Ecological aspects of Lebiasina erythrinoides (Characiformes: Lebiasinidae) from an andean piedmont stream in Colombia

Univ. Sci. 21 (1): 83-97, 2016. doi: 10.11144/Javeriana.SC21-1.eaol Bogotá original article Ecological aspects of Lebiasina erythrinoides (Characiformes: Lebiasinidae) from an andean piedmont stream in Colombia Alexander Urbano-Bonilla1, Jhon Zamudio1, Javier Alejandro Maldonado-Ocampo1* Edited by Juan Carlos Salcedo-Reyes () 1. Laboratorio de Ictiología, Unidad de Ecología y Sistemática (UNESIS), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 N° 43-82, Bogotá D.C., Colombia. * Received: 11-02-2015 Accepted: 12-02-2016 Published on line: 11-03-2016 Citation: Urbano-Bonilla A, Zamudio J, Maldonado-Ocampo JA. Ecological Aspects of Lebiasina erythrinoides (Characiformes: Lebiasinidae) from an Andean piedmont stream in Colombia, Universitas Scientiarum, 21 (1): 83-97, 2016. doi: 10.11144/Javeriana.SC21-1.eaol Funding: N/A Electronic supplementary material: N/A Abstract The present study describes ecological aspects of Lebiasina erythrinoides; 200 individuals were sampled throughout an annual hydrological cycle from October 2008 to September 2009 in La Calaboza stream, a Piedmont tributary of the Rio Cravo Sur. The studied population had more females than males (1.5:1) and preferred habitats dominated by shoreline vegetation and rocky substrates. Prior to reproductive events, individuals presented an increase in the condition factor (K) and the gonosomatic index (GSI). On average, 648.8 oocytes are discharged twice a year: at the beginning of the rainy season, and during falling water phase. The mean sizes at sexual maturity found for females were 73.5 mm standard length (SL) and for males 70 mm SL. Rounding up, an average minimum size of capture of 75 mm SL is proposed. Most specimens of the population (65 %) were found to be maturing or mature (stages II and III), 28.5 % immature (stage I), 5.0 % in post reproduction stage V, and 1.5 % in reproductive phase (IV). Results suggest this species is omnivorous with a preference for invertebrates (IRI = 41.2 %) and vegetal material (IRI = 27.8 %), but also includes a variety of other items. The values of the diet are correlated with hydrological cycle and size. Keywords: Lebiasininae; diet; reproduction; hydrological cycle; Orinoco Basin. Introduction Species of the genus Lebiasina belong to the subfamily Lebiasininae (Netto-Ferreira et al. 2011), and are found widely distributed in drainages of Central America (Costa Rica, Panama), northern South America (Colombia, Ecuador, Venezuela) and the Orinoco and Amazon River Basins. Currently, 27 nominal species have been described in this genus (Netto-Ferreira 2012, Netto-Ferreira et al. 2013). Ten have been found in Colombia, in streams of the Caribbean, Pacific, Magdalena-Cauca, Amazonas and Orinoco hydrographic zones (Maldonado-Ocampo et al. 2008). Some of the Lebiasina species found in Colombia prefer small stream habitats with clear water and abundant shore vegetation that provides them food and shelter from predators (Ardila-Rodríguez 2004, 2008a, 2008b, Román-Valencia & Vélez 1986, Universitas Scientiarum, Journal of the Faculty of Sciences, Pontificia Universidad Javeriana, is licensed under the Creative Commons Attribution 4.0 International Public License 84 Ecological aspects of Lebiasina erythrinoides Román-Valencia 1996, 2004). Lebiasina erythrinoides (Valenciennes 1850) is the only species of the genus found in Andean piedmont streams of the Orinoco River Basin in Colombia (Maldonado-Ocampo et al. 2008). This species is abundant in most of the drainages of the piedmont region of Colombia’s Casanare department (UrbanoBonilla et al. 2009). Aspects of the biology of L. erythrinoides are known mostly from previous studies in Venezuela (Machado-Allison 1974, Taphorn & Lilyestrom 1980, Sette 1991, 1993). Whereas in Colombia, only preliminary information about its geographic distribution and habitat characterization is available (Maldonado-Ocampo et al. 2005). The piedmont region in the Colombian Orinoco, where L. erythrinoides and around 465 freshwater fish species are distributed, has been characterized in recent years by a landscape transformation (terrestrial and aquatic ecosystems); mainly due to deforestation, cattle, mining, material extraction along the river banks, and oil production (Machado-Allison et al. 2010, Urbano-Bonilla et al. 2014). To contrast this trend in the transformation along this region, new protected areas focusing on aquatic ecosystem have been proposed (Machado-Allison et al. 2010). Nonetheless, this strategy has to be associated with a better knowledge of the life history of the fish distributed there. Without this information, monitoring how the new propose conservation areas are helping to preserve ecosystem functioning and biodiversity will be difficult. Herein the length/weight ratio, mean size at sexual maturity, condition factor K, gonadal development, gonosomatic index and fecundity, diet and feeding habits of L. erythrinoides are described. Materials and methods Study Area: The Andean piedmont in Casanare Department extends along the foothills of the eastern branch of the Andes from 06° to 04° north latitude and 73° to 71° west longitude, between 350 and 1100 masl (Romero et al. 2004). This study was done in La Calaboza stream, a tributary of the Rio Cravo Sur, in the piedmont of the Yopal municipality, Casanare Department, Colombia, located at 5° 21' 9" North, 72° 25' 12" West. The average monthly precipitation for the region (1981 – 2010) is 199.2 mm with a maximum of 360.1 mm in May and a minimum of only 9.6 mm in January, with a total annual of 2 390.1 mm (IDEAM 2010). Sampling: Monthly sampling in a 500 m length stretch was performed from October 2008 to September 2009 in effort to include the entire annual hydrological cycle. Time collecting effort in all sampling events took two hours; using a 3 m x 1.3 m seine with 3 mm mesh, and hook and line (hooks #2 and #3). All the individuals captured in each sample were collected and fixed. Once collected, the fish were anesthetized and slaughtered in a benzocaine solution and later fixed in 10 % formalin for examination in the lab. All specimens were deposited in the Reference Freshwater Fish Collection of the Department of Biology, Pontificia Universidad Javeriana, Bogotá, Colombia (MPUJ). During each collecting event, physicochemical parameters (temperature, conductivity, pH, dissolved oxygen using an Oakton-waterproof multiparameter meter) were recorded at one specific point along the 500 m stretch. Percentage substrate were estimated along the stretch transect, and riparian vegetation was characterized. Universitas Scientiarum Vol. 21 (1): 83-97 http://ciencias.javeriana.edu.co/investigacion/universitas-scientiarum 85 Urbano-Bonilla et al. Data analysis: Ten size classes in 15 mm standard length (SL) intervals were established to estimate size class frequency (Sturges 1926). To calculate the length/ weight ratio, we recorded e (...truncated)