Wednesday November 4, 2026
Phys —
Two recent review articles in the journals Trends in Ecology & Evolution and Fish and Fisheries, to which researchers from the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) contributed, focus on the influence of humans on the diversity of fish behavior and on how management can help preserve this diversity.
Who would have thought? Although Amazon mollies are genetically identical as clones of their mothers, individual fish systematically differ from one another in their behavior—even when raised under identical conditions. This is true even for juvenile fish. In fact, among all fish species studied to date, there is immense variation among individuals, including shy and bold or social and less social individuals. Researchers refer to these as behavioral types.
Fish account for about half of all vertebrate species and exhibit an impressive diversity of behaviors within populations, between populations of the same species and between populations living in different ecosystems. As with all vertebrates, behavioral diversity in fish arises from the interplay of various factors. These include an animal’s internal state (e.g., hunger level), its genetic makeup, its ability to flexibly adapt its behavior and the external conditions to which it is exposed. And this diversity can be systematically altered by humans.