Eat or be eaten: factors that determine nutritional condition of Engraulis anchoita larvae from patagonian population of the species
The Patagonian population of Engraulis anchoita inhabits the coastal sector comprised between 42° and 46° S. Its spawning and rearing areas are associated with the tidal frontal system of Peninsula Valdés, which forms in late spring and breaks during early autumn. Oceanographic frontal conditions can enhance primary production and zooplankton biomass, representing an enriched food source for fish larvae. Larval nutritional condition was estimated using three indices: Fulton’s Condition Index, RNA/DNA ratio and growth performance. Two oceanographic sections were compared, one in which the presence of the frontal system was observed and another devoid of such effect. Condition indices reflected an enhanced nutritional condition of anchovy larvae in the section where the front persisted. Generalized linear models were applied to determine the effect of environmental variables on larval condition. RNA/DNA ratio was considered as the dependent variable, whereas surface chlorophyll concentration, copepod nauplii abundance, jellyfish volume and larval standard length were used as predictors. In general, the nutritional condition improved with the abundance of copepod nauplii, potential food source for the anchovy larvae. In contrast, the RNA/DNA ratio decreased with the increase of jellyfish abundance, suggesting that, in the study area, these organisms might act as competitors of anchovy larvae.
| Main Authors: | , , , , , , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociación Argentina de Ecología
2016
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| Online Access: | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/71 |
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