INVESTIGADORES
CIANCIO Javier Ernesto
congresos y reuniones científicas
Título:
Plastic response to a novel environment by exotic anadromous rainbow trout (Oncorhynchus mykiss)
Autor/es:
LIBEROFF, ANA; CARLA RIVA ROSSI; JAVIER CIANCIO; MIGUEL PASCUAL
Lugar:
Mar del Plata
Reunión:
Conferencia; 2nd World Conference on Biological Invasions and Ecosystem Functioning, November , Mar del Plata, Argentina; 2011
Resumen:
Salmonid species have successfully
established exotic populations around the globe. Their high level of diversity and phenotypic
plasticity might have played a key role on establishment in suitable new
environments and adaptation in response to new selective pressures. However,
anadromous forms (e.g. ocean migratory) have been less successful in novel environments
reflecting the problems of organisms with more complex life cycles to adapt. Rainbow
trout (Oncorhynchus mykiss) introduced
in the Santa Cruz
river is the first known case of development of a self sustained partial
anadromous population where anadromous and freshwater resident forms coexist. These
fish differ from their native parental populations in several life history
traits, most notably in their high level of iteroparity (the ability to repeat
spawning). In general, iteroparity occurs at the expense of female gonadal
investment, itself closely related to juvenile survivorship and early growth. However,
this study shows that in Santa Cruz
fish maternal investment remains high and maternal effects (non-genetic
heritance of characters) on anadromous progeny is significant, reflecting in better
early condition and growth of anadromous descendents as compared to resident
offspring. Whether these distinctive traits are pure phenotypic plasticity or the
result of genetic adaptation is still unknown. Regardless, Santa Cruz river and surrounding marine areas
appear to provide matching conditions for requirements of the anadromous life
cycle. Because migration to the ocean in Santa
Cruz river fish appears to be triggered by high
juvenile growth, maternal effects might have played a key role during initial
colonization stages, speeding up the development of anadromy.