CONICET | Buscador de Institutos y Recursos Humanos

1.Habitat fragmentation and loss threaten freshwater biodiversity worldwide. Habitats that are essential as fish spawning and nursery sites are critical, and must be identified for conservation purposes. Littoral zones within Patagonian lakes, especially shallow vegetated areas, represent important areas for the Creole perch, Percichthys trucha.2.Spawning behaviour has been little studied, so it is not known whether these movements are performed in groups. We therefore studied a particular area of a deep lake in Northern Patagonia to identify the environmental conditions under which spawning occurs, and to analyse spawning aggregation behaviour in relation to the lunar cycle.3.To identify spawning site, spawning occurrence time, and the environmental parameters that determine it, we analysed fish capture data. We also set up underwater cameras at three depth strata in the shallow zone to detect spawning aggregation behaviour. Aggregation was scored as the greatest number of individuals present in a single frame, and the number present per depth strata. Finally, we analysed the relationship between lunar cycle and Creole perch abundance by depth.4.This is the first visual record of a spawning bed and the spawning aggregation behaviour of Creole perch in Patagonian lakes. Mature Creole perch abundance in the shallow strata during the austral spring suggests that vegetated areas constitute spawning sites. Spawning aggregation takes place two days before the full moon, at a shallow depth.5.Knowledge of reproductive behaviour and spawning sites are key to conservation of the species, whose reproductive success and population stability depend on them. Given that these reproductive behaviours are important phenomena in the life history of the species, our findings have important implications for conservation and management.

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