| Full text | |
| Author(s): |
Total Authors: 2
|
| Affiliation: | [1] Universidade Estadual Paulista. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Zoologia e Botânica - Brasil
[2] Universidade Estadual Paulista. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Zoologia e Botânica - Brasil
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | Biota Neotropica; v. 10, n. 2, p. 153-158, 2010-06-00. |
| Abstract | |
The structure in size, density, feeding, fecundity, and presence of ectoparasites in two populations of Laetacara aff. araguaiae was investigated in two streams, in Northwestern São Paulo State, one structurally more heterogeneous (HET) and other relatively more simplified (SIM). Six samples were taken in each stream, three in the wet period (October, December/2007, February/2008) and three in the dry period (April, July, September/2008), which were performed during 15 minutes of sampling in each stream, using a 3 mm-mesh sieve. A total of 118 individuals in HET stream (49 in the wet season and 69 in dry) and 146 in SIM stream were captured (82 in wet and 64 in dry). Fish collected in HET stream were larger than those collected in the SIM, both in wet and dry periods. The density was similar between two streams, with an increase agreeing with the peak of the dry period. Fragments of aquatic insects were the most important items of diet, which showed little spatial and temporal variation. Fecundity was significantly higher in HET, ranging from 977 to 1,602 oocytes, in contrast with females of the SIM, which had 338 to 814 oocytes. The ectoparasites (Digenea) were present only in specimens of the SIM, and were attached to the fins (dorsal and anal) with higher prevalence in October. Feeding and density were similar in the two populations of Laetacara aff. araguaiae, contrasting with the structure in size and fecundity. The differences in these demographic parameters do not occur randomly and are possibly reflecting the high rates of parasitism in the more simplified stretch that determines lower resources allocation to growth and reproduction of fishes in this population. (AU) | |
| FAPESP's process: | 06/02276-0 - Development and maintenance of the Thematic Project web site Fauna and flora of the forest fragments in the northwestern portion of the São Paulo state: basis for conservation and biodiversity studies |
| Grantee: | Paulo Sérgio de Souza Filho |
| Support Opportunities: | Scholarships in Brazil - Technical Training Program - Technical Training |
| FAPESP's process: | 01/13340-7 - Evaluation of the biotic integrity of the rivers of the northwest region of the State of São Paulo, Alto Paraná basin, using communities of fish |
| Grantee: | Lilian Casatti |
| Support Opportunities: | BIOTA-FAPESP Program - Young Investigators Grants |
| FAPESP's process: | 04/04820-3 - Fauna and flora from forest fragments in the northwest region of São Paulo State: the basis to biodiversity conservational studies |
| Grantee: | Orlando Necchi Junior |
| Support Opportunities: | BIOTA-FAPESP Program - Thematic Grants |