INVESTIGADORES
LANCELOTTI julio Lucio
artículos
Título:
A natural experiment of dietary overlap between introduced Rainbow Trout (Oncorhynchus mykiss) and native Puyen (Galaxias maculatus) in the Santa Cruz River, Patagonia
Autor/es:
MARINA TAGLIAFERRO; IVAN ARISMENDI; JULIO LANCELOTTI; MIGUEL PASCUAL
Revista:
ENVIRONMENTAL BIOLOGY OF FISHES
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2014 vol. 97
ISSN:
0378-1909
Resumen:
Diet overlap between the native Puyen
(Galaxias maculatus) and juvenile exotic Rainbow Trout
(Oncorhynchus mykiss) was studied in 52 sites located
along 306 km of the mainstem of the Santa Cruz River,
one of the largest rivers in Patagonia. The relative abun-
dance of both species varied along the river, with three
clearly defined areas including an upstream ?high
Rainbow Trout to Puyen ratio? area (with abundances of
75 and 25 %, respectively), a midstream ?intermediate
Rainbow Trout to Puyen ratio? area (relative abundances
between 75 and 25 %), and a downstream ?low Rainbow
Trout to Puyen ratio? area. The diet of the 2 species was
analyzed across these 3 areas examining stomach content.
Diet similarity between species was analyzed using a non-
metric multidimensional scaling ordination technique; prey
electivity was evaluated with the Ivlev?s Index; feeding
tactics were studied by estimating prey-specific abun-
dance. Both species showed a generalist feeding tactic,
with Puyen exhibiting a more varied diet. Prey electivity
was similar in both species, with the mayfly (Meridialarischiloeensis), stoneflies (Klapopteryx kuscheli and
Antarctoperla michaelseni), and the amphipod (Hyalella
sp.) being the most frequently consumed prey. A signifi-
cant diet overlap was found only in the downstream areas
where a higher proportion of native fish occurs. The low
diet overlap in upstream locations might be because of the
high density of Rainbow Trout; while mid-stream could be
due to the high secondary productivity spots. Our results
suggest that the diet of native Puyen changed in relation to
the abundances of Rainbow Trout in the stream.