Biology Reference
In-Depth Information
Conclusion
Mechanisms of larval dispersal and recruitment to freshwater are both
governed by biological, physiological, and hydrodynamical processes
(Murphy and Cowan, 2007). For
S
.
lagocephalus
, the last steps of
metamorphosis take place between the PL0 and PL2 stages. Competence is
acquired at PL0 stage and post-larvae can therefore recruit at this stage. The
characterisation of the different stages of
S
.
lagocephalus
recruits provides
managers with precise knowledge of the developmental state of different
cohorts observed while monitoring gobiid populations or larvae fi sheries.
The analysis of the fi sh's morphology brings information on its locomotion
and feeding modes. For this type of amphidromous species the locomotion
is critical as feeding and migration depend on it.
The physiological state of post-larvae has been characterised, as
were the hormones responsible for triggering metamorphosis, migration
and recruitment. Data show that morphological changes observed in
S
.
lagocephalus
during the recruitment of post-larvae and the colonisation of
insular hydrosystems are under the control of the TH. The morphological
changes observed in
S
.
lagocephalus
represent therefore a true metamorphosis
as they are in Elopomorphs and Pleuronectiforms. Further studies should
aim at collecting larvae in the marine environment before recruitment. This
would allow investigating the initiation of metamorphosis in
S
.
lagocephalus
,
namely the appearance of the sucker and the role of TH during this event,
compulsory in transforming larvae into competent post-larvae, capable of
colonising the juvenile and adult habitat.
Acknowledgments
We thank P. Bosc, P. Valade and the staff of ARDA (Association Réunionaise
pour le Développement de l'Aquaculture) for their help during sampling
and for housing the experiments, and the authorities of Reunion Island.
References
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Sicyopterus lagocephalus
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