Is there anything you can bring kayaking, swimming, or really anywhere people are fishing that will scare the fish away from the fishers? Ideally something not very obvious, and for kayaking something you can easily turn on near fishers and off when you’re not near them?
How is disrupting an ecosystem comparable to directly intervening to save a specific individual?
If you want to lobby against and mount protests against angling, do it, but don’t compound the problem by further stressing the fish or tempting them away from their natural habitats and food sources.