Abstract Temporary pools are freshwater bodies of significant interest due to their high species diversity, and the colonization and extinction processes observed at temporal scales. The aim of the present study was to perform a short-term ecological comparison in a group of shallow temporary pools in northern Chilean Patagonia in two periods, August and September 2018. The results revealed marked differences in terms of species richness in the study pools at different conductivities and chlorophyll a concentrations. The dominant species was the calanoid copepod Boeckella gracilis Daday, 1902, while the presence of the rare Anostracan Branchinecta rocaensis Cohen, 1982 was reported in conditions of low chlorophyll a and low conductivity. The community was studied using co-occurrence null models that revealed the absence of structured patterns in species associations, and the presence of niche overlap, with many repeated species that have a similar ecological niche. The present results are identical with observations from temporary pools in southern Chilean Patagonia.

Eight different salinity effects on embryonic survival and embryonic and hatching phase time duration of jollytail (Galaxias maculatus) were assessed. Mean survival rates were higher at salinities values of 0, 4, 8, 12, 16 and 20 with 84.9, 84.0, 85.5, 86.1, 82.6 and 75.8% respectively with no significant differences between them; in contrast to salinity of 24 was obtained by 10.4%, significantly different from other treatments. Salinity of 28 caused 100% of mortality. According to results, the embryo is unable to resist ocean salinity and its tolerance limit is between 24 and 28. The highest larval survivals at 10 days after hatching occurred in those treatments in which embryos were performed to intermediate salinities of 8, 12 and 16 with 79.3, 80.3 and 74.6% respectively, with no significant differences between them. These results demonstrate high post-hatching viability. Embryonic time period (50%) were shorter at low salinities 0, 4, 8 and 12 with 28.7, 28.0, 29.7 and 29.7 days and the largest, in the treatments of salinities of 16 and 20 with 34.0 and 34.3 days. No significant differences were found between all of them. Regarding the average hatching time periods (50%) in the treatments of salinities of 0, 4, 8, 12, 16, 20 and 24 were 5.0, 5.5, 7.5, 8.8, 13, 0, 14.3 and 15.8 days respectively, without significant differences between them.

Se evaluó e l efecto de la salinidad en la supervivencia embrionaria, período embrionario y período de eclosión de puye, Galaxias maculatus. Se utilizaron ocho tratamientos, con salinidades de 0, 4, 8, 12, 16 y 20 obteniéndose supervivencias embrionarias promedios respectivas de 84,9; 84,0; 85,5; 86,1; 82,6 y 75,8%, sin diferencias significativas entre ellas, mientras que con salinidad de 24 se obtuvo sobrevivencia de 10,4%, significativamente diferente al resto de los tratamientos y con salinidad de 28 causó 100% de mortalidad. A diferencia del estado juvenil y adulto, el embrión es incapaz de resistir la salinidad marina y su umbral de tolerancia se encuentra entre salinidades de 24 y 28. Las mayores supervivencias promedios larvales a 10 días de vida fueron con salinidades intermedias de 8, 12 y 16 de 79,3; 80,3 y 74,6% respectivamente, sin diferencias significativas entre ellas, demostrando alta viabilidad del embrión post-eclosión. Los períodos embrionarios promedios (50%) más breves fueron a bajas salinidades 0, 4, 8, 12 con 28,7; 28,0; 29,7 y 29,7 días y los más extensos en los tratamientos con salinidades de 16 y 20, con 34,0 y 34,3 días, sin diferencias significativas entre ellos. Los períodos de eclosión promedio (50%) con salinidades de 0, 4, 8, 12, 16, 20 y 24 fueron de 5,0; 5,5; 7,5; 8,8; 13,0; 14,3 y 15,8 días respectivamente, sin diferencias significativas entre ellos.

This study aims to evaluate the effect of temperature and salinity on Galaxias maculatus embryo survival. Embryos were incubated at 5, 10 and 15°C and 0, 10 and 30 psu. At 5°C all salinities induced 100% mortality. Furthermore, salinity of 30, regardless temperature, caused 100% mortality. In freshwater, embryos reached 74.7 and 69.3% survival at 10°C and 15°C, respectively. While, at 10 psu, the larvae survivals were higher, 88.7 and 80.0% with 10 and 15°C respectively. These findings suggest that there is not a temperature-salinity interaction effect on embryonic development of G. maculatus. In conclusion the embryonic development of this fish is only possible at fresh and brackish waters and it is not viable at salt water.

We evaluated the effect of six constant temperatures on embryonic survival, embryonic period and hatching period of Galaxias maculatus from 7 to 22°C under laboratory conditions. The results of embryo survival were: 90.6 ± 2.0, 88.7 ± 8.6, 87.7 ± 0.7, 89.7 ± 4.2, 70.0 ± 5.6 and 49.5 ± 7.4% at temperatures of 7, 10, 13, 16, 19 and 22°C. Except for the temperature of 22°C, there were no significant differences between them (P < 0.05). These results characterize the embryo as eurythermic regardless of being a subantarctic waters species. Regarding the embryonic period (tH50%), the results were 40.8 ± 0.6, 27.0 ± 0.0, 17.3 ± 0.6, 16.3 ± 0.6 and 13.3 ± 0.6 days at temperatures of 7, 10, 13, 16 and 19°C respectively, with significant differences between them (P < 0.05) and in the case of the hatching period (tH50%), was 8.3 ± 0.6, 6.3 ± 1.5, 5.0 ± 0.0 and 6.3 ± 0.6, 5.0 ± 1.0 and 4.3 ± 0.6 days at temperatures of 7, 10, 13, 16, 19 and 22°C respectively with significant differences between them (P < 0.05). These results suggest that the range of temperatures between 10 and 16°C is optimal for the incubation of G. maculatus eggs, since in that range high embryonic survival (>87.7%) combined with embryonic periods of less than 27 days and hatching periods less than 6.3 days were obtained. These results will optimize embryo survival and eventually rearing of the species for commercial purposes or restocking.

