Distribution of introduced and native fish in Patagonia (Argentina): patterns and changes in fish assemblages

Abstract

The interaction between native fishes and salmonids introduced in Patagonia at the beginning of the 20th Century, developed at the same time as the environmental change. The phenomenon of global warming has led to the formulation of predictions in relation to changes in the distribution of species, in the latitudinal dimension, both at intralacustrine, or small streams levels. The aim of the present work includes three main objectives: a) to compose a general and updated picture of the latitudinal distribution range of native and alien fishes, b) to analyze the historical changes in the relative abundance of Percichthys trucha, Odontesthes sp., and salmonids in lakes and reservoirs, and c) to relate the diversity and relative abundance of native and salmonid fishes to the environmental variables of lakes and reservoirs. We analysed previous records and an ensemble of data about new locations along the northern border of the Patagonian Province. We compared current data about the relative abundance of native fishes and salmonids in lakes and reservoirs, with previous databases (1984)(1985)(1986)(1987). All samplings considered were performed during spring-summer surveys and include relative abundance, as proportions of salmonids, P. trucha, and Odontesthes sp. For the first time, we found changes in fish assemblages from twenty years back up to the present: a significant decline in the relative abundances of salmonids and an increase of P. trucha. We studied the association between the diversity and relative abundance of native and salmonid fishes and the environmental variables of lakes and reservoirs using Canonical Correspondence Analysis. Relative abundance showed mainly geographical cues and the diversity relied largely on morphometric characteristics. Relative abundance and diversity seem to have a common point in the lake area, included into the PAR concept. Native abundance and alien diversity were negatively related with latitude. Greater native diversity was observed in lakes with high PAR compared with salmonids.Historical changes such as southward dispersion, relative abundance changes, and geographical patterns for relative abundance and diversity are basic concepts needed not only in future research but also in management design for Patagonian fish populations.

Populations of Odontesthes (Teleostei: Atheriniformes) in the Andean region of Southern South America: body shape and hybrid individuals

“…In particular, morphological variation within O. hatcheri involves body height and the relative positions of the anus, pelvic and anal fins. In agreement with Aigo et al (2008), who positively relate abundance of O. hatcheri to the area of the lake, and the dependence of cephalic shape of O. hatcheri on coastline development (Crichigno et al, 2013), significant relationships between DFs and independent variables affecting quality and quantity of planktonic food availability (TP and altitude) were observed. Part of this variation could be ascribed to phenotypic plasticity (Crichigno et al, 2012).…”

“…This species is commonly found in rivers, lakes, and reservoirs of both Atlantic and Pacific Patagonian drainages (Aigo et al, 2008).…”

“…This species is able to establish populations in environments where mean summer air temperatures are higher than 20ºC (Cussac et al, 2009). The southernmost locality known for O. bonariensis in Patagonia is the Reservoir Ezequiel Ramos Mexía on the Limay river (39º30´S, 69º00´W, Aigo et al, 2008).…”

“…1); O. hatcheri in the southwest and O. bonariensis in the north east (Baigún & Ferriz, 2003;Dyer, 2006;Aigo et al, 2008), and both are remarkably tolerant of high salinity levels but not of sea water (Tsuzuki et al, 2000a, b;Gómez & Ferriz, 2001). Genetic data from Sommer et al (2010) indicate that O. hatcheri has a closer relationship with marine species than with O. bonariensis.…”

Native and exotic fishes in a Patagonian reservoir with rainbow trout cage culture: spatial and trophic resource use

“…Along with ERT, the native puyen Galaxias maculatus (Jenyns), big puyen Galaxias platei Steindachner, the catfishes Hatcheria macraei (Girard) and Diplomystes viedmensis MacDonagh (Muñoz-Ramírez et al, 2014), O. hatcheri, P. trucha (including, according to Ruzzante et al, 2006Ruzzante et al, , 2011 several nominal forms considered by López-Albarello, 2004), and the exotic rainbow trout, Atlantic salmon Salmo salar Linnaeus, brown trout Salmo trutta Linnaeus, and brook trout Salvelinus fontinalis (Mitchill), have been reported in the reservoir (Cussac et al, 1998;Macchi et al, 1999;Aigo et al, 2008). O. hatcheri, P. trucha, rainbow trout, and S. trutta are the most frequently captured species.…”