Spectacled porpoises are among the rarest cetaceans with very few living observations, facing gillnet bycatch in sub-Antarctic fisheries.
Gillnet bycatch causes drowning as animals cannot surface. The lack of population data means any bycatch mortality has unknown but potentially significant population effects. Their sub-Antarctic range is increasingly subject to industrial fisheries as climate change makes previously ice-covered areas accessible. The extreme rarity of observations makes any welfare monitoring practically impossible.