How do you lay pipelines across nearly 200 rivers, without stirring up important fish spawning grounds? We talk to Antonio Zaccala, 48, the man from Milan who's responsible..

Antonio Zaccala is a civil engineer working for Russian company Starstroi as Deputy Construction Manager for Winter Crossings. His job on Sakhalin Island is to make life as comfortable as possible for the fish. Especially the salmon, which are a vital part of the islands's economy.

Despite years of experience in the Middle East, South East Asia and West Africa, Antonio admits that the Sakhalin project is a challenge:

"There are more than 1000 watercourse to cross. And cross twice - once for an oil pipeline and once for gas. That includes 360 winter river crossings (180 rivers, crossed twice). The winter crossings are the rivers of 'high sensitivity' - the salmon spawning grounds."

Why 'Winter Crossings'? Burying pipelines along watercourses in the winter avoids interfering with the fish while they're busy breeding (which takes place in spring and early summer), and ensures water flow in rivers is at its lowest, minimising sedimentation.

In May, when spring arrives and the thaw sets in, the peace and quiet of the icebound river banks gives way to a much more chaotic scene, according to Antonio:

"There will be fast flowing water everywhere! We'll have to stop work for two or three weeks; there will be a lot of mud all along the pipeline route and our job is to ensure that riverbanks around the crossings do not erode with all the melt-water, and that water and sediment from the site do not run into the rivers."

"Our target is to complete the river crossings before the thaw - we won't be installing any more sensitive rivers once the ice has melted. We'll have to start again next winter."

The work seems to be going well. More than half of both pipelines have been completed. But is it working for the salmon?

"We cannot deny there's been some temporary impact, but we shall keep it at the minimum level" says Mr Zaccala. Indeed, last year, fish returned to spawn in as little as 3 months after crossing work was completed on some rivers.

After years in the business, Antonio has seen a lot of changes in the industry: "The techniques have changed. One of the new methods we have now is Horizontal Directional Drilling (drilling under the river) where the river isn't disturbed at all, but it can't be used everywhere." "We have improved our techniques for trenching too (laying pipe in a trench dug in the river bed): we can now avoid pollution and damage to the rivers and streams."

However, according to Antonio, the most important change is in the Mind: "The attitude of the workforce has changed; it is much more sensitive to the environment these days. Our clients, and the media, now expect it." It's a move that Antonio welcomes: "I agree, we should and do take the issue of river crossing very seriously: we should do it for the sake of the World."

After the thaw (in May), Antonio won't be hanging his boots up and going on holiday: he's got seismic fault line crossings to puzzle over for the summer, until the ice comes back in December, and then he can finish crossing those rivers!