Unprecedented sightings of juvenile white sharks at the northern end of Monterey Bay signal a significant shift in the young white sharks' range.
Researchers conclude the northward range shift demonstrates water temperatures within their preferred temperature range of juvenile white sharks are becoming harder to find.
The animals have historically remained in warmer waters in the southern California Current; Between 1982 and 2013, the northernmost edge of the juveniles' range was located near Santa Barbara (34° N).
But after the dramatic North Pacific marine heatwave that hit the California coast between 2014-2016, their range shifted dramatically north to Bodega Bay (38.5° N). Ever since the young sharks' range limit has hovered near Monterey (36° N). This spatial shift is significant as it creates potential conflicts with commercial fisheries, protected species conservation, and public safety concerns.
Scientists from Monterey Bay Aquarium and their research partners analysed data from tags deployed on juvenile white sharks since 2002 to see where the animals were spending most of their time. The team analyzed 22 million electronic data records from 14 sharks and then compared these data to 38 years of ocean temperatures to map the cold edge of the animals' thermal preferences. The resulting chart showed a significant northward shift in the young white sharks' range.