Conservation of the endemic dwarf carnivores of Cozumel Island, Mexico.

Cozumel Island, Mexico, harbours two endemic species of dwarf procyonids: the Pygmy Raccoon Procyon pygmaeus and the Dwarf Coati Nasua nelsoni. Both species are Critically Endangered, and are among the world&rsquo;s most threatened Carnivora. Here we summarise the research we have been conducting on their ecology, evolution, genetics, and conservation. We also summarise the conservation initiatives we have been undertaking and promoting in order to advance the conservation of these unique species and their habitats. This effort illustrates the importance of an interdisciplinary approach in conservation science and action in maximising effectiveness. Nevertheless, the precarious status of the species make it imperative to continue and expand the work we have carried out in Cozumel to prevent two imminent global extinctions.<br /

Diversity of soft-bottom macroinvertebrates from the continental shelf off Jalisco and Colima, Mexico

Three cruises (DEM I, II and III) were conducted along the coast of Jalisco and Colima (Mexico) during three hydroclimatic seasons, defined by the pattern of the surface currents. Trawl samples were taken at seven sites along the coastline and four bathymetric levels (20, 40, 60 and 80 m). During the three cruises, 170 invertebrate species were identified. The crab Portunus xantusii affinis was the most abundant species: 62.6% during DEM I, 26.8% during DEM II and 42% during DEM III. The diversity (H') estimated was moderate to low, of 1.93, 2.62 and 2.39 for the three cruises, respectively. No significant differences in diversity were observed among the three cruises and the differences in diversity among depths were only significant during DEM I. The minimum sample sizes for diversity and richness indicate that at least 20,422 organisms are needed to estimate diversity and 34,476 for richness

Variation of the bathymetric distribution patterns of the macrobenthic fauna on the continental shelf off Jalisco and Colima, Mexico [Variaci�n de los patrones de distribuci�n batim�trica de la fauna macrobent�nica en la plataforma continental de Jalisco y Colima, Mexico]

The abundance, in terms of number of individuals and biomass, of the invertebrate communities in one sector of the soft-bottom continental shelf off Jalisco and Colima (Mexico) was analyzed. The cruises were carried out during three hydroclimatic seasons, as defined by the surface current patterns

Variation of the bathymetric distribution patterns of the macrobenthic fauna on the continental shelf off Jalisco and Colima, Mexico [Variaciön de los patrones de distribuciön batimétrica de la fauna macrobentönica en la plataforma continental de Jalisco y Colima, Mexico]

The abundance, in terms of number of individuals and biomass, of the invertebrate communities in one sector of the soft-bottom continental shelf off Jalisco and Colima (Mexico) was analyzed. The cruises were carried out during three hydroclimatic seasons, as defined by the surface current patterns

Larval fish assemblages in waters off the central Pacific coast of Mexico

Spatial and seasonal variation of the ichthyoplankton assemblages was analysed using monthly samples collected during a 1 year cycle off the central Pacific coast of Mexico. Zooplankton samples were collected at 12 stations during 11 months, from December 1995 to December 1996. The analysis of coastal oceanographic conditions revealed two main seasonal patterns, one related to the California Current influence and the other a tropical one. A temporal recomposition of the ichthyoplankton assemblages was found to be related to each oceanographic pattern. During the California Current period (January-May) the larval, fish assemblage was respresented mainly by Auxis sp., Bentosema panamense, Cetengraulis mysticetus, Opistonema sp., Symphurus elongatus, Gobionellus sp., Dormitator latifrons and Bregmaceros bathymaster. The tropical season assemblage (July, October and November) was represented by Harengula thrissina, Euthynnus lineatus, Vinciguerria lucetia, Syacium ovale, and representatives of the Eleotridae and Pomacentridae. An inshore-offshore gradient was observed during the tropical oceanographic periods, with a thermic stratification of the water column over the shelf. Conversely, during the California Current period, with coastal advective processes, the assemblages of fish larvae were more homogeneous. Although a mixed, richer faunistic composition was expected in this transitional area, the overall biogeographic affinity of the surveyed community remained stable even in contrasting conditions