Se evaluó el efecto de seis temperaturas constantes en la sobrevivencia embrionaria, periodo embrionario y periodo de eclosión de Galaxias maculatus de 7 a 22°C, en condiciones de laboratorio. Los resultados de la sobrevivencia embrionaria fueron: 90,6 ± 2,0; 88,7 ± 8,6; 87,7 ± 0,7; 89,7 ± 4,2; 70,0 ± 5,6 y 49,5 ± 7,4% a temperaturas de 7, 10, 13, 16, 19 y 22°C. Exceptuando la temperatura de 22°C, no hay diferencias significativas entre ellas (P > 0,05). Estos resultados caracterizan al embrión como euritérmico independientemente de ser una especie de aguas subantárticas. En relación al periodo embrionario (tH50%), los resultados fueron de 40,8 ± 0,6; 27,0 ± 0,0; 17,3 ± 0,6; 16,3 ± 0,6 y 13,3 ± 0,6 días a temperaturas de 7, 10, 13, 16 y 19°C respectivamente, con diferencias significativas entre ellas (P < 0,05), y en el caso del periodo de eclosión (tH50%), fue de 8,3 ± 0,6; 6,3 ± 1,5; 5,0 ± 0,0; 6,3 ± 0,6; 5,0 ± 1,0 y 4,3 ± 0,6 días a temperaturas de 7, 10, 13, 16, 19 y 22°C respectivamente, con diferencias significativas entre ellas (P < 0,05). Los resultados sugieren que el rango de temperaturas entre 10 y 16°C es óptimo para la incubación de ovas de G. maculatus, ya que se obtienen combinadamente altos porcentajes de sobrevivencia embrionaria >87,7%, periodos embrionarios <27 días y periodos de eclosión <6,3 días. Estos resultados permitirán optimizar la sobrevivencia embrionaria y el eventual cultivo de la especie para fines comerciales o de repoblamiento.

The calanoids copepods are abundant in zooplankton assemblages in Patagonian inland waters, and within context the aim of determine the fertility parameters on populations of copepods representative of different inland water of Chilean Patagonia (37°-52° S). For this purpose, it was considered two to four populations of the the following species: Boeckella gracilipes, B. michaelseni, B. poppei, and Tumeodiaptomus diabolicus, it was considered for female individuals the total length, eggs number, and ratio between total length. The results revealed at species level that B. poppei was significantly different in comparison to another species in all of the three species. At populations level it was found differences in three species considered. The results revealed that the reproductive parameters are variable in function of the environmental conditions of the populations. The results denoted that the reproductive parameters are markedly influenced by environmental conditions, and it would be associated with ecological consequences such as populational structures and properties of zooplankton community ecology.

Los copépodos calanoideos son abundantes en los ensambles zooplanctónicos de aguas continentales de la Patagonia, y en este contexto, se analizaron parámetros de fertilidad en cuatro especies de calanoideos representativos de aguas continentales de la Patagonia (37°-52° S) con el objetivo de determinar los parámetros de fertilidad en poblaciones de copépodos representativas de la Patagonia chilena. Para este propósito se consideraron dos a cuatro poblaciones de las siguientes especies: Boeckella gracilipes, B. michaelseni, B. poppei, y Tumeodiaptomus diabolicus, se consideraron individuos hembras con huevos a las que se midió el largo total, número de huevos y la razón entre número de huevos con el largo total. Los resultados mostraron que a nivel de especies B. poppei fueron significativamente diferentes para las otras tres especies. A nivel de poblaciones, se encontraron diferencias a nivel de poblaciones en algunas especies. Los resultados que los parámetros reproductivos variaron en función de los parámetros ambientales variaron en función de las condiciones ambientales de las poblaciones y estaría asociado con las condiciones ecológicas tales como estructuras poblacionales y las propiedades de las comunidades zooplanctónicas.

The crustacean zooplankton of Chilean inland waters are characterized by abundant calanoid copepods, mainly from the gemís Boeckella. The present study aims to update the distribution of Boeckella gracilis in the inland waters of the Araucania region (38-39°S) and to use null model analysis to understand the B. gracilis species associations. In the literature for Chile, this species is reported to be found in one northern lake and in three lakes of northern Patagonia. These fmdings are complemented by reports of this species for coastal and mountain ponds and mountain lakes of the Araucania region. These results agree with descriptions of this species for South American inland waters. The results of the null model analysis reveal factors regulating the species associations, whether comparing all the inhabitats or the guild structure, although some simulations show the opposite situation due to the presence of repeated species at many sites.

Los crustáceos zooplanctónicos en aguas continentales chilenas están caracterizados por la abundancia de copépodos calanoideos, principalmente del género Boeckella. El objetivo del presente trabajo es actualizar la distribución de esta especie en aguas continentales de la región de la Araucania (38-39°S), y el uso de modelos nulos para comprender sus especies asociadas. Las descripciones de la literatura indican que en Chile esta especie está en un lago del norte, y tres lagos en el norte de la Patagonia. Estos resultados están complementados con reportes de esta especie en pozas costeras, pozas y lagos de montaña en la región de la Araucania. Estos resultados concuerdan con las descripciones de esta especie para aguas continentales Sudamericanas. Los resultados del análisis de modelos nulos revelan que las asociaciones de especies tuvieron factores reguladores, ya sea comparando todos los habitantes y como estructura de gremios, aunque en algunas simulaciones se observó una situación opuesta, esto se debió a la presencia de especies repetidas en muchos sitios.