Current use and simulation of fish thermal habitat availability in lakes of the Argentine Patagonian Andes under climate change scenarios RCP 4.5 and RCP 8.5

VIGLIANO PABLO; RECHENCQ MAGALI; MARIA VALERIA FERNANDEZ; LIPOLD GUSTAVO; MACCHI PATRICIO

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018

0048-9697

The goal of this paper is to investigate current habitat use in relation to the thermal habitat 24 availability and food source of Percichthys trucha (Creole perch), Oncorhynchus mykiss (rainbow 25 trout), Salmo trutta (brown trout) and Salvelinus fontinalis (brook trout) as well as to model future 26 potential thermal habitat availability for these species under climate change scenarios RCP 4.5 and 27 8.5. This study was conducted in three interconnected lakes of Northern Patagonia (Moreno Lake 28 system). Data on fish abundance was obtained through gill netting and hydroacoustics, and 29 thermal profiles and fish thermal habitat suitability index curves were used to identify current 30 species-specific thermal habitat use. Surface air temperatures from the (NEX GDDP) database for 31 RCP scenarios 4.5 and 8.5 were used to model monthly average temperatures of the water column 32 up to the year 2099 for all three lakes, and to determine potential future habitat availability. In 33 addition, data on fish diet were used to determine whether food could act as a forcing factor in 34 current habitat selection. Our results show that the four species considered in this study do not 35 use all the thermally suitable habitats currently available to them in the three lakes, and that 36 higher fish densities are not necessarily constrained to their "fundamental thermal niches" sensu 37 Magnuson et al. (1979), as extensive use is made of less suitable habitats. This is apparently 38 brought about by food availability acting as a major forcing factor in habitat selection and use, and 39 is also influenced by other factors such as lake morphometry, reproductive drives and predation 40 avoidance. Uncertainties related to the multidimensionality inherent to habitat selection and 41 climate change imply that fish resource management in Patagonia will not be feasible through 42 traditional incremental policies and strategic adjustments based on short-term predictions, but 43 will have to become highly opportunistic and adaptive.