Boletim do Instituto de Pesca

Morphometric relationships as proxies for reproductive maturity in the clam Anomalocardia flexuosa (Linnaeus, 1767)

Itala Oliveira — 2025-02-03

The objective of this study was to describe the morphometric relationships between different shell dimensions of the bivalve Anomalocardia flexuosa, to check the changes in the growth pattern, and to determine the adult and juvenile phases and the size of sexual maturity of the species using morphometric measurements. Considering the 52,873 specimens measured in the present study, all the allometric relationships established for A. flexuosa were significant, and both the relations between length × height and length × width showed positive allometry. The K means clustering separated the dataset between juveniles and adults and defined 13.20–14.60 mm shell as the interval of length for the transitional phase. The growth pattern was significantly different between juveniles and adults, in which juveniles presented isometric growth and adults had a negative allometric growth. The fit of the logistic model indicated that the shell length at sexual maturity was 13.80 mm. The A. flexuosa juvenile shell had a more rounded shape than the adult. Processes related to animal development and environmental characteristics may influence the shell shape. The maturity size found in the present study is according to the range of maturity proposed in the literature.

Effect of stocking density on the growth and survival of the ornamental fish Laetacara dorsigera

Brendow Matheus Koide Cascais — 2025-02-12

Laetacara dorsigera is a fish species that has excellent potential for ornamental fish farming. The present study aimed to evaluate the effect of stocking density on its growth in two experiments, with three treatments and four repetitions, lasting 45 days each. The first experiment used 0.25, 0.50, and 0.75 fish L^-1, and the second used the best density found in the first experiment, plus densities of 0.30 and 0.40 fish L^-1. The measured zootechnical parameters were survival rate, mean total lengths, and mean initial and final weights, as well as relative growth, specific growth, and weight gain rates. A significant difference was observed in the first experiment for the final length (18.7 and 17.5 mm, in the densities of 0.25 and 0.50 fish L^-1, respectively), relative growth rate percent, and specific growth rate weight% (0.25 fish L^-1) and survival (0.50 fish L^-1). In the second experiment, there was no significant difference for the densities tested. The density of 0.50 fish L^-1 is the most viable, due to the greater final survival achieved and no significant difference for the other parameters analyzed.

Biodiversity assessment using BRUVS in a port area of Pernambuco, northeast Brazil

Edson Bortoletto Garciov-Filho — 2025-02-11

Located in the second-largest estuary in Pernambuco, Brazil, the Suape Port Industrial Complex (CIPS) and its surroundings are regions of high environmental and economic importance that experience the effects of constant anthropogenic action. To understand the interference of these acts and the marine environment in this area, to identify its taxonomic diversity and abundance, and to guide management and mitigation measures for the fauna and marine ecosystem of this location, using the non-lethal baited remote underwater video system (BRUVS) method, between July 2021 and October 2022, we conducted a survey of the fauna in the coastal zone of the CIPS area, with a sampling area of 180 km² and 800 sampling points. Among the 118 species identified, the most abundant were Haemulon aurolineatum, Decapterus macarellus, and Caranx crysos, with a greater association of individuals in the sand/gravel + phytobenthos substrate, sand/gravel, and limestone formation. Although no non-significant differences were observed in the diversity of species by lunar phase, the relative abundance was greater during the new moon. When evaluating the depth gradients, those with the highest relative abundance and diversity were observed in the extracts at 20–25 and 25–30 m.

Ultrasonography for sex determination of Lebranche mullet

Ingrith Mazuhy Santarosa — 2025-02-04

Ultrasonography has been increasingly used in aquaculture breeding programs for non-invasive determination of sex and the gonad maturation stage in fish. For the first time, this image exam was performed on a mugilid (Lebranche mullet). Nineteen male and 12 female fish were submitted to this evaluation, which were selected because they were identified to be in the final gonad maturation stage, which was previously confirmed through spermiation by abdominal pressure and ovarian sampling biopsy (oocytes of 626 ± 12 μm), respectively. The ultrasound images were obtained after anesthesia, using a linear multifrequency probe at the frequency of 8 MHz in females and 10 MHz in males, which revealed significant differences in echogenicity between the gonads. In males, the testes presented a hypoechoic and homogeneous aspect, while in females the ovaries had a hyperechoic appearance and granular echotexture, compared to adjacent body structures. The scanning time for sexual identification and characterization of reproductive system structures in each fish was 2.58 ± 1.68 seconds for males and 2.40 ± 1.05 seconds for females, there was no significant difference (p > 0.05) in relation to sexing time. Thus, the identification of the sex of the Lebranche mullet (Mugil liza) through ultrasonography proved to be an effective, fast and non-invasive method when applied to fish with mature gonads during the species’ reproductive period.

