The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis in the southern Caspian Sea. Survival rate and natural mortality were cal...The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis in the southern Caspian Sea. Survival rate and natural mortality were calculated using catch curve and Pauly methods, respectively. Natural and fishing mortality have been estimated up to 0.633 yr^-1 and 0.437 yr^-1, respectively. According to catch curve method, the annual survival rate of anchovy kilka has been estimated up to 0.343 yr^-1. With owning this survival rate, the instantaneous coefficient of total mortality of anchovy kilka has been estimated up to 1.07 yr^-1. The exploitation rate of anchovy kilka has been estimated up to 0.408. The catch amounts of anchovy kilka decreased gradually mainly due to overfishing, predators and ecological disturbances occurred in the Caspian Sea. The results suggest that the population of anchovy kilka were overexploited in the past years and were vulnerable to their natural predators.展开更多
Over the past 100 years, worldwide surface temperatures have increased at an unprecedented rate, contributing to warming of the oceans, melting ice fields and glaciers, and other adverse climatic effects. Southeast Fl...Over the past 100 years, worldwide surface temperatures have increased at an unprecedented rate, contributing to warming of the oceans, melting ice fields and glaciers, and other adverse climatic effects. Southeast Florida＇s vulnerability derives from its geographic location, low elevation, porous geology, unusual ground and surface water hydrology, subtropical weather patterns, and proximity to the Atlantic Ocean. The region is especially susceptible to sea level rise. After several millennia of stable sea levels prior to the 20th century, sea levels have been rising at accelerating rates due to thermal expansion of the oceans and from land-based ice melt The Everglades ecosystem and the water supplies for southeast Florida are particularly vulnerable as neither can be protected without significant expenditures of public dollars, and even these efforts may not prove to be successful. New approaches may be required to improve the resilience and prolong the sustainability of the region＇s water resources and ecosystem. The efforts to adapt to sea level changes in both the urban area and ecosystem as outlined herein are date and incident based-climate changes may occur earlier or later so instead of spending limited public dollars early, expenditures can be adjusted given future information.展开更多
文摘The objective of this study was to estimate natural, fishing and total mortality, survival and exploitation rates of Clupeonella engrauliformis in the southern Caspian Sea. Survival rate and natural mortality were calculated using catch curve and Pauly methods, respectively. Natural and fishing mortality have been estimated up to 0.633 yr^-1 and 0.437 yr^-1, respectively. According to catch curve method, the annual survival rate of anchovy kilka has been estimated up to 0.343 yr^-1. With owning this survival rate, the instantaneous coefficient of total mortality of anchovy kilka has been estimated up to 1.07 yr^-1. The exploitation rate of anchovy kilka has been estimated up to 0.408. The catch amounts of anchovy kilka decreased gradually mainly due to overfishing, predators and ecological disturbances occurred in the Caspian Sea. The results suggest that the population of anchovy kilka were overexploited in the past years and were vulnerable to their natural predators.
文摘Over the past 100 years, worldwide surface temperatures have increased at an unprecedented rate, contributing to warming of the oceans, melting ice fields and glaciers, and other adverse climatic effects. Southeast Florida＇s vulnerability derives from its geographic location, low elevation, porous geology, unusual ground and surface water hydrology, subtropical weather patterns, and proximity to the Atlantic Ocean. The region is especially susceptible to sea level rise. After several millennia of stable sea levels prior to the 20th century, sea levels have been rising at accelerating rates due to thermal expansion of the oceans and from land-based ice melt The Everglades ecosystem and the water supplies for southeast Florida are particularly vulnerable as neither can be protected without significant expenditures of public dollars, and even these efforts may not prove to be successful. New approaches may be required to improve the resilience and prolong the sustainability of the region＇s water resources and ecosystem. The efforts to adapt to sea level changes in both the urban area and ecosystem as outlined herein are date and incident based-climate changes may occur earlier or later so instead of spending limited public dollars early, expenditures can be adjusted given future information.
