Viruses of Atlantic Bonefish (Albula vulpes) in Florida and the Caribbean show geographic patterns consistent with population declines.

Atlantic Bonefish (Albula vulpes) are economically important due to their popularity with recreational anglers. In the State of Florida, USA, bonefish population numbers declined by approximately 60% between the 1990s and 2015. Habitat loss, water quality impairment, chemical inputs, and other anthropogenic factors have been implicated as causes, but the role of pathogens has been largely overlooked, especially with respect to viruses. We used a metagenomic approach to identify and quantify viruses in the blood of 103 A. vulpes sampled throughout their Western Atlantic range, including populations in Florida that have experienced population declines and populations in Belize, Mexico, Puerto Rico, and The Bahamas that have remained apparently stable. We identified four viruses, all of which are members of families known to infect marine fishes (Flaviviridae, Iflaviridae, Narnaviridae, and Nodaviridae), but all of which were previously undescribed. Bonefish from Florida and Mexico had higher viral richness (numbers of distinct viruses per individual fish) than fish sampled from other areas, and bonefish from the Upper Florida Keys had the highest prevalence of viral infection (proportion of positive fish) than fish sampled from any other location. Bonefish from Florida also had markedly higher viral loads than fish sampled from any other area, both for a novel narnavirus and for all viruses combined. Bonefish viruses may be indicators of environmentally driven physiological and immunological compromise, causes of ill health, or both. Supplementary information: The online version contains supplementary material available at 10.1007/s10641-022-01306-9.

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

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.

Redescription of Vieja hartwegi (Taylor Miller 1980) (Teleostei: Cichlidae) from the Grijalva River basin, Mexico and Guatemala, with description of a rheophilic morph.

Vieja hartwegi was described by Taylor and Miller in 1980 based on 45 juvenile and sub-adult specimens, but this species shows an enormous variation in coloration patterns during ontogenic development and between individuals. Additionally, morphological data have demonstrated the existence of two forms in V. hartwegi: the typical morph of a moderately deep to slightly elongated body shape with midlateral band, and a rheophilic morph with an elongated to slightly deep body shape and lack of midlateral band. Herein we redescribe V. hartwegi adding adults and individuals from broad geographic ranges, as well as a rheophilic morph recently discovered in the upper reaches of the Grijalva River basin in Mexico. The set of characters include coloration, meristic, morphometric and osteological features. Vieja hartwegi is a polymorphic species whose forms may be segregating because of habitat preferences and food habits.

Diversidad de las comunidades de peces en dos áreas marinas protegidas del Caribe y su relación con el pez león / Diversity of native reef fish communities in two protected areas in the Caribbean Sea and its relationship to the invasive lionfish

Resumen El pez león (Pterois volitans) invadió la región del Caribe y tiene el potencial de alterar la composición y estructura de las comunidades de peces en los arrecifes coralinos. El objetivo de este estudio fue analizar los índices de diversidad en las comunidades de peces nativos en sitios invadidos por el pez león en dos áreas marinas protegidas (AMP) del Caribe y compararlos con datos previos a la invasión. En ambas AMP, Parque Nacional Guanahacabibes (PNG) en el occidente de Cuba y Parque Nacional Arrecifes de Xcalak (PNAX) en el S de Quintana Roo, se realizaron censos visuales de las especies de peces en hábitats durante las épocas de seca y lluvia del 2013-2015. Se evaluaron nueve sitios, mediante conteos estacionarios. Se registró mayor riqueza de especies en el PNG (43.47±5.14) que en el PNAX (40.22±4.96). No se observaron diferencias entre épocas en ninguna de las AMP. El pez león se ubicó entre las especies más abundantes del PNG. La abundancia media en el PNG (0.76 ± 1.25) fue mayor a la registrada en el PNAX (0.19±0.46). La diversidad disminuyó después de la llegada del pez león en un solo sitio del PNG y en dos sitios del PNAX, pero al parecer estos resultados están más asociados al efecto de la pesca que a la presencia del pez león. A partir de los resultados y asumiendo que los cambios en las comunidades de peces por el pez león podrían no detectarse aún, recomendamos seguir los monitoreos de los descriptores comunitarios para detectar cambios futuros en las comunidades de peces.

