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Tilapia aquaculture is one of the fastest-growing segments of fish production in Brazil. Nile tilapia ( Oreochromis niloticus) is largely cultivated in the state of Parana, where Streptococcus agalactiae is the cause of severe disease outbreaks. The objective of this paper was to evaluate an inactivated S. agalactiae vaccine in tilapia for the control of streptococcal disease outbreaks. Tilapia, weighing approximately 20 g each, were intraperitoneally (i.p.) inoculated with 0.1 mL of the vaccine at a dose of 2.0 × 108 colony-forming unit (CFU) mL−1. One group of tilapia (treatment 1) received one vaccine dose, and the other group of tilapia (treatment 2) received two doses, with an interval of 21 days. The control group was i.p. inoculated with 0.1 mL tryptic soy broth fish−1. Immunized and control tilapia were i.p. challenged with 0.1 mL of 3.0 × 107 CFU mL−1 at 30 days post vaccination. The fish were monitored daily for disease signs and for mortality for 16 days post challenge. A statistically significant difference ( P=0.0045) was found between the mortality of treatments 1 and 2. The value of relative per cent of survival of 83.6% and 96.4%, respectively, indicate that this vaccine was efficient in Nile tilapia. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize the limnological parameters and analyse the biological effects of different ponds in a commercial fish farm in the Pará State, Brazil. One pond is designated for fingerling production (N) while the other is for fattening and termination (F). The other three ponds are named supply tanks, from which the water from the Parauapebas River is collected to fill N and F tanks. For the physical–chemical analysis, samples from N and F ponds were collected at a depth of 50 cm close to the water's outlets of the ponds, with the aid of a commercial kit for water analysis. Caenorhabditis elegans nematodes were used for water quality biomonitoring and exposed for 24 h to samples from all five tanks collected during three different days, being assessed through physiological endpoints. During the study, values of transparency and pH were higher in N, both with significant differences between the ponds. The other parameters did not show any differences among them in the different days and times analysed. The results showed that the water quality of N and F ponds is in accordance with the current legislation in the country. Despite being in accordance with legislation and with acceptable metal levels, samples caused toxicity to worms, which indicate that for fish production, a continuous supervision is essential for the success of the activity. Therefore, the limnological variables in relation to biomonitoring should be constantly assessed in fish farm enterprises in order to maintain a more efficient and sustainable productive system. [ABSTRACT FROM AUTHOR]

This work aimed to assess the occurrence of compensatory growth in Nodipecten nodosus farmed in Caraguatatuba, Brazil, during intermediate phase at the densities of 50 (control), 800, 1600 and 3200 m−2. Subsequently the densities were reduced to 50 m−2 for the growout phase, in which each treatment consisted of scallops originating from the same density used during the intermediate phase, with mean height equal to the average recorded in each density. The treatments were named according to the original density (T50, T800, T1600 and T3200). At the end of the intermediate phase, height, survival and specific growth rate (SGR) were significantly higher for the density of 50 m−2. After the growout phase, height was higher in T50, but the total SGR and increase in height were lower. Survivals, adductor muscle dry weight, total dry weight and condition index did not differ significantly. In addition, during the intermediate phase, SGR was higher in scallops at 50 m−2, but, at the beginning of the growout phase, SGR decreased in T50 scallops and increased in those of the other treatments. The results indicated the occurrence of compensatory growth in N. nodosus, which would allow increasing stocking densities in the intermediate phase. [ABSTRACT FROM AUTHOR]

