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Variation of abundance and demographic structure of the introduced pumpkinseed, Lepomis gibbosus (Actinopterygii: Perciformes: Centrarchidae), in relation to littoral habitats and water body use

100%

Uzunova E. P., Georgieva M., Pavlova M. N., Studenkov S., Popov V.

Acta Ichthyologica et Piscatoria

2012

tom 42

nr 2

Background. The pumpkinseed, Lepomis gibbosus (L.), is one of 23 introduced fish species in Bulgarian freshwaters. With this study we attempt to contribute to clarifying the factors that effect pumpkinseed abundance and demographic structure in water bodies differing in macro- and microhabitat parameters. Materials and Methods. Fish were collected during the breeding period of pumpkinseed (May–June 2010) by minnow traps arranged in 31 sites in the littoral zone of 13 fresh water bodies (former- and active sand-pit lakes, reservoirs, adaptive ponds of refineries). Demographic structure (length and age) and abundance (Catch Per Unit Effort; CPUEN; fish per trap per hour) of pumpkinseeds from different sites were compared to provide information about ecological requirements of this species. Results. L. gibbosus dominated at 24 sites and comprised 86.7% of all fish caught. The mean pumpkinseed abundance was 6.35 ± 7.2 fish per trap per hour (mean ± SD). Pumpkinseeds were most numerous in the littoral zones of the former sand-pit lakes, where pumpkinseed’s CPUEN achieved values of 20 fish per trap per hour. Water body use had a significant effect on pumpkinseed abundance and the statistical analyses revealed that the littoral zones in the active sand-pit lakes were characterized by the lowest number of pumpkinseeds than the other types. Microhabitat parameters such as silt and sand bottom substrate also significantly affected pumpkinseeds abundance, size, and age, while gravel significantly affected body length but not abundance and age. Aquatic vegetation also had a significant impact on the abundance and at sites with dense vegetation pumpkinseeds were more abundant than at the sites with sparse vegetation. At the sites where piscivore fish occurred, the mean length and mean age of pumpkinseed were lower. Conclusion. Human activities facilitate establishment of the pumpkinseed population, mainly by extending suitable breeding places for pumpkinseed and eliminating its natural competitors and predators. Some parameters as sand or silt bottoms in littoral area and dense submerged vegetation may use as indicator of suitable conditions for pumpkinseed.

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Influence of biofertilisers on the vegetative growth, mineral content and physiological parameters of pepper (Capsicum annuum L.) cultivated under organic agriculture conditions

100%

Vlahova V., Popov V., Boteva H., Zlatev Z., Cholakov D.

Acta Scientiarum Polonorum. Hortorum Cultus

2014

tom 13

nr 4

In recent years, biofertilisers have emerged as a promising component of an integrated nutrient supply system in agriculture. The objective of this study was to examine the influence of selected biofertilisers on the vegetative growth, the content of N, P2O5 and K2O in the leaves and stems, and on the physiological parameters of pepper of the variety of ‘Sofiiska Kapiya’ cultivated under organic agriculture conditions. This experiment was carried out from 2009 to 2011 on the experimental fields of the Agroecological Centre at the Agricultural University-Plovdiv (Bulgaria), situated on the territory of a certified ecological farm. The study included the following biofertilisers – Boneprot, Lumbrical, Baikal EM “Effective Microorganisms”, Emosan, and Bio One. The results of the biometric measurements of the average plant height at the end of the vegetative period showed the highest values for the variant treated with Emosan on the Boneprot basic fertilisation (62.60 cm – 2009; 64.80 cm – 2010, and 63.87 cm – 2011). Upon feeding with the biofertilisers Emosan and Baikal EM on basic fertilisation with Boneprot (2009, 2010 and 2011) at the pepper mass fruit yield stage, plants showed higher values of net photosynthesis (PN) that were also similar to the high values observed in the flower bud stage. The highest intensity of transpiration (ȿ) was observed for the variants treated with the biofertilisers Baikal EM (2009 and 2011) and Emosan (2010) on basic fertilisation with Boneprot. It was concluded that the feeding with Emosan stimulated the vegetative growth of the pepper plants due to the high concentrations of nutrient-providing proteins contained in this biofertiliser. The results showed that biofertilisers do not significantly impact the P content of the pepper leaves and stems, but changes were more obvious in the leaves. The fertilisation with the studied biofertilisers increased the K2O content in leaves and stems compared to the control (non-fertilised) plants; the values were higher for the leaves.

Ograniczanie wyników

1 Acta Ichthyologica et Piscatoria

1 Acta Scientiarum Polonorum. Hortorum Cultus

2 Popov V.

1 Boteva H.

1 Cholakov D.

1 Georgieva M.

1 Pavlova M. N.

1 Studenkov S.

1 Uzunova E. P.

1 Vlahova V.

1 Zlatev Z.

1 2014

1 2012

Wyniki wyszukiwania

Variation of abundance and demographic structure of the introduced pumpkinseed, Lepomis gibbosus (Actinopterygii: Perciformes: Centrarchidae), in relation to littoral habitats and water body use

Influence of biofertilisers on the vegetative growth, mineral content and physiological parameters of pepper (Capsicum annuum L.) cultivated under organic agriculture conditions