Neobenedenia melleni (MacCallum, 1927) (Monogenea) is a widespread pathogen in marine teleost cultures all over the world. The present paper reports this parasite species in farmed cobia (Rachycentron canadum) in Brazil, for the first time. Some comments on preventive actions for avoiding the disease are made.Keywords: Mariculture, pathogens, ectoparasites. ResumoNeobenedenia melleni (MacCallum, 1927) (Monogenea) é um patógeno amplamente distribuído em cultivo de teleósteos marinhos no mundo. Este estudo relata pela primeira vez essa espécie de parasito em cultivo de cobia, Rachycentron canadum, no Brasil. Comentários sobre prevenção para evitar a doença são discutidos.Palavras-chave: Maricultura, patógenos, ectoparasitos.Research relating to sea-farmed cobia (Rachycentron canadum Linnaeus, 1766) has been increasing recently. The great growth potential of cobia, their easy adaptability and ability to breed in captivity, excellent meat quality and carcass utilization, among other attributes, have induced rapid growth of cobia farming all over the world (CHANG et al., 2007). However, one of the main limitations affecting cobia culture is the diseases caused by helminth ectoparasites (monogeneans) (LIAO et al., 2004), especially Neobenedenia species (OGAWA et al., 2006).Infestations by ectoparasites in farmed fish have been recorded since the late 1950s (OGAWA et al., 1995). Deveney et al. (2001) described an outbreak of Neobenedenia elleni (MacCallum, 1927) parasitizing Lates calcarifer in Australian waters that resulted in the loss of 200,000 fish due to secondary infection. This parasite has been found in many species of ornamental marine fish and sea farming in different countries, thus demonstrating its low specificity to the hosts (BULLARD et al., 2003). In Brazil, Sanches and Vianna (2007) Capsalid monogeneans have a monoxenic, short life cycle, which allows epizootic outbreaks especially in hosts subjected to high stocking densities (THONEY; HARGIS JUNIOR, 1991). It has been demonstrated that water temperature influences the growth, maturity, egg production and infestation levels of Neobenedenia species (HIRAZAWA et al., 2010). These parasites feeds on mucus and epithelial cells of the host, which leads to changes in fish behavior: they drag their bodies against a substrate, such as net cages, thereby causing injuries culminating in secondary infections. Parasitized fish presents lesions in the cornea and skin, blindness, weakness, loss of appetite, hemorrhage, mucus hypersecretion and death due to secondary infections (OGAWA et al., 1995;HIRAYAMA et al., 2009). Our purpose in this paper was to document the first occurrence of capsalid monogeneans in cobia (R. canadum) farmed in Brazil. We have also suggested procedures that can be adopted for disease prevention.Ten juvenile specimens of R. canadum, with mean weight 317 ± 155 g, coming from floating net cages of a marine farm in Ilhabela, São Paulo, Brazil, were sent to our laboratory in March 2010, for diagnostic purposes. The fish were stocked ...

Salt-water recirculation systems using automatic feeders are a new frontier for marine aquaculture. The definition of the feed frequency is fundamental for the correct use of automatic feeders. Different feeding frequencies (1, 3, 6, 12 and 18 times a day) using automatic feeders were evaluated in two experiments on the performance of the dusky grouper (Epinephelus marginatus) in salt-water recirculation system. In the first experiment, three feeding frequencies were evaluated: feeding once a day; three times a day and six times a day. In the second experiment, three feeding frequencies were evaluated: feeding six times a day; 12 times a day and 18 times a day.Waters parameters (temperature, salinity, oxygen level, total ammonia, pH and oxidation-reduction potential) were maintained at specific ranges for the species. Among all the evaluated frequencies, 12 times a day provided the best productive performance, obtaining superior results for final weight, final biomass, specific growth rate and daily weight gain. For juveniles of the dusky grouper, the ideal feeding frequency is regular feedings every 2 hours, which is impractical to run without the use of automatic feeders.

