TRIPLOID CATARINA SCALLOP (ARGOPECTEN VENTRICOSUS SOWERBY II, 1842): GROWTH, GAMETOGENESIS, AND SUPPRESSION OF FUNCTIONAL HERMAPHRODITISM

Aquaculture, 186 (1-2): 13-32

C. A. Ruiz-Verdugo, J. L. Ramírez, S. K. Allen Jr., A. M. Ibarra-2000

Abstract:

Triploidy was induced in catarina scallop, Argopecten ventricosus, using two concentrations of cytochalasin-B (CB). Growth of triploid scallops exceeded that of diploids in all evaluated traits. The largest percent difference between the diploid control group and the treated groups was seen after diploid scallops reached the peak of sexual maturation and began spawning. The gonad of triploid scallops was easily recognizable by visual inspection because of a brownish discoloration and lack or few egg masses present. That characteristic allowed for the separation of 'putative triploids' (PTs), which when compared with diploid scallops from within the same treatment (treated diploids), had a significantly larger muscle weight than the differences seen between treated and control groups. Gametogenesis and the condition of hermaphroditism in this normally functional hermaphrodite were greatly affected by the triploid condition. In the female portion of the gonad, few oocytes developed. The male portion of the gonad was arrested early during development, and the male acini were replaced by female acini, producing all female gonads in increasing percentages during the culture period, suppressing the normal condition of hermaphroditism. Oocytes of diploids were larger than those of triploids early in the culture, probably because of delayed maturation in triploids. Later during the culture, oocytes of triploids were larger than those of diploids only when compared with treated diploids.

(Centro de Investigaciones Biológicas del Noroeste, S.C., Programa de Acuacultura y Biotecnología Marina, Laboratorio de Genética Acuícola, Apdo Postal 128, La Paz, Baja California Sur 23000, Mexico)

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