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Volume 39 - Number 1 - 2004
Article


Embryonic and larval development of sea bass Paralabrax dewegeri Metzelaar (Pisces: Serranidae)

David Querales1, Jesús Rosas2, Aidé Velásquez1, Tomas Cabrera1 & Carlos Maneiro1

 

(1) Escuela de Ciencias Aplicadas al Mar

(2) Instituto de Investigaciones Científicas, Universidad de Oriente, Isla de Margarita, Venezuela

 

E-mail: rosas@ne.udo.edu.ve


The embryonic and larval development of Paralabrax dewegeri are described from fertilization to metamorphosis. The gametes were obtained from spontaneous spawning. Fertilized eggs are spherical, floating, transparent, pelagic, with smooth chorion with one oil globule. The average egg diameter was 0.89 ± 0.02 mm and the average oil globule diameter was 0.19 ± 0.01 mm. The morula stage was observed 2 h after fertilization, the blastula stage at 2 h: 40 min. The gastrulation started at 3 h: 50 min and finished at 6 h: 50 min. At 7 h: 20 min the germinal ring was observed. The neurula stage started at 7h: 50 min. The differentiation between head and embryo tail with 10 to 12 somites was observed 9 h after fertilization and 35 min later the optical and auditory capsules were observed. After 10 h: 50 min, pigmentation embryo process started. Twelve hours after fertilization 20 to 25 somites were observed, and some pigments into the oil globule which is located between the head and the tail. At 12 h: 50 min the disperse dorsolateral pigmentation spreaded out from the posterior region of the head to the caudal region. Hatching took place 16 h :20 min after fertilization, at 27 ± 1ºC. Recently hatched larvae have an average body length of 1.44 ± 0.07 mm. About 48 h after hatching the yolk sac was reabsorbed. The notochord flexion occurred from day 12 to 15, and the metamorphosis was completed at day 30 after hatching.


Key words: Reproduction, embryogenesis, fish larvae, Atlantic ocean, Venezuela


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1Laboratorio de Zooplancton, Instituto de Ciencias del Mar y Limnología,Universidad Nacional Autónoma de México. A. P. 70-305, 04510 México, D. F. México
 
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