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An adult female Brazilian cownose ray (Rhinoptera brasiliensis), housed in Ubatuba Aquarium died after loss of appetite period. During necropsy, an enterolith was discovered partially obstructing the intestinal lumen. Examination of the enterolith revealed a bonefish spine nidus. Enterolithiasis has been linked to multiple factors including diet, genetics, alkaline intestinal environments and, as in this particular case, the ingestion and retention of foreign bodies. The composition of this enterolith from a cownose ray was primarily monohydrocalcite. This short communication, apparently the first to report enterolithiasis in stingrays, emphasizes the need for post-mortem examinations of carcasses on macroscopic and microscopic levels., (© 2024 John Wiley & Sons Ltd.)

The andrological study of a species involves the macro- and microscopic analyses of the internal reproductive organs and the evaluation of seminal parameters and ultrastructural characteristics of the spermatozoa. As in other vertebrates, the male reproductive tract in chondrichthyans consists of testes and reproductive ducts (efferent duct, epididymis, Leydig's gland, ductus deferens and seminal vesicle). In this study the authors used three adult specimens of Zapteryx brevirostris from wild capture kept at the Ubatuba Aquarium, Brazil. Semen was collected by abdominal massage over the location of the seminal vesicle, preceded by ultrasonographic evaluation. The semen collected was diluted 1:200 and subject to quantitative and morphological analyses. Ultrastructural analysis was performed using transmission and scanning electron microscopy. Correlation was observed between successful collection and ultrasonographic image of an engorged seminal vesicle, as well as testicles with easily delimitable margins and higher echogenicity. It was possible to identify free spermatozoa with helical filiform appearance, as well as spermatozeugmata. The average sperm concentration resulted in 5 million packets per millilitre and 140 million spermatozoa per millilitre. The sperm nucleus is described as follows: cone shaped, parachromatin sheath less dense than the chromatin of the nucleus, smooth depression of the nuclear fossa, abaxial axoneme 9 + 2 and accessory axonemal columns in positions 3 and 8 and oval shaped, with flattened inner surface in cross-section. These results broaden the knowledge of the andrology of this species, contributing to ex situ breeding programmes., (© 2023 Fisheries Society of the British Isles.)

There are only a few studies that describe the larval development of Echinaster or aspects on culture systems for the genus. For starfishes, the choice of suitable substrates has received special attention since it could influence the acid-base balance of the water, movement capacity and predation rate. The objective of this study was to evaluate the ideal food-related substrate for the rearing of juvenile Echinaster brasiliensis. A batch of fertilized eggs released in spontaneous spawning was collected and kept in a plankton-kreisel until metamorphosis. Data on preference of food-related substrate was recorded for 10 weeks from day 58 post-release. From release to 132 days old, arm length increased from 0.81 mm to 1.31 ± 0.03 mm. Considering the sudden increase in arm length (AL), it was estimated that feeding started around 40 days of age. Regarding food-related substrate preferences, biofilm grown on "rocks" showed a significant difference among other treatments, adding up to 50% of preference (p < .05). For sponge and biofilm from bio media, there was no statistical difference for the whole period. In this study, sponges showed to be the least preferred food-related substrate for post-settlement juveniles. Considering that Echinaster and other starfish are commonly maintained on a diet of collected or cultured sponges, difficulties in sourcing a ready supply throughout the year represent limitations to their sole use within commercial or laboratory-scale production. In this sense, the use of biofilm from biological media for the feeding of juvenile starfish is not yet reported in the literature and showed to be an easy and promising option., (© 2023 Wiley Periodicals LLC.)

Colouring has a great influence on the commercialization of ornamental fish. The aim of this study was to evaluate different concentrations of canthaxanthin in the diet of the blood swordtail Xiphophorus helleri in an effort to obtain a more intense red colour. Six concentrations of canthaxanthin (0, 50, 100, 250, 400 and 600 mg kg -1 diet) were used. The experiment lasted 60 days. Fish were evaluated for increased red pigmentation through the use of photographs (performed by smartphone) and imaging applications considering the Hunter method and the CMYK and productive performance. No significant differences were observed for productive performance. The use of photographs by means of a smartphone and the use of imaging applications proved to be adequate to assess differences in colour in the species. Swordtail red pigmentation did not show significant increase regardless of canthaxanthin dosages. Varieties of ornamental fish bred for red coloration may have limits for increased colour due to the storage capacity of carotenoids by chromatophores., (© 2023 Fisheries Society of the British Isles.)

Endemic to the south-west Atlantic Ocean, the shortnose guitarfish (Zapteryx brevirostris) is a small species, classified as endangered by the IUCN. Although reproduction in captivity has been successful for some species, a range of factors can limit the success of captive breeding programmes for elasmobranchs. In Brazil, the Ubatuba Aquarium was the first public aquarium to reproduce small-sized elasmobranchs. Since 2018, at least five parturition events have been recorded for Z. brevirostris at the institution. From a total of 13 live neonates that rearing was attempted, the mean ± standard error of weight, total length (TL) and disc width at birth were 17.47 ± 1.6 g, 13.25 ± 0.7 cm and 6.53 ± 0.2 cm, respectively. The mean weight as well as mean TL were higher for females at all births, with 26.15 g and 15.07 cm for females in comparison with 17.09 g and 13.94 cm for males. Considering the increasing risk of extinction that the species is facing, age and growth studies are fundamental for the success of conservation, improving the knowledge of Z. brevirostris life cycle so that a more efficient and sustainable management can be carried out. This study provides important data, as well as directions for captive breeding of the species., (© 2022 Fisheries Society of the British Isles.)

