1 s À1 , respectively. Enzyme activity increased in the presence of the ions (1 mM) K + , Li + and Ca 2+ , but was inhibited by Fe 2+ , Cd 2+ , Cu 2+ , Al 3+ , Hg 2+ , Zn 2+ and Pb 2+ as well as by the trypsin inhibitors TLCK and benzamidine.
Aquaculture Reports, Nov 1, 2020
This study assessed the activity of the main digestive enzymes in juveniles of the painted river ... more This study assessed the activity of the main digestive enzymes in juveniles of the painted river prawn Macrobrachium carcinus. Prawns reared in 24 m 2 tanks at a density of 10 individuals. m − 2 for 45 days were fed a commercial diet with 40 % crude protein. A sample of 21 prawns with 2.92 ± 0.60 g and 27.87 ± 1.50 mm had their midgut glands (MG) dissected. Assays prospecting total proteolytic activity, total amylase, α-amylase, trypsin, chymotrypsin, β-galactosidase, agarase and lipase in the MG were performed. The activities of several aminopeptidase (alanine, arginine, glycine, histidine, isoleucine, leucine, proline and tyrosine aminopeptidase) were also evaluated. In addition, the effect of calcium (CaCl 2) on trypsin activity was assessed. The following mean (± SD) activities were found: total proteolytic activity (8.00 ± 0.003 U.mg-1); total amylase (0.322 ± 0.002 U.mg-1); α-amylase (8.730 ± 0.008 U.mg-1); trypsin (12.7 ± 0.001 mU.mg-1); chymotrypsin (19.94 ± 0.0019 mU. mg-1); β-galactosidase (59.4 ± 0.18 U.mg-1); agarase (13.34 ± 0.15 U.mg-1) and lipase (0.019 ± 2.73 U.mg-1). Amongst aminopeptidases, only alanine, arginine, glycine and leucine aminopeptidase were found to be active. At concentrations from 5 to 90 mM, the activity of trypsin was not affected by CaCl 2. Compared to other prawn species, M. carcinus has a wide range of digestive enzymes and a tendency towards greater use of animal protein. As studies on the digestive enzymes of juvenile prawns of the Macrobrachium genus are scarce, the present results represent basic data that may serve as a reference for future studies and also aid in the formulation of diets specific for this important group of crustaceans.
Aquaculture, Nov 10, 2003
ABSTRACT The effects of vitamin C (ascorbic acid, AA) and vitamin E (tocopherol) on the maternal ... more ABSTRACT The effects of vitamin C (ascorbic acid, AA) and vitamin E (tocopherol) on the maternal performance and offspring quality of the freshwater prawn Macrobrachium rosenbergii were investigated. Prawn females were fed four diets containing different levels of 2-ascorbyl-l-polyphosphate (ApP) and α-tocopherol acetate (α-TA) during 155 days. Three diets contained increasing AA levels (59, 121 and 918 μg g−1 DW) and a basal level of α-TA (around 300 μg g−1 DW), while a fourth diet contained comparatively higher α-TA levels (899 μg g−1 DW) combined with 957 μg AA g−1 DW. Higher dietary levels of AA and α-TA did not affect moulting, growth, or mortality rates of the broodstock. Also, breeding frequency and fecundity were not related to the dietary treatments. However, the contents of AA and α-tocopherol in the midgut gland, ovary, eggs, and newly hatched larvae increased along with higher dietary levels of these vitamins. Larvae from females fed higher levels of AA and α-TA tended to present an increased tolerance when exposed to increasing ammonia concentrations. The present results therefore suggest that broodstock diets containing around 60 μg AA g−1 DW and 300 μg α-TA g−1 DW are sufficient to ensure proper reproduction and offspring viability. However, feeding M. rosenbergii females higher dietary levels of both AA and α-TA (each around 900 μg g−1 DW) might increase larval quality, as demonstrated in this study by the higher tolerance to the exposure to ammonia.
Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, Aug 1, 2022
Effect of different diet pellet sizes on the growth of juvenile cobia (Rachycentron canadum) [Efe... more Effect of different diet pellet sizes on the growth of juvenile cobia (Rachycentron canadum) [Efeito de diferentes tamanhos de pellets sobre o crescimento de juvenis de bijupirá (Rachycentron canadum)]
Agrária, Sep 30, 2018
This study identified regions of the Brazilian coast that present more adequate temperature condi... more This study identified regions of the Brazilian coast that present more adequate temperature conditions for the cage culture of cobia (Rachycentron canadum). A survey of sea surface temperatures (SST) along the coast (up to the 200 m isobath) used data from the Aqua/NASA satellite. Water temperature classes that affect the development of cobia and may lead to changes in physiological activities, especially related to feed intake, growth, and mortality, were established, according to the literature. Cobia is able to grow at temperatures between 19 and 32 ºC, but the range considered optimum for growth was 27-29 ºC. The coastal area stretching from eastern Pará to the north of Bahia was considered to have the most suitable temperature conditions for commercial aquaculture of cobia. The coastline encompassing the state of Amapá to the west of Pará, and the whole coast of the southeast region presented SSTs above or below the range considered optimum for the growth of cobia, respectively. In the southern coast of Brazil, the commercial farming of cobia may not be feasible due to the low SST during most of the year.
Fishes
The effects of temperature manipulation, addition of sperm solution, and exposure to alkalized pH... more The effects of temperature manipulation, addition of sperm solution, and exposure to alkalized pH and/or hydrogen peroxide (H2O2) as possible spawning inducers in laboratory-conditioned and unconditioned adults of the yellow clam (Amarilladesma mactroides) were evaluated. In three trials, clams were laboratory-conditioned for 14 days and exposed to thermal shocks (from 20 °C to 23–29 °C), while clams from three additional trials were not conditioned but acclimatized for 45 min before spawning induction. Although conditioning advanced gonad maturity and increased the condition factor, none of the thermal treatments triggered spawning in these first trials. Histological analysis indicated that the gonads of conditioned clams were not mature. Alternatively, unfertilized and fertilized eggs, and larvae were observed after unconditioned clams were induced to spawn. The gonads of unconditioned clams were in an advanced stage of maturity. Exposure to temperature shocks, alone or in combina...
Brazilian Journal of Biology
The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern B... more The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern Brazil to the north coast of Argentina. In the last decades, populations of this species have been impacted by mass mortality events, overfishing and other anthropogenic activities. The production of juveniles in captivity would allow feasibility studies to be carried out to restore the natural stock as well as the production in aquaculture systems. Given the scarcity of studies on the maintenance of this species in captivity, a culture system and a management protocol were developed and tested. Wild-caught clams (total length ≥50 mm) were used in a series of 14 day-long trials. Survival was higher in clams that were allowed to bury into the sand. A permanent ink marker covered with a thin layer of a quick-hardening adhesive proved to be a reliable method to tag clams. The maintenance of yellow clams in this system resulted in high survival and growth, increases in the condition factor an...
Avances en Nutrición Acuicola, 2008
Journal of Shellfish Research, 2001
Boletim Do Instituto De Pesca, 2014
The farming of cobia ( Rachycentron canadum ) in offshore floating cages has been a subject of re... more The farming of cobia ( Rachycentron canadum ) in offshore floating cages has been a subject of recent research efforts and commercial ventures in Brazil. This study presents an economic feasibility analysis of an experimental farm off the coast of Pernambuco, northeastern Brazil. Different levels of productivity (5, 10 and 15 kg m-3), sale prices (R$ 7.00, R$ 11.00 and R$ 15.00 kg-1) and farm size (6, 12 and 24 cages of 1,600 m³) were considered. Given these scenarios, the offshore farming of cobia will only be profitable when the sale price is R$ 15.00 kg-1 and the productivity is equal or higher than 10 kg m-3. If the sale price is R$ 11.00 kg-1, cobia farming would only be feasible if 15 kg m-3 are produced in 12 or more cages. Feed ranged from 39.8 to 76.4% of operating expenses according to the productivity level. Offshore farming of cobia in northeastern Brazil may be economically feasible, but it becomes more attractive with an increased number of production units. The needs ...
