Figure 1

Fluctuations of recruitment in tropical juvenile eels in Indonesia between 1997 and 1999. Monthly abundance of 3 tropical juvenile eels collected at the new moon in the Poigar River estuary, north Sulawesi Island of Indonesia from 1997 to 1999 (for October 1997 samples: O₁ = first new moon, O₂ = second new moon) (Arai et al. 1999; Sugeha et al. 2001). Juvenile eels were collected at the mouth of the tropical river, and they were caught along a 10 m transect along the beach within 1.5 m from shore using 2 triangular scoop nets (mouth 0.3 m², 1 mm mesh). The nets were fished simultaneously at depths of 25 to 50 cm in 10 replicate passes at hourly intervals (Arai et al. 1999; Sugeha et al. 2001). The temporal patterns of juvenile catches suggest tropical juveniles recruit to the estuary throughout the year with considerable inter-annual variation in the recruitment patterns. The recruitment patterns are clearly different from those of European, American, Japanese, Australian and New Zealand eels, which have much shorter seasonal ranges in recruitment period during about half the year or less (Matsui 1952; Haro and Krueger 1988; Gandolfi et al. 1984; Sloane 1984; Jellyman 1977). This figure was drawn using the original data from Arai et al. (1999) and Sugeha et al. (2001).