Abstract

The reproductive cycle of the herbivore gastropod Strombus gigas (Linnaeus, 1758) is anaIyzed from two different coral reefs, Chinchorro bank on the Caribbean sea and Alacranes reef from the Gulf of Mexico, to determine the variability and similarities of their reproductive cycle under diverse environmental conditions, mainly to understand the behavior of gonads during the spawning season ofboth sites by a direct method. Twenty organisms were sampled monthly and processed for histological section, from March to November at Alacranes reef and from June to September at Chinchorro. For S. gigas of Alacranes, gametogenesis was the dominant stage from March to November, with presence of mature organisms only from June to October. While at Chinchorros, during the reproductive season gametogenesis involved no more than 40 %, with mature organisms involving from 40 to 50 %. There was an increase of mature organisms during September at both localities, but at least at Alacranes, there was no evidence of an accumulation of mature organisms through the winter or of a later spawn. Spawn was detected from June to August with a peak in July but just in 10% of the samples from Alacranes and 40% from Chinchorros. Although 40% post spawners during July atAlacranes, suggest an important spawn from May to July.\This study showed two gametogenic strategies as a response to the environment:\i) Populations of fast gametogenesis during a short lapse of time (S. gigas from Chinchorro), and\ii) Population with a continuous gametogenesis throughout most of the year (S. gigas 110m Alacranes).\The variations on the reproductive cycle of a species among different localities can be associated to environmental levels of instability. Predation and competition induce massive spawning and reduction of the spawning periods.\The knowledge of their reproductive cycle of S. gigas is mandatory for proper management of their populations. The scope of this paper to present and compare the reproductive cycle of S. gigas populations from mainly fishing sites from Mexico, their variations and similarities in relation to prevailing environmental characteristics of their habitats.

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