New bridge project across Songkhla Lake a threat to survival of endangered Irrawaddy dolphins?

On October 18, the Cabinet approved a bridge construction project to link Krasae Sin district in Songkhla province with Khao Chaison district in Phatthalung province at a cost of 4.84 billion baht.

Even though the bridge would benefit the people through logistics, tourism and quality of life, some parties are concerned whether the project would affect the environment, especially the last 14 Irrawaddy dolphins there.

The World Bank had asked the government to consider the project's impact on the environment and the endangered dolphins. The government was securing 70% bridge cost from the World Bank.

Marine biologist Thon Thamrongnawasawat said the future of Irrawaddy dolphins is uncertain unlike dugongs or Bryde's whales.

He also pointed out that the number of Irrawaddy dolphins in Songkhla Lake is likely to drop every year.

"The bridge construction across Songkhla Lake would cause unexpected impact on the ecosystem and dolphins, such as noise during construction and decline in dolphin foods," he said.

He urged the government to consider the project's impact on the ecosystem and Irrawaddy dolphins before commencing construction.

Thon, who is also deputy dean of Kasetsart University's Faculty of Fisheries, added that the construction project would indirectly kill dolphins even though nobody wants that to happen.

"Hence, apart from a clear project plan, the government should offer cash to preserve dolphins," he added.

Many freshwater dolphins, including Irrawaddy species, are facing various threats, such as wastewater pollution, habitat destruction, dam construction and overfishing.

About 7,000 dolphins exist around the world, which is low compared to tens of thousands of dugongs and hundreds of thousands of Bryde's whales.

Songkhla Lake was chosen as a protected area for the last 14 Irrawaddy dolphins. Thailand is one of five areas where Irrawaddy dolphins exist, along with India, Indonesia, Myanmar and Cambodia.

Even though the guidelines on cooperation with related agencies to protect Irrawaddy dolphins is included in the bridge construction project, Thon said such a guideline is quite difficult, especially artificial insemination.

"It would take many years for researchers to study artificial insemination for Irrawaddy dolphins," he said.
 

The International Union for Conservation of Nature listed Irrawaddy dolphins among endangered species, raising questions regarding how the extinction of these dolphins affects humans apart from direct impact on the ecosystem.

Even though the death of one dolphin may be a little problem for someone, it is a big problem for the ecosystem, and the consequence could be severe. For instance, ecosystem deterioration would cause food shortage due to a decline in fish. It would also cause a decline in ecotourism revenue as locals would be unable to organise boat trips to greet dolphins.

Meanwhile, is it worth boosting the economy in exchange for the extinction of Irrawaddy dolphins?