Boletim Do Instituto De Pesca, 2018
The effect of unilateral eyestalk ablation on ovarian histology of Farfantepenaeus paulensis afte... more The effect of unilateral eyestalk ablation on ovarian histology of Farfantepenaeus paulensis after spawning was evaluated in the present study. Wild females were captured in deep-sea waters of southern Brazil (27°S) and randomly divided in two groups: unilaterally eyestalk ablated and unablated (intact) females. A total of six eyestalk ablated and five unablated females were sampled after spawning in separated tanks. Morphological variables were recorded and ovaries were histologically evaluated according to oocyte type and diameter. In the ovarian tissue of unablated females, basophilic oocytes (48.8 ± 18.7 µm) were dominant (99.7 ± 0.6%), with presence significantly lower in the ablated females (93.5 ± 13.8%). Larger acidophilic oocytes (114.9 ± 16.9 µm), with yolk granules in the cytoplasm, were detected only in the ovaries of ablated females. The significantly higher occurrence of atretic oocytes (4.8 ± 10.3%) is another distinguishable feature in the ovaries of ablated females ...
This study identified regions of the Brazilian coast that present more adequate temperature condi... more This study identified regions of the Brazilian coast that present more adequate temperature conditions for the cage culture of cobia ( Rachycentron canadum ). A survey of sea surface temperatures (SST) along the coast (up to the 200 m isobath) used data from the Aqua/NASA satellite. Water temperature classes that affect the development of cobia and may lead to changes in physiological activities, especially related to feed intake, growth, and mortality, were established, according to the literature. Cobia is able to grow at temperatures between 19 and 32 oC, but the range considered optimum for growth was 27–29 oC. The coastal area stretching from eastern Para to the north of Bahia was considered to have the most suitable temperature conditions for commercial aquaculture of cobia. The coastline encompassing the state of Amapa to the west of Para, and the whole coast of the southeast region presented SSTs above or below the range considered optimum for the growth of cobia, respective...
Regional Studies in Marine Science, 2021
Aquaculture Reports, 2021
Abstract Aquaculture in Brazil probably started in the 17th century, during the Dutch occupation ... more Abstract 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.
Revista Brasileira de Reprodução Animal, 2009
O presente artigo apresenta um breve histórico e a situação atual da piscicultura marinha no Bras... more O presente artigo apresenta um breve histórico e a situação atual da piscicultura marinha no Brasil. Ênfase será dada à biologia e ao estado da arte do cultivo do beijupirá (Rachycentron canadum), espécie nativa do litoral brasileiro que, nos últimos anos, vem sendo alvo de uma série de estudos e iniciativas de cultivo. As principais dificuldades e as perspectivas de desenvolvimento desta nova atividade no Brasil são discutidos.
Revista Brasileira de Engenharia de Pesca, Jul 20, 2020
This study assessed the gonadal development of cobia (Rachycentron canadum) reared in floating ca... more This study assessed the gonadal development of cobia (Rachycentron canadum) reared in floating cages off the coast of Pernambuco, northeastern Brazil, in order to verify the possibility that these fish would breed under these conditions. From the 132 individuals sampled between January and September 2011, total length (TL) varied between 26.2 and 61.0 cm, and the total weight (TW), between 121 and 2,436 g. The male to female ratio was 1:1 and the mean gonadosomatic index (IGS) of the females varied between 0.37 and 1.38; the highest value being classified as final maturation. For males, mean IGS ranged from 0.25 to 0.62. The distribution of TL and TW among males and females was not significantly different. Immature, maturing and fully mature males were collected. Conversely, the relatively short rearing period of nine months did not allow the sampling of fully mature females. Nevertheless, the present results indicate the possibility that cagereared cobia may produce offspring. The development of cobia farming in open waters off Pernambuco should therefore consider strategies to minimize or avoid the escape of eggs and/or larvae to the natural environment.
