Dinâmica populacional do caranguejo dulcícola Dilocarcinus pagei Stimpson, 1861 (Brachyura, Trichodactylidae), na represa da Usina Hidrelétrica de Furnas/Marimbondo, Icém, SP
Data
2011-02-24
Autores
Davanso, Thiago Maia [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A dinâmica populacional de Dilocarcinus pagei foi investigada enfocando os seguintes aspectos: maturidade sexual morfológica, maturidade gonadal, proporção sexual, período reprodutivo e recrutamento. Os animais foram coletados mensalmente, com a utilização de peneiras e/ou manualmente no período de outubro/05 a setembro/07, na represa da Usina Hidrelétrica de Furnas/Marimbondo, município de Icém, região noroeste do Estado de São Paulo (20°19’40,0”S e 49°10’18,1”N). A maturidade sexual morfológica foi calculada empregando-se o estudo do crescimento relativo e a maturidade gonadal por meio do LC50. A proporção sexual foi investigada tanto mensalmente como no número de indivíduos distribuídos por classes de tamanho (χ 2=2,261E-05; χ 2=2,26071E-05). Para os períodos reprodutivo e de recrutamento, as fêmeas denominadas maduras (gônadas desenvolvidas, fêmeas ovígeras e com juvenis) e os juvenis foram analisados mensalmente e associados aos fatores ambientais monitorados. Um total de 1.000 indivíduos foram obtidos, sendo 567 machos e 433 fêmeas. Destas, 4 eram ovígeras (FO) e 35 portavam juvenis (FF). Dentre as relações biométricas utilizadas para determinação da maturidade sexual morfológica, a mais significativa para os machos foi entre a largura da carapaça (LC) e o comprimento do própodo do quelípodo (CP), enquanto que em fêmeas foi entre LC e a largura do abdome (LA). A partir destas, estimou-se o valor de 28,7mm para os machos e 24,2mm para as fêmeas. Os valores de LC50 (mm), apesar de próximos, mostraram um maior tamanho para as fêmeas, sendo 39,2mm para os machos e 39,9mm para as fêmeas. Esta diferença, provavelmente, está relacionada à uma estratégia reprodutiva das fêmeas em aumentar a quantidade de ovócitos maduros armazenados na cavidade cefalotorácica. A proporção sexual diferenciada para os meses e, para as classes de tamanho...
The population dynamics of Dilocarcinus pagei was investigated focusing the following aspects: morphological sexual maturity, gonadal maturity, sex ratio, reproductive and recruitment period. The animals were collected monthly, using seive and/or manually during the period from October 5 to September 7, in Furnas dam Furnas/Marimbondo Hydroelectric Plant, in the city of Icém, northwest region of the State of São Paulo (20°19’40,0”S e 49°10’18,1”N). Sexual and morphological maturity was calculated using the study of relative growth and gonadal maturity through the CW50. The sex ratio was investigated both monthly and in the number of individuals distributed by size classes (χ 2=2,261E-05; χ 2=2,26071E-05). For reproductive and recruitment periods, females denominated mature (developed gonadas, ovigerous females and with juveniles) and juveniles were analyzed monthly and associated to environmental factors. A total of 1.000 animals were collected, being 567 male and 433 female. Among females, 4 were ovigerous (OF) and 35 carried juveniles (FF). Among biometrical relationships used to determine the morphological sexual maturity, the most significant for the male was between the carapace length (CL) and the cheliped propodus length (CPL), while in the female was between CL and the abdomen length (AL). From these relationships, we estimated the value of 28,7mm for the male, and 24,2mm for the female. The CW50(mm) values, although near, demonstrated a larger size for the female, being 39,2mm for the male, and 39,9mm for the female. This difference probably is related to a reproductive strategy of the female to increase the quantity of mature oocytes storaged in the carapace cavity. The sexual proportion differentiated for months and for size classes can be related to differential growing, mortality index, food restriction, behavior differences, migration, and the usage... (Complete abstract click electronic access below)
The population dynamics of Dilocarcinus pagei was investigated focusing the following aspects: morphological sexual maturity, gonadal maturity, sex ratio, reproductive and recruitment period. The animals were collected monthly, using seive and/or manually during the period from October 5 to September 7, in Furnas dam Furnas/Marimbondo Hydroelectric Plant, in the city of Icém, northwest region of the State of São Paulo (20°19’40,0”S e 49°10’18,1”N). Sexual and morphological maturity was calculated using the study of relative growth and gonadal maturity through the CW50. The sex ratio was investigated both monthly and in the number of individuals distributed by size classes (χ 2=2,261E-05; χ 2=2,26071E-05). For reproductive and recruitment periods, females denominated mature (developed gonadas, ovigerous females and with juveniles) and juveniles were analyzed monthly and associated to environmental factors. A total of 1.000 animals were collected, being 567 male and 433 female. Among females, 4 were ovigerous (OF) and 35 carried juveniles (FF). Among biometrical relationships used to determine the morphological sexual maturity, the most significant for the male was between the carapace length (CL) and the cheliped propodus length (CPL), while in the female was between CL and the abdomen length (AL). From these relationships, we estimated the value of 28,7mm for the male, and 24,2mm for the female. The CW50(mm) values, although near, demonstrated a larger size for the female, being 39,2mm for the male, and 39,9mm for the female. This difference probably is related to a reproductive strategy of the female to increase the quantity of mature oocytes storaged in the carapace cavity. The sexual proportion differentiated for months and for size classes can be related to differential growing, mortality index, food restriction, behavior differences, migration, and the usage... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Caranguejo se água doce - Reprodução, Pesca, Decapoda
Como citar
DAVANSO, Thiago Maia. Dinâmica populacional do caranguejo dulcícola Dilocarcinus pagei Stimpson, 1861 (Brachyura, Trichodactylidae), na represa da Usina Hidrelétrica de Furnas/Marimbondo, Icém, SP. 2011. 69 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2011.