Several routine aquaculture practices, such as densification, handling and transport, are considered potential stressors and can cause physiological alterations that compromise the animals' welfare and survival. Studies of plant‐based anaesthetic products have become a trend worldwide, mainly due to their potential uses and the variety of species that can provide suitable substances. In Brazil, the use of essential oils (EO) in fish farming for use in sedation and anaesthesia has already been explored. However, despite the excellent biological activity of the EO, as a result of their main compounds or due to the synergy between the active compounds, it is also necessary to investigate the adverse effects that they can cause and accordingly establish the appropriate dosage for their use. Sedative and anaesthetic properties of the EOs of at least 30 plant species have been described for native fish species reared in Brazil such as Colossoma macropomum, Rhamdia quelen, Brycon amazonicus, Lophiosilurus alexandri, Piaractus mesopotamicus, P. mesopotamicus × C. macropomum, Pseudoplatystoma reticulatum and Serrasalmus rhombeus. However, the mechanisms of action of the EOs need to be elucidated, as well as the undesirable side effects they may cause in fish. This review presents information on the use of EOs as anaesthetics and sedatives in native fish species farmed in Brazil, with emphasis on C. macropomum and, as a future perspective, the application of new technologies is emphasized to potentialize the biological activities of EOs, thus contributing with environment‐friendly natural alternatives for the promotion of sustainable aquaculture. [ABSTRACT FROM AUTHOR]

Studies of acanthocephalans have increased due to outbreaks in Brazilian fish farms. This review aimed to compile results of studies carried out in Brazil, which have reported occurrences of acanthocephalans in fish from fish farms, discuss histopathological and haematological implications, and describe the different treatments in use to combat these parasites. Scientific articles, short communications, monographs, dissertations and theses are included. Eight species of acanthocephalans have been recorded: Neoechinorhynchus buttnerae, Neoechinorhynchus sp. and Echinorhynchus jucundus, Echinorhynchus gomesi, Polyacanthorhynchus macrorhynchus, Polyacanthorhynchus sp., Pomphorhynchus sp., and Quadrigyrus sp. Studies of histopathology and haematology have reported perforations, inflammation and changes in host intestines and immune cells, due to infection with acanthocephalans. Early-stage testing, both in vitro and in vivo, has shown essential oils, oleoresins and plant extracts to be highly efficacious in combating acanthocephalans. However, there are no national records regulating the use of these anthelmintics in commercial fish farms. In view of this, we are recommending good management practices, including (a) cleaning tanks after fish removal (drying the soil and adding hydrated lime); (b) crop cycles with time intervals, (c) acquisition of healthy fry followed by quarantine; and (d) controlled feeding. [ABSTRACT FROM AUTHOR]

Worldwide, the availability of suitable areas for aquaculture has become a significant concern. In Brazil, the former Ministry of Fisheries and Aquaculture (MPA) has begun to promote discussions and plan meetings on Local Mariculture Development Plans (PLDMs): a planning tool for the establishment of parks and aquatic areas. However, hundreds of groups and individuals still practice aquaculture awaiting a definitive license. This study aimed to serve as a tool to identify suitable sites for the installation of cobia cage farming and also to contribute to the PLDM zoning process. We created 27 criterion maps for marine fish farming. Their individual weights were assigned based on the best judgment of technicians, researchers and other stakeholders using the pair‐wise comparison method. The criteria and their weights were combined using multi‐criteria decision rules, and a final map according to suitability was derived by reclassification. Of the total area, 54,663 ha (14%) were composed of restrictions, and 341,083 ha (86%) were found useful; of which <1% is considered top score. Even so, these are more than enough to ensure the growth of activity. In Rio de Janeiro state, two bays have suitable areas to marine fish culture development. To ensure the sustainability of marine fish farming, we suggested the adoption of limited production areas based on assimilation and production capacity. Through this methodological approach, it was possible to identify suitable areas for cobia farming development. Additionally, the results may serve as a useful tool on which the PLDM can be based on. [ABSTRACT FROM AUTHOR]

In Southeastern Brazil, there is good cultivation potential for the pearl oyster Pinctada imbricata, which is often found on mussel ropes or seed collectors across the north coast of Sao Paulo State. Despite this, very few studies have focused on the biology of this species in Brazil. This research aimed to partially address this lack of information by evaluating the optimal season and preferred depth range (surface, first and second metres of depth) for the settlement of juvenile P. imbricata on artificial collectors. Two replicate artificial collectors made from braided fishing nets and comprising of horizontally and vertically suspended lines were deployed at Cocanha Beach, Brazil, and left in situ for a period of 5 months. At the end of the deployment period, the density of juveniles was significantly greater on the surface than the first and second metres of depth. It was also found that the period from November to March was more favourable for the placement of collectors and settlement of juveniles. Furthermore the results of the study confirm that is feasible to capture juvenile P. imbricata using artificial collectors to provide a continuous supply of commercial cultures. [ABSTRACT FROM AUTHOR]

