Saltwater lobsters (species of Homarus and Nephrops) and freshwater crayfish (Astacus, Procambarus, and others) are generally the largest crustaceans in their neighborhood. The American lobster once weighed as much as 40 lb/19 kg, while today it’s typically 1–3 lb/450–1,350 gm. And more than 500 species of crayfish have evolved in the fresh waters of isolated rivers and streams, especially in North America and Australia. Most are relatively small, but the Australian marrons and “Murray lobsters” can exceed 10 lb/4.5 kg. Crayfish are the most easily cultured of the crustaceans, and have been raised in natural ponds in the Atchafalaya Basin of Louisiana for better than two centuries. They’re also prized in Sweden.