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Reproductive aspects of Pomacea flagellata (Mollusca: Ampullariidae) at Bacalar lagoon, Quintana Roo, México. The freshwater snail Pomacea flagellata is native from Southeastern Mexico. Studies about this species are scarce and none has treated their reproduction. This snail has been exploited at Bacalar lagoon for many years, leading to a significant decrease in their abundance and currently, a permanent ban was proposed by the government. This work aimed to assess the temporal variations of mating frequency and the abundance of egg clutches of P. flagellata at Bacalar lagoon, as well as their relation with snails density and environmental variables. Sampling was done during the three climatic seasons

Diversity patterns of the deep-sea megafauna in the Caribbean Basin and the Guiana ecoregion were analyzed in order to test the hypothesis of species richness variation as a function of depth and the hypothesis of non-differences between ecoregions by analyzing spatial patterns of five taxa and a merged assemblage. Collections of five taxa (corals, sea stars, sea urchins, sea lilies and gastropods) were obtained from seven oceanographic expeditions aboard the R/V Pillsbury at 310 stations between 60 and 7500 m depth. Data were sorted according to depth zones and ecoregions and were analyzed in order to estimate species richness, changes in species composition and distinction of β-diversity by species turnover or by nestedness. The observed patterns of diversity were consistent between taxa and their assemblage: Species richness increased from the continental shelf (60–200 m deep) to the slope (200–2000 m deep), followed by a decrease at the continental rise-abyssal zone. We detected marked changes in species composition according to depth ranges. Changes in species composition in relation to ecoregions were also detected. In general, the Caribbean Basin lacks important physical barriers, causing high deep-sea ecosystem connectivity; however, variation in composition could be related to changes in environmental conditions associated with productivity and/or continental influences.

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Densidad y reproducción de la concha reina Eustrombus gigas (Mesogastropoda: Strombidae) en Cabo Cruz, Parque Nacional Desembarco del Granma, Cuba. The queen conch Eustrombus gigas is an important fisheries resource in the Caribbean region. In Cuba Island the studies about this resource are very scarce and particularly in the Southeastern regions of the country. With the aim to get important fishery information about this gastropod, adult Queen Conch density and frequency of reproductive activity were evaluated in Cabo Cruz, Cuba, during 2009-2010. Data from three seasons were obtained (rainy, dry and cold fronts periods) from three different areas: Farito, Guafe and Laguna. The highest density was observed in cold fronts season (468.5ind./ha) and the lowest occurred during the dry season (268.5ind./ha). The highest density was reported at Laguna (520.4ind./ha) and the lowest at Farito (290.9ind./ha). In total, 158 reproductive events were observed. The highest frequency was reported in rainy season (36%), followed by dry (9%) and cold fronts (5%) seasons. Reproductive behavior (mating and egg laying) was related to temperature and photoperiod. Reproductive activity was observed during the whole year, which suggests the existence of an important Queen Conch reserve in the Southeastern region of Cuba and an apparently self-sufficient population for recruitment. From our results we may conclude that, the population's sustainable exploitation is viable if the following management measures are observed: functional zoning within the area, rotation of fishing areas and a closed season. We recommend that the Laguna site should be protected as a reproduction zone and banned for fishing activities. Rev. Biol. Trop. 61 (2): 645-655. Epub 2013 June 01.