Zooplancton en la ruta alimentaria de Arctocephalus gazella
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Date
1999
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Abstract
Se determinó la composición, distribución y abundancia relativa del zooplancton durante las
migraciones tróficas de hembras de lobo fino antártico, Arctocephalus gazella, en torno a las islas Farellones Foca (Archipiélago Piloto Pardo), importante lugar de crianza de este mamífero, durante febrero de 1991. Los muestreos zooplanctónicos se realizaron con red Bongo de 330 mu entre 0 y 260 m, durante el seguimiento de seis lobos. Se identificaron nueve taxa zooplanctónicos, destacando Thaliacea, Copepoda y Euphausiacea, tanto por su dominancia numérica, como por su constancia en las muestras. Euphausiacea estuvo representada por tres especies: Euphausia superba, E. frigida y Thysanoessa macrura. La primera de ellas fue la más abundante (83,5% del total de eufáusidos), constituida mayoritariamente por larvas calyptopis II y adultos. Estadios larvales de E. frigida y T. macrura presentaron abundancias relativas muy inferiores. EI hecho que en la mayoría de los puntos en que se alimentó A. gazella, se encontraron ejemplares adultos de E. superba, sugiere la posibilidad que los lobos finos se hayan alimentado de este eufáusido, La presencia de ejemplares adultos de E. frigida y T. macrura en algunas estaciones, sugiere tambien la posibilidad que los lobos finos se alimenten de estos eufáusidos, cuando E. superba se encuentra en bajo número o ausente.
The composition, distribution and relative abundance of zooplankton during feeding trips of female Antarctic fur seals Arctocephalus gazella, at Seal Island (Archipelago Piloto Pardo), were studied, during February, 1991. Six female fur seals were tracked during their feeding trips to the sea. Where feeding occurred, zooplankton was obtained with Bongo net (330 mu mesh) between 260 m and the surface. Nine taxa were identified. The main taxa were Thaliacea, Copepoda and Euphausiacea, for their dominance and constancy in the samples. The following species of Euphausiacea Were found: Euphausia superba, E. frigida and Thysanoessa macrura. The most abundant was E. superba (83,5% total of euphausiids), represented mainly by calyptopis II larvae and adults. Mainly larval stages of E. frigida and T. macrura were found in small quantities. Adult E. superba were found in most of the stations, suggesting a preference of fur seals for feeding on this Euphausiid. The presence of adults of E. frigida and T. macrura at some stations, suggests the possibility that fur seals feed upon these Euphausiids when E. superba either is very scarce or absent.
The composition, distribution and relative abundance of zooplankton during feeding trips of female Antarctic fur seals Arctocephalus gazella, at Seal Island (Archipelago Piloto Pardo), were studied, during February, 1991. Six female fur seals were tracked during their feeding trips to the sea. Where feeding occurred, zooplankton was obtained with Bongo net (330 mu mesh) between 260 m and the surface. Nine taxa were identified. The main taxa were Thaliacea, Copepoda and Euphausiacea, for their dominance and constancy in the samples. The following species of Euphausiacea Were found: Euphausia superba, E. frigida and Thysanoessa macrura. The most abundant was E. superba (83,5% total of euphausiids), represented mainly by calyptopis II larvae and adults. Mainly larval stages of E. frigida and T. macrura were found in small quantities. Adult E. superba were found in most of the stations, suggesting a preference of fur seals for feeding on this Euphausiid. The presence of adults of E. frigida and T. macrura at some stations, suggests the possibility that fur seals feed upon these Euphausiids when E. superba either is very scarce or absent.
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Keywords
Zooplancton, Lobo Fino Antártico
Citation
Serie Científica, nº 49, pp. 51-71, 1999