One technical fishway and two innovative nature-like fishways were installed at three dams on the Acushnet River in Acushnet, Massachusetts to facilitate migration of river herring and juvenile American eels （elvers...One technical fishway and two innovative nature-like fishways were installed at three dams on the Acushnet River in Acushnet, Massachusetts to facilitate migration of river herring and juvenile American eels （elvers）. Pre-construction and post-construction monitoring of river herring and elver populations used census counting and abundance estimation, respectively. Numbers of adult river herring returning to the upstream spawning grounds during the pre-construction phase were very low; elver counts declined during the pre-construction period and served as baseline levels to determine the effectiveness of the new fishways. Post-construction monitoring of river herring and elvers indicated an increasing trend of spawning adult river herring returning to the spawning grounds, with the total count in the fourth year of post-construction representing an increase of 1,140% over baseline, pre-construction conditions. Results also show increased elver recruitment into the river as well as increased proportions of elvers accessing habitat in the upper watershed that was mostly inaccessible prior to fishway installation. The new fishways at the three dams on the river have improved diadromous fish passage, thereby increasing the probability of restoring healthy populations of river herring and American eels to the Acushnet River system.展开更多
Dams,culverts,and other water diversion/control structures are the most widespread human alteration to riverine habitat globally.While many of these structures often serve critical services(i.e.,source of agricultural...Dams,culverts,and other water diversion/control structures are the most widespread human alteration to riverine habitat globally.While many of these structures often serve critical services(i.e.,source of agricultural and municipal water,power generation,flood protection,and sensitive ecosystem protection),they cause changes to local ecology by impeding animal movement and altering the adjoining habitat and associated ecological processes(Nilsson et al.,2005;Liermann et al.,2007).The disruption of fish movement by barriers has contributed to the decline of both migratory and non-migratory fish populations around the world.展开更多
Irrigation infrastructure expansion threatens the diversity of freshwater fish worldwide.Irrigation infrastructure creates migration barriers which can block access to important nursery,feeding and spawning habitat.La...Irrigation infrastructure expansion threatens the diversity of freshwater fish worldwide.Irrigation infrastructure creates migration barriers which can block access to important nursery,feeding and spawning habitat.Lao PDR is a landlocked country situated within the Lower Mekong River Basin where there is a substantial dependency on rice and fish for food,income and livelihoods.The country is experiencing an unprecedented boom in irrigation infrastructure investment,with modernisation programs being implemented in every province.Despite significant investment in infrastructure upgrades,and the potential impact on freshwater fish,little consideration has been given to fish passage solutions.In 2008,we commenced a fish passage program in Lao PDR.The intent of this case study is to outline the pivotal elements of the program of knowledge development and transfer,in the context of river connectivity and fisheries management in Lao PDR.We also highlight challenges in international research in development and lessons learned.展开更多
文摘One technical fishway and two innovative nature-like fishways were installed at three dams on the Acushnet River in Acushnet, Massachusetts to facilitate migration of river herring and juvenile American eels （elvers）. Pre-construction and post-construction monitoring of river herring and elver populations used census counting and abundance estimation, respectively. Numbers of adult river herring returning to the upstream spawning grounds during the pre-construction phase were very low; elver counts declined during the pre-construction period and served as baseline levels to determine the effectiveness of the new fishways. Post-construction monitoring of river herring and elvers indicated an increasing trend of spawning adult river herring returning to the spawning grounds, with the total count in the fourth year of post-construction representing an increase of 1,140% over baseline, pre-construction conditions. Results also show increased elver recruitment into the river as well as increased proportions of elvers accessing habitat in the upper watershed that was mostly inaccessible prior to fishway installation. The new fishways at the three dams on the river have improved diadromous fish passage, thereby increasing the probability of restoring healthy populations of river herring and American eels to the Acushnet River system.
文摘Dams,culverts,and other water diversion/control structures are the most widespread human alteration to riverine habitat globally.While many of these structures often serve critical services(i.e.,source of agricultural and municipal water,power generation,flood protection,and sensitive ecosystem protection),they cause changes to local ecology by impeding animal movement and altering the adjoining habitat and associated ecological processes(Nilsson et al.,2005;Liermann et al.,2007).The disruption of fish movement by barriers has contributed to the decline of both migratory and non-migratory fish populations around the world.
基金The program was funded by the Australian Centre for International Agricultural Research.
文摘Irrigation infrastructure expansion threatens the diversity of freshwater fish worldwide.Irrigation infrastructure creates migration barriers which can block access to important nursery,feeding and spawning habitat.Lao PDR is a landlocked country situated within the Lower Mekong River Basin where there is a substantial dependency on rice and fish for food,income and livelihoods.The country is experiencing an unprecedented boom in irrigation infrastructure investment,with modernisation programs being implemented in every province.Despite significant investment in infrastructure upgrades,and the potential impact on freshwater fish,little consideration has been given to fish passage solutions.In 2008,we commenced a fish passage program in Lao PDR.The intent of this case study is to outline the pivotal elements of the program of knowledge development and transfer,in the context of river connectivity and fisheries management in Lao PDR.We also highlight challenges in international research in development and lessons learned.