Zootecnica e Nutrizione Animale, 1990
Boletim Do Instituto De Pesca, 2009
Food Chemistry, Dec 1, 2011
An alkaline peptidase was purified from the viscera of the silver mojarra (Diapterus rhombeus) in... more An alkaline peptidase was purified from the viscera of the silver mojarra (Diapterus rhombeus) in a threestep process: heat treatment, ammonium sulphate fractionation and molecular exclusion chromatography (Sephadex Ò G-75), with final specific activity 86-fold higher than the enzyme extract and yield of 22.1%. The purified enzyme had an estimated molecular mass of 26.5 kDa and NH 2-terminal amino acid sequence IVGGYECTMHSEAHE. Higher enzyme activity was observed at pH 8.5 and between 50 and 55°C. The enzyme was completely inactivated after 30 min at 55°C and it was significantly more stable at alkaline pH. K m , K cat and K cat Á K À1 m values, using BApNA as substrate, were 0.266 mM, 0.93 s À1 and 3.48 mM À1 s À1 , respectively. Enzyme activity increased in the presence of the ions (1 mM) K + , Li + and Ca 2+ , but was inhibited by Fe 2+ , Cd 2+ , Cu 2+ , Al 3+ , Hg 2+ , Zn 2+ and Pb 2+ as well as by the trypsin inhibitors TLCK and benzamidine.
Aquaculture Reports, Nov 1, 2020
This study assessed the activity of the main digestive enzymes in juveniles of the painted river ... more This study assessed the activity of the main digestive enzymes in juveniles of the painted river prawn Macrobrachium carcinus. Prawns reared in 24 m 2 tanks at a density of 10 individuals. m − 2 for 45 days were fed a commercial diet with 40 % crude protein. A sample of 21 prawns with 2.92 ± 0.60 g and 27.87 ± 1.50 mm had their midgut glands (MG) dissected. Assays prospecting total proteolytic activity, total amylase, α-amylase, trypsin, chymotrypsin, β-galactosidase, agarase and lipase in the MG were performed. The activities of several aminopeptidase (alanine, arginine, glycine, histidine, isoleucine, leucine, proline and tyrosine aminopeptidase) were also evaluated. In addition, the effect of calcium (CaCl 2) on trypsin activity was assessed. The following mean (± SD) activities were found: total proteolytic activity (8.00 ± 0.003 U.mg-1); total amylase (0.322 ± 0.002 U.mg-1); α-amylase (8.730 ± 0.008 U.mg-1); trypsin (12.7 ± 0.001 mU.mg-1); chymotrypsin (19.94 ± 0.0019 mU. mg-1); β-galactosidase (59.4 ± 0.18 U.mg-1); agarase (13.34 ± 0.15 U.mg-1) and lipase (0.019 ± 2.73 U.mg-1). Amongst aminopeptidases, only alanine, arginine, glycine and leucine aminopeptidase were found to be active. At concentrations from 5 to 90 mM, the activity of trypsin was not affected by CaCl 2. Compared to other prawn species, M. carcinus has a wide range of digestive enzymes and a tendency towards greater use of animal protein. As studies on the digestive enzymes of juvenile prawns of the Macrobrachium genus are scarce, the present results represent basic data that may serve as a reference for future studies and also aid in the formulation of diets specific for this important group of crustaceans.
