Composition and spatio-temporal variation of the fish community in the Chacmochuch Lagoon system, Quintana Roo, Mexico

The composition, distribution and abundance of fishes were determined in the Chacmochuch Lagoon System, a natural protected area located on the north coast of Quintana Roo. Monthly diurnal sampling was carried out at 10 sampling stations in March, June and September, 2002. During each field trip, bottom type, submerged and surrounding vegetation, salinity, temperature, dissolved oxygen and other variables were measured. Distribution and abundance of fishes were examined by means of a principal component analysis. Fifty species were recorded; Gerres cinereus, Floridichthys polyommus, Eugerres plumieri, Harengula jaguana, Sphyraena barracuda, and Archosargus rhomboidalis were dominant, and no significant difference in species composition was found between seasons. Apart from a single site where turbidity and nutrient concentration were particularly high, the other sites could be classified mainly according to salinity. Fish composition changed along this gradient

Composición y estructura de la ictiofauna del río Hondo, México-Belice, con base en el uso del arpón

ResumenSe determinó la composición y estructura de la ictiofauna del río Hondo y la variación espacial de éstas en función de los parámetros ambientales. Se realizaron 3 muestreos durante marzo, abril y mayo de 2012, en 6 sitios a lo largo del río. Los datos usados para determinar la estructura se obtuvieron con ayuda de un arpón de 58.5cm, utilizado durante 2h de buceo libre en cada punto de muestreo. Para complementar la lista de especies se utilizaron redes agalleras, palangres, nasas y anzuelos. Además, se realizó una revisión bibliográfica y se consultó material de la colección de peces de ECOSUR en Chetumal. La lista sistemática se conformó por 40 especies en 33 géneros, 18 familias y 11 órdenes. La familia mejor representada fue Cichlidae, incluida la especie exótica Oreochromis niloticus. Los parámetros ambientales que mejor describieron la variación de la distribución y abundancia en los peces en el río Hondo fueron: la anchura del río, distancia a la boca, transparencia, profundidad, concentración de oxígeno disuelto y conductividad. La relación entre las especies y las variables ambientales fue alta en ambos ejes (0.89 y 0.79). Ambientalmente, el río se puede zonificar en 3 partes, aunque su ictiofauna puede dividirse en 2 conjuntos principales.AbstractComposition and structure of the Hondo River ichthyofauna and its spatial variation were determined as a function of environmental parameters. Six sites along the river were sampled in March, April and May 2012. Data for estimating structure of fish assemblages was obtained by means of a 58.5cm harpoon during 2 hours of free diving at each sampling site. The species list for the study area was completed with the aid of gillnets, longlines, double-cone traps, and hook-and-line. In addition, a bibliographical research performed as well as the ichthyological collection of ECOSUR at Chetumal was checked. The systematic list includes 40 species in 33 genera, 18 families and 11 orders. The richest family was Cichlidae, including the exotic Oreochromis niloticus. The environmental parameters that best described distribution and abundance of fish in the Hondo River were river width, distance to mouth, transparency, depth, dissolved oxygen concentration, and conductivity. Correlation between species and environmental parameters was high in both axis (0.89 and 0.79). The river was classified into 3 environmental zones, although its fish fauna could be divided in 2 main assemblages

Length-weight relationships and relative condition factor in razor surgeonfish, Prionurus laticlavius (Teleostei: Acanthuridae) from the southwestern coast of the Gulf of California, Mexico: Relación peso-longitud y factor de condición relativo del navajón barbero Prionurus laticlavius (Teleostei: Acanthuridae) de la costa sudoccidental del Golfo de California, México

The razor surgeonfish, Prionurus laticlavius, listed on the IUCN Red List of Threatened Species under the Least Concern category, plays an important ecological role as energy regulator in reef communities, but it is sought by the aquarium and aquaculture industry, and also is consumed by people. This study estimated the length-weight relationship (LWR) and relative condition factor (Krel) in P. laticlavius. The equation for length-weight relationship was TW= 0.02 TL3.01 for the Overall category, and the relative condition factor was 1.28. A total of 379 fish (3-45.6 cm total length) were collected in the southwestern coast of the Gulf of California using harpoon (for large fishes) and hand net (for small fishes), of which 181 were females (20.2-45.6 cm), 137 males (20.6-43.4 cm), and 61 juveniles (3-19.5 cm). Allometric coefficient b of LWR for the Overall category suggested isometric growth (b = 3.01), positive allometric growth for juveniles (b = 3.14), and negative allometric growth for adults (2.75). Results of Krel showed higher values for females during the warm season. The population showed a good nutritional condition, mainly in the warm season. This work is the first to estimate LWR and Krel for P. laticlavius, which will inform stock assessment and the management of this species in the Gulf of California

Freshwater fishes and water status in Mexico: A country-wide appraisal.

