Sand tiger shark
Sand tiger shark eating a three-foot dogfish (Orb Lab/Facebook)

A team of scientists monitoring sharks in Delaware Bay in the US made an unusual catch when they ended up with a shark eating a dogfish eating the bait.

The team from the University of Delaware's Ocean Exploration Remote Sensing, Biogeography Lab (Orb Lab) were trying to recapture sharks they had tagged to study them for scientific research.

Posting on the group's Facebook page, the team said: "A crew struck out to recapture sharks carrying tags containing valuable information about the species assemblage encountered by these coastal apex predators.

"We caught one large female on our first line but we were not expecting to catch her like this.

"This unlucky smooth dogfish couldn't resist the menhaden used as bait and fell victim to one of the top predators in the bay. The dogfish was about three feet long and completely swallowed by the sand tiger shark."

The shark was being monitored to gain information about shark population levels in the ocean. After catching it, the team measured the predator, gave it a new tag and re-released it into the sea.

Sand tiger sharks inhabit waters around the world and they are a cousin of the great white shark. Contrary to its name, it is not related to the tiger shark.

They can grow up to three metres and tend to hunt bony fish, squid and crustaceans. It is the most widely kept breed of shark in aquariums due to its large size and tolerance of captivity.

The species is considered vulnerable on the International Union for Conservation of Nature Red List.