So when I saw this piece suggesting that squid fishing in New Zealand had caused sea lion decline, I first guessed that it was because the sea lions were starving for want of squid. That's part of it, but it also seems that the fishery may be directly killing sea lions:
The study reviewed all previous data and concluded the most plausible explanation for the decline in breeding females in the Auckland Islands was competition for resource between the squid fishery and sea lions, and that sea lions were too often casualties of fishing by-catch."Casualties of fishing by-catch" = tangled and drowned in trawling nets. Bummer.