INVESTIGADORES
LUPPI Tomas Atilio
artículos
Título:
Larval salinity tolerance of the South American salt-marsh crab, Neohelice (Chasmagnathus) granulata: physiological constraints to estuarine retention, export and reimmigration.
Autor/es:
ANGER KLAUS; SPIVAK EDUARDO; LUPPI TOMAS; BAS CLAUDIA; ISMAEL DEBORAH
Revista:
Helgoland marine research
Editorial:
Springer
Referencias:
Año: 2008 vol. 62 p. 93 - 102
ISSN:
1438-387x
Resumen:
Abstract The semiterrestrial crab Neohelice (=Chasmagnathus)
granulata (Dana 1851) is a predominant species in
brackish salt marshes, mangroves and estuaries. Its larvae
are exported towards coastal marine waters. In order to estimate
the limits of salinity tolerance constraining larval
retention in estuarine habitats, we exposed in laboratory
experiments freshly hatched zoeae to six diVerent salinities
(532). At 5, the larvae survived for a maximum of
2 weeks, reaching only exceptionally the second zoeal
stage, while 38% survived to the megalopa stage at 10.
Shortest development and negligible mortality occurred at
all higher salt concentrations. These observations show that
the larvae of N. granulata can tolerate a retention in the
mesohaline reaches of estuaries, with a lower limit of ca.
1015. Maximum survival at 25 suggests that polyhaline
conditions rather than an export to oceanic waters are
optimal for successful larval development of this species. In
another experiment, we tested the capability of the last
zoeal stage (IV) for reimmigration from coastal marine into
brackish waters. Stepwise reductions of salinity during this
stage allowed for moulting to the megalopa at 410.
Although survival was at these conditions reduced and
development delayed, these results suggest that already the
zoea-IV stage is able to initiate the reimmigration into estuaries.
After further salinity reduction, megalopae survived
in this experiment for up to >3 weeks in freshwater, without
moulting to juvenile crabs. In a similar experiment starting
from the megalopa stage, successful metamorphosis
occurred at 410, and juvenile growth continued in freshwater.
Although these juvenile crabs showed signiWcantly
enhanced mortality and smaller carapace width compared
to a seawater control, our results show that the late larval
and early juvenile stages of N. granulata are well adapted
for successful recruitment in brackish and even limnetic
habitats.