Leatherback sea turtles are the largest living reptiles and one of the most ancient animal lineages. They face critical threats from plastic pollution, bycatch, and nesting beach loss that impose severe welfare costs.
Leatherback welfare spans the full geographic range of one of the world most impressive migratory animals. Individual leatherbacks navigating from tropical nesting beaches to cold-water jellyfish aggregations in the North Atlantic or North Pacific cover distances that dwarf the migrations of most other species. Along these routes, they face the welfare gauntlet of longline gear, drift nets, plastic ingestion, and pollution exposure. Plastic ingestion is a particularly welfare-significant threat: leatherbacks that mistake plastic bags for jellyfish ingest material that cannot be digested, causing gut blockage, internal injury, and starvation in animals whose energy reserves are already committed to a major reproductive migration. Bycatch entanglement causes drowning — an acute welfare harm for air-breathing animals — or severe injury from gear entanglement that may not be immediately fatal but causes lasting damage. At nesting beaches, the long crawl of nesting females is energetically demanding, and disturbance that causes abandonment of nesting attempts imposes welfare costs through wasted energy and reproductive loss in a species with very slow population recovery rates.