|
|
|
Registros recuperados: 23 | |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
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 |
| |
|
| |
|
|
Hansen, J.E.; Gru, D.L.; Perrotta, R.G.. |
An extensive area of the continental shelf -between 37°20' and 34°40'S - was reviewed through hidroacoustical methods in order to evaluate the anchovy biomass. Within the area of highest concentration, further data on anchovy abundance were recorded, and fish samples were taken. Large anchovy shoals were located at about 170 nm from Mar del Plata, mainly in zones with sharp changes in oceanographic conditions. The distribution of the species was not uniform, but "contagious", and the log-normal distribution provided the best fit for the echo-integrator recorded data. The biomass was estimated at 1,061,727 tons (Confidence limits in between 921,010 and 1,223,930 tons). Some parameters of the population were estimated, such as: lenght-weight relationship,... |
Tipo: Journal Contribution |
Palavras-chave: Length-weight relationships; Sex ratio; Age composition; Growth curves; Echo surveys; Mortality; 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: 1986 |
URL: http://hdl.handle.net/1834/2038 |
| |
|
| |
|
| |
|
|
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 |
| |
|
| |
|
| |
|
|
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 |
| |
|
| |
|
|
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 |
| |
|
| |
|
| |
Registros recuperados: 23 | |
|
|
|