Salmon often served in sashimi has noticeable white stripes, but those are actually fat deposited from feed used in farmed fish. Wild-caught salmon, which move constantly to find food, typically lack those white lines and are leaner with firmer texture. Farmed salmon (e.g., Norwegian) are fed plant-based feeds (soy, oils, fish meal) that increase fat, producing a softer, richer flesh, while wild Alaska salmon (no farming allowed) is drier and chewier. Choose salmon by cooking method and personal taste rather than assuming higher-grade (more marbled) fish is always better.
