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Age, growth and mortality of Sciaena umbra (Sciaenidae) in the Gulf of Tunis
The growth and mortality of the brown meagre, Sciaena umbra from the Gulf of Tunis, were investigated using a sample of 276 specimens, ranging from 15.3 to 49.2 cm total length and from 43 to 1565 g total weight. Specimens were collected from artisanal fisheries between October 2008 and September 2011. Otoliths were extracted, thin cross-sections were realized and radii were measured. The log-linear morphometric relationships between total length-total weight and total length-otolith radius were significant (p < 0.05), showed positive allometry (b=3.15) and isometry (b=0.90), respectively. The marginal analysis suggested that only one growth increment was deposited per year. The maximum age of the brown meagre was 22 years for males and 31 years for females. The fit of the von Bertalanffy growth function was significantly different between sexes (p <0.05): TL∞=43.8 cm, k=0.145 y–1, t0=–4.88 y for males and TL∞=50.1 cm, k=0.105 y–1, t0=–5.71 y for females. The instantaneous total (Z) and natural (M) mortalities were estimated for each sex, resulting in an exploitation ratio (E=F/Z) of 0.43 for males and 0.46 for females.
Keyword(s)
brown meagre, thin otoliths, growth, mortality, Gulf of Tunis, Mediterranean Sea
Se investigo el crecimiento y la mortalidad de Sciaena umbra del golfo de Tunez, utilizando una muestra de doscientos setenta y seis especimenes que miden de 15.3 cm a 49.2 cm de longitud total y pesan de 43 g a 1565 g. Las muestras se recogieron de pesquerias artesanales entre octubre de 2008 y septiembre de 2011. Se extrajeron los otolitos, se realizaron secciones transversales delgadas y se midieron los radios. Las relaciones morfometricas logaritmicas entre la longitud total y el peso total de una parte y la longitud total y el radio de otolito de otra parte resultaron significativas (p<0.05) y mostraron respectivamente alometria positiva (b=3.15) e isometria (b=0.90). El analisis marginal sugirio que se depositaba un solo anillo de crecimiento por ano. La edad maxima de la corvina negra es de 22 anos para los machos y de 31 anos para las hembras. El ajuste de la funcion de crecimiento de von Bertalanffy resulto significativamente diferente entre los sexos (p<0.05): TL‡=43.8 cm, k=0.145 y.1, t0=-4.88 y para los machos y TL‡=50.1 cm, k=0.105 y.1, t0=.5.71 y para las hembras. La mortalidad instantanea total (Z) y natural (M) se estimo para cada sexo, dando como resultado una tasa de explotacion (E=F/Z) de 0.43 para los machos y de 0.46 para las hembras.
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File | Pages | Size | Access | |
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Publisher's official version | 9 | 400 Ko |