The effect of sunlight on the efficacy and persistence of an experimental tablet formulation based on Bacillus thuringiensis sorovar. israelensis (C4P1) was evaluated against Aedes aegypti larvae under simulated field conditions. The initial mortality ranged from 93 to 100%, and the residual activity (≥ 70% mortality) recorded in containers exposed to sunlight or shade were, respectively, 13-35 days and 40-54 days. The results suggest that C4P1 can provide long-term larvicidal effect and operational advantages. Key words: Bacillus thuringiensis israelensis -Aedes aegypti -tablet formulationBacillus thuringiensis sorovar. israelensis (B.t.i) has been used since the 80's in several programs for controlling black fly and mosquito species worldwide. It is considered highly toxic to the target organisms and environmentally safe. Furthermore, no resistance has been detected on populations submitted to long-term exposure to this pathogen (Regis & Nielsen-LeRoux 2000). B.t.i formulations have been continuously improved to optimise their potency, stability (shelf life), ease of field application and residual activity (Couch 2000). Trials under simulated field conditions have been considered a reliable methodology to evaluate the efficacy and persistence of B.t.i based products because, under these conditions, many factors involved in residual activity can be better controlled and investigated than under real field conditions (Thiéry et al. 1999.In the present work, the effect of sunlight on the efficacy and residual activity of a new tablet formulation based on B.t.i, C4P1 against Aedes aegypti larvae (Recife-Lab strain), was investigated under simulated field conditions. C4P1 is an experimental slow release solid formulation, developed by Far-Manguinhos-Fiocruz, Rio de Janeiro, Brazil. Initially, the larvicidal activity of the technical powder was determined by bioassay according to the standard protocol (de Barjac & LargetThiéry 1984). The LC 50 and the LC 90 were titrated against the B.t.i reference powder (IPS82), from Institut Pasteur. The technical powder showed LC 50 = 0.30 ± 0.01 mg/l and LC 90 = 0.44 ± 0.01 mg/l, resulting in potency of 1,146 ± 52 ITU/mg (International Toxic Units).The tests under simulated conditions were carried out in March (1st set) and May (2nd set) 2000 to evaluate the residual activity of C4P1 related to the incidence of sunlight. The containers, placed in an outdoor area, were submitted to direct sunlight and shade. The tests were conducted in plastic containers (38 x 42 x 30 cm) filled with 20 l of tap water where the temperature ranged from 27 to 29°C in the shade and from 27 to 32°C, in direct sunlight. Each container was treated with 1 tablet/ 10 l. Fifty early fourth-instar larvae (L4) were introduced into each container and the mortality rate was recorded 48 h after, by counting the surviving larvae. This procedure was always used to determine the initial mortality. Thereafter, the evaluation of residual activity was carried out using 50 L4 or 300 first instar (L1) larvae per conta...

RESUMOO diagnóstico precoce de patologias no meio aquático constitui-se em uma necessidade vital para o sucesso dos cultivos. Considerados como parasitos oportunistas, surtos de infestação de monogenóides capsalídeos podem ocasionar mortalidades massivas gerando enormes prejuízos nos cultivos. Exemplares de garoupa-verdadeira Epinephelus marginatus (Lowe, 1834), com peso médio de 142,74 ± 38,65 g, apresentaram recusa da alimentação e sintomas como o escurecimento do corpo, natação errática, opacidade dos olhos, exoftalmia e hemorragias em diversas áreas do corpo. Alguns peixes apresentavam lesões no globo ocular e cegueira. Após análises dos peixes foi identificada a ocorrência do parasito Neobenedenia melleni. Este trabalho teve por objetivo testar o efeito de diferentes tratamentos por imersão em diferentes concentrações de formalina e água doce na erradicação de monogenoides capsalideos na garoupa-verdadeira. Foram testados três tratamentos em forma de banhos: T1 (água doce por 10 minutos); T2 (formalina: 1:2.000 por 10 minutos) e T3: (formalina: 1:4.000 por 10 minutos). Os tratamentos foram avaliados através de raspado de tecido epitelial, montados entre lâminas e lamínulas e observado ao microscópio de luz. Observou-se que nas condições testadas o T1 e o T2 foram eficientes na eliminação dos monogenóides capsalídeos na garoupa-verdadeira. The precocious diagnosis of pathologies in the aquatic way is constituted in a vital need for the success of the cultivations. Considered as parasites opportunists, infestations of monogeneans capsalides can cause missal mortalities resulting in enormous damages in the cultivations. Juveniles of dusky grouper Epinephelus marginatus (Lowe, 1834), with medium weight of 142.74 ± 38.65 g, presented refusal of the feeding and symptoms as the darkening of the body, erratic swimming, opacity of the eyes and hemorrhages in several areas of the body. Some fishes presented lesions in the eyeball and blindness. After analyses of the fish the occurrence of the parasite Neobenedenia melleni was identified. This work objective was to test therapeutic treatments seeking the monogenean capsalid eradication in juveniles of dusky grouper. Three treatments were tested in form of baths: T1 (fresh water for 10 minutes); T2 (formalin: 1:2,000 for 10 minutes) and T3: (formalin: 1:4,000 for 10 minutes). The treatments were evalueted by scraping epithelium tissue, mounted in slide glass and cover slip and observed by light microscope. It was observed that in the tested conditions T1 and T2 were efficient in the elimination of the monogeneans capsalids without presenting lethality in the dusky grouper. PALAVRAS-CHAVE

