Attributes / relations provided by
♦ ¹Food of Northwest Atlantic Fishes and Two Common Species of Squid, Ray E. Bowman, Charles E. Stillwell, William L. Michaels, and Marvin D. Grosslein, NOAA Technical Memorandum NMFS-NE-155 (2000)
♦ ²Annual variation in diets, feeding locations and foraging behaviour of gannets in the North Sea: flexibility, consistency and constraint, K. C. Hamer, E. M. Humphreys, S. Garthe, J. Hennicke, G. Peters, D. Grémillet, R. A. Phillips, M. P. Harris, S. Wanless, Mar Ecol Prog Ser 338: 295–305, 2007