Biology of Boeckella poopoensis Marsh, 1906 (Copepoda, Calanoida) in natural conditions in temporary saline lakes of the central Argentina

Abstract

Boeckella poopoensis Marsh, 1906 is the dominant copepod in saline lakes from northern Patagonia to southern Peru. It is a tolerant species, which has been registered at salinities between 20 and 90 g.L -1 , and is important because it integrates the diet of flamingos and fishes of commercial and sport interest. The aims of this study were to analyze the characteristics of populations of B. poopoensis in the central region of Argentina and to establish their relationships with environmental parameters. Monthly samples during 2007 were taken in four temporary lakes of La Pampa province. Environmental parameters and density, size, biomass, number and size of eggs were determined. The salinity ranged between 13.38 and 32.90 g.L -1. In three lakes that had previously continuously contained water, B. poopoensis was registered throughout the whole study. In the fourth lake, which was filled in January, it was present only when salinity exceeded 15 g.L -1. The population of the lake that was filled differed from that of the other lakes in terms of the density and biomass of adults and copepodites. The number of ovigerous females represented a higher percentage of the population during the colonization of the lake that had been dried and these produced the highest number of eggs. In the three lakes in which B. poopoensis was always recorded, its characteristics were more influenced by the availability of food than by temperature or salinity. It was found that the strategies of the species vary throughout the hydroperiod; at the beginning, thrives when the salinity rises and impedes the presence of less tolerant species. At this point, the production of relatively small eggs is high, allowing rapid colonization. When the lakes become relatively stable, B. poopoensis allocates more energy to reach larger sizes and although egg production is not so high, they are larger, allowing it to maintain stable populations. Keywords: Boeckella poopoensis, halophilic copepods, saline lakes, temporary lakes. Resumen: Boeckella poopoensis Marsh, 1906 es el copépodo dominante en lagos salinos desde el norte de Patagonia hasta el sur del Perú. Es una especie halotolerante registrada con salinidades entre 20 y 90 g.L -1 y es importante dado que integra la dieta de flamencos y de peces de interés comercial o deportivo. El objetivo del estudio fue analizar características de poblaciones de B. poopoensis en la región central de Argentina y establecer sus relaciones con los parámetros ambientales. Durante 2007 se tomaron muestras mensuales en cuatro lagos temporarios de la provincia de La Pampa. Se determinaron parámetros ambientales y la densidad, espectro de tallas, biomasa, número y tamaño de los huevos. La salinidad varió entre 13,38 and 32,90 g.L -1. En tres lagos que habían contenido agua en forma continua, B. poopoensis se registró durante todo el estudio. En el cuarto, que se llenó en enero, sólo estuvo presente cuando la salinidad superó 15 g.L -1. La densidad y biomasa de los adultos y copepoditos de la población del la...

Composition and abundance of the mesozooplancton in Sauce Grande shallow lake (Buenos Aires Province, Argentina)

“…El Carancho, Calderón), pero con abundancias mayores a las registradas en este estudio (e.g. Garibotti et al 2009, Echaniz et al 2015, Vignatti et al 2016. Garibotti et al (2009) también reportó abundancias mayores a las registradas en el presente trabajo, aunque el período de muestreo correspondió a la primavera del 2006.…”

Environmental and zooplankton parameter changes during the drying of a saline shallow temporary lake in central Argentina

“…Therefore, many aspects of their ecology, under et al 2013a; b; 2015). Other studies have also compared the conditions recorded in different periods (annual cycles) for a given lake and showed differences in physical and chemical variables, as well as in zooplankton biological traits (Echaniz & Vignatti, 2011; Echaniz et al 2006; 2012; 2013a;2016;Vignatti et al 2012a). Moreover, three studies conducted in La Pampa showed changes in limnological parameters and zooplankton traits during the filling or drying phases of temporary, subsaline and saline lakes, (Echaniz & Vignatti, 2010;Vignatti et al 2012a;.…”

“…This issue is of primary interest, because species assemblages recorded in the lakes of central Argentina differ from those in other continents. Particularly, many endemic species to the Neotropical region are represented (Adamowicz et al 2004; Echaniz, 2010; Echaniz et al 2006; 2012; Vignatti, 2011;Vignatti et al 2012b;2016), and ecological knowledge about them is relatively scarce.The present study aimed to describe the variation in species composition, and in three biological parameters (i.e. individual density, biomass, and body size) of a zooplankton community inhabiting a saline, shallow, and temporary lake, that underwent drying in La Pampa Province.…”

“…These lakes are inhabited by the crustaceans B. poopoensis and M. eugeniae and by the rotifers Hexarthra fennica and Brachionus plicatilis (Vignatti, 2011;Vignatti et al 2012a;2012b;2016; Echaniz, 2010; Echaniz et al 2006; 2013a; 2013b;2015;2016). Whereas these crustacean species are endemic to Neotropical halophilic lakes, the rotifers are cosmopolitan and are broadly distributed given their wide tolerance to salinity (Fontaneto et al 2006;Echaniz et al 2016).Moina eugeniae has, thus far, been found in hypo-mesosaline ranges, specifically in the Pey-Ma Lake, with a salinity level of 48 g L −1 (Echaniz et al 2013a). Therefore, the present study provides the first record for this species in the hypersaline range.…”

“…Moreover, low temperature could not affect the reproduction of these two species, since ovigerous M. eugeniae females were found throughout the winter months in two temporary saline lakes in 2006 (a period of relative hydrological stability) (Echaniz & Vignatti, 2011; Echaniz et al 2013b). In addition, in three mesosaline lakes of La Pampa, with relatively stable salinity, the highest population densities of B. poopoensis were recorded during the winter months, when a high proportion of nauplii and different stages of copepodites were found (Vignatti et al 2016).A feature of many shallow lakes of the region is that the combination of their temporary nature and their high salinity hinders their colonization by fish (Menni, 2004; Rosso, 2006). This situation, verified in Ojo de Agua Uriburu, may also lead to relatively large-sized zooplankton crustaceans, such as B. poopoensis and M. eugeniae.…”