Testimonies from surviving crew members who were aboard the fishing boat that sank in waters off Jeju Island on Friday suggest that the excessive amount of fish caught may have caused the ship to go down.

According to the Jeju branch of the Korea Coast Guard on Saturday, all of the rescued crew members had testified that the catch volume was three to five times the usual amount.

The Coast Guard is reportedly investigating the possibility that the excessive catch may have led to the vessel's loss of resilience.

The crew members said they had hung nets carrying mackerel they had caught by the starboard, and that the vessel tipped over on the right side.

They also transferred some ten-thousand boxes of their catch, each reported to weigh around 20 kilograms, to a carrier vessel before the ship capsized.

An official at the Coast Guard said investigators also plan to look into potential structural defects after recovering the vessel from the seabed.