New research explores why whale entanglements persist in the California Current despite new fishing regulations.

Ten years after a major marine heatwave, entanglement rates remain higher than pre-2014 levels.

Warm water pushes cool, nutrient-rich zones toward the shore, 'compressing' whale habitats into smaller areas.

Surging anchovy populations near the coast lure whales into shallow waters where fishing gear is concentrated.

Whales foraging nearshore are more likely to encounter fixed gear from Dungeness crab and other fisheries.

More whales mean more interactions. Humpback populations have grown steadily over the last 50 years.

While populations are up, climate-driven habitat changes are the primary cause of extreme entanglement spikes.

The Habitat Compression Index (HCI) can forecast risky conditions 6 to 12 months in advance.

Lost or derelict fishing gear remains a threat year-round, even when fishing seasons are closed.

Using HCI as a 'rate tracker' helps managers make better decisions to protect whales and sustain fisheries.

Understanding the lens of habitat compression is key to reducing serious injury for these ocean giants.