Zooplankton characteristics on the southern coast of Patagonia (Argentina)
Two acoustic surveys were conducted in the autumn and spring of 1996 aimed at stock assessment of Patagonian sprat Sprattus fuegensis (Jenyns, 1842) in the area extending from 50° to 55° S, from the coast to a depth of 60 m. The zoo- and ichthyoplankton, as well as the oceanographic conditions, were...
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todo:paper_00740195_v17_n3-4_p245_Sabatini2023-10-03T14:53:34Z Zooplankton characteristics on the southern coast of Patagonia (Argentina) Sabatini, M.E. Giménez, J. Rocco, V. Calanus australis Copepods Drepanopus forcipatus Patagonian sprat Sprattus fuegensis Zooplankton acoustic survey community composition fish stock assessment Argentina Calanus australis Drepanopus forcipatus Sprattus fuegensis Two acoustic surveys were conducted in the autumn and spring of 1996 aimed at stock assessment of Patagonian sprat Sprattus fuegensis (Jenyns, 1842) in the area extending from 50° to 55° S, from the coast to a depth of 60 m. The zoo- and ichthyoplankton, as well as the oceanographic conditions, were also studied in order to identify and describe the reproductive and nursery grounds. Studies of zooplankton as a measure of the trophic potential of such areas are particularly relevant for S. fuegensis because the species is zooplanktivorous throughout its entire life cycle and, furthermore, it plays a key role on the southern Patagonian shelf by linking several trophic levels. A Nackthai sampler (400 μm mesh size) was used for zooplankton collection, oblique surface-to-bottom tows were carried out. Two size fractions (larger and smaller than 5 mm) were separated and weighted (wet weight). The biomass of the smaller fraction was usually the same, or sometimes even higher, as the large one, in both autumn and spring. In light of these results, we conducted a detailed analysis of the specific composition and numerical abundance of the fraction smaller than 5 mm, and found that this fraction was almost entirely composed of the calanoid copepods Drepanopus forcipatus Giesbrecht, 1888 and Calanus australis Brodsky, 1959. Biomass concentration, abundance of individuals, and the number of species were higher in the spring. During this season, Drepanopus forcipatus was the dominant species, with up to 90 % of the total individuals. Calanus australis was relatively more abundant in autumn, when it was dominant, particularly in the Grande Bay area. These two copepods can be considered key species in the pelagic food web of the area. © Instituto Español de Oceanografía, 2001. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00740195_v17_n3-4_p245_Sabatini |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Calanus australis Copepods Drepanopus forcipatus Patagonian sprat Sprattus fuegensis Zooplankton acoustic survey community composition fish stock assessment Argentina Calanus australis Drepanopus forcipatus Sprattus fuegensis |
| spellingShingle |
Calanus australis Copepods Drepanopus forcipatus Patagonian sprat Sprattus fuegensis Zooplankton acoustic survey community composition fish stock assessment Argentina Calanus australis Drepanopus forcipatus Sprattus fuegensis Sabatini, M.E. Giménez, J. Rocco, V. Zooplankton characteristics on the southern coast of Patagonia (Argentina) |
| topic_facet |
Calanus australis Copepods Drepanopus forcipatus Patagonian sprat Sprattus fuegensis Zooplankton acoustic survey community composition fish stock assessment Argentina Calanus australis Drepanopus forcipatus Sprattus fuegensis |
| description |
Two acoustic surveys were conducted in the autumn and spring of 1996 aimed at stock assessment of Patagonian sprat Sprattus fuegensis (Jenyns, 1842) in the area extending from 50° to 55° S, from the coast to a depth of 60 m. The zoo- and ichthyoplankton, as well as the oceanographic conditions, were also studied in order to identify and describe the reproductive and nursery grounds. Studies of zooplankton as a measure of the trophic potential of such areas are particularly relevant for S. fuegensis because the species is zooplanktivorous throughout its entire life cycle and, furthermore, it plays a key role on the southern Patagonian shelf by linking several trophic levels. A Nackthai sampler (400 μm mesh size) was used for zooplankton collection, oblique surface-to-bottom tows were carried out. Two size fractions (larger and smaller than 5 mm) were separated and weighted (wet weight). The biomass of the smaller fraction was usually the same, or sometimes even higher, as the large one, in both autumn and spring. In light of these results, we conducted a detailed analysis of the specific composition and numerical abundance of the fraction smaller than 5 mm, and found that this fraction was almost entirely composed of the calanoid copepods Drepanopus forcipatus Giesbrecht, 1888 and Calanus australis Brodsky, 1959. Biomass concentration, abundance of individuals, and the number of species were higher in the spring. During this season, Drepanopus forcipatus was the dominant species, with up to 90 % of the total individuals. Calanus australis was relatively more abundant in autumn, when it was dominant, particularly in the Grande Bay area. These two copepods can be considered key species in the pelagic food web of the area. © Instituto Español de Oceanografía, 2001. |
| format |
JOUR |
| author |
Sabatini, M.E. Giménez, J. Rocco, V. |
| author_facet |
Sabatini, M.E. Giménez, J. Rocco, V. |
| author_sort |
Sabatini, M.E. |
| title |
Zooplankton characteristics on the southern coast of Patagonia (Argentina) |
| title_short |
Zooplankton characteristics on the southern coast of Patagonia (Argentina) |
| title_full |
Zooplankton characteristics on the southern coast of Patagonia (Argentina) |
| title_fullStr |
Zooplankton characteristics on the southern coast of Patagonia (Argentina) |
| title_full_unstemmed |
Zooplankton characteristics on the southern coast of Patagonia (Argentina) |
| title_sort |
zooplankton characteristics on the southern coast of patagonia (argentina) |
| url |
http://hdl.handle.net/20.500.12110/paper_00740195_v17_n3-4_p245_Sabatini |
| work_keys_str_mv |
AT sabatinime zooplanktoncharacteristicsonthesoutherncoastofpatagoniaargentina AT gimenezj zooplanktoncharacteristicsonthesoutherncoastofpatagoniaargentina AT roccov zooplanktoncharacteristicsonthesoutherncoastofpatagoniaargentina |
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