Login
Register
Print Friendly
Juvenile amphidromous gobies from the Hawaiian Islands employ chemical cues to locate freshwater streams and guide them up their water falls.
University of Minnesota, 1980 Folwell Avenue, St. Paul, MN 55108 U.S.A.
Email: PWS@FW.UMN.EDU
The Hawaiian islands have only 4 species of riverine freshwater fish, all of which are members of the goby family and possess an amphidromous life history. These fish spend their adult lives in the headwaters of streams where they lay eggs in nests. Upon hatching, larvae are immediately swept to sea where they develop for a few months, after which they re-enter streams. Juveniles swim great distances inland, often coming out of the water using their fused fins to scale the large (100m) waterfalls which characterize these island systems. This study asked whether odor cues serve to guide these tiny (1 cm) fish during this journey. Behavioral responses of recently captured juvenile gobies were assayed in 2-choice maze with miniature waterfalls located at the head ends. Gobies demonstrated a strong preference to enter and scale flowing stream water when tested against seawater. This preference persisted when the former was diluted 100-fold. Stream waters were also strongly preferred over spring water suggesting that organic compounds released into streams serve as the attractant(s). This was confirmed by tests of washings of various stream items which found algae to be especially attractive while pheromones released by conspecifics stimulated climbing behavior. Tests of different stream waters suggested the attractants are innately recognized. (Funded by the State of Hawai'i)
Room 1 Friday 11.10 am
