Age and growth of Anguilla bicolor bicolor leptocephali in the eastern Indian Ocean
Abstract:A sampling survey for leptocephali was conducted in the eastern Indian Ocean to the west of Sumatra from 5 to 20 June 2003 in an overlapping area with the historical survey in September to November 1929 during the Danish Round the World Expedition. The age and larval growth rate of 34 Anguilla bicolor bicolor collected in 2003 were estimated using their otolith microstructure to obtain new information about the early life history of this sub-species. The total lengths and ages of these leptocephali were 44·1–55·5 mm and 114–158 days, respectively. Their hatching dates ranged from 3 January to 20 February 2003. Combining these age data and the estimated age of leptocephali collected by others in the same area, this sub-species was estimated to have a wide range of spawning periods. Individual growth rates of the leptocephali in 2003 ranged from 0·32 to 0·39 mm day−1 with a mean ±s.d. of 0·35 ± 0·02 mm day−1. These values were lower than the growth rates of leptocephali of other tropical eels such as Anguilla celebesensis or Anguilla borneensis, suggesting that A. b. bicolor from the eastern Indian Ocean have a longer leptocephalus period of oceanic migration.
Document Type: Regular Paper
Affiliations: 1: Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo, 164-8639, Japan 2: Research Center for Oceanography, Indonesian Institute of Sciences, Jl. Pasir Putih 1, Ancol Timur, Jakarta 11480, Indonesia
Publication date: 2007-02-01