Determinação da idade, através da leitura de escamas, de Salminus brasiliensis (Cuvier, 1816) coletados no Rio Mojiguaçu, Cachoeira de Emas, Pirassununga / SP.
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Data
2020-01-28
Autores
Faleiros, Tâmer de Oliveira
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Universidade Estadual Paulista (Unesp)
Resumo
O presente trabalho estimou a idade e o crescimento do Dourado Salminus brasiliensis coletados no rio Mojiguaçu, região de Cachoeira de Emas, a partir dos anéis etários contidos nas escamas. Os gráficos de crescimento em comprimento foram ajustados pela expressão linear de Ford-Walford e logo após foi utilizado a expressão matemática de Von Bertalanffy (1938). Foi coletado um total de 538 espécimes e identificados n = 126 machos e n = 144 fêmeas, entre fevereiro de 2007 a dezembro de 2010, onde foram medidos o peso, o comprimento total e a altura. O valor de θ dos machos foi de 3,07 e fêmeas de 3,19, comprovando um maior crescimento e peso das fêmeas em relação aos machos. Para os machos e fêmeas foram encontrados o valor máximo de 6 anéis etários com o Lt = 54,22 cm para os machos e Lt = 76,84 para as fêmeas. Os valores de L∞ para machos foi de 115,64 cm enquanto para as fêmeas foi de 331,46 cm. Os dados obtidos não corroboram com a literatura pertinente, sendo alguns dos possíveis motivos, a aplicação da metodologia, que excluiu os indivíduos menores através da coleta com tarrafas, coletas realizadas apenas na Cachoeira de Emas e a presença de indivíduos residentes na área de estudo, que possui uma grande fartura de alimentos. Os fatores bióticos e abióticos também foram avaliados, demonstrando correlações apenas na precipitação total (mm) e Comprimento total médio (cm), com uma desaceleração do crescimento nos períodos de menor precipitação.
The present work estimated the age and growth of Dourado Salminus brasiliensis collected in the Mojiguaçu River, region of Cachoeira de Emas, from the age rings contained in the scales. The graphs of growth in length were adjusted by the Ford-Walford linear expression and shortly afterwards the mathematical expression of Von Bertalanffy (1938) was used. A total of 538 specimens were collected and n = 126 males and n = 144 females were identified between February 2007 and December 2010, where weight, total length and height were measured. The θ value of males was 3.07 and females of 3.19, proving greater growth and weight of females in relation to males. For males and females, the maximum value of 6 age rings was found with Lt = 54.22 cm for males and Lt = 76.84 for females. The L∞ values for males were 115.64 cm while for females it was 331.46 cm. The data obtained do not corroborate with the pertinent literature, being some of the possible reasons, the application of the methodology, which excluded the smaller individuals through the collection with nets, collections made only at Cachoeira de Emas and the presence of individuals residing in the study area that has a great abundance of food. Biotic and abiotic factors were also evaluated, showing correlations only in total precipitation (mm) and Average total length (cm), with a slowdown in growth during periods of lower precipitation
The present work estimated the age and growth of Dourado Salminus brasiliensis collected in the Mojiguaçu River, region of Cachoeira de Emas, from the age rings contained in the scales. The graphs of growth in length were adjusted by the Ford-Walford linear expression and shortly afterwards the mathematical expression of Von Bertalanffy (1938) was used. A total of 538 specimens were collected and n = 126 males and n = 144 females were identified between February 2007 and December 2010, where weight, total length and height were measured. The θ value of males was 3.07 and females of 3.19, proving greater growth and weight of females in relation to males. For males and females, the maximum value of 6 age rings was found with Lt = 54.22 cm for males and Lt = 76.84 for females. The L∞ values for males were 115.64 cm while for females it was 331.46 cm. The data obtained do not corroborate with the pertinent literature, being some of the possible reasons, the application of the methodology, which excluded the smaller individuals through the collection with nets, collections made only at Cachoeira de Emas and the presence of individuals residing in the study area that has a great abundance of food. Biotic and abiotic factors were also evaluated, showing correlations only in total precipitation (mm) and Average total length (cm), with a slowdown in growth during periods of lower precipitation
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Palavras-chave
Dourado, Anéis etários, Crescimento, Von Bertalanffy, Peixe, Fish, Age rings