Oceanic migration behaviour of Pacific eels from Samoa

Ecology and evolution of migration in the freshwater eels of the genus Anguilla Schrank, 1798

“…A variety of recent advancements made by means of molecular genetic and ecological studies have better elucidated the ecology and evolution of anguillid eels. Scales of spawning migration distinctly differ among tropical eel species ( Aoyama et al., 2003 , 2018 ; Robinet et al., 2008 ; Réveillac et al., 2008 , 2009 ; Schabetsberger et al., 2013 , 2015 ; 2019 ; Arai, 2014a ; Arai and Abdul Kadir, 2017a ; Han et al., 2019 ; Hewavitharane et al., 2020 ). Less than 100 km of small-scale migration and 1000–3000 km of mid-scale migration are suggested in A. clelebesensis and A. borneensis ( Aoyama et al., 2003 , 2018 ; Arai, 2014a ) and A. marmorata , A. bicolor bicolor , A. mossambica and A. bengalensis bengalensis ( Robinet et al., 2008 ; Réveillac et al., 2008 , 2009 ; Arai, 2014a ; Arai and Abdul Kadir, 2017a ; Aoyama et al., 2018 ; Han et al., 2019 ), respectively.…”

“…Recent advances and the availability of electronic tags such as PSATs, data storage tags and accelerometers, marine remote sensing tools and computer modelling systems provide new means to understand the spawning migration and behaviour of anguillid eels without involving the use of expensive ocean research vessels. The development of PSATs has enabled data to record for longer periods during the oceanic migration of maturing eels to spawning sites ( Aarestrup et al., 2009 ; Manabe et al., 2011 ; Schabetsberger et al., 2013 , 2015 ; 2019 ; Westerberg et al., 2014 ; Béguer-Pon et al., 2015 ; Wysujack et al., 2015 ; Amilhat et al., 2016 ; Righton et al., 2016 ; Chen et al., 2018 ; Higuchi et al., 2018 ). As a distinct behaviour of migrating silver eels as revealed by PSATs, all eel species examined showed similar diel vertical migration (DVM) patterns, with migrating eels preferring shallower water (100–300 m) at night and deeper water (500–700 m) during the daytime ( Aarestrup et al., 2009 ; Manabe et al., 2011 ; Schabetsberger et al., 2013 , 2015 ; 2019 ; Westerberg et al., 2014 ; Béguer-Pon et al., 2015 ; Wysujack et al., 2015 ; Amilhat et al., 2016 ; Righton et al., 2016 ; Chen et al., 2018 ; Higuchi et al., 2018 ).…”

“…The development of PSATs has enabled data to record for longer periods during the oceanic migration of maturing eels to spawning sites ( Aarestrup et al., 2009 ; Manabe et al., 2011 ; Schabetsberger et al., 2013 , 2015 ; 2019 ; Westerberg et al., 2014 ; Béguer-Pon et al., 2015 ; Wysujack et al., 2015 ; Amilhat et al., 2016 ; Righton et al., 2016 ; Chen et al., 2018 ; Higuchi et al., 2018 ). As a distinct behaviour of migrating silver eels as revealed by PSATs, all eel species examined showed similar diel vertical migration (DVM) patterns, with migrating eels preferring shallower water (100–300 m) at night and deeper water (500–700 m) during the daytime ( Aarestrup et al., 2009 ; Manabe et al., 2011 ; Schabetsberger et al., 2013 , 2015 ; 2019 ; Westerberg et al., 2014 ; Béguer-Pon et al., 2015 ; Wysujack et al., 2015 ; Amilhat et al., 2016 ; Righton et al., 2016 ; Chen et al., 2018 ; Higuchi et al., 2018 ). DVMs have been observed in the temperate eels A. dieffenbachii ( Jellyman and Tsukamoto, 2005 , 2010 ), A. anguilla ( Aarestrup et al., 2009 ; Westerberg et al., 2014 ; Wysujack et al., 2015 ; Amilhat et al., 2016 ; Righton et al., 2016 ), A. japonica ( Manabe et al., 2011 ; Chen et al., 2018 ; Higuchi et al., 2018 ) and A. rostrata ( Béguer-Pon et al., 2015 ) and the tropical eels A. marmorata ( Schabetsberger et al., 2013 , 2015 , 2019 ; Chen et al, 2018 ), A. obscura , and A. megastoma ( Schabetsberger et al., 2013 , 2015 , 2019 ) and A. bicolor pacifica ( Chen et al., 2018 ).…”

“…The multiple spawning sites in A. celebesensis and A. interioris were definitely in contrast to temperate species. It is assumed that western South Pacific eels such as A. marmorata , A. megastoma , A. obscura and A. reinhardtii spawn somewhere within the South Equatorial Current ( Jellyman, 2003 ; Schabetsberger et al., 2013 , 2015 ; 2019 ; Hewavitharane et al., 2020 ), and it has been suggested these western South Pacific eels may migrate a short distance between their continental habitats and spawning sites by means of recently developed pop-up satellite archival tag (PSAT) studies ( Schabetsberger et al., 2013 , 2015 , 2019 ). These findings suggest that certain tropical anguillids exhibit considerably short-scale migrations between spawning areas and continental habitats compared to temperate species that make large-scale migrations.…”

Research, management and conservation of anguillid eels—A global perspective

“…Understanding the oceanic migration behaviour (Schabetsberger et al., ) and population structure of tropical anguillids residing in the Pacific, a very poorly understood region, is vital for their conservation and management. Gubili et al.…”