This study aimed at identifying and quantifying the parasites of wild and cultured dusky grouper Epinephelus marginatus. During a year and thereby all four seasons, 20 wild and 20 cultured groupers were examined for the presence of parasites, except in the last season, in which 19 wild and 20 cultured fish were examined, totalling 159 groupers analysed from Ubatuba, southeastern Brazil. Prevalence, mean intensity of infection, mean abundance and mean relative dominance were calculated. Five species of parasites were identified in fish from both origins: Pseudorhabdosynochus beverleyburtonae (Monogenea), Neobenedenia melleni (Monogenea), Pseudempleurosoma sp. (Monogenea), Helicometrina nimia (Digenea) and larvae of Contracaecum sp. (Nematoda). The prevalence of ectoparasites, in most cases, was higher than endoparasites. The most abundant parasite was the monogenea Pseudorhabdosynochus beverleyburtonae in both wild and cultured fish, along all seasons. Neobenedenia melleni was observed in wild and cultured fish in all seasons, with a gradual increase in the number of parasites from the coldest to the hottest seasons, with the highest prevalence and mean intensity in the summer. Helicometrina nimia was found in all seasons in both wild and cultured fish, except for summer, where its presence was detected only in wild fish. Pseudempleurosoma sp. and larvae of Contracaecum sp. showed low prevalence occurring in wild and cultured fish in the autumn and spring, respectively. This study revealed high intensities of potentially pathogenic parasites that could favour disease outbreaks in culture conditions.

This study aimed to develop a protocol of semen cryopreservation of the mutton snapper Lutjanus analis. The interaction between three extenders (pH 6.1; 7.8 and 8.2), two concentrations of dimethyl sulfoxide (dMSO, 5 and 10%) and three cooling rates (-90; -60 and -30°C.min ) on the sperm motility rate and motility time were analyzed by a factorial experiment. A sample of 30 fishes (1,261 ± 449 g) collected in the nature was kept in floating net cages. The semen was frozen by using cryogenic straws, in nitrogen vapour and transferred, later, to liquid nitrogen. Fertilization test was accomplished to evaluate the viability of the cryopreserved sperm. The highest sperm motility rate and motility time (P < 0.05) was achieved by combining extender C (ph 8.2) with dMSO (10%) and cooling rate of -60°C.min -1 (P < 0.05). The use of cryopreserved sperm presented fertilization rates higher than 59% validating the present protocol for mutton snapper.

Salt water recirculation systems using automatic feeders are a new frontier for marine aquaculture. It is possible to decrease the vulnerability of the traditional fish farming in open systems and reduce wasteful feeding and discharge of effluents, as well as increase the economic returns. An experiment with common snook fingerings (4.31 ± 1.42 g and 8.4 ± 1.0 cm) was performed. Three feeding treatments were evaluated: six, twelve and eighteen feeding times per day. Each treatment had three replications. Among the three tested frequencies (fed 6, 12 and 18 times a day), the feeding frequency of 12 times per day (every two hours) showed the best values of the parameters evaluated for production performance. The final weight values, condition factor, specific growth rate and daily weight gain of the treatment 12 feeding times per day were all significantly higher than the lower and higher frequencies. Our results demonstrate that high feeding frequency is not synonymous of higher performance, but is extremely necessary to find out the best range for the target species. Besides, this relationship between feeding frequency and growth performance might change over weight range. Therefore, future studies should address higher weight ranges for comparison to our results.

The interaction between cultured barber goby Elacatinus figaro (cleaner fish) and the dusky grouper Epinephelus marginatus, and the efficiency of the cleaner fish in removing ectoparasites were evaluated. When the interaction between these two species was observed, cleaner fish showed a preference for the largest groupers. In a second trial, treatments: TWC (Control) – two groupers without a cleaner fish, T1C – two groupers with one cleaner fish, T3C – two groupers with three cleaner fish and T6C – two groupers with six cleaner fish were tested in four replicates. After 8 days, monogeneans were removed and identified as Neobenedenia melleni. The highest mean abundance of parasites was found on the groupers in the TWC group (37 parasites per host) and the lowest on those in the T6C group (4.1 parasites per host). By increasing the number of cleaner fish, a higher cleaning efficiency was obtained, as observed in T6C, where almost 90% of the parasites were removed. Possibly, this removal would have been complete if the number of cleaners had not been reduced in the treatments due to the mortalities observed. This study demonstrates the possibility of using gobies to remove monogeneans and in improving grouper health.