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

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

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

A phylogeny of Astyanax (Characiformes: Characidae) in Central and North America

Schmitter-Soto, Juan J. (2016): A phylogeny of Astyanax (Characiformes: Characidae) in Central and North America. Zootaxa 4109 (2): 101-130, DOI: http://doi.org/10.11646/zootaxa.4109.2.

Fatal predation of oilfish, Ruvettus pretiosus (Gempylidae), by a young short-finned pilot whale, Globicephala macrorhynchus (Delphinidae)

We found a dead whale (Globicephalus macrorhynchus) whose probable cause of death was an internal injury produced by a 1m-long oilfish (Ruvettus pretiosus) that had bitten the whale´s stomach from the inside. This is the first record of an oilfish in Mexican Caribbean waters. KEY WORDSMarine mammals, mesopelagic fishes, feeding behavior, new records, Caribbean seaDescribimos un intento fatal de depredación de un escolar, Ruvettus pretiosus, por un joven calderón de aletas cortas, Globicephala macrorhynchus. Éste es el primer registro de un escolar en aguas del Caribe mexicano. PALABRAS CLAVEMamíferos marinos, peces mesopelágicos, conducta alimenticia, nuevos registros, mar Carib

Changes in the Fish Community of a Western Caribbean Estuary after the Expansion of an Artificial Channel to the Sea

Increased connectivity between coastal lagoons and the sea is expected to entail a greater proportion of marine species in the former. Chetumal Bay, estuary of the Hondo river into the Caribbean, had a limited access to the sea until the opening of the Zaragoza Canal. We sought changes in the fish community from 1999–2001 (just after an expansion of the canal) to 2015–2018. The same fishing gear was used, in the same localities, during all seasons. Total fish abundance and mean local richness decreased, although total abundance increased in the polyhaline zone. Diversity was greater in the oligohaline zone in 1999–2001, and in the mesohaline zone in 2015–2018. Three guilds were absent in 2015–2018: Medium-sized herbivores, large piscivores, and medium-sized planktivores. Abundance of small benthivores decreased by decade; medium-sized piscivores and small planktivores became more abundant in 2015–2018 in the polyhaline zone. These changes may be due to the opening of the channel, but illegal fishing outside the bay may explain the decrease in juveniles of large piscivores, and erosion in the innermost part may be destroying important habitats. Our findings can be a reference for similar situations, as coastal development and climate change interact and affect tropical estuaries

Distribution patterns of Charaxinae (Lepidoptera: Nymphalidae) in Yucatan Peninsula, Mexico

The objectives of this work were to ascertain which environmental, anthropogenic or geographic factors influence the present distribution of Charaxinae in Yucatan Peninsula and to identify distribution patterns which might be linked to biological conservation in the region. We obtained records from collections, literature and field, and analyzed the data with DCA and CCA. We analyzed both matrices, species data (17 species, 151 sites) and environmental data (11 independent variables, 151 sites). Six environmental, physiographic and anthropic descriptors, namely latitude, distance to Caribbean coast, mean annual temperature, distance to present-day urban settlements, altitude, and humidity were statistically significant. Distribution abundance of Charaxinae was higher towards north and south and lower in mid-latitude of the Yucatan Peninsula. We discerned five distribution patterns of Charaxinae in Yucatan Peninsula; each one formed by different species and with different optima along those six variables, confirming that seven species are indicative of conserved environments. We obtained distributional limits for some species according to latitude and humidity (Anaea troglodyta aidea)