CRUSTACEA OF THE POND OF TOMASHEV KOLOK IN THE SAMARA CITY

The species composition and seasonal dynamics of quantity of Crustacean populations in small urban pond is studied. The list of 15 Crustacean species is presented. Daphnia longispina, Ceriodaphnia reticulata and Cyclops copepodits dominate in the first half of summer to July, Chydorus sphaericus dominate in August and September.

Cyclomorphosis in Daphnia magna and Ceriodaphnia reticulata (Cladocera) from northern Tunisian groundwater: influence of temperature and invertebrates?

In the present study, we investigated cyclomorphosis in two cladocerans, Daphnia magna and Ceriodaphnia reticulata, sampled from northern Tunisian groundwater (wells) during two seasons (spring and summer). Seasonal distribution of the two species was apparent, with dominance of D. magna only in spring and C. reticulata during the whole study period. Our results showed correlations between caudal spine length of D. magna and water temperature (, ), and between caudal spine length and the density of coleopteran larvae (Stictonectes escheri, Graptodytes sp., Gyrinus urinator, and Haliplus lineaticollis) (, ). In C. reticulata, we registered a correlation (, ) only between its size and the density of larvae of Ephemeroptera (Cloeon cognatum) but no correlation with water temperature was found.

Assessment of four different media for the mass culture of Ceriodaphnia reticulata (Jurine) as a live fish feed

Experiments on the mass culture of Ceriodaphnia reticulata (Jurine) were carried out in aquarium water for 54 days with different media like cowdung (1.5g/L), pulse bran water (50g/L), poultry manure (0.45g/L) and snail faeces (faeces of six apple snails). All the media were fertilized by 50-100% of the initial amount of feed in every 7 days. About 100 individuals of C. reticulata were inoculated as starter in 50 litres of water (2 individuals/ml).The temperature of the media ranged from 24-30oC during study period. pH of the culture media varied i.e., 9.1 ± 0.40 in cowdung; 8.72 ± 0.73 in pulse bran water, 8.82 ± 0.72 in poultry manure and 7.5 ± 0.55 in snail faeces. The highest average population of C. reticulata was observed in cowdung (8.56 ± 4.11individuals/ml), moderate in poultry manure (4.21 ± 2.97 individuals/ml) and snail faeces (2.52 ± 3.01individuals/ml). The lowest growth of C. reticulata was recorded in pulse water (0.37 ± 0.69 individuals/ml). The culture media with cowdung as well as poultry manure and snail faeces were found to be useful for artificial mass production of C. reticulata. DOI: http://dx.doi.org/10.3329/jasbs.v39i2.17849 J. Asiat. Soc. Bangladesh, Sci. 39(2): 129-138, December 2013

Historia de vida de Daphnia Magna y Ceriodaphnia Reticulata en condiciones de laboratorio: uso potencial como alimento para peces

Los cladóceros por su pequeña talla, rápido desarrollo y temprana reproducción, son utilizados como alimento vivo en piscicultura. Este trabajo tuvo como objetivo estudiar la historia de vida de Daphnia magna y Ceriodaphnia reticulata (Crustacea - Cladocera), bajo condiciones de laboratorio para definir su potencial como alimento en piscicultura. Fueron realizados cultivos experimentales de D. magna y C. reticulata manteniendo 12 individuos por especie en recipientes independientes de 100 ml. Como alimento se utilizó seston proveniente de la ciénaga de San Marcos – Sucre, filtrado con malla de 40 μm y mantenido en dos acuarios de 25 litros. Los parámetros poblacionales fueron medidos cada 12 horas a lo largo del periodo de vida de los especímenes. El tiempo del desarrollo embrionario fue de 16 horas para C. reticulata y 24 horas para D. magna. Se obtuvieron diferencias significativas (P≥0.05) en el crecimiento poblacional, siendo mejor el desempeño de C. reticulata (fecundidad media de 1.12 neonatos/hembra, edad y talla de la maduración de 5.9 días y 77.9 μm, respectivamente) que el de D. magna (fecundidad media de 0.71 neonatos/hembra, edad y talla de la maduración de 9 días y 256 μm, respectivamente). Los cladóceros estudiados mostraron diferencias en los parámetros poblacionales, lo que sugiere estrategias de adaptación diferentes con relación al recurso alimenticio ofrecido. En general se encontró que por su tamaño y rápido crecimiento son potencialmente útiles como alimento al inicio de la alimentación exógena de postlarvas de Prochilodus magdalenae, Brycon sinuensis y Colossoma macropomum, principales especies piscícolas en la región.

Zooplankton dynamics during autumn circulation in a small, wind-sheltered, Mediterranean lake

Few studies have been undertaken on zooplankton dynamics during the transition from late stratification to early mixing in lakes. The Plankton Ecology Group (PEG) model of plankton seasonality only considers water temperature, edible phytoplankton and fish predation as zooplankton-controlling factors during that period. The water-column edible algal and bacterial fractions, heterotrophic nanoflagellates, ciliates, rotifers, cladocerans and copepods were studied during 93 consecutive days of mixing-transition in a wind-sheltered, Mediterranean lake without planktivorous fish. Abundances of all zooplankton populations except ciliates, Daphnia longispina and copepodites, were related to water temperature. In addition to PEG controlling factors, time series analysis indicated competition between ciliates and Ceriodaphnia reticulata and Polyarthra dolichoptera and D. longispina, predation of Arctodiaptomus salinus on ciliates, herbivory of adult copepods on the 5–20 μm phytoplanktonic size and delayed effects shorter than one week. The remaining zooplankton populations did not show any edible size preference. Ceriodaphnia reticulata showed evidence of herbivory on bacteria and picoplankton and competition with Hexarthra fennica in shorter periods. Phyto- and zooplankton production were decoupled. These results, and others from warmer periods and latitudes, suggest that the current model of lake plankton seasonality must be reviewed.

Variations de la structure trophique du lac-réservoir oligotrophe Bin El Ouidane (Maroc)

L'étude combinée des apports par les crues, du plancton, des contenus algaux du tractus digestif des Cladocères et du régime alimentaire de quelques espèces de poissons dans le lac de barrage oligotrophe Bin El Ouidane a permis de dégager les conclusions suivantes : - les apports particulaires et dissous par les crues durant la période d'étude 1995-1997 ont une influence marquée sur la dynamique saisonnière du zooplancton via les changements dans la dynamique du peuplement phytoplanctonique ; - durant les trois années d'étude, le maximum de biomasse zooplanctonique se situe généralement juste après les pics printanier et estival du phytoplancton mettant ainsi en évidence l'importance du zooplancton herbivore dans la chaîne alimentaire pélagique du lac ; - l'étude des contenus algaux du tractus digestif des Cladocères Daphnia longispina, Daphnia lumholtzi, Diaphanosoma brachyurum, Ceriodaphnia dubia, Ceriodaphnia reticulata et Bosmina longirostris a montré que l'essentiel des espèces sont des filtreuses herbivores qui adoptent un comportement nutritionnel variable en fonction du temps lié à la disponibilité en phytoplancton, à leur âge et aux caractéristiques biotiques et abiotiques de l'écosystème lacustre ; - l'étude préliminaire du régime alimentaire de trois espèces de poissons Tinca tinca, Eupomotis gibbosus et Cyprinus carpio montre que leur spectre alimentaire est nettement dominé par le plancton. La fraction faunistique au niveau de leur tube digestif est représentée essentiellement par les Cladocères de grande taille et les Chironomes. Ceci met en évidence l'importance de ces poissons, à régime essentiellement planctonophage, dans la régulation des peuplements planctoniques de la retenue Bin El Ouidane.