Abstract Lionfish (Pterois volitans) invaded the Caribbean region with the potential to alter the composition and structure of native coral reef fish communities. The objective of this study was to analyze the diversity indices of these fish communities potentially affected by lionfish predation and to compare with pre-invasion data. The study was undertaken in two Caribbean marine protected areas (MPAs): Guanahacabibes National Park (PNG) in W Cuba and Xcalak Reefs National Park (PNAX) in S Quintana Roo. We carried out visual censuses of fish species in reef habitats during the dry and rainy seasons of the period 2013-2015. For this, nine sites were defined and evaluated using stationary counts. Our results showed higher species richness (43.47 ± 5.14) and mean abundance (0.76 ± 1.25) in PNG than in PNAX (40.22 ± 4.96, 0.19 ± 0.46, respectively). Diversity decreased after the arrival of lionfish in a single site of PNG and in two sites of the PNAX, but apparently, these results are more related to the fishing activity effect than to the lionfish presence. Based on the results and assuming that changes in the native fish communities by lionfish may not yet be detected, we recommend to continue the monitoring community descriptions in order to detect future changes in native fish communities. Rev. Biol. Trop. 66(1): 189-203. Epub 2018 March 01.

Land use and biotic integrity in shallow streams of the Hondo River basin, Yucatán Peninsula, Mexico / Uso del suelo e integridad biótica en arroyos someros de la cuenca del río Hondo, península de Yucatán, México

Abstract Aquatic environments face a variety of threats in the Hondo River basin, Southeastern Yucatán Peninsula. Some of these impacts, like pollution by pesticides, may depend on land use and cover. Our objective was to assess the effect of land use/cover using a previously published index of biotic integrity (IBI), based on fishes and designed for shallow streams in the Hondo River basin. Our hypothesis was that land uses that cause deforestation and pollution, such as urbanization, cattle breeding, or sugar cane fields, would be reflected in low IBI values, at least at some spatial scales. The 23 sites originally used in 2008-2009 to estimate by electrofishing the relative abundance and other characteristics of selected fish species and guilds to construct the IBI, were revisited in February 2010, to validate by direct inspection the type of land use/cover suggested by landscape information in digital databases. We analyzed the effect of seven types of land use/cover (agriculture, pasture, human settlements, water bodies, wetlands, forest, and secondary vegetation) on the IBI values, at four spatial scales, i.e., the percent of every land use/cover at progressively larger circles (125, 250, 500, and 1 000 m diameter) centered on the water body where the IBI value was measured. Correlations were established among the percent land/use cover by scale around 23 sites, and with their corresponding IBI values. Then, Student's t tests were calculated to examine significant differences in land use/cover between groups of localities above and below the median IBI value, and Mann-Whitney's U tests were applied to compare IBI values between localities with andwithout a given landscape cover. Agriculture, human settlements, and secondary vegetation correlated negatively with the IBI; forests positively. Differences were significant (p<0.05) for forest (higher in sites with higher IBI values) and human settlements (lower in sites with higher IBI). Of all the landscape categories located in the Hondo River basin, with the exception of pasture, those of anthropogenic origin tended to be detrimental to aquatic biotic integrity.

