Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel)

Fritillaria borealis is a cosmopolitan species, very frequent in sub-antarctic and antarctic waters. The objective of this paper was to analyze its size structure and maturity stages at two sites in Ushuaia Bay: a coastal site exposed to anthropogenic pressure (E1) and a reference site (E2) located...

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Autores principales: Presta, M.L., Hoffmeyer, M.S., Capitanio, F.L.
Formato: JOUR
Materias:
Appendicularians
Beagle channel
Maturity stages
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_16798759_v63_n3_p279_Presta
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_16798759_v63_n3_p279_Presta
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spelling todo:paper_16798759_v63_n3_p279_Presta2023-10-03T16:29:46Z Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel) Presta, M.L. Hoffmeyer, M.S. Capitanio, F.L. Appendicularians Beagle channel Maturity stages Fritillaria borealis is a cosmopolitan species, very frequent in sub-antarctic and antarctic waters. The objective of this paper was to analyze its size structure and maturity stages at two sites in Ushuaia Bay: a coastal site exposed to anthropogenic pressure (E1) and a reference site (E2) located in the external zone of the bay. Zooplankton was collected during the 2012 seasonal cycle. The sampling method involved the use of a 67 μm-mesh net. Appendicularians were classified in four maturity stages: I) undifferentiated gonads, II) testis and ovary differentiated, III) expanded testis, IV) discharged testis, expanded ovary. Our results showed that the highest densities of F. borealis occurred in spring and summer at both sites; coinciding with high values of chlorophyll-a. The percentage of juveniles (I and II) exhibited a spatial and temporal pattern similar to that observed for chlorophyll-a values. During spring-summer, juveniles and mature specimens (III and IV) showed a greater gonadal development than those individuals found in autumn-winter. In conclusion, the mismatching in the population structure and the pattern of densities of F. borealis between coastal and external zones would suggest the existence of two sub-populations susceptible to the influence of the anthropogenic impact in the bay. © 2015, Universidade de Sao Paulo. All Rights Reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_16798759_v63_n3_p279_Presta
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Appendicularians
Beagle channel
Maturity stages
spellingShingle Appendicularians
Beagle channel
Maturity stages
Presta, M.L.
Hoffmeyer, M.S.
Capitanio, F.L.
Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel)
topic_facet Appendicularians
Beagle channel
Maturity stages
description Fritillaria borealis is a cosmopolitan species, very frequent in sub-antarctic and antarctic waters. The objective of this paper was to analyze its size structure and maturity stages at two sites in Ushuaia Bay: a coastal site exposed to anthropogenic pressure (E1) and a reference site (E2) located in the external zone of the bay. Zooplankton was collected during the 2012 seasonal cycle. The sampling method involved the use of a 67 μm-mesh net. Appendicularians were classified in four maturity stages: I) undifferentiated gonads, II) testis and ovary differentiated, III) expanded testis, IV) discharged testis, expanded ovary. Our results showed that the highest densities of F. borealis occurred in spring and summer at both sites; coinciding with high values of chlorophyll-a. The percentage of juveniles (I and II) exhibited a spatial and temporal pattern similar to that observed for chlorophyll-a values. During spring-summer, juveniles and mature specimens (III and IV) showed a greater gonadal development than those individuals found in autumn-winter. In conclusion, the mismatching in the population structure and the pattern of densities of F. borealis between coastal and external zones would suggest the existence of two sub-populations susceptible to the influence of the anthropogenic impact in the bay. © 2015, Universidade de Sao Paulo. All Rights Reserved.
format JOUR
author Presta, M.L.
Hoffmeyer, M.S.
Capitanio, F.L.
author_facet Presta, M.L.
Hoffmeyer, M.S.
Capitanio, F.L.
author_sort Presta, M.L.
title Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel)
title_short Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel)
title_full Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel)
title_fullStr Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel)
title_full_unstemmed Population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): Seasonal cycle in Ushuaia Bay (Beagle Channel)
title_sort population structure and maturity stages of fritillaria borealis (appendicularia, tunicata): seasonal cycle in ushuaia bay (beagle channel)
url http://hdl.handle.net/20.500.12110/paper_16798759_v63_n3_p279_Presta
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AT hoffmeyerms populationstructureandmaturitystagesoffritillariaborealisappendiculariatunicataseasonalcycleinushuaiabaybeaglechannel
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