Abstract

The marine gastropod Melongena corona bispinosa is a benthic organism that inhabits the coastal lagoons of the Yucatan Peninsula, Mexico. It is extracted more frequently at Chelem lagoon. This activity is done all the year and without restrictions, being necessary to make biological and fisheries studies in order to establish a suitable regulation. Samples of M. corona bispinosa were taken monthly from January to December of 2000. The length shell and total weight of the organisms were estimated; The soft parts of 30 males and 30 females adult were extracted, and the gonads were separated for histological characterization, obtaining the reproductive cycle. The reproductive cycle was defined in four stages; (I) immature: the gametes cannot be identified. (II) ripening: active cellular division, mature gametes may or may not be present. (III) Mature: dominance of mature gametes. (IV) Post copulation or post spawn: the follicles are partially or totally empty, with some mature gametes and phagocytes present. Males: inmature organisms were observed in three periods. Juanary-March, May-August and Ocober-December. Ripening organisms were observed all over the year , except in April; indicating slow gametogenic activity with plentiful gamete accumulation. A high proportion of mature organisms were observed all over the period, although the proportion decreased in August (13%) and October (14%). Organisms in post copulation were found in Juanary, May –July, september-December, being evident a low proportion of this stage (<20%). Females. Immature organisms were observed all over the year, with a peak from june to August; ripening organisms were observed in December, May-June, and September-October. Mature organisms were observed from January to April. A spawn stage was assumed being fast and short, with two peaks at April and November

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