Precautionary rules for exotic trout aquaculture in fishless shallow lakes of Patagonia: minimizing impacts on the threatened hooded grebe (Podiceps gallardoi)
2010
Lancelotti, Julio L. | Pozzi, Luciana M. | Yorio, Pablo M. | Diéguez, María C. | Pascual, Miguel A.
1.Conflicts between habitat use and conservation are inherent to the management of wetlands. A major challenge for their management is to preserve habitat while addressing the demands from multiple users. In southern Patagonia (Argentina), a growing aquaculture activity based on rainbow trout introductions in shallow lakes is generating concerns about the effects on the waterbird fauna, including some endemic species.2.Generalized linear models (GLM) were used to analyse data on the endemic hooded grebe (Podiceps gallardoi) collected over a diverse set of lakes to: (1) build presence-absence models as a function of environmental variables; (2) assess current and potential overlap with trout aquaculture; (3) explore the power of alternative lake assignment algorithms based on habitat variables to segregate critical habitat and aquaculture activities; and (4) explore the correlation between the probability of grebe presence and their abundance in given lakes.3.Hooded grebe presence is clearly correlated with macrophyte cover, lake area, and water conductivity. Medium size lakes, with a combination of emerging macrophytes, adjacent to open water areas had the highest probability of both hooded grebe presence and abundance.4.Different lake allocation scenarios are identified that could grant significant protection to hooded grebes without substantial losses for trout producers. The a priori probability to hold hooded grebe, assigned by the model based on lake characteristics, provides a tool that can be used by managing authorities to derive precautionary management rules to regulate aquaculture and to preserve primary hooded grebe habitat.
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