Banca de DEFESA: TALITA FREGADOLLI PERES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : TALITA FREGADOLLI PERES
DATE: 26/02/2026
TIME: 09:00
LOCAL: Online
TITLE:

INDUCED REPRODUCTION AND INITIAL DEVELOPMENT OF PIRAMUTABA (Brachyplatystoma vaillantii) IN THE AMAZON BASIN (BRAZIL).

KEY WORDS:

Amazon catfish. Fish larvae. Hipofization. Larval ontogeny. Induced reproduction.

PAGES: 93
BIG AREA: Ciências Agrárias
AREA: Recursos Pesqueiros e Engenharia de Pesca
SUBÁREA: Aqüicultura
SPECIALTY: Piscicultura
SUMMARY:

The piramutaba, Brachyplatystoma vaillantii (Valenciennes, 1940), is a catfish species of great ecological and economic importance in the Amazon. However, overexploitation has compromised its natural stocks. Furthermore, the lack of information regarding its reproduction and early development makes it essential to conduct studies that support conservation and aquaculture efforts. This study describes induced reproduction as well as the morphological and morphometric changes from hatching to the juvenile stage of the species. Eight sexually mature broodstock (three females weighing 4 kg and five males weighing 2.67 ± 0.21 kg) were used. Females received two doses of carp pituitary extract (0.5 mg/kg and 5 mg/kg), while males received a single dose (1 mg/kg). After 248.1 degree-hours (equivalent to 8 h 44 min) at an average temperature of 27.6 °C ± 1.1, dry stripping of oocytes was performed. A total of 140 g of oocytes (3.5% of female body weight) were obtained, with 2,200 oocytes/g. Hatching occurred 13 h and 40 min post-fertilization at an average temperature of 26.8 °C ± 0.18. After hatching, 129 specimens were analyzed and categorized into larval stages (yolk-sac stage - 37, flexion - 31, postflexion - 31) and juvenile stage (30). Initially, larvae measuring 2.52 to 5.56 mm in standard length (SL) (mean: 3.88 mm ± 0.57) presented a hyaline body with an elliptical yolk sac and a slightly curved notochord. The head was flattened, nostrils simple, eyes small, and mouth terminal. In larvae measuring 5.17 to 8.77 mm SL (mean: 6.79 mm ± 1.21), the yolk sac was reduced, the notochord flexed due to the formation of the hypural plate, and the eyes became fully pigmented. The mouth became functional, with maxillary barbels extending beyond the anus. During the postflexion stage (8.98 to 23.42 mm SL, mean: 13.10 mm ± 3.62), the snout was rounded, nostrils became paired, the head was dorsoventrally flattened, barbels extended beyond the anal fin, and pigmentation was intense in the anterior region of the body. The number of myomeres ranged from 48 to 50. In the juvenile stage (23.05 - 37.07 mm SL, mean: 30.54 mm ± 2.99), the fins were fully developed (dorsal = I+6; anal = IV+10-11; pelvic = I+5-6; pectoral = I+9-10), the caudal fin was forked with long filaments, and pigmentation consisted of numerous punctate dendritic chromatophores irregularly distributed in the dorsal region of the body. Larvae of B. vaillantii can be distinguished from their congeners by the total number of myomeres, snout shape, and pigmentation pattern. This information supports the identification of wild-caught larvae, contributing to management and conservation strategies.

COMMITTEE MEMBERS:
Presidente - ***.237.228-** - ANA KARINA DIAS SALMAN - EMBRAPA
Interno - ***.305.370-** - LUIZ FRANCISCO MACHADO PFEIFER - EMBRAPA
Interno - 1905088 - RONALDO DE ALMEIDA
Externo à Instituição - MATHEUS PEREIRA DOS SANTOS - UFRRJ
Externo à Instituição - DAVID AUGUSTO REYNALTE TATAJE