The idea of sharks possibly using Loch Ness is not new; that's long been one of the hypotheses explaining the Loch Ness Monster. But until now, nobody has suggested sleeper sharks, perhaps because they're secretive and so rarely seen.
Sleeper sharks can exceed 20 feet and weigh upwards of 4 tons. Sleeper sharks probably use rivers and lakes to find food, and there is an abundance of salmon and other fish in Loch Ness and Lake Iliamna.
Sightings are often consistent with descriptions of sleeper sharks in that the monsters' shape and colors usually match that of sleeper sharks. Salmon and lots of other prey species have been found in sleeper sharks' stomachs.