Larval morphological changes and salinity tolerance of aquarium-held freshwater goby Rhinogobius sp. BF

Abstract

Larval development and salinity tolerance of Rhinogobius sp. BF are described from artificially-reared eggs, larvae and juveniles. Aquarium-held R. sp. BF spawned small-type eggs (n=816, long axis 1.9 mm, short axis 0.6 mm) on May 17 2004, which were guarded in the nest by a male. Newly-hatched larvae (3.2 mm in notochord length) had a small yolk, and some melanophores apparent on the snout to caudal region. Twenty-two days after hatching (6.8 mm in standard length; SL), the notochord tip projected upwards, and dorsal and anal fin rays appeared. Between thirty (12.0 mm SL) to forty-five days (14.2 mm SL), the larvae settled to the bottom of the aquarium. Sixty days after hatching (15.4 mm SL), all fins and scales were completed (juvenile stage). All larvae subjected to marine salinity (35 psu) died within three days, indicative of the lentic landlocked life history recorded for the species.