Habitat use of Hatcheria macraei (Trichomycteridae) in north Patagonian River

BARRIGA, JUAN PABLO; BATTINI, MIGUEL ANGEL; ESPINÓS, NICOLÁS ANDRÉS; CHIARELLO-SOSA, JUAN MAURO

St. Louis

Simposio; Conservation, Ecology, and Management of Catfish: The Second International Symposium; 2010

North Central Division Ictalurid Technical Committee and Southern Division Catfish Management Technical Committee of the American Fisheries Society

The goal of this work was to identify the main habitat variables that influence the presence and abundance of a small stream dwelling catfish in the Pichileufu River, Argentina. A total of 295 sampling units (1 m2), covering all available habitats, were sampled in three river sections. In each one, fishes were captured using electrofishing and 17 habitat variables were registered. A principal component analysis (PC) and a partial canonical correspondence analysis (CCA) were performed in order to determine habitat variability and fish habitat preferences. There was an important difference between areas occupied and unoccupied by catfish along PC1 and PC2 axis (ANOVA, p< 0.001, n=295). Catches per unit effort (CPUE, fish m-2) of H. macraei juveniles were correlated to gravel-pebble substrate (Pearson, r= 0.32, p<0.05), interstitial space (r=0.19, p<0.01), cobbles (r=-0.20, p<0.05) and also riparian vegetation (r=-0.18, p<0.05). Adults CPUE were related to temperature (r=0.36, p<0.05), pH (r=0.31, p<0.001), cobbles (r=0.33, p<0.001), filamentous algae (r=0.21, p<0.05), interstitial space (r=0.24, p<0.01), gravel-pebble (r=-0.28, p<0.01) and sand (r=-0.32, p<0.01). The first CCA axis was primarily related to habitat features modelled by the water velocity and the second CCA axis was mainly related to the size of substrate. Our results indicate that both juveniles and adults of H. macraei preferred those habitats with fast water velocity; such as riffles or runs, with important interstitial space, and avoided depositional zones with fine substrate particles.