Aquaculture, Nov 10, 2003
ABSTRACT The effects of vitamin C (ascorbic acid, AA) and vitamin E (tocopherol) on the maternal ... more ABSTRACT The effects of vitamin C (ascorbic acid, AA) and vitamin E (tocopherol) on the maternal performance and offspring quality of the freshwater prawn Macrobrachium rosenbergii were investigated. Prawn females were fed four diets containing different levels of 2-ascorbyl-l-polyphosphate (ApP) and α-tocopherol acetate (α-TA) during 155 days. Three diets contained increasing AA levels (59, 121 and 918 μg g−1 DW) and a basal level of α-TA (around 300 μg g−1 DW), while a fourth diet contained comparatively higher α-TA levels (899 μg g−1 DW) combined with 957 μg AA g−1 DW. Higher dietary levels of AA and α-TA did not affect moulting, growth, or mortality rates of the broodstock. Also, breeding frequency and fecundity were not related to the dietary treatments. However, the contents of AA and α-tocopherol in the midgut gland, ovary, eggs, and newly hatched larvae increased along with higher dietary levels of these vitamins. Larvae from females fed higher levels of AA and α-TA tended to present an increased tolerance when exposed to increasing ammonia concentrations. The present results therefore suggest that broodstock diets containing around 60 μg AA g−1 DW and 300 μg α-TA g−1 DW are sufficient to ensure proper reproduction and offspring viability. However, feeding M. rosenbergii females higher dietary levels of both AA and α-TA (each around 900 μg g−1 DW) might increase larval quality, as demonstrated in this study by the higher tolerance to the exposure to ammonia.
Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, Aug 1, 2022
Effect of different diet pellet sizes on the growth of juvenile cobia (Rachycentron canadum) [Efe... more Effect of different diet pellet sizes on the growth of juvenile cobia (Rachycentron canadum) [Efeito de diferentes tamanhos de pellets sobre o crescimento de juvenis de bijupirá (Rachycentron canadum)]
Agrária, Sep 30, 2018
This study identified regions of the Brazilian coast that present more adequate temperature condi... more This study identified regions of the Brazilian coast that present more adequate temperature conditions for the cage culture of cobia (Rachycentron canadum). A survey of sea surface temperatures (SST) along the coast (up to the 200 m isobath) used data from the Aqua/NASA satellite. Water temperature classes that affect the development of cobia and may lead to changes in physiological activities, especially related to feed intake, growth, and mortality, were established, according to the literature. Cobia is able to grow at temperatures between 19 and 32 ºC, but the range considered optimum for growth was 27-29 ºC. The coastal area stretching from eastern Pará to the north of Bahia was considered to have the most suitable temperature conditions for commercial aquaculture of cobia. The coastline encompassing the state of Amapá to the west of Pará, and the whole coast of the southeast region presented SSTs above or below the range considered optimum for the growth of cobia, respectively. In the southern coast of Brazil, the commercial farming of cobia may not be feasible due to the low SST during most of the year.
Fishes
The effects of temperature manipulation, addition of sperm solution, and exposure to alkalized pH... more The effects of temperature manipulation, addition of sperm solution, and exposure to alkalized pH and/or hydrogen peroxide (H2O2) as possible spawning inducers in laboratory-conditioned and unconditioned adults of the yellow clam (Amarilladesma mactroides) were evaluated. In three trials, clams were laboratory-conditioned for 14 days and exposed to thermal shocks (from 20 °C to 23–29 °C), while clams from three additional trials were not conditioned but acclimatized for 45 min before spawning induction. Although conditioning advanced gonad maturity and increased the condition factor, none of the thermal treatments triggered spawning in these first trials. Histological analysis indicated that the gonads of conditioned clams were not mature. Alternatively, unfertilized and fertilized eggs, and larvae were observed after unconditioned clams were induced to spawn. The gonads of unconditioned clams were in an advanced stage of maturity. Exposure to temperature shocks, alone or in combina...
