Universidade do Algarve Faculdade de Ciências do Mar e do ...

Abstract
Ria Formosa is one of the largest lagoon systems on the Portuguese
coast. This type of habitat is considered particularly vulnerable to destruction
and degradation mainly because of human activities. This makes the knowledge
of the ichthyofauna, and particularly the way it uses this system extremely
necessary to proceed with an adequate management of the system and the
species. Being so, the main objectives of this study were to determine the
suitability of the use of acoustic telemetry and conventional tagging on the study
of the movements and habitat use by four of the most important sparid fishes
that inhabit Ria Formosa. Preliminary results on movements, home range and
activity period of Diplodus vulgaris, Diplodus sargus, Sarpa salpa and Sparus
aurata were ensuing objectives.
Results on conventional tagging (n=1980) showed that juveniles of D.
vulgaris and S. salpa perform small displacements demonstrating high site
fidelity. The small number of recaptures of tagged D. sargus and S. aurata did
not allow any conclusions.
The use of acoustic telemetry (n=21) allowed us to observe that D.
vulgaris and D. sargus show high site fidelity, with the first having a smaller
home range. In contrast, S. salpa dispersed throughout the study area. S.
aurata showed homing abilities after being released 3,8 km away from the
capture position. Two different behavioral patterns were noticeable, some
individuals being more active during the night while others were more active
during the day.
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