Embryonic and larval developmental stages of African giant catfish Heterobranchus bidorsalis (Geoffroy Saint Hilaire, 1809) (Teleostei, Clariidae)

Abstract

The dearth of African giant catfish Heterobranchus bidorsalis seeds poses great threat to its aquaculture and biodiversity, hence detailed knowledge and understanding of its embryology is indispensable for its artificial propagation and conservation programmes. Photomicrographs of extruded oocyte through all developmental cell stages of live embryo to larval stage are documented with the aid of a light microscope. The optical transparency of the developing embryo enabled us to describe its deep structures, distinctive features and characterize the stages pictorially. Extruded oocyte had a mean diameter of 1 ± 0.1 mm, ~20% increase when hydrated, and bounded by double thin perivitelline membranes. The first mitotic cleavage occurred at 69 min post-fertilization (pf) resulting in 2, 4 (2 × 2 array of cells), 8 (2 × 4), 16 (4 × 4), 32 (4 × 8), 64 (2 × 4 × 8) blastomeres, then developed to morula, blastula and gastrula stages. Blastula was featured by formation of enveloping layer and yolk syncytial layer. Onset of epiboly at 3 h 57 min depicted the commencement of gastrula while closure of blastopore at 11 h 8 min marked its completion. Neurulation period was distinct from segmentation where organogenesis was fully active. Embryo sudden muscular contraction was noticed at ~17 h pf, increased prior to hatching with caudal locomotion firstly at 42 s interval. Heartbeat of embryo commenced at ~1 h before its unique eclosion at average of 72 beats/min while first larva emerged at 21 h at a controlled temperature of 28.5 ± 0.5°C. Mean total length (TL) of larvae and their pouch thickness were 5 ± 1 mm and 0.05 ± 0.02 mm respectively. 1 –day old larvae revealed 8 distinctive neuromeres and by day 3, epicanthus folds of the eyes were fully uncovered; and thereafter commenced exogenous feeding. At day 4, larvae recorded mean TL of 9 ± 1 mm and 15 caudal fin rays. The fin bifurcation to dorsal and adipose fins was observed at third and half weeks post-hatchability with the dorsal fin length to adipose fin was 1.7:1. This study, for the first time, presents significant morpho-sequential developmental stages of H. bidorsalis and registers its unique form of eclosion.

Embryonic and larval developments of brackish water catfish,Mystus gulio(Hamilton and Buchanan, 1822) induced with human chorionic gonadotropin and consequent larval rearing

“…The hatching in fish is facilitated by muscular contraction or twitching at caudal part (Honji et al., ; Olaniyi & Omitogun, ). In this study, vigorous movement of caudal part broke down perivitelline membrane at tail region and hatchling emerged out as tail first, which is similar to the observations made in M. montanus (Arockiaraj et al., ), H. fossilis (Puvaneswari et al., ) and H. bidorsalis (Olaniyi & Omitogun, ). However, Langeland and Kimmel () opined that during hatching, head comes out first and tail comes out last from the embryo in most of the teleosts.…”

“…Olaniyi and Omitogun () reported polster and tail bud as markers for the identification of cranial and caudal parts, respectively, during neurulation. This study revealed distinct neurulation and segmentation period in M. gulio , which is similar to the observation of Olaniyi and Omitogun () in H. bidorsalis , but in contrary to the report of Kimmel et al. () in Denio rerio .…”

“…However, Langeland and Kimmel () opined that during hatching, head comes out first and tail comes out last from the embryo in most of the teleosts. Hatching period depends on fertilization period within oocytes; hence, faster the fertilization shorter the hatching period and survival of the embryos (Olaniyi & Omitogun, ). In this study, hatching period for M. gulio was 30 min.…”

Comparison of proximate composition and sensory attributes of Clariid catfish species of Clarias gariepinus, Heterobranchus bidorsalis, and their hybrids

“…Clarias gariepinus (Burchell, 1822) and Heterobranchus bidorsalis (Geoffroy Saint Hilaire, 1809) are of high economic importance in many countries of the world especially African and Asian continents (Legendre et al. ; Adebayo and Fagbenro ; Olaniyi and Omitogun , ); and also serve mainly as food in many homes and hotels (Omitogun et al. ).…”

Generation of viable progeny from dead brooders of endangered catfish Clarias magur (Hamilton, 1822)

“…However, the same stages of C. magur embryos incubated at water temperature of 25–29 °C was observed to be delayed by 15 min (2-cells stage) to 1 h (somite stage) after the fertilization (Table 2). Usually, such differences in embryonic development in teleost fish species occur because of the incubation water temperature (Olaniyi and Omitogun, 2014); the higher the water temperature, the faster is the embryonic development and hatching (Hogendoorn and Vismans, 1980). The most salient result obtained in this study is successful hatching of 88%–92% embryos obtained from dead donors compared to 92%–93% from live control.…”