Upstream migration without complete osmoregulatory switching in an amphidromous goby: Estimated by body condition changes in different salinity environment

研究成果: Contribution to journalArticle査読

2 被引用数 (Scopus)

抄録

The floating goby Gymnogobius petschiliensis Rendahl is an amphidromous fish, which migrates upstream from the sea in the juvenile period and then inhabits not only freshwater areas but also brackish water. Most of the species that have such migratory polymorphism switch their osmoregulatory mechanism in synchrony with the timing of migration, but in G. petschiliensis it is known that even individuals living in freshwater areas behaviourally prefer brackish water to freshwater conditions in a laboratory. To clarify whether this species lives in freshwater areas with high osmoregulatory cost, the relationship between physiological cost and salinity was investigated using adult fish of the species captured in a freshwater area. Adults were kept individually in 13 L tanks with various salinity levels under fasted conditions. Their loss of body weight in freshwater conditions was more rapid than in 2/3 seawater, whereas the frequencies of horizontal and vertical movement in 13 L tanks did not differ significantly between freshwater and 2/3 seawater conditions. This suggests that the weight loss reflects not behavioural performance but physiological cost. In addition, no adults died even when transferred from freshwater to seawater conditions, indicating that they have high tolerance to salinity change in estuarine areas even after migrating to freshwater areas. These results support the hypothesis that G. petschiliensis migrates to freshwater areas while maintaining high hypo-osmoregulatory ability and paying a high physiological cost. Because G. petschiliensis phylogenetically originates from the coastal species, this example of migration without completely switching the osmoregulatory mechanism may help us to understand the diverse processes of upstream migration in marine fish.

本文言語英語
ページ(範囲)67-75
ページ数9
ジャーナルJournal of Experimental Marine Biology and Ecology
514-515
DOI
出版ステータス出版済み - 5 1 2019
外部発表はい

All Science Journal Classification (ASJC) codes

  • 生態、進化、行動および分類学
  • 水圏科学

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