The Longhurst codes mentioned in the table are as follows: NAST = North Atlantic Subtropical gyre, NATR = North Atlantic Tropical gyre, WTRA = Western Tropical Atlantic, SATL = South Atlantic gyre, SSTC = South Subtropical Convergence, NPTG = North Pacific Tropical gyre. Sites with two Longhurst province assignments indicate transitional zones. A division of sampling sites into groups representing four major ocean provinces and three groups based on abundance along a similar transect are indicated in the last two columns, respectively.