Abstract

Fish are fascinating animals. Individual fish have places they call home as well as their own daily routines. We wanted to find out whether oyster cages (gear used to farm oysters) provide habitat for fish. Do they like to hang out there? Do they live there? Which species spend time there and what do they get up to?

We used two methods, underwater video cameras and environmental DNA, to uncover the secret lives of fish. The videos let us see which species hung out at the cages and watch their behaviors. Environmental DNA helped us find the species that are hard to see on camera, like very small or nocturnal fish.

We found 7 fish species on video and 42 species using environmental DNA. Some species were abundant at the oyster cages. We even watched them getting up to behaviors like foraging for food and sheltering from predators and currents. Oyster cages can act as artificial reefs, providing valuable habitat for fish!