Validation of otolith daily increments in the tropical eel Anguilla marmorata

Abstract

To determine the periodicity of the deposition of growth increments in the otolith of the glass eels of the tropical eel Anguilla marmorata, an otolith validation experiment was performed. Glass eels were captured at the mouth of the Poigar River, north Sulawesi Island, Indonesia, and then immersed in an alizarin complexone (ALC) solution to mark their otoliths. After being held under natural conditions in the river for 20 d, it was found that the number of rings outside the ALC mark was 20.1 ± 0.7 (mean ± SD), which coincided with the number of days after the ALC treatment. This validation experiment indicated that the growth increments in the otoliths of A. marmorata glass eels were deposited daily and can be used for daily age determination.

Tropical eels Anguilla spp. recruiting to Réunion Island in the Indian Ocean: taxonomy, patterns of recruitment and early life histories

“…Wider growth increments that have been interpreted by previous authors to occur in association with metamorphosis were used to separate the Leptocephalus zone from the metamorphosis zone. Since Umezawa et al (1989), Arai et al (2000) and Sugeha et al (2001b) established that otolith increment-deposition occurs daily in Anguilla japonica, A. celebesensis and A. marmorata, the number of these increments for the oceanic larval stages were counted from the first feedingcheck to the freshwater recruitment-check (when present). The resulting number of increments was interpreted as the duration of marine life (LecomteFiniger 1992(LecomteFiniger , 1994.…”

Ecology of Anguilliform Leptocephali: Remarkable Transparent Fish Larvae of the Ocean Surface Layer

“…Several studies have validated that daily rings are deposited in the otoliths of anguillid glass eels that have recruited to coastal areas in both temperate (Tsukamoto 1989;Martin 1995;Cieri and McCleave 2001) and tropical species (Arai et al 2000;Sugeha et al 2001a). Daily deposition was indicated in a study of artificially spawned and reared A. japonica early stage leptocephali (Umezawa et al 1989;Shinoda et al 2004).…”

Effects of metamorphosis timing and the larval growth rate on the latitudinal distribution of sympatric freshwater eels, Anguilla japonica and A. marmorata, in the western North Pacific

“…DGIs in each of the developmental stages and otolith radius were counted and measured from these landmarks as shown in Figure 2. Because otolith increments in A. marmorata and A. japonica were confirmed to be deposited on a daily basis (Tabeta et al 1987;Umezawa et al 1989;Sugeha et al 2001b), the increment number was considered as the daily age in each individual examined in the present study. The drastic change in otolith Sr/Ca from the primordium to the otolith edge coincided with major life history events in the life of the young eels, like first feeding, metamorphosis, etc., as reported in previous studies for both temperate and tropical anguillid species Tsai 1992, 1994;Otake et al 1994;Tzeng 1996;Arai et al 1997Arai et al , 1999aCieri and McCleave 2001;Marui et al 2001).…”

“…The Sr concentration in the otolith decreases dramatically during metamorphosis, and a visible metamorphosis check (MC) is also deposited during this period. Since the growth increments of otoliths of anguillid eels are deposited on a daily basis (Martin 1995;Arai et al 2000;Cieri and McCleave 2001;Sugeha et al 2001b), the age of the leptocephalus at metamorphosis can be determined from the number of DGIs from the primordium and the MC where the increment pattern and Sr/Ca ratios dramatically change (Tzeng and Tsai 1994;Tzeng 1996;Arai et al 1999a). In other words, since the structure of growth increments in the anguillid eel's otoliths change with growth and growth checks appear in every life history stage transition, the duration of each life history stage can be determined by counting the DGIs in each section of an otolith.…”