In the wake of Hanjin Shipping's collapse and with Panamax vessels being sold for scrap in a depressed market, it's not hard to find a cheap containership these days. But why would anybody want to buy a mammoth cargo vessel when shipping rates have dropped so low?

A Bergen, Norway-based company called Marine Harvest ASA answered that question recently when it applied to the Norwegian government for a license to grow and harvest fish inside a cargo ship.

Reversing the conventional wisdom that fisherman are usually happiest when they stay on the dry side of the boat and keep the fish on the wet side, the company sees the glut of empty ships as a business opportunity. "It's more or less kick-starting fish farming again in a new way," Marine Harvest CEO Alf-Helge Aarskog told Bloomberg News.

As the world's biggest producer of Atlantic salmon, Marine Harvest is struggling to meet demand for the fish, thanks to strict regulations designed to fight infestations of sea lice, a natural parasite that can be deadly to young fish. Instituted to protect fish stocks for future generations, the rules make it difficult to build traditional fish farms on Norway's open ocean.

Aarskog's idea of raising salmon inside a cargo ship would avoid the shallow-water lice by drawing water from depths below 30 feet. And if the idea of building a floating fish farm is rejected, the company is also experimenting with raising salmon inside doughnut-shaped enclosures located near shore or in deepwater cages moored far out at sea.