How gillnet bycatch and underwater noise affect harbor porpoise welfare and what measures can protect this vulnerable species.
Harbor porpoise welfare suffers from both acute and chronic threats. Gillnet bycatch causes drowning deaths that are acutely distressing - entangled porpoises struggle for air before drowning. Acoustic pollution causes chronic welfare harm through disrupted foraging, communication, and navigation. The welfare impact of acoustic masking is often invisible but real - porpoises unable to detect prey effectively face nutritional stress, and those unable to navigate accurately experience anxiety and disorientation. Pinger technology demonstrates that bycatch can be dramatically reduced at minimal cost; acoustic pollution requires broader policy responses including shipping noise limits and construction exclusion zones.