Lake Geneva, which straddles the border of Switzerland and France, has been a tourist resort since the Victorian era. And for much of that time, visitors have been tucking into the local speciality: perch. However, in recent years, the fish has been in short supply. Ironically, numbers have dropped as pollution in the lake has decreased, but the fishermen are also having to contend with a new foe: a green alga that is choking their nets. Local initiatives are working to solve the problems, but in the meantime, the fishermen are left struggling with algae-covered nets and an ever-diminishing catch. Photographs by Laurent Geslin

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