Sea lamprey ( Petromyzon marinus ) are anadromous fish that spend one to two years as haematophagous ectoparasites in marine environments. This study provides the first quantitative insight into their feeding phase, which remains poorly understood. We investigate the occurrence of P. marinus feeding on basking sharks ( Cetorhinus maximus ) in the Northeast Atlantic. Between 2011 and 2020, 775 records of basking sharks were col...

Groups of basking sharks engaged in circling behaviour are rarely observed, and their function remains enigmatic in the absence of detailed observations. Here, underwater and aerial video recordings of multiple circling groups of basking sharks during late summer (August and September 2016–2021) in the eastern North Atlantic Ocean showed groups numbering between 6 and 23 non‐feeding individuals of both sexes. Sharks swam slowl...