Mexico is the southernmost country in North America, and extends into Central America, south of the Isthmus of Tehuantepec. The northern half of M´exico is located on the Temperate belt and is arid in character (Nearctic), while the rest is within the Tropical belt (Neotropical). Climate varies from extremely temperate desert in the north, to tropical humid in the south.M´exico has more than 500 freshwater fish species, about 271 of them country endemics, and approximately 48 endemics from binational basins. There are still some 30–40 fish species not yet described. There are 563 fish species colonizing coastal flood plain species. In addition to the numbers of colonizing fishes, the burden of introduced exotics has also been growing. In 1904, only 4 species were recognized as exotics; by 1997 the number had increased to 94, and by 2008 to 11

New records of ray-finned fishes (Actinopterygii) from Puerto Morelos Reef National Park (Mexican Caribbean)

We documented the nearshore ray-finned fishes in Puerto Morelos Reef National Park (PMRNP) by sampling 57 localities, including rocky intertidal pools, sandy bottoms, Thalassia beds, coral reefs, artificial reefs, karstic-slab bottoms, demersal-pelagic areas, and sessile-Sargassum patches. We recorded seven species new to Caribbean Mexican waters and one hundred and six species new to the PMRNP, most of which are small cryptobenthic reef fish. The resultant checklist includes 349 species, and specimens of 285 of which (81.7%) have been deposited in an ichthyological museum collection. These include both voucher organisms and with tissue samples for genetic analysis. A comparison with inventories at other localities of the Greater Caribbean indicates that more targeted sampling for cryptobenthic and deep-reef fishes is needed to provide a complete inventory. We also comment on the local use of some species as fishery resources

Microorganisms and spatial distribution of the sinkholes of the Yucatan Peninsula, underestimated biotechnological potential?

Investigación basada en el potencial bio-tecnológico de las micro-especies que habitan los cenotes de la Península de YucatánAbstract Objective: To detect the spatial distribution of the sinkholes of the Peninsula of Yucatan (SPY) and identify those cenotes where microorganisms have been registered. Methods: The geographic coordinates of the SPYs were obtained from various databases, as well as from scientific publications relating to the terminology ‘sinkholes’, ‘karst systems’ and ‘cenotes’. All coordinates were transformed into the Universal Transverse Mercator reference system (UTM) with datum WGS84. An infrared composite image was created with 432 RGB bands from the Landsat 8 satellite. The points with the location of the cenotes were imported into the Software TerrSet. Results: Total 1026 coordinates of sinkholes were recorded in the Yucatan Peninsula. In 18 sinkholes (<2%), microorganisms have been recovered and identified in various taxonomic levels, and only 6 sinkholes (<0.6%) has their biotechnological potential been evaluated. Conclusions: The microorganisms that inhabit the sinkholes of the Yucatan Peninsula are a reservoir with practically unexplored biotechnological potential.CONACY

Quantifying and addressing the prevalence and bias of study designs in the environmental and social sciences

Abstract: Building trust in science and evidence-based decision-making depends heavily on the credibility of studies and their findings. Researchers employ many different study designs that vary in their risk of bias to evaluate the true effect of interventions or impacts. Here, we empirically quantify, on a large scale, the prevalence of different study designs and the magnitude of bias in their estimates. Randomised designs and controlled observational designs with pre-intervention sampling were used by just 23% of intervention studies in biodiversity conservation, and 36% of intervention studies in social science. We demonstrate, through pairwise within-study comparisons across 49 environmental datasets, that these types of designs usually give less biased estimates than simpler observational designs. We propose a model-based approach to combine study estimates that may suffer from different levels of study design bias, discuss the implications for evidence synthesis, and how to facilitate the use of more credible study designs

Validity of Rocio gemmata (Teleostei: Cichlidae)

Schmitter-Soto, Juan J. (2021): Validity of Rocio gemmata (Teleostei: Cichlidae). Zootaxa 4991 (1): 195-200, DOI: https://doi.org/10.11646/zootaxa.4991.1.1