Short Wave Why Swedish scientists gave salmon cocaine
27 snips
May 12, 2026 
Jack Brand, an aquatic ecologist at the Swedish University of Agricultural Sciences who studies how human drugs in waterways affect fish behavior. He describes surgically exposing salmon to cocaine and its metabolite, finding the breakdown product had surprising potency. The team tracked altered movement and energy use, pondered long-term and cocktail effects, and discussed advanced wastewater fixes.
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How Researchers Gave Salmon Cocaine
- Jack Brand and team implanted slow-release cocaine and metabolite pellets into 105 hatchery salmon and tracked them with acoustic tags in a lake.
- They sedated fish, performed minor surgery to insert implants and pinging tags, then used hydrophones to record movements.
Metabolite Affects Fish More Than Cocaine
- The cocaine metabolite commonly found in wastewater had a stronger effect on salmon behavior than cocaine itself.
- Brand found the metabolite often occurs at higher concentrations and may be biologically active in fish despite being considered inert in mammals.
Human Drugs Target Shared Brain Systems
- Many human-targeted neuroactive drugs act on evolutionarily conserved brain receptors present across vertebrates, making wildlife susceptible to their effects.
- That shared biology explains why wastewater pharmaceuticals can alter behavior, foraging, and reproduction in fish.