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Pond Management (pond + management)
Selected AbstractsDispersal characteristics of three odonate species in a patchy habitatECOGRAPHY, Issue 1 2003S. Angelibert Dispersal has a potentially profound effect on the dynamics of populations especially when a population occupies a patchy habitat. Ponds surrounded by terrestrial landscape are an example of patchy distribution of physical conditions and constitute "islands" for odonates. Few studies have focussed on dispersal in odonates. We have used the direct method of dispersal observing (capture-mark-recapture technique) in order to estimate the degree of linkage in three patchy populations of odonate localised on three ponds. We also examined the differences in dispersal ability within and among three species (Coenagrion puella, Coenagrion scitulum and Libellula depressa). The ponds were situated in southwest France on a limestone plateau. In this arid area, these ponds constitute the only surface water available and are relatively sparsely distributed. The size of the ponds ranged from 48 to 79 m2 and they were 200 and 775 m apart. We demonstrated that three factors influence the dispersal ability of these odonates. The first is represented by the abiotic factors and especially weather conditions. This determines the number of days that dispersal is possible. The second is interspecific differences. We showed that sensitivity to weather conditions, species size and species behaviour influence dispersal ability. The third factor is the intraspecific characteristics. We demonstrated that there are differences in dispersal ability according to sex and age. To conclude, we discuss the importance of pond management to maintain the existing odonate populations and to facilitate introduction of new populations in this region where little exchange occurs between ponds. [source] Impacts of long-term changes in fishery management on the trophic level water quality in Czech fish pondsFISHERIES MANAGEMENT & ECOLOGY, Issue 1-2 2000L. Pechar The management of Czech fish ponds changed little from the Middle Ages until the end of the nineteenth century. The intensification of fish production was initiated during the first half of the twentieth century. During the 1930s, liming and manuring of the ponds became common. A greater density of stocking led to the use of artificial feeds in the form of pellets and grain. These changes in pond management have led to an increase in fish production from ,,50 to >,500 kg ha,1 year,1 over the last 5 decades. At the same time, the quality of the water and sediments has been deteriorating, and the functioning of the pond ecosystem has been disturbed. There are now massive blooms of phytoplankton, especially cyanobacteria, accompanied by great fluctuations in the oxygen concentration and pH. Data collected since 1925, when systematic research on the ponds started, allow the mechanisms responsible for the changes to be traced. [source] Fillet yield and fat content in common carp (Cyprinus carpio) produced in three Austrian carp farms with different culture methodologiesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2009C. Bauer Summary The fat content and fillet yield of common carp (Cyprinus carpio) from three carp farms were investigated with respect to pond management and overall climatic conditions. The mean fat content of the trimmed fillet varied from 2.7 to 6.9% and differed significantly among the three facilities (P < 0.001). It is suggested that differences in the fillet fat content may be based on the climatic conditions as well as the different management strategies (feeding, stocking biomass). The mean fillet yield was calculated as 34.0,39.0%. No significant correlation between fish weight and fillet yield (, = ,0.16) was found. Results suggest that producing smaller fish for fillets of serving size may lead to a higher production and conclude with lower production risks and costs. [source] Factors affecting the predation of otter (Lutra lutra) on European pond turtle (Emys orbicularis)JOURNAL OF ZOOLOGY, Issue 2 2006J. Lanszki Abstract In this case study, the ecological background of an unusual hunting behaviour was investigated, when otters Lutra lutra preyed upon European pond turtles Emys orbicularis in a Hungarian fish pond system during an 18-month period. Predation on turtle was found only during cold periods (established by spraint analysis and also by the collection of 182 turtle carcasses in 2003). The relationship was not close between fish availability and turtle consumption (rP=,0.325, P=0.19). The crude protein content of the turtle head and leg was higher than that of fish, frog and turtle body, whereas the energy content of the samples was similar. The mean body weight of the killed turtles (460 g) fell within the range of the optimal prey size of the otter. Turtles were used as cache foods by otters during extreme environmental conditions (as in the long winter), but occurred only rarely as buffer foods during moderate winter. In fish ponds, the conservation of the coexistent otter and turtle depends on pond management. The maintenance of a higher fish availability in ponds during winter makes it possible to avoid the need to acquire a proper hunting technique on turtle, indicated by the scarcity of primary fish food. [source] Impact of pond management on tambaqui, Colossoma macropomum (Cuvier), production during growth-out phaseAQUACULTURE RESEARCH, Issue 7 2009Levy Carvalho Gomes Abstract This study evaluated the impact of pond management on tambaqui, Colossoma macropomum (Cuvier), rearing during the growout phase. Juvenile tambaqui were stocked in ponds with three different management regimes: (1) natural ponds (Nat); (2) limed ponds (Lim); and (3) limed and bimonthly fertilized ponds (LimFer). The experiment lasted 210 days and the growth parameters were evaluated monthly. Water quality and effluent measurements were performed every 15 days and at the end of the experiment yield parameters were obtained. There was no difference in weight and length among treatments. Stomach contents and zooplankton availability were not influenced by pond management, but the rearing period had an influence on them. Food conversion rate (FCR) was better in fish from the Lim treatment than in fish from the Nat treatment. The pH, hardness and alkalinity values were significantly higher in the Lim and LimFer ponds, where the liming procedure was performed. The effluent analysis showed a more potentially impacting effluent in the LimFer treatment, where phosphorus and orthophosphate concentrations showed values significantly higher than those in Lim and Nat ponds. The results show that the Lim treatment is the best approach, as in this treatment fish achieve market size, better FCR, yield and have a reduced environmental impact. [source] | |||||||||||||