This are newly settled spot prawns (Pandalus platyceros). They are only a month old in this picture and about 1/4 of an inch (4 mm) in size. The adult spot prawn get to be 10.5 in (27 cm) long and are considered to be the largest shrimp on the west coast of the US. Spot prawns start out their lives as male, then switch to females as they get older. They can live for about 6 years in California and up to 11 years in Alaska.
They are on the Monterey Bay's Seafood Watch best choice list as spot prawns are often caught in traps, rather than nets like normal-sized shrimp. Dragging nets along the bottom of the sea floor often causes damage to the habitat and produces a lot of by-catch, as many other animals are caught along with the shrimp. Using traps minimizes by-catch and damage to the surrounding habitat.