Black catfish ( Rhamdia quelen) is a species of interest for aquaculture in Brazil, Argentina and Uruguay. A feeding trial was conducted to evaluate the effect of feeding R. quelen larvae on either only an artificial diet or in combination with Artemia nauplii (AN) on larval performance and fatty acid composition. For 12 days, larvae were fed from first feeding (3 days after hatching, TL = 5.88 ± 0.23 mm) with artificial food only or a combination of artificial food and AN (co-feeding). At the end of the trial, total length of co-fed larvae was significantly higher than that of larvae fed solely artificial food ( P < 0.001). No significant differences were found in survival rates. Co-feeding microdiet with a small amount of AN significantly affected larval fatty acid composition. Lipid and fatty acid composition of food and larvae revealed the importance of n-3 fatty acids for growth of black catfish larvae and that, as most freshwater fish, R. quelen larvae can elongate and desaturate linolenic acid to n-3 highly unsaturated fatty acids. Results suggest that R. quelen larvae can be fed from first feeding on microdiets as unique food source, although better larval performances are obtained by co-feeding with a small amount of AN. [ABSTRACT FROM AUTHOR]

The article discusses a study on the effect of the salinity on the daily growth rate (DGR) and carrageenan yield (CY) of Kappaphycus alvarezii, a type of gigartinales. The study examined the effect of different salinities of green, brown, and red varieties of K. alvarezii found at Praia Grande, Itacuruçá Island, Brazil. It found the brown variant had higher DGR results at a lower salinity than the others. Further details of the results are offered.

The conversion of mangrove areas into shrimp farming ponds has been indicated as the main activity responsible for the reduction in the area of this ecosystem along the northeastern coast of Brazil. The present study was conducted using remote sensing methods and a geographical information system with the aim of quantifying the participation of this activity in the reduction of the mangrove areas along the northern coast of the State of Pernambuco (northeast, Brazil), where shrimp farming has been implanted in last recent years. From 1973 to 2005, there was reduction of about 2.052 ha of mangrove, 197 ha of which were converted into shrimp ponds. Thus, the real contribution of shrimp farming to this reduction was just 9.6% of the total area. Other anthropogenic activities, such as agriculture, urban expansion and tourism, contributed greatly to the reduction in the mangrove areas along the northern coast of the State of Pernambuco. [ABSTRACT FROM AUTHOR]

The aim of this work is to correlate the histological gonad analysis of adult male Macrobrachium amazonicum of a wild population with morphotypes identified in populations reared in earthen ponds. A total of 500 adult male specimens were collected in the Mosqueiro Island, Municipality of Belém, State of Pará, Brazil. The animals were classified on the basis of body and cheliped colour, second right cheliped spination, total length, cheliped length and weight. The gonads of each morphotype were fixed, processed by histological techniques and stained with haematoxylin and eosin. All four morphotypes, translucent claw (TC), cinnamon claw (CC), green claw 1 (GC1) and green claw 2 (GC2), were identified in the wild population, indicating the same population structure described for cultured animals. The M. amazonicum testes are composed of multiple lobes. The TC gonads showed a population of germ cells in the eccentric portion of the seminiferous tubule and few spermatozoa in the central region. Cinnamon claw males exhibited a large cell population with intense meiotic activity and sparse spermatozoa. Regardless of the different external morphologies of GC1 and GC2, no histological differences were found in their gonads; both had a large number of gametes and similar spermatogenic cell population. Despite the external morphological evidences of the four morphotypes, the histological criteria indicate the existence of only three morphotypes: TC, CC and green claw (GC). [ABSTRACT FROM AUTHOR]