Resumen Los ambientes acuáticos en la cuenca del río Hondo, sureste de la península de Yucatán, enfrentan diversas amenazas. Algunos de estos impactos, e.g. contaminación por plaguicidas, pueden depender del uso de suelo o cobertura. El objetivo fue evaluar el efecto del uso del suelo/cobertura sobre un índice biótico de integridad (IBI) basado en peces, publicado previamente, diseñado para arroyos someros en esta cuenca. La hipótesis era que los usos del suelo que involucran deforestación y contaminación, entre ellos urbanización, ganadería o cultivo de caña de azúcar, se verían reflejados en valores bajos del IBI, por lo menos a ciertas escalas espaciales. Los 23 sitios usados originalmente para estimar por electropesca la abundancia relativa y otras características de especies y gremios selectos de peces, para construir el IBI, fueron visitados de nuevo en febrero 2010 para validar por inspección directa el tipo de uso del suelo/cobertura sugerido por la información de paisaje en bases de datos digitales. Se analizó el efecto de siete tipos de uso del suelo/cobertura (agricultura, ganadería, asentamientos humanos, cuerpos de agua, humedales, bosque y vegetación secundaria) sobre los valores del IBI, a cuatro escalas espaciales, i.e., el porcentaje de cada uso del suelo/cobertura en círculos progresivamente mayores (125, 250, 500 y 1 000 m de diámetro) centrados en el cuerpo de agua donde se midió el valor del IBI. Los porcentajes de uso del suelo/cobertura por escala se correlacionaron entre sí y con los valores correspondientes del IBI para explorar su asociación; luego, mediante pruebas t de Student se buscaron diferencias significativas en cobertura entre grupos de localidades por encima y por debajo del valor mediano del IBI, así como pruebas U de Mann-Whitney para comparar valores del IBI entre localidades con o sin una cobertura dada. La agricultura, asentamientos humanos y vegetación secundaria mostraron una relación negativa con el IBI, lo cual sugiere un impacto de las actividades humanas sobre la salud de los ecosistemas acuáticos. Las diferencias fueron significativas para el bosque (mayor en sitios con mejor integridad acuática) y los asentamientos humanos (menor en sitios con mayor valor del IBI). De todas las clases paisajísticas en la cuenca del río Hondo, las de origen antrópico, excepto los pastizales para ganadería, tendieron a ser perjudiciales para la integridad biótica acuática.

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

A phylogeny is presented for 34 species of Astyanax, 27 of them once included within A. aeneus or A. fasciatus in Central America and Mexico, based on 52 morphological characters (mostly osteological, but also pigmentation and meristics), with three outgroups. Monophyly is not supported for A. aeneus s. lat., as Brazilian species such as A. fasciatus s. str. and others occur also within that clade. There were only five resolved clades, three of them including both Brazilian and Central American species, one purely Nicaraguan, and one for central-northern Mexico and Texas. Coincidence with previous cladistic hypotheses is only partial. The genus Bramocharax Gill is not recovered, and thus confirmed as a synonym of Astyanax Baird & Girard. The findings point at a more complex biogeographic history of the region than usually recognized.

An Index of Biotic Integrity for shallow streams of the Hondo River basin, Yucatan Peninsula.

An Index of Biotic Integrity (IBI) is proposed, based on the fish communities and populations in streams of the Hondo River basin, Mexico-Belize. Freshwater environments in this area are threatened by exotic fishes, eutrophication, and pesticide pollution, among other problems. This IBI should allow to identify the most vulnerable sites and eventually guide rehabilitation efforts. Data on composition, structure, and function of fish communities were evaluated. Twenty-three sites in the Mexican part of the basin were explored; a stratified sample of 13 sites was used to design the IBI, and the rest were used to test and refine the index. Thirty-four candidate indicator metrics were scanned for their correlation with an index of water and habitat quality (IWHQ), as well as for the possible influence of stream width and altitude or distance to the Hondo River mainstem. Twelve variables were selected to constitute the IBI: relative abundances of Astyanax aeneus, 'Cichlasoma' urophthalmus, Poecilia mexicana, Poecilia sp. (a new species, probably endemic to the upper Hondo River basin), Xiphophorus hellerii, and X. maculatus; relative abundances of bentholimnetic, herbivore, and sensitive species; percentage of native and tolerant species; and Pielou's evenness index. Most of the sites have a low-medium quality and integrity, showing impact due to partial channelization or to suboptimal water quality, reflected in scarcity or absence of sensitive species, frequent excess of tolerant species, occasional presence of exotics, dominance of herbivores (perhaps due to proliferation of filamentous algae), or dominance of the opportunistic species P. mexicana. The streams with better water and habitat quality are those farthest away from the river mainstem, probably because of lower human population and economical production.