INVESTIGADORES
CUSSAC Victor Enrique
artículos
Título:
Annual dynamics variation of landlocked Galaxias maculatus (Jenyns 1842) population in a northern Patagonia river: occurrence of juvenile upstream migration
Autor/es:
BARRIGA, J.P.; M.A. BATTINI; V.E. CUSSAC
Revista:
JOURNAL OF APPLIED ICHTHYOLOGY-ZEITSCHRIFT FUR ANGEWANDTE ICHTHYOLOGIE
Editorial:
Blackwell
Referencias:
Año: 2007 vol. 23 p. 128 - 135
ISSN:
0175-8659
Resumen:
Galaxias maculatus, broadly distributed in the southern hemisphere,
presents both diadromic and landlocked populations.
The upstream migration of larvae and juveniles from the sea to
freshwater habitats is a characteristic phenomenon of diadromous
populations, but upstream migration has never been
reported in those that are landlocked. The objective of this
study was to establish the population dynamics of a peculiar
riverine landlocked population that presents an upstream
migration at the larvaejuvenile transition from the Piedra
del A ´ guila Reservoir to the Caleufu´ River (Argentina).
A spawning season from September to November and the
arrival of shoals of metamorphic larvae and juveniles from
February to April to the adult habitat were coincidental
with lacustrine landlocked populations, but not with diadromous
populations. Growth rate and age at migration,
147 ± 22.6 days, were also similar to other landlocked and
diadromous populations. The arrival of these shoals produced
a 20-fold increase in fish density while the two cohorts of
G. maculatus overlapped in time and space. No significant
differences in morphology or vertebrae number were detected
when riverine and reservoir adults were compared. The great
life history plasticity of G. maculatus, shown to be even greater
in our results, could be the key to explain the wide distribution
of this species in the southern hemisphere. Likewise, discovering
this juvenile potamodromous behaviour in a landlocked
population will provide a new view for the analysis of the ways
of this species_ dispersion in continental waters.