Rev. biol. mar. oceanogr. 49(3): 461-475Article |
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Feeding success and selectivity of larval anchoveta Engraulis ringens in a fjord-type inlet from northern Patagonia (Southeast Pacific) |
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Mauricio F. Landaeta1, María J. Ochoa-Muñoz1,2 and Claudia A. Bustos1 |
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1Laboratorio de Ictioplancton (LABITI), Facultad de Ciencias del Mar y de Recursos Naturales, Universidad de Valparaíso, Avenida Borgoño 16344, Reñaca, Viña de Mar, Chile
2Programa Maestría en Ciencias en Manejo de Recursos Marinos, Centro Interdisciplinario de Ciencias Marinas (CICIMAR), Departamento de Plancton y Ecología Marina, Av. Instituto Politécnico Nacional s/n Col. Playa Palo de Santa Rita, La Paz, Baja California Sur, CP. 23096, México
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The diet and selectivity of larval anchoveta Engraulis ringens was studied during 4 consecutive days (austral spring) in Hornopirén inlet, a fjord-like environment of southern Chile. This environment was characterised by sharp halocline around 10 m depth, separating brackish and saltier waters. The potential prey field, microzooplankton, was collected at 4 depths (0, 5, 10 and 30 m), while the ichthyoplankton was collected at 2 strata, surface (0-10 m depth) and deep (10-45 m depth). Nauplii and copepodites were the major components of microzooplankton. The analysis of 487 gut contents of larval anchoveta indicates that similar volume of prey was ingested in both layers and during both tides. However, in the upper, brackish and warmer water, larval E. ringens ingested significantly less prey but of larger size, selecting nauplii and copepodites as the main prey items. In the deep, saltier and colder water, larvae ingested more prey of smaller size, showing only selectivity for nauplii. The feeding incidence of E. ringens increased twice during the flood, when the abundance of copepodites in the field also increased. Therefore, complex biophysical interactions occur in Patagonian fjords during the feeding process of larval stages of this commercially important species in tight relationship with the spatio-temporal distribution of prey.
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Key words: Diet, microplankton, southern Chile, tides, stratification |
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