Purchasing a steady supply of fresh and canned fish is a privilege to which most inland Canadians have never given a second thought. They take it for granted at their peril, as this startling new essay collection reveals. Produced by a seasoned crew of writers, environmentalists, and government whistleblowers, A Stain upon the Sea is a wakeup call in the tradition of Rachel Carson’s Silent Spring, the early-1960s classic that alerted the world to the negative effects of pesticides.

At issue is intensive salmon farming, where the interplay of traditional fishing communities, First Nations, aquaculture corporations, ineffective bureaucratic regulators, and sport fishers frames a battle that could determine the health of a critical food source in the 21st century.

Despite the cautionary notes of scientists and environmentalists, intensive farming of fish has been growing at a swift pace. With that growth has come a variety of harmful effects on the ocean environment, on wild fish populations, and on the long string of ocean wildlife, coastal communities, and consumers connected to the health of those populations. Lice and other parasites that originate in the farms have devastated the wild fish stock. The heavy use of antibiotics and hormonal changes in the salmon are also marks against an industry that, while touting itself as part of the solution to hunger, may ultimately decrease the supply of nutritional food.

The authors also ring alarm bells over the very real health threats posed by the industry’s reliance on a soup of Second World War chemical weapons derivatives that are designed to control the pests that prey upon penned-in salmon. To appease a world where high-end food is often more about appearance than nutrition, salmon are being injected with chemical dyes – potential carcinogens – that provide a variety of pink tones to the fish flesh.

The material in the essays ranges from whimsical travelogues to scientific polemics and policy recommendations to descriptions of beautiful seascapes where an insidious silence has replaced the annual salmon spawning runs.