 A sluggish species , the sicklefin lemon shark is usually seen cruising sedately just above the sea bottom or lying still on it , as unlike most requiem sharks , it is capable of actively pumping water over its gills . However , it will approach the surface in pursuit of food . This shark seldom undertakes long @-@ distance movements . A study at Aldabra Atoll in the Seychelles found , of the tagged sharks that were later recaptured , over 90 % were still within 2 km ( 1 @.@ 2 mi ) of their initial tagging location . Another study at Moorea in French Polynesia found that some of the local sharks were year @-@ round residents of the island , while others were more transitory and visited only occasionally . 
