Source: PixdausGolden Cownose Ray (Rhinoptera steindachneri) migration off Key West, Florida.
Cownose rays are known for their long migrations in large schools. They are strong swimmers, able to cover long distances. The Monterey Bay aquarium site reports that the population in the Gulf of Mexico migrates in schools of as many as 10,000 rays, clockwise from western Florida to the Yucatan in Mexico.
A 1989 article from the journal Copeia: A Massive School of Cownose Rays, Rhinoptera bonasus (Rhinopteridae), in Lower Chesapeake Bay, Virginia (Blaylock 1989) describes the following massive migration event:
A concentration of Cownose rays, Rhinoptera bonasus, so great as to render direct counting of individuals impossible, was observed during surveys of the lower Chesapeake Bay on 25 July and 2 Aug. 1988.The Florida Museum of Natural History website includes further detail on the migration habits of this species:
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The school was too large to photograph in it's entirety. Therefore, while flying transects across it, portions were photographed vertically...
The migration patterns, in the Atlantic, include a northward movement in the late spring and southward movements in the late fall. Southbound migration has been observed to contain larger schools than the northbound migration. Smith and Merriner (1987) believe that the changes in water temperature, coupled with sun orientation, may initiate seasonal mass migration. They also suggest that the southward migration might be influenced by solar orientation while the northward migration might be influenced by water temperature cooling below 22ºC, but further studies are needed to confirm this. The migratory congregation, thus far, has not been linked to feeding or premigratory mating activity.
By the way nice picture!
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