Mangrove-associated fish assemblages off the southern Panama Bight region (tropical eastern Pacific)

The Panama Bight ecoregion (PBE) in the eastern Pacific contains probably the best developed mangrove forests in the American continent. Fishes inhabiting the mangrove-estuary mosaic play fundamental ecological roles and sustain the artisanal fishery operating there. Here, using data collected along ~300 km between 2012 and 2017, we examine the spatial dynamics of mangrove fish assemblages that undertake intertidal migrations in the southern part of the PBE (southern Colombian Pacific coast), where the largest and least disturbed mangroves of Colombia are located. Sixty-one fish species used intertidal mangrove habitats in these areas, constituting ~30% of all fishes inhabiting the whole mosaic of mangrove habitats in this ecoregion. Species within Clupeidae, Ariidae, Centropomidae and Tetraodontidae, all common in mangroves of the eastern Pacific, were the most dominant. Half of the fish species found are commercially important to the artisanal fishery. Differences in fish community structure could be related to salinity differences, but other environmental and ecological factors could also play a role in explaining these differences. A better understanding of the ecological role of mangrove fishes in the region could be gained by examining the ichthyofauna of other habitats within the mosaic and their trophic relationships.(AU)

La ecorregión del Panama Bight (EPB) en el océano Pacifico oriental contiene probablemente los bosques de manglar más desarrollados de America. Los peces que habitan el mosaico estuario-manglar juegan papeles ecológicos fundamentales y sostienen las pesquerías artesanales que operan allí. Usando datos colectados a lo largo de ~300 km entre 2012 y 2017, examinamos la dinámica espacial de ensamblajes de peces de manglar que realizan migraciones intermareales en el EPB sur (costa sur del Pacífico colombiano), donde se encuentran los manglares más grandes y menos intervenidos de Colombia. Sesenta y un especies de peces ingresaron en zonas intermareales de manglar, constituyendo ~30% de todos los peces que pueden ser encontrados en el mosaico de hábitats de manglar de esta ecoregión. Especies de Clupeidae, Ariidae, Centropomidae y Tetraodontidae, todas comunes en manglares del Pacífico oriental, fueron las más dominantes. La mitad de los peces encontrados son importantes comercialmente para la pesquería artesanal. Las diferencias en la estructura de la comunidad pueden estar relacionadas con diferencias en salinidad, pero otros factores ambientales y ecológicos podrían también jugar un rol explicando las diferencias encontradas. Un mejor entendimiento del rol ecológico de los peces de manglar de la región podría alcanzarse examinando la ictiofauna de otros hábitats de este mosaico y sus relaciones tróficas.(AU)

Thermal Jeans Fragmentation within ~ 1000 AU in OMC-1S.

We present subarcsecond 1.3 mm continuum ALMA observations towards the Orion Molecular Cloud 1 South (OMC-1S) region, down to a spatial resolution of 74 AU, which reveal a total of 31 continuum sources. We also present subarcsecond 7 mm continuum VLA observations of the same region, which allow to further study fragmentation down to a spatial resolution of 40 AU. By applying a Mean Surface Density of Companions method we find a characteristic spatial scale at ~ 560 AU, and we use this spatial scale to define the boundary of 19 'cores' in OMC-1S as groupings of millimeter sources. We find an additional characteristic spatial scale at ~ 2900 AU, which is the typical scale of the filaments in OMC-1S, suggesting a two-level fragmentation process. We measured the fragmentation level within each core and find a higher fragmentation towards the southern filament. In addition, the cores of the southern filament are also the densest (within 1100 AU) cores in OMC-1S. This is fully consistent with previous studies of fragmentation at spatial scales one order of magnitude larger, and suggests that fragmentation down to 40 AU seems to be governed by thermal Jeans processes in OMC-1S.

Complex Organic Molecules tracing shocks along the outflow cavity in the high-mass protostar IRAS 20126+4104.

We report on subarcsecond observations of complex organic molecules (COMs) in the high-mass protostar IRAS 20126+4104 with the Plateau de Bure Interferometer in its most extended configurations. In addition to the simple molecules SO, HNCO and H213CO, we detect emission from CH3CN, CH3OH, HCOOH, HCOOCH3, CH3OCH3, CH3CH2CN, CH3COCH3, NH2CN, and (CH2OH)2. SO and HNCO present a X-shaped morphology consistent with tracing the outflow cavity walls. Most of the COMs have their peak emission at the putative position of the protostar, but also show an extension towards the south(east), coinciding with an H2 knot from the jet at about 800-1000 au from the protostar. This is especially clear in the case of H213CO and CH3OCH3. We fitted the spectra at representative positions for the disc and the outflow, and found that the abundances of most COMs are comparable at both positions, suggesting that COMs are enhanced in shocks as a result of the passage of the outflow. By coupling a parametric shock model to a large gas-grain chemical network including COMs, we find that the observed COMs should survive in the gas phase for ∼ 2000 yr, comparable to the shock lifetime estimated from the water masers at the outflow position. Overall, our data indicate that COMs in IRAS 20126+4104 may arise not only from the disc, but also from dense and hot regions associated with the outflow.