Brazilian Journal of Biology
The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern B... more The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern Brazil to the north coast of Argentina. In the last decades, populations of this species have been impacted by mass mortality events, overfishing and other anthropogenic activities. The production of juveniles in captivity would allow feasibility studies to be carried out to restore the natural stock as well as the production in aquaculture systems. Given the scarcity of studies on the maintenance of this species in captivity, a culture system and a management protocol were developed and tested. Wild-caught clams (total length ≥50 mm) were used in a series of 14 day-long trials. Survival was higher in clams that were allowed to bury into the sand. A permanent ink marker covered with a thin layer of a quick-hardening adhesive proved to be a reliable method to tag clams. The maintenance of yellow clams in this system resulted in high survival and growth, increases in the condition factor an...
Avances en Nutrición Acuicola, 2008
Journal of Shellfish Research, 2001
Boletim Do Instituto De Pesca, 2014
The farming of cobia ( Rachycentron canadum ) in offshore floating cages has been a subject of re... more The farming of cobia ( Rachycentron canadum ) in offshore floating cages has been a subject of recent research efforts and commercial ventures in Brazil. This study presents an economic feasibility analysis of an experimental farm off the coast of Pernambuco, northeastern Brazil. Different levels of productivity (5, 10 and 15 kg m-3), sale prices (R$ 7.00, R$ 11.00 and R$ 15.00 kg-1) and farm size (6, 12 and 24 cages of 1,600 m³) were considered. Given these scenarios, the offshore farming of cobia will only be profitable when the sale price is R$ 15.00 kg-1 and the productivity is equal or higher than 10 kg m-3. If the sale price is R$ 11.00 kg-1, cobia farming would only be feasible if 15 kg m-3 are produced in 12 or more cages. Feed ranged from 39.8 to 76.4% of operating expenses according to the productivity level. Offshore farming of cobia in northeastern Brazil may be economically feasible, but it becomes more attractive with an increased number of production units. The needs ...
Boletim Do Instituto De Pesca, 2018
The effect of unilateral eyestalk ablation on ovarian histology of Farfantepenaeus paulensis afte... more The effect of unilateral eyestalk ablation on ovarian histology of Farfantepenaeus paulensis after spawning was evaluated in the present study. Wild females were captured in deep-sea waters of southern Brazil (27°S) and randomly divided in two groups: unilaterally eyestalk ablated and unablated (intact) females. A total of six eyestalk ablated and five unablated females were sampled after spawning in separated tanks. Morphological variables were recorded and ovaries were histologically evaluated according to oocyte type and diameter. In the ovarian tissue of unablated females, basophilic oocytes (48.8 ± 18.7 µm) were dominant (99.7 ± 0.6%), with presence significantly lower in the ablated females (93.5 ± 13.8%). Larger acidophilic oocytes (114.9 ± 16.9 µm), with yolk granules in the cytoplasm, were detected only in the ovaries of ablated females. The significantly higher occurrence of atretic oocytes (4.8 ± 10.3%) is another distinguishable feature in the ovaries of ablated females ...
This study identified regions of the Brazilian coast that present more adequate temperature condi... more This study identified regions of the Brazilian coast that present more adequate temperature conditions for the cage culture of cobia ( Rachycentron canadum ). A survey of sea surface temperatures (SST) along the coast (up to the 200 m isobath) used data from the Aqua/NASA satellite. Water temperature classes that affect the development of cobia and may lead to changes in physiological activities, especially related to feed intake, growth, and mortality, were established, according to the literature. Cobia is able to grow at temperatures between 19 and 32 oC, but the range considered optimum for growth was 27–29 oC. The coastal area stretching from eastern Para to the north of Bahia was considered to have the most suitable temperature conditions for commercial aquaculture of cobia. The coastline encompassing the state of Amapa to the west of Para, and the whole coast of the southeast region presented SSTs above or below the range considered optimum for the growth of cobia, respective...
Regional Studies in Marine Science, 2021
Aquaculture Reports, 2021
Abstract Aquaculture in Brazil probably started in the 17th century, during the Dutch occupation ... more Abstract 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.