IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Reproductive strategy and egg morphology of the copepod Acartia tonsa in a temperate estuary, Argentina
Autor/es:
BERASATEGUI, A. A.; HOFFMEYER, M. S.; BIANCALANA, F.; DUTTO, M. S.
Lugar:
Pucon, Chile
Reunión:
Simposio; 5th International Zooplankton Production Symposium; 2011
Resumen:
Reproductive strategy andegg morphology of the copepod Acartia tonsa ina temperateestuary, ArgentinaAnabela Berasategui, Monica S. Hoffmeyer, Florencia Biancalana,Mar¨ªa S. DuttoInstituto Argentino de Oceanograf¨ªa, Centro Cient¨ªfico Tecnol¨®gico Bah¨ªa Blanca, CONICET,Camino la Carrindanga km 7.5, B8000FWB Bah¨ªa Blanca, Buenos Aires, Argentina. E-mail: aberasa@criba.edu.arThe warm-water species  Acartia tonsa has a wide distribution in estuarine areas, showing variation in morphological and physiological characteristics of itssubitaneous and resting eggs. This work aims to evaluate the temporal variability in female size(PL-prosome length), egg production (EP), egg hatching success (HS) and egg morphology of Acartia tonsa in the Bah¨ªa Blanca estuary. Experimental incubations were conducted with field females simulating in situ environmental conditions. Non-parametric tests were used to analyze the relationships among all variables. Three morphological types of eggs (I, II, III) were describedaccording to their spine length(SL) by optic microscopy and SEM (SL I: ¡Ü 2.55 ¦Ìm; SL II: 3, 25 -7.95 ¦Ìm; SL III:8.5 -16.15 ¦Ìm). Low egg production was recorded during the winter period (6.56 eggs. f-1.d-1) in which the presence of the three morphotypeswas observed. However, the chorion morphology was independent of the hatching response, being the three morphological types,resting eggs with delayed hatching. Eggs differed significantly in diameter (D) and SLduring winterfrom the eggs that were laid during summer. Negative correlationsbetweenSL-temperature(-0.95) andbetweenD-temperature(-0.75), werefound. On the other hand, a positive correlation (0.74) between D (including spines) and PL was detected. During the summer period smaller females, higher egg production of subitaneous type I eggs (12.95 eggs. f-1.d-1) andhigher hatching success, were observed. Temporal variability in the reproductive A.tonsa strategy,would allow it toremain in the plankton throughout the year.