Sex change was induced in Epinephelus marginatus juveniles using a nonsteroidal aromatase inhibitor (AI), a synthetic androgen (17α-methyltestosterone; MT), and a combination of both (MT + AI) in a 90-day experiment. A detailed remodeling of the gonads, the plasma level of gonadal steroids, and immunostaining of pituitary follicle-stimulating hormone (FSH), luteinizing hormone (LH), and somatolactin (SL) cells were analyzed. Sex inversion reached the final spermatogenesis stages using MT, while AI triggered spermatogenesis, but reaching only the spermatid stage. Estradiol (E 2 ) levels did not change in fish treated with AI but decreased throughout the experimental period in animals treated with MT and MT + AI. Testosterone (T) levels increased in animals treated with MT during the first 60 days (and combined with AI in the first 30 days), decreasing in all experimental groups at 90 days, while AI-treated animals had increased plasma 11-ketotestosterone (11-KT) levels after 90 days. In control fish, FSH- and SL-producing cells (ir-FSH and ir-SL) were restricted to pars intermedia (PI) of the adenohypophysis. Pituitary ir-FSH cells were decreased at the end of the experimental period in all treatments compared with the CT animals. LH-producing cells (ir-LH) were present in proximal pars distalis (PPD) and pars intermedia (PI) of adenohypophysis and did not change after the experimental period. The decreased number of ir-FSH cells at the end of the experiment in all treatments could be related to the negative feedback loop triggered by the increase in natural and/or synthetic androgens.

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.

Anesthesia can be utilized as a non-lethal procedure to allow easy handling of teleosts and elasmobranchs in captivity or in the wild. For this, anesthetic protocols need to be established according to the species. The aim of this study was to determine the ideal concentration of eugenol for anesthesia of Zapteryx brevirostris. Four concentrations were tested: 21.25, 42.50, 85.00 and 170.00 mg L-1 (ratio of 1:5 with absolute ethanol). The perfect concentration of eugenol for this species was 85.0 mg L-1 , which enabled up to 300 seconds of work on the fish, without any response to handling.

Many aspects of sex change in reef fishes have been studied, including behavior and social organization. However, gonad histology remains the most robust way to identify sexual patterns in fishes. Some uncommon tissues remain poorly described, such as the accessory gonadal structures found in species from the Gobiidae family, which are rare in other bony fishes. This is the first report of the testicular gland in Gramma brasiliensis and for the Grammatidae family. Between April 2011 and February 2012 eighty specimens were collected during four dive campaigns on the Taipus de Fora reef (13°56'20"S 38°55'32"W), Bahia, Northeast Brazil, and their sex was determined. Thirteen per cent of the active-females and 90% of the active-males had testicular gland tissue in their ovotestis. This discovery led to additional research into the characteristics of the gland tissue and its relationship with gonadal maturation. Three patterns of testicular gland development were found in Brazilian basslet ovotestis. Both ova and sperm-producing gonad contained testicular gland tissue, and the appearance of this tissue seems to be the first modification of ovotestis tissue marking the beginning of the protogynous sex-change process in G. brasiliensis.

This study aims developing and evaluate a protocol of semen cryopreservation of the lane snapper Lutjanus synagris. Firstly, sperm motility rate, motility time, density and spermatocrit were appraised to characterize the sperm quality of the lane snapper. The effect of three extenders with distinct ionic compositions and pH values combined with seven concentrations of cryoprotector dimethylsulfoxide (0; 2.5; 5.0; 7.5; 10.0; 12.5 e 15.0%), five cooling rates (110, 90, 60, 45 e 30°C -min), nine equilibration time (1; 2,5; 5; 10; 15; 20; 25; 30 e 60 minutes) e five dilutions ratio (1:1; 1:3; 1:6; 1:10 e 1:20) on the sperm motility rate and motility time were analyzed. Fertilization test was accomplished to evaluate the viability of the cryopreserved sperm. The higher sperm motility rate and motility time (P<0.05) was achieved by combining extender with pH 8.2 with 10% concentration of dimethylsulfoxide and cooling rate 60°C -min, 1 minute of equilibration time and 1:3 (v/v) dilution ratio. The use of cryopreserved sperm presented fertilization rates >60% validating the present protocol for lane snapper. The cryoconserved sperm of lane snapper is a viable alternative, being possible to maintain appropriate sperm viability.

Neobenedenia melleni (MacCallum, 1927) (Monogenea) is a pathogen widely spread in marine teleost cultures around the world. The present paper recorded this parasite species in the Goliath grouper Epinephelus itajara for the first time Brazil. The use of freshwater bath for parasite control was successful for the Goliath grouper.

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-1) 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.

Sea lice (copepods) are widespread pathogens in marine teleost cultivation around the world. The sea louse Caligus mutabilis Wilson, 1905, is recorded here for the first time in sea-farmed gag grouper, Mycteroperca microlepis, in Brazil.

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.

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.

This work had as objective tests therapeutic treatments seeking the monogenea eradication in fingerlings Florida Pompano (Trachinotus carolinus) servants in cage net in the area of Ubatuba, State of São Paulo. The fingerlings presented an accentuated weigh loss and strong discoloration and through observation of scraped of gills under light microscope were identified a high amount of monogenea. Three treatments were tested in form of baths: T1 (fresh water for 5 minutes); T2 (formalin: 1:1.000 for 20 minutes) and T3: (formalin: 1:4.000 for 30 minutes). The treatments were appraised through scraped of gills, mounted among you laminate and lamínulas and observed to the light microscope. It was observed that in the tested conditions all of the treatments were efficient in the elimination of the monogenea without presenting lethality to the fish. The treatment is recommended T1 (take a bath in fresh water for 5 minutes) for the facility in the application and for the absence of use of chemical products.