Jesús Emilio Michel-Morfín

Estimation of the Abundance and Population Structure of the Purple Snail Plicopurpura pansa (Gould, 1853) Comparing Two Methods

A study using a mark-recapture method was used in order to estimate the abundance and population structure of the Purple snail Plicopurpura pansa (Gould, 1853), on a rocky shore in Tenacatita Bay, Jalisco, Mexico. A comparison of the results obtained by this method and the linear transects parallel to coast was performed, the latter has been the method most commonly used in previous studies for this species. The results indicate significant differences in estimates of population parameters obtained by the two methods used; we found that in a general of linear transection methods tend to underestimate the abundance of these snails. Given the implications of these findings for the management of a species with potential for exploitation, such as the Purple snail, we discuss the possible causes and significance of this discrep- ancy of the methods.

Recreational Beaches as Factors of Involvement in a Coral Community: Colima Case Study

Despite the great ecological importance of coral reefs, they are under threat due to both natural and anthropogenic causes. When communities are located close to the coast, intensified human activity including pollution, overfishing, indiscriminate extraction, and deforestation of associated terrestrial ecosystems can destabilize a coral ecosystem, resulting in loss of coral cover. This research analyzes different factors that can affect coral health, particularly associated with proximity to recreational beaches on the coast of Colima, Mexico. Environmental and anthropogenic factors affecting the loss of coral cover are analyzed in the La Boquita, as the main coral ecosystem of greater proximity to the beaches of great tourist load in Manzanillo. We also characterize some of the signs of stress response demonstrated by the Pocillopora genus, which is the most dominant in the region. We analyze various factors directly or indirectly related to tourists from nearby beaches, and the ways in which these factors can interact with other elements of stress, thereby helping to promote stress and affecting adaptive and reproductive capacity of the coral community. The communities of La Boquita and Carrizales are subject to different stressful conditions, and this is reflected in most indicators of reef health. La Boquita community shows signs of greater effects arising from excessive tourism and overfishing that have contributed to loss of coral coverage. Part of the current problem is caused by an influx of visitors from the beach of the same name. Negative effects stemming from lack of knowledge and awareness on the part of visitors and service providers are compounded by authorities’ insufficient efforts to carry out sustained and efficient surveillance, control, and use of these reefs.

Composition of Prosobranchia-Pulmonata (Mollusca: Gastropoda) in rocky intertidal zone in the Marine Priority Region 32, Guerrero, Mexico

The aim of this research was the description of the taxocoenosis of Prosobranchia and Pulmonata subclasses (Gastropoda) associated with the rocky intertidal zone of the Marine Priority Region 32, Guerrero, Mexico. Based on known species richness, we examine the composition of the community based on the representation of families, assess abundance, the geographic distribution of species, estimate descriptive statistics of size, and estimate diversity. Sampling was conducted at 7 sites, the sampling unit was 1 m-2 and the sampling area was 10 m-2. One hundred and four species of subclass Prosobranchia and 4 species of subclass Pulmonata were identified. Columbellidae and Muricidae families showed higher species richness, meanwhile family Muricidae was the most abundant. Acanthais triangularis was the most representative species of the study area, and Macrocypraea cervinetta showed the greatest size. Twenty three species were found with broad distribution, 27 taxa with frequent distribution and 54 taxa with restricted distribution. Twenty eight species were represented by a single organism and 6 species with 2 organisms, these species were considered rare and were found in sites whose characteristic wave exposure is low to medium. Species richness was high and corresponds to that expected in the tropics.El objetivo de esta investigacion fue la descripcion de la taxocenosis de las subclases Prosobranchia y Pulmonata (clase Gastropoda), asociados a la zona intermareal rocosa de la Region Marina Prioritaria 32, Guerrero, Mexico. Basada en la riqueza de especies, la composicion de la comunidad a partir de la representacion de las familias, se evaluo la abundancia, distribucion geografica de las especies, se estimo los estadisticos descriptivos de las tallas (en largo) de las poblaciones y la diversidad. El muestreo se llevo a cabo en 7 sitios, la unidad de muestreo fue de 1 m-2 y el area de muestreo de 10 m-2. Se identificaron 104 especies de prosobranquios y 4 de pulmonados. Las familias Columbellidae y Muricidae fueron las mejores representadas en riqueza de especies y la familia Muricidae en abundancia. Acanthais triangularis se considero como la representativa de la zona, la especie Macrocypraea cervinetta mostro la mayor talla. Ademas, 23 especies presentaron amplia distribucion, 27 distribucion regular y 54 distribucion restringida. Veintiocho especies estuvieron representadas por un unico organismo, y 6 especies por 2 organismos, estas especies son consideradas raras. Las especies raras se encontraron en las estaciones cuya caracteristica de exposicion del oleaje es de bajo a medio. La riqueza de especies fue alta y corresponde a lo esperado en una zona tropical

Gasterópodos con potencial económico asociados al intermareal rocoso de la Región Marina Prioritaria 32, Guerrero, México

Resumen es: Los gasteropodos tienen numerosas especies de importancia comercial, de ellos se utilizan la carne y concha, ademas del uso potencial de sus toxinas para...

First report of partial albinism in the blue lobster Panulirus inflatus (Bouvier, 1895) from the Mexican Pacific (Crustacea, Decapoda, Palinuridae)

Abstract The first case of partial albinism registered in the Mexican Pacific by the blue lobster Panulirusinflatus is presented. The specimen was collected on the southern coast of Jalisco know as Punta “El Estrecho”. It constitutes one of the few registered cases of albinism in invertebrates from the Eastern Tropical Pacific.