Historical and recent reductions in genetic variation of the Sarotherodon galilaeus population in the Sea of Galilee
The Sea of Galilee has great significance as a natural habitat and a freshwater source for Israel. Anthropogenic impacts have been placing significant pressure on the species inhabiting this lake, among which is Sarotherodon galilaeus, an omnivorous fish with a relatively large population and significance for commercial fishing. An alarming decline in annual catch towards 2008 suggested that this unique population might be at risk. With that in mind, we characterized the current genetic variation of this species in Israel with reference to fish from Ghana, based on D-loop and microsatellite markers. Genetic variation and differentiation were found mostly among fish from Ghanaian localities and between fish from Israel and Ghana, whereas fish from all Israeli localities had uniform and limited variation, a signature compatible with historical founder effect followed by local adaptations. Such historical processes could leave a population vulnerable as reflected in the sudden and recent population decline. Comparing genetic variation between archived 30 year-old scales and modern lake fish revealed further reduction in genetic variation coincident with the recent population decline. Thus, a recently occurring genetic bottleneck had placed this unique and isolated population at an even higher risk. We carefully discuss the events leading to the current risk status for S. galilaeus in Israel and highlight the need for vigilant monitoring and active management to support a more sustainable future for this and other fish communities in this important habitat.
KeywordsCichlid fish St. Peter’s fish Lake Kinneret Genetic bottleneck Isolated population Archived biological samples
The authors wish to thank all who assisted in sampling of fish: Dr. Daniel Golani (The Hebrew University of Jerusalem), David Cummings (Kinneret Limnological Laboratory, IOLR), Dr. Noam Leader, Dr. Dana Milstein, Dr. Amit Dolev and Gizel Hazzan (Israel National Parks Authority), Menachem Lev (Kibbutz Ein Gev fishing vessel) and colleagues from the laboratory and the Animal Sciences Department. We further thank Prof. Moshe Gophen (Migal - Galilee Research Institute, Kiryat Shemona, Israel) for sharing old archived scales and Dr. Gila Kahila Bar-Gal and Lia Haddas (The Hebrew University of Jerusalem) for helping with DNA extraction from archived scales. We thank the reviewers and editor for their constructive comments. The study was funded by the Chief Scientist of the Israeli Ministry of Agriculture and Rural Development under Grant #186-0001-11 to LD and GH. LD is chair of the Vigevani Senior Lectureship in Animal Sciences.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Fish sampling was done under special permits 2012/38733 and 2014/40233 for sampling protected wildlife as reviewed and approved by the Israel Nature and National Parks Protection Authority.
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