Dispersal pattern of glass eel stage of Anguilla australis revealed by otolith growth increments

Larval duration of the tropical eel Anguilla celebesensis from Indonesian and Philippine coasts

“…The total lengths of fully-grown leptocephali of the temperate eels A. anguilla, A. rostrata and A. japonica, were estimated as 75 mm (Jespersen 1942), 70 mm (Kleckner & McCleave 1985 and 60 mm (Tabeta & Konishi 1986), respectively, while those of tropical species collected in the Indo-Pacific region have been reported as being around 50 mm (Arai et al 2001a). However, 2 species, A. rostrata (Wang & Tzeng 2000) and A. australis (Shiao et al 2001), which recruit over a wide latitudinal range from subtropical to temperate regions, have shown a cline in the total length of glass eels that appears to correlate to the distance from their spawning areas, with the size ranges at the lower latitudes (41 to 55 mm) being similar to those of tropical species.…”

Confirmation of morphological differences betweenAnguilla australis australisandA. australis schmidtii

“…Though several ecological studies of the life history and biology of glass eels have been conducted, research on the early life history of A. australis during its oceanic phase is still insufficient (Aoyama et al 1999;Arai et al 1999;Marui et al 2001 ;Shiao et al 2001). Most researchers have assumed that leptocephali travel to Australia on the East Australian Current (Schmidt 1928;Cairns 1941;Sloane 1984;Jellyman 1987;Beumer & Sloane 1990;Shiao et al 2001), which originates from the South Equatorial Current and flows along the eastern seaboard of Australia (Wyrtki 1962;Church 1987). However, other leptocephali must also travel to New Caledonia, Norfolk Island, New Zealand, and the Chatham Islands by various currents that branch off the East Australian Current (Ridgway & Dunn 2003).…”

“…Subsequently, Dijkstra & Jellyman (1999) sequenced the control region (611 base pairs) of the mitochondrial DNA (mtDNA) of specimens identified as A. australis australis and A. australis schmidtii, and concluded the two subspecies share a common gene pool. Based on the genetic studies, several recent ecological papers (Aoyama et al 1999;Arai et al 1999;Jellyman et al 1999;Marui et al 2001 ;Shiao et al 2001) eels from Australia and New Zealand as A. australis without commenting on morphological differences between the populations. Jellyman (1987) recognised seasonally consistent differences in number of vertebrae of the glass eels that recruited to New Zealand, and speculated that variations in water temperature during the hatching of eggs could account for the differences.…”

Migratory behaviour and habitat use by American eels Anguilla rostrata as revealed by otolith microchemistry

“…(Otake et al 1994, Tzeng & Tsai 1994, Tzeng 1996, Tzeng et al 1997, 2000, in press, Secor 1999, Secor & Rooker 2000. The variability in migratory behaviours associated with habitat selection has recently been investigated for leptocephali metamorphosing to glass eels over the continental shelf (Cheng & Tzeng 1996, Wang & Tzeng 1998, 2000, Arai et al 2000, Shiao et al 2001) and for estuarine-and freshwater-resident yellow and silver eels (Tzeng et al 1997). Otolith microconstituents are measured precisely along a radius between the nucleus and edge of the otolith so as to reconstruct a chronology of environmental conditions related to age and life stage.…”