Eduardo Gomes Sanches

There has been a growing interest in identifying alternative feed ingredients and additives for aquaculture. Although seahorses generally do not accept commercial aquafeeds, among the residues of shrimp processing, the legs—or pleopods—resemble small crustaceans and may be accepted as frozen prey by adult animals. The aim of this study was to evaluate and compare the nutritional composition and lipid profile of marine shrimp ( Xiphopenaeus kroyeri ) pleopods (Plop) and a conventional food item, shrimp ( Litopenaeus vannamei ) post‐larvae (Ptla), and to assess their effects on the performance of adult seahorses ( Hippocampus reidi ). In addition, the effects of pleopod as a single food source on body reserves and reproductive potential were evaluated. The diets were assessed for caloric content, proximate composition, and lipid profile. Twenty adult specimens of H. reidi were subjected to a 90‐day trial to assess performance, and a subset of 10 individuals was further evaluated for histological parameters. Plop exhibited a higher proportion of polyunsaturated fatty acids (PUFAs) with chains shorter than 20 carbons compared to Ptla, while both diets presented adequate levels of highly unsaturated fatty acids (HUFAs; chains of 20 carbons or more). In this study, Plop resulted in improved animal performance. More than 80% of the individuals evaluated exhibited medium to high body reserves, along with a progressive increase in hepatocyte vacuolation and in both the size and number of vitellogenic oocytes. Considering its easy accessibility, low commercial cost, and the fact that Plop does not require culturing systems, it represents a promising alternative feed resource for ornamental aquaculture and public aquaria.

Given the morphological conformation of seahorses, there are several difficulties associated with the evaluation of body reserves and physical condition. This study proposes the development and validation of a body condition scoring system (BCS) applicable to Hippocampus reidi. This study comprises two phases: first, the development of the BCS methodology, followed by its application to a group subjected to an experimental diet, which serves to validate our findings. Weight gain and biometric parameters of 31 seahorses were weekly monitored for a period of 90–150 days. Additionally, histological analysis of organs of the digestive and reproductive tract was carried out to characterize and validate the scoring system, as well as a skin lipid profile evaluation as a measure of lipid mobilization. It is proposed that animals should be evaluated for abdominal muscle coverage, thoracic narrowing, contrast between the dorsal and abdominal region and muscle coverage between dorsal rings. We found significant differences between size and accumulation of fat in the liver as well as the degree of development of the gonads in the animals evaluated. Better energy reserves and reproductive potential are therefore expected for animals with a higher BCS. Our BCS methodology presents itself as an alternative of high practicality, simplicity and low cost, being an innovative tool for the evaluation of energy reserves in Syngnathids.

Several studies pointed out that skeletal abnormalities, although widespread among species, are rare in wild populations. There is a gap in the knowledge of such anomalies on endangered fish species regarding types of deformities, geographical distribution, and possible consequences on key behaviors. Here, we describe new records of skeleton deformities in the endangered Atlantic Goliath Grouper (AGG), Epinephelus itajara, based on 20 years of scientific dives and collections focused on studing AGG spawning aggregations and movement using telemetry in Florida (U.S.) and along the Brazilian coast. Five different deformities were recorded (pughead, shorttail, pughead no-eye, finless, and shorttail-pughead). We also compiled and discussed previous records from the literature and the challenges posed by these deformities. We proposed hypotheses related to the challenges imposed by each type of deformity on wild juvenile AGG. Despite the low frequencies in wild populations, abnormal individuals may have a higher survival rate in aquaculture facilities.

Artemia, commonly known as brine shrimp, holds a significant role as live prey in ornamental and commercial fish aquaculture. This study addressed the nutritional deficiency in adult Artemia biomass, exploring alternative enrichers available in Brazil. Evaluating a commercial aquafeed (Polinutre Poli Camarão 400PL) and a lipid emulsion (BioViv HUFA Continum), adult Artemia were subjected to different enrichment protocols, including periods of 1, 12, and 24 hours with each enricher, as well as a test group raised 100% on the commercial feed. Protein content for Artemia exclusively fed the commercial aquafeed (CF100) reached values very similar to those provided by the main commercial products available worldwide and other commonly used live prey. Enrichment time effects were observed from 12 h onwards, showing positive impacts on protein accumulation. Lipid content peaked at 12 h, followed by a decrease at 24 h. Further studies are needed to assess whether the combination of feed-based protocols followed by 12-h lipid emulsion enrichment can surpass the current results, providing high levels of protein content while maintaining a complete lipid profile.

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.

Thousands of seahorses are traded every year as marine ornamental species. Although packing methods for live adult seahorses have already been addressed, there is no information on the transportation of juvenile seahorses. Thus, this study aimed to evaluate the possibility of packing and transportation for newly-birthed seahorses. Three batches of newborn long-snout seahorses Hippocampus reidi were transported in three independent events from Ubatuba, north coast of São Paulo, to the city of São Paulo, covering 248 km in each trip, with an average duration of 3.5 h. A mean of 350 offspring of one day old was distributed in 1 L containers with round borders at equal densities, provided with constant aeration by portable pumps. Aeration was kept so that large bubbles would create an ascending flow keeping juveniles in suspension throughout transportation. Values of survival achieved in this study, even after 10 days post-transportation, were surprisingly high, reaching over 70%. No significant shift in water temperature, pH, or salinity was observed for any transportation events. For oxygen levels, although portable pumps were used, a drop of around 15% in DO level was recorded. In view of the trending ornamental fish market, considering the limited swimming capacity of newly born seahorses and that a great number of marine fish undergo a planktonic phase, this study provides important directions to a better understanding on seahorse transportation and yet, directions for the design of new transport methodology for an efficient shipping protocol for other species.

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.

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.

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.