Measurements of valve circumferences and ventricular wall of fetal hearts in Chile.

Diagnosis of cardiac pathology, valvular stenosis, cardiac dilation, and/or cardiac hypertrophy is underestimated if measures of weight, wall thickness, and valve circumference are not obtained. Routine study methodology protocols allow us to obtain values of these measurements for a correct diagnosis of these cardiopathies. The aim of the study is to establish reference values for cardiac measurements in fetuses and to compare them with an international curve of reference. One hundred seventy-one autopsies from week 17 through 41 of gestation were performed on fetuses from the Pathology Unit at the Hospital Barros Luco in Santiago de Chile. Cases with malformations were not considered. Anthropometric and cardiac measurements for each gestational week were taken. A tabulation of data with values (in percentiles) of cardiac weight, valve circumference, and ventricular wall thickness was obtained. Values were similar to an international reference. The curves of values obtained allow for identification of normal parameters of heart weight, valve circumference, and ventricular wall thickness, thereby providing easily accessible data for each gestational week. Abnormal values that fall outside of the curve must be attributed to cardiac fetal pathology.

Reproducción del pez Brotula clarkae (Pisces: Ophidiidae) en el Pacífico colombiano

Reproduction of the fish Brotula clarkae (Pisces: Ophidiidae) in the Colombian Pacific. We studied the reproductive ecology of the fish Brotula clarkae based on 754 individuals obtained from the industrial and artisanal fisheries in the Colombian Pacific (March 1994 to December 1996). Histological sections (paraplast embedding and Harris’s hematoxylin-eosin stain) were made from 151 females (26-100 cm total length). Additionally, mean diameter and particular features are described for oocyte phases and ovarian development stages. The mean size at initial sexual maturity of females was determined with two methods (graphic and statistic) in 61.3 cm and 62.3 cm respectively. The general sex ratio was 1:1.There are several spawn pulses between May and October. The mean fecundity by spawn pulse was 1 005 657 eggs. We recommend a fishing ban during the reproduction period and a minimal catch size above 62.3 cm. Rev. Biol. Trop. 55 (3-4): 957-967. Epub 2007 December, 28.

Con el fin de desarrollar estrategias de uso sostenible del recurso pesquero, se evaluó la reproducción de la merluza (Brotula clarkae), proveniente de las pesquerías industrial y artesanal del Pacífico colombiano(marzo de 1994 a diciembre de 1996). Se examinaron 754 individuos, obteniendo una proporción sexual global de 1:1. Se realizaron cortes histológicos (inclusión en paraplasto y tinción con hematoxilina-eosina) de 151 hembras que se encontraban en un ámbito de tallas de 26 cm a 100 cm de longitud total, determinándose el diámetro promedio y las características particulares de las diferentes fases de desarrollo ovocitario, estableciendo también las distintas etapas de desarrollo ovárico. Se determinó la talla media de inicio de madurez sexual para las hembras por medio de dos métodos (gráfico y estadístico), obteniéndose 61.3 cm y 62.3 cm, respectivamente. Se encontró que la especie presenta desove fraccionado con varios pulsos durante su perido reproductivo, el cual se estableció entre mayo y octubre, estimándose la fecundidad absoluta promedio por pulso de desove en 1 005 657 huevos. Se sugieren como posibles medidas de ordenamiento pesquero el mantener la talla media de captura por encima de la talla media de inicio de madurez y establecer vedas que protejan el periodo reproductivo.

[Reproduction of the fish Brotula clarkae (Pisces: Ophidiidae) in the Colombian Pacific]. / Reproducción del pez Brotula clarkae (Pisces: Ophidiidae) en el Pacífico colombiano.

We studied the reproductive ecology of the fish Brotula clarkae based on 754 individuals obtained from the industrial and artisanal fisheries in the Colombian Pacific (March 1994 to December 1996). Histological sections (paraplast embedding and Harris's hematoxylin-eosin stain) were made from 151 females (26-100 cm total length). Additionally, mean diameter and particular features are described for oocyte phases and ovarian development stages. The mean size at initial sexual maturity of females was determined with two methods (graphic and statistic) in 61.3 cm and 62.3 cm respectively. The general sex ratio was 1:1. There are several spawn pulses between May and October. The mean fecundity by spawn pulse was 1,005,657 eggs. We recommend a fishing ban during the reproduction period and a minimal catch size above 62.3 cm.