Environmental stress on Corbicula fluminea (Bivalvia) in the Parana River delta (Argentina): Complex pollution-related disruption of population structures
Corbicula fluminea was collected at monthly intervals in November 1991-June 1993, and in March, April 1995 at a site located in the vicinity of strong sources of industrial and sewage effluents (confluence of the Rivers San Antonio and Vinculacion, SaV); and in November 1994 and March, April 1995 at...
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| Autores principales: | , , , , |
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1997
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00039136_v138_n4_p483_Boltovskoy http://hdl.handle.net/20.500.12110/paper_00039136_v138_n4_p483_Boltovskoy |
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| Sumario: | Corbicula fluminea was collected at monthly intervals in November 1991-June 1993, and in March, April 1995 at a site located in the vicinity of strong sources of industrial and sewage effluents (confluence of the Rivers San Antonio and Vinculacion, SaV); and in November 1994 and March, April 1995 at a presumably less polluted one (Parana de las Palmas River, PP), in the lower delta of the Parana River (Argentina). Abundances at SaV ranged between 430 and 10,300 ind. m-2 being noticeably higher than those at PP, as well as those at 19 stations between and around these two locales. Shell lengths at SaV were monotonous throughout the 19-months period, over 90% of the clams varying between 16 and 22.5 mm in length; no discernible cohorts were recorded. At PP, on the other hand, juveniles below 5 mm were largely dominant, and shells above 25-30 mm in length were very common. Larvae retrieved from the gills of gravid clams showed much greater mortality rates in waters from SaV (up to 75 % after 120 hr), than in those from PP and in the control (approximately 10 % after 192 hr). The first internal growth-related mark in clams from SaV was closer to the umbo (mean: 14.2 mm), than that in clams from PP (mean: 24 mm). It is concluded that inadequate water quality at SaV is responsible for 100 % mortalities of newborns, for dwarfed adult clams, and for the lack of discernible cohorts. |
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