Wednesday January 25, 2023
Mongabay —
Alongside the millions of Atlantic Salmon clustered in the open net pens that dot the waterways around Broughton Archipelago’s over 200 islands, sea lice, a tadpole-shaped parasite, feast on the fish.
In the zeal to establish a salmon market northwest of Vancouver, Canada, many aquaculture companies set up open net pens—cage-like structures where a layer of fishnet separates the farmed salmon from those in the wild—in the 1980s. They were also, however, creating conducive conditions for the spread of sea lice, a blood-sucking parasite found on the aquatic animal.
By the early 2000s, communities living in the archipelago began noticing wild juvenile pink salmon—native fish of the Pacific Ocean that aren’t gathered in the pens—returning from their freshwater spawning grounds also infested with the lice. These fish were on their way to the ocean, swimming near the salmon farms and through the meandering inlets—a path they have taken for millennia for this seasonal journey.
In 2002, the number of wild pink salmon (Oncorhynchus gorbuscha) that came to the rivers and creeks on Broughton Archipelago to spawn crashed from over three million fish in 2000 and 2001 to a measly 147,000—an unprecedented decline that natural variations in salmon populations could not explain.