Certain migratory shark species in the North Atlantic may be delaying their migration south due to ocean warming, according to a study led by researchers at Stony Brook University's School of Marine and Atmospheric Sciences (SoMAS). The research tracked six shark species over five years using tagging and acoustic tracking methods.
The study, published in Conservation Biology, found that warming ocean temperatures delayed the southern migrations of five shark species by one to 29 days. "Both temperature and photoperiod (length of sunlight) influenced the timing of the sharks’ southernly migration," said lead author Maria Manz, a SoMAS PhD student. This delay could impact conservation strategies and ecosystem balance within the Atlantic Ocean.
The research team included Manz's graduate advisor Professor Michael Frisk, Professor Robert Cerrato, Assistant Professor Oliver Shipley, and other scientists from the east coast. Their findings suggest that future ocean temperatures will further delay sharks' southern migrations.
The study used data from 155 sharks across six species: blacktip, dusky, sand tiger, sandbar, thresher, and white sharks. Acoustic tagging was employed to track these highly migratory species as they moved from northern regions to southern habitats each year.
Manz developed mathematical models to predict shark movements and identify key environmental drivers of their migration. The results indicated that projected increases in sea surface temperatures (SST) might cause coastal sharks to remain longer in northern habitats during autumn.
This research was supported by the New York State Department of Environmental Conservation (DEC) and conducted under permits from DEC, NOAA, and the New Jersey Department of Environmental Protection.