A group of biologists from Swiss and Tanzanian institutions has uncovered the role of early cichlid fish diversification in Lake Victoria, attributing it to their success in the deeper regions of the lake. Published in the journal Nature, the study involved the analysis of sediment cores from Lake Victoria. Martin Genner, affiliated with the University of Bristol, provided insights into the team’s findings in a News & Views article within the same journal issue.
Lake Victoria, Africa’s largest lake by surface area, formed around 17,000 years ago and has since expanded in both size and depth. Over the years, various fish species have been introduced, leading to the presence of over 500 cichlid fish species alone. This study aimed to investigate the historical evolution of fish in the lake by analyzing sediment cores from different locations.
The research unveiled 7,623 fish tooth fossils, dating back to the lake’s formation, representing the diverse fish populations in Lake Victoria. The researchers constructed a timeline of fish evolution within the lake. During the lake’s early days when it was still shallow, catfish, cichlids, and carp-like cyprinoids inhabited the area. As the lake deepened, most fish species remained in the shallows. However, cichlids were an exception, venturing into deeper waters and diversifying, which contributed to their thriving.
The study suggests that cichlids’ success wasn’t solely due to their early arrival but stemmed from their genetic predisposition to adapt to the lake’s changing environment. They exhibited greater ecological versatility, evolved jaws, and a remarkable ability to hybridize with other cichlid species, enabling them to thrive in the deeper regions of Lake Victoria.
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