Fish assemblage distribution along a stretch of neotropical urban river

Daiane Elen Cavallari — 2025-01-31

The objectives of this study were to evaluate some descriptors of fish assemblages in different stretches of a Neotropical urban river, located in the municipality of Sorocaba, São Paulo, Brazil, and to evaluate possible differences between them and the influence of seasonality. Collections were carried out between June/2019 and February/2020. The results obtained in relation to the physical and chemical variables of the water indicate that this is a river with the urban river syndrome and that seasonality has a relevant influence. The fish assemblage showed homogeneity in relation to richness and differences regarding diversity, dominance, and abundance in the stretches of the river studied. The multivariate ANOSIM analysis confirmed that the dry and rainy months are not similar to each other in terms of fish composition. The canonical correlation analysis explained 85.58% of the total data variation, indicating that water temperature and rainfall are important factors that influence species composition. It was concluded that the descriptors of the fish community in the studied stretches (richness, abundance, diversity, and dominance) undergo changes due to seasonal variations, which in urban rivers can be amplified, due to the consequences of the loss of vegetation cover, increased soil impermeability, reduction in the water infiltration rate, surface runoff, and maximum flows.

Structure and diversity of the fish assemblage in a port area of the coastal zone of the Eastern Amazon in Brazil

Athina da Silva Carvalho — 2025-02-11

The aim of the present study was to characterize the ichthyofauna of the Coqueiros Strait in the state of Maranhão, Brazil. Sampling was conducted at three-month intervals from February to December 2022 at four sampling points using barrier nets with a 35-mm mesh between opposing knots, measuring 40 meters in length and approximately 6 meters in height. Both abiotic (salinity, temperature, dissolved oxygen, pH, and redox potential) and biotic data (weight, sex, and total length) were collected. A total of 41 species belonging to 25 families were recorded, with the families Ariidae and Sciaenidae being the most represented in terms of abundance distribution. Equitability was assessed, and the abundance-biomass comparison curve indicated an environment without significant degradation. The results indicate that the Coqueiros Strait region is crucial for the development of ichthyofauna in the Golfão Maranhense, highlighting the need for ongoing monitoring and sustainable management practices to protect these vital ecosystems.

Effects of an Enterococcus faecium‐based probiotic on growth performance and resistance of Amazon ornamental fish Heros severus under short-term fasting

Keber Santos Costa Junior — 2025-02-05

This study aimed to evaluate the deprivation and feeding frequency of H. severus fingerlings fed a diet supplemented with autochthonous probiotic E. faecium and challenged with the pathogen A. hydrophila. The experiment was carried out in 2 × 5 factorial, consisting of two food frequencies (two and four times a day) and four food deprivations with probiotic (P:7/0, P:6/1, P:5/2 and P:Alt) and one control (C:7/0). The deprivation factor, higher values of growth parameters were observed for fish from the treatments P:7/0 and P:6/1, as well greatest resistance of the A. hydrophila. Therefore, the use of probiotic E. faecium provided greater growth and resistance for H. severus.

Morphological and molecular analysis of Eustrongylides sp. (Nematoda: Dioctophymatidae) in zebrafish (Danio rerio) from Brazil

Melissa Querido Cárdenas — 2025-01-28

The zebrafish, Danio rerio, is an important vertebrate model organism across various scientific disciplines. The current study reports the nematode larva, Eustrongylides sp., presence, in zebrafish from a pet shop, acquired by Fundação Oswaldo Cruz for toxicity studies. Morphological and molecular data from this nematode are given herein, contributing to the understanding of this helminth and aiding future studies. The occurrence of this larva demonstrates the importance of controlling the management of D. rerio, since this fish is widely used as an experimental model.

Perspective and potential of grape co-products for aquaculture

Cybele Pinheiro Guimarães — 2025-02-19

The growing demand for aquaculture feed, combined with environmental concerns, has driven the search for sustainable alternatives to conventional feed ingredients. Grape by-products, such as pomace, stalks, seeds, and skin, have great potential because of their nutritional properties, including high concentrations of dietary fiber, proteins, lipids, vitamins, and bioactive compounds, such as polyphenols. The compounds present in these by-products have bioactive properties that can benefit the health of aquatic organisms. Despite the significant discharge of these byproducts into the environment, their inclusion in fish and shrimp diets can improve zootechnical parameters such as growth performance, health, and meat quality, while contributing to the sustainability of aquaculture, reducing waste, and promoting a more efficient production cycle. This article aimed to explore the applicability of viticulture by-products in aquaculture, highlighting the beneficial effects of the bioactive compounds present in these by-products and discussing their potential for use in aquaculture production.