Shares of shipwreck hunting and deep-ocean exploration company Odyssey Marine Exploration sank faster than a badly-holed galleon yesterday, dropping almost 60 per cent from their Friday closing price.

However, David Saul, the former premier who is a director and major shareholder of the Florida-headquartered business, is optimistic the company will rebound from a setback that resulted in its share price falling so steeply.

Odyssey Marine Exploration has made headlines in the past for high profile discoveries, including the wrecks of SS Republic, SS Central America and HMS Victory.

The company is in the business of discovering and recovering valuable treasures from the seabed, such as the cargo of shipwrecks or seafloor minerals.

It was news regarding the latter that sent its shares into a nosedive on the Nasdaq.

The company is seeking to dredge and extract phosphate sand off the coast of Mexico, in what it calls the “Don Diego” project. But its application for an environmental licence to do so has been rejected by the Mexican Secretary of Environment and Natural Resources.

The refusal was centred on concern about the welfare of sea turtles in the area of the proposed project.

“The denial was focused only on a single issue, the potential impact of dredging operations on sea turtles, which we believe was based on misinformation,” said Mark Gordon, president of Odyssey Marine Exploration.

“Fortunately, we have been working with the world’s foremost experts in sea turtle biology and management to develop turtle protection, habitat enhancement and monitoring programmes.”

In his statement, Mr Gordon said it was hoped that once this information is presented to the Mexican government and authorities “it will be clear that the Don Diego project will have a significant positive impact on the local and migratory turtle populations, and that the ultimate approval of our project will enhance the local turtle populations”.

Meanwhile in Bermuda, Dr Saul, who is the second biggest individual shareholder of the company, owning more than 1.2 million shares, said: “Now that we know the specific reason why they turned down the applications, we think we have an answer for that.”

He said the phosphate resource identified in the “Don Diego” project would help provide fertiliser for agricultural use in Mexico.

Odyssey Marine Exploration’s market capital was estimated at $63 million last week, but dropped to $25 million yesterday after its shares, which traded at $8.37 on Friday, closed at $3.45.