On a small fishing boat out in the Baltic Sea, Pekka Kotilainen rifles through buckets of fishing gear, mixed with rubbish and mussel shells.
"We'll have something like one kilometre of nets by the end," he says, picking out old fishing nets that were abandoned or lost in the water but which still catch fish and other wildlife.
"They will take fish, which will die and go rotten, but also birds and marine mammals," Kotilainen, a scientist at the Helsinki-based Finnish Environment Institute tells AFP.
Finding and plucking the plastic "ghost nets" out of the water is painstaking work as many are not visible and can be tangled on rocks or even shipwrecks on the seafloor.
But the submerged plastic is gradually worn down by the sea's currents, releasing harmful microplastics into the ecosystem, says Kotilainen.
The UN's environmental and food agencies have estimated that ghost nets account for one tenth of all the plastic waste in the world's oceans.
And they have been known to trap animals as large as dolphins and whales, causing them slow, painful deaths.
- Operation ghost net -
One of the world's busiest shipping lanes, the Baltic Sea has been singled out by the European Union and environmental charities as in urgent need of action over high pollution levels.
Although Finnish authorities have been actively trying to address that over the years, unlike in larger Baltic states such as Sweden and Germany, Finland has not tackled ghost nets until now.
"In Finland we are a bit behind," says Kotilainen, who is part of a team that recently launched the first initiative against ghost nets in waters off Finland.
"Many countries already have done this before. But maybe we have woken up a bit."
With its long tradition of fishing for salmon, herring and perch, several areas off Finland's west coast were identified after months of research and testing as likely ghost net problem zones.
Two fishing boats were equipped to drag the seabed using weighted-down hooks "designed to be as soft as possible" on the seafloor, Kotilainen says.
- Dragging zone -
Out at sea, the red and white trawler Kalkas rocks heavily in the Baltic wind.
Once it reaches the day's dragging site about half an hour from Reposaari harbour, it slows to a halt.
The crew starts the winch to lower the dragging equipment 14 metres (46 feet) down to the seafloor.
Slowly but surely the boat covers its three-kilometre (1.9-mile) dragging zone, or "transect", then the team winches the drag back to the surface.
This time, the hooks are empty.
"We have a bit more than 300 kilometres now dragged," Kotilainen says.
"In about 10 percent of the transects we've caught something."
He says that the problem of ghost nets appears to be smaller in Finnish waters than in neighbouring Sweden -- the Finnish seas are frozen for longer so there's less fishing.
Nonetheless, the team has fished out around 1,000 metres' worth of abandoned nets so far, along with many ropes, weights and other fishing gear.
- Throwing money into the sea -
Depending on its results, the team will recommend whether to expand the ghost net recovery.
Another