Dam building not the sole cause of declining fisheries

This statement by the WWF is at best misleading and at worst patently false. The WWF and other more strident advocates against construction of the Don Sahong Dam repeat the mantra that “Hou Sahong is the only channel for dry season fish migration in the Siphandone region”.

Traditional fishers in the Siphandone region used to catch the small species that migrate through the Siphandone channels in the dry season, where they accumulated below natural barriers like the waterfalls, or by creating manmade barriers of rock stone and bamboo. Nowadays the increasing value of wild fish has encouraged more people to target these migrating fish with modern, cheap and highly efficient gears (i.e. monofilament gill nets) and with illegal practices like bank-to-bank “fish fences”.

Historically, Hou Sadam was another viable dry season passage for fish migrating across the waterfall zone. However, in recent years increasing fishing pressure has completely blocked this channel at several key locations. WWF and others fail to explain why Hou Sahong is the only viable dry season passage – because it’s too big to block.

Although the Don Sahong dam will close Hou Sahong to the upstream migration of fish, the Don Sahong Project has proposed several new upstream migration pathways. These will be built by re-creating the channel gradient of Hou Sahong in two neighbouring channels (Hou Xang Pheuak and Hou Sadam).

Hydropower projects often construct artificial fish passages that attempt to simulate natural channels. But in the Siphandone there are a multitude of existing natural channels. So, well before any concrete is poured, the project has started trialling new migration pathways across the waterfall zone in these channels.

In 2009, project staff identified choke points in neighbouring channels that block fish migration. In each dry season since then, local people have worked with the project to create fish passages in Hou Xang Pheuak and Hou Sadam. In April, these efforts fully restored Hou Saddam as an upstream migration pathway across the waterfall zone. The initial results show that physical modification of a channel combined with local co-management of the passage can be an effective mitigation measure.

More work is required to complete the fish passage works in Hou Xang Pheuak because it is a much larger system, with a discharge similar to Hou Sahong. However, the achievements in Hou Sadam and early results from Xang Pheuak already show the method will work.

Statements by the WWF completely overlook the very real impact that unregulated exploitation of migrating fish is already having on the viability of fish stocks. Numerous reports describe the transformation in Mekong fish stocks in recent years from more fishers using more efficient gears and often illegal practices. These changes are very obvious in the Siphandone. There, local fishers report falling catches and dwindling stocks of the larger, high-value species, but exploitation continues to intensify.

Therefore another important project mitigation measure is to collaborate with Lao government agencies in persuading local fishers to change their ways and adopt sustainable fishing practices.

The region has already benefitted from project actions to pay local fishers to remove their illegal traps from trial fish passages and to educate these fishers in the value of these pathways in sustaining their fishery. During the construction phase, the project plans to equip all affected people with new skills that allow them to break their dependence on a dwindling fishery and get income from other forms of work.

 

Dr Peter Hawkins is senior environmental manager of the Don Sahong hydropower project.