Loss of genetic variability can be detrimental to a population's survival traits and fitness. These effects are likely to be maximized in shrimp closed broodstock rearing systems where post-larvae are often produced from crosses of breeders collected from an associated grow-out farm after mass selection. Longtime broodstock management in closed systems is also expected to lead to reduction in or even complete eradication of genetic variability. The present work aimed at monitoring the genetic variability of a Litopenaeus vannamei hatchery in the state of Pernambuco (Brazil), during three successive replacements, using microsatellite markers. No significant genetic diversity losses have been observed through the values of mean heterozygosity ( Ho=0.460 and He=0.660 in the first sample; Ho=0.420 and He=0.620 in the second sample; and Ho=0.600 and He=0.660 in the third sample). However, some alleles appear to have been lost after three replacements. The diversity level was considered to be high and is comparable to those reported for wild populations, suggesting that the original imported founder stock of Brazilian L. vannamei is likely to have had a high genetic diversity, possibly due to multiple origins. [ABSTRACT FROM AUTHOR]

Mature Brazilian flounders Paralichthys orbignyanus were captured in coastal southern Brazil and their reproduction in captivity was studied. Brazilian flounder will spawn naturally in captivity when the water temperature is around 23 °C and 14 h of light is provided daily. Females were induced for ovulation and hand stripping using human chorionic gonadotropin, luteinizing hormone-releasing hormone analogue or carp pituitary extract. There was no need to inject males, as running milt was observed during the spawning season. Fertilization and hatching rates were above 80% independent of the hormone used. Notochord length at hatching was 2.18±0.07 mm for larvae hatching from naturally spawned eggs. Larvae were reared in salt water (30–35 g L−1) at 24 °C and under continuous illumination. Larviculture was with green water ( Tetraselmis tetrathele 50 × 104 cells mL−1). Rotifers (10–20 ind mL−1) were offered as first food 3 days after hatching and gradually replaced by Artemia nauplii (0.5–10 ind mL−1). Larvae settled to the bottom 20 days after hatching and completed metamorphosis within a week after that. The total length for newly metamorphosed juveniles was 12.9±2.2 mm and the mean survival was 44.8%. The results demonstrate the feasibility of producing Brazilian flounder fingerlings for stock enhancement or grow-out purposes. [ABSTRACT FROM AUTHOR]

The pejerrey Odontesthes bonariensis (Valenciennes, 1835) is an inland water fish from the Pampas region comprising part of Argentina, Uruguay and the South of Brazil. Pejerrey is a very popular fish in this region and has a long history of domestic and international introductions, which attests to the high quality and market value of its flesh, as well as its attractiveness as a game fish. The desirable characteristics of pejerrey also make it a good candidate for aquaculture, and the first trials on pejerrey cultivation (atheriniculture) were started more than a century ago in Argentina. In spite of the considerable interest in its development, little progress has been made and atheriniculture is still restricted to propagation and stocking for sport fishing purposes. In this review, we summarize the history of atheriniculture and the biological, technological, scientific, cultural and infrastructural constraints to pejerrey aquaculture development thus far. We also suggest possible scenarios of pejerrey aquaculture development compatible with the socio–economic conditions of South American countries. Our projections also take into consideration recent scientific findings on the biology of pejerrey and technological advances in seafood processing, storage and transportation, as well as the latest trends of seafood consumption and international markets. The best production strategy remains to be determined by trial and error but it is likely that, initially, production should focus on a differentiated, high-quality fish for the premium or international markets rather than attempting to compete with the cheap fish from natural sources. An international cooperation project with Japan has successfully demonstrated the feasibility of breeding pejerrey in captivity and mass producing seeds efficiently in Argentina, and has provided the foundation for the development of intensive and extensive farming of this species. [ABSTRACT FROM AUTHOR]

Different growth models in cultures of Oreochromis niloticus (L.) and Cyprinus carpio L. were compared in Pernambuco, Brazil, The Chapman-Richards growth model was shown to be the most appropriate for Oreochromis niloticus, while Silva's model best expressed growth for Cyprinus carpio. [ABSTRACT FROM AUTHOR]