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| Registros recuperados: 23 | |
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| Hansen, J.E.; Madirolas, A.. |
| Information resulting from four spring acoustic surveys carried out between 1993 - 1996 to assess bonaerensis anchovy (Engraulis anchoita) biomass (34°- 41°30´S) is presented. Annual estimates, successively higher, went from 1.5 to 5.3 millon tons and the respective coefficient of variability that followed the same trend ranged between 7.4. and 28.0. . In general terms, the largest abundances were those recorded within the coastal strata off the Río de la Plata followed by those of the most southern stratum. Nevertheless, during the 1996 survey, the latter showed very high biomass values and, consequently, the largest mean. The region corresponding to the main commercial anchovy fishing ground during the season represented, in any case, relatively low... |
| Tipo: Journal Contribution |
Palavras-chave: Echo surveys; Biomass; Sexual maturity; Growth; Mortality; Biomass; Growth; Sexual maturity; Mortality; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_3394; Http://aims.fao.org/aos/agrovoc/c_7016; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 1999 |
URL: http://hdl.handle.net/1834/2531 |
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| Hansen, J.E.; Cousseau, M.B.; Gru, D.L.. |
| A total of 7263 otoliths were collected from anchovy samples taken during two pelagic cruises which were carried out in the Spring of 1978. An statistical analysis of back calculated length distributions of one-year-old fish (L1)was made. The L1 mean values taken by geographical latitude form a cline, with higher values in the northern samples, and decreasing Southwards. Within this latitudinal gradient two main anchovy populations can be identified, one in the region of Buenos Aires Province and the other in Patagonian waters. The L1 of the females is significatively larger than that of the males for the former population, whereas in the Patagonian area differences between sexes are not significant. The parameters of the von Bertalanffy Growth curves, as... |
| Tipo: Journal Contribution |
Palavras-chave: Stock identification; Otolith reading; Growth curves; Mortality; Mortality; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 1984 |
URL: http://hdl.handle.net/1834/2043 |
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| Jaramillo-González, J.; Acosta, A.. |
| Los arrecifes coralinos del mundo han sufrido un declive durante las pasadas tres décadas. Estos cambios se han evaluado en arrecifes en franja; sin embargo, se desconoce si los tensores causantes de dichos cambios afectan la dinámica de una comunidad coralina en los primeros estados de la sucesión antes del desarrollo de un arrecife. Para resolver este interrogante, se monitoreó durante 2004, 2005 y 2006 una comuniddad coralina aislada en San Andrés. Se compararon temporalmente la abundancia, cobertura y mortalidad parcial sufrida por la comjnidad coralina y sus poblaciones de coral dominantes. La comunidad coralina no presentó variación estadística en riqueza, abundancia, cobertura, ni en área de mortalidad parcial. Sin embargo, esta comunidad si varió... |
| Tipo: Journal Contribution |
Palavras-chave: Coral; Dynamics; Mortality; Mortality; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 2009 |
URL: http://hdl.handle.net/1834/3605 |
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| Hansen, J.E.; Madirolas, A.. |
| Two pelagic surveys to study were carried out during 1993. Those surveys covered the regions inhabited by either the bonaerensis stock in october (34-41°S)and the patagonian stock in November - December (41-45°30'S). Pre-stratified random sampling designs, including two random steps to allocate the transects, were adopted to perform the acoustic sampling by echo integration. A midwater trawl net (9-16 m vertical opening, 10 mm mesh-sized codend)was used to collect fish samples. The biomass of the northern stock was acoustically estimated to be about 1,45 million tons, whereas that of the southern stock was almost 740,000 t. Young anchovies, up to two-year old, allow for most of theose abundance values within each stock. The arrays of individuals at the sea... |
| Tipo: Journal Contribution |
Palavras-chave: Pelagic fisheries; Geographical distribution; Biomass; Mortality; Echo surveys; Stock assessment; Geographical distribution; Biomass; Stock assessment; Pelagic fisheries; Mortality; Http://aims.fao.org/aos/agrovoc/c_5083; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_24251; Http://aims.fao.org/aos/agrovoc/c_5659; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 1996 |
URL: http://hdl.handle.net/1834/1955 |
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| Gil-Agudelo, D.L.; Navas-Camacho, R.; Rodríguez-Ramírez, A.; Reyes-Nivia, M.C.; Bejarano, S.; Garzón-Ferreira, J.; Smith, G.W.. |
| Los arrecifes coralinos, uno de los más bellos e importantes ecosistemas de nuestro planeta, han existido por más de 200 millones de años, sobreviviendo a grandes cambios durante su historia (glaciaciones, extinciones masivas, entre otros). Sin embargo, durante las últimas tres décadas se han registrado grandes y súbitos cambios en el medio marino que a juicio de algunos investigadores ponen en peligro la supervivencia de corales y arrecifes coralinos. Uno de los mayores problemas que enfrentan los arrecifes coralinos hoy en día es la aparición de enfermedades que atacan a los corales, la base de estos ecosistemas. No existe un concenso sobre si estas enfermedades son realmente nuevas o no, pero lo que sí se sabe es que algunas de ellas están creando... |
| Tipo: Journal Contribution |
Palavras-chave: Coral reefs; Mortality; Coral reefs; Mortality; Http://aims.fao.org/aos/agrovoc/c_1880; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 2009 |
URL: http://hdl.handle.net/1834/3616 |
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| Renzi, M.A.; Santos, B.A.; Simonazzi, M.. |
| Hake Merluccius hubbsi population structure in 1993, 1994, 1996, 1997 and 1998 and age and sex distribution during 1997 are analyzed. Data were obtained in research surveys. At the end of winter 1997 concentrations of juveniles were found in the San Jorge Gulf Argentine Sea, SW Atlantic, with maximum yields of 10,000 individuals per trawl hour for age 1 and 2,500 individuals per trawl hour for age 2. The highest concentrations of adults were found in the Gulf and South of 47°S, between the 100 and 200 m isobath, maximum yields of up to 1,700 individuals per trawl hour for age 3 and up to 90 individuals per trawl hour for age 7 and older. In spite of the decrease in population abundance, the basic age structure juveniles, young adults and old adults was... |
| Tipo: Journal Contribution |
Palavras-chave: Sex ratio; Age composition; Mortality; Fishery surveys; Gadoid fisheries; Age composition; Sex ratio; Mortality; Http://aims.fao.org/aos/agrovoc/c_29093; Http://aims.fao.org/aos/agrovoc/c_7014; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 2003 |
URL: http://hdl.handle.net/1834/2471 |
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| Registros recuperados: 23 | |
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