Largest aggregation sighted had 1,400 animals

Ten large aggregations of basking sharks were identified between June 1980 and November 2013, ranging from 36 to at least 1,398 animals within an 11.5-mile (18.5-kilometer) radius of the central point in the aggregation. Data on breaching, circular swimming movements, and/or apparent feeding behaviour were recorded in seven of the ten largest aggregations. The largest aggregation ever recorded on the aerial survey was at least 1,398 animals photographed on November 5, 2013 in southern New England waters. As luck would have it, the NEFSC’s EcoMon survey sampled the same area on November 16 and 17, 2013, providing an estimate of the zooplankton community characteristics in that area at that time of year. “Photogrammetry, the use of photographs to measure objects, has provided estimated lengths of animals at the surface and allowed us to classify animals in the aggregation as likely juveniles or mature adults,” said Crowe, who works at the NEFSC’s Woods Hole Laboratory in Woods Hole, Mass.

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