Larval fish assemblages in waters off the central Pacific coast of Mexico

Spatial and seasonal variation of the ichthyoplankton assemblages was analysed using monthly samples collected during a 1 year cycle off the central Pacific coast of Mexico. Zooplankton samples were collected at 12 stations during 11 months, from December 1995 to December 1996. The analysis of coastal oceanographic conditions revealed two main seasonal patterns, one related to the California Current influence and the other a tropical one. A temporal recomposition of the ichthyoplankton assemblages was found to be related to each oceanographic pattern. During the California Current period (January-May) the larval, fish assemblage was respresented mainly by Auxis sp., Bentosema panamense, Cetengraulis mysticetus, Opistonema sp., Symphurus elongatus, Gobionellus sp., Dormitator latifrons and Bregmaceros bathymaster. The tropical season assemblage (July, October and November) was represented by Harengula thrissina, Euthynnus lineatus, Vinciguerria lucetia, Syacium ovale, and representatives of the Eleotridae and Pomacentridae. An inshore-offshore gradient was observed during the tropical oceanographic periods, with a thermic stratification of the water column over the shelf. Conversely, during the California Current period, with coastal advective processes, the assemblages of fish larvae were more homogeneous. Although a mixed, richer faunistic composition was expected in this transitional area, the overall biogeographic affinity of the surveyed community remained stable even in contrasting conditions

Fishing power, efficiency and selection of gillnets for the shortfin grunt (Microlepidotus brevipinnis Steindachner, 1869), in the southern coast of Jalisco, Mexico [Poder de pesca, selectividad y eficiencia de las redes de enmalle para la Sarangola (Microlepidotus brevipinnis Steindachner, 1869) en la costa sur de Jalisco, M�xico]

Gillnet selectivity, fishing power and catch efficiency for Microlepidotus brevipinnis (Steindachner, 1869) off Bahia de Navidad, Jalisco, Mexico, were estimated. Field experiments were conducted using gillnets of 7.62 and 8.89 cm of mesh-size, during April 1994 to March 1995. A total of 457 organisms were caught with the 7.62 cm mesh-size, and 592 with the 8.89 mesh-size. Results shows gillnet of 8.89 cm mesh size caught 3 cm larger organisms and 110 g more weighted fish than those caught by the 7.62 mesh-size. The 7.62 mesh-size caught 1.9 times organisms and 1.3 more weight than the 7.62 cm mesh-size. Selectivity analysis indicates an optimum length (100% probability of retention) was 27.7 cm TL for the 7.62 mesh-size and 32.3 cm TL for the 8.89 cm mesh-size. The relative efficiency analysis was estimated as relative catchability ratio between nets and it varied in a range of 25% to 39% with fish length

Fishing power, efficiency and selection of gillnets for the shortfin grunt (Microlepidotus brevipinnis Steindachner, 1869), in the southern coast of Jalisco, Mexico [Poder de pesca, selectividad y eficiencia de las redes de enmalle para la Sarangola (Microlepidotus brevipinnis Steindachner, 1869) en la costa sur de Jalisco, México]

Gillnet selectivity, fishing power and catch efficiency for Microlepidotus brevipinnis (Steindachner, 1869) off Bahia de Navidad, Jalisco, Mexico, were estimated. Field experiments were conducted using gillnets of 7.62 and 8.89 cm of mesh-size, during April 1994 to March 1995. A total of 457 organisms were caught with the 7.62 cm mesh-size, and 592 with the 8.89 mesh-size. Results shows gillnet of 8.89 cm mesh size caught 3 cm larger organisms and 110 g more weighted fish than those caught by the 7.62 mesh-size. The 7.62 mesh-size caught 1.9 times organisms and 1.3 more weight than the 7.62 cm mesh-size. Selectivity analysis indicates an optimum length (100% probability of retention) was 27.7 cm TL for the 7.62 mesh-size and 32.3 cm TL for the 8.89 cm mesh-size. The relative efficiency analysis was estimated as relative catchability ratio between nets and it varied in a range of 25% to 39% with fish length