This is the incredible moment two whale sharks trapped inside a fishing net were set free.
The amazing images show divers Chris Rohner and Clare Prebble helping free the tangled pair - which then swim alongside them to say thanks.
Marine biologist Simon Pierce captured the release after approaching fisherman off Mafia Island, Tanzania, who were preparing for the rescue.
There were two sharks in the net - one 8m long adult and a smaller 5m fish - throughout the dive which took place in November.
Simon, from New Zealand, said: "The main conservation challenge there is conflict between fishermen and sharks.
"The fishers use nets to catch small fish and tuna which feed on the same little shrimps the whale sharks eat.
"They look for schools of fish on the surface and quickly run a net around them.
"The fish are trapped within the loop and the net is pulled in by hand. It's hard, labour-intensive work with 30-50 fishers on each boat.
"If whale sharks are amongst the fish then they often get enclosed in the net themselves.
"A lot of the sharks have entanglement scars so it's obvious this can be a problem.
"The larger shark eventually swam right up to the net so the fishers lowered the floats so he could swim across without tangling.
"The shark gave a couple of big kicks and swam away fine before the second, smaller shark followed."
Simon, 35, is the Principal Scientist in charge of the Global Whale Shark Research Programme for the Marine Megafauna Foundation.
He added: "Our project team has started to work with the fishermen and they're great.
"They help us to find the sharks and even report in their sighting information when we're not there.
"The fishers aren't interested in catching the sharks - they want to let them escape with no fuss so they can keep the fish in the net.
"During the day it all worked like the well-practiced operation it is. No damage to the net and the sharks escaped without any injury.
"Mafia is one of the best places in the world to see whale sharks as individual sharks spend a long time in the area.
"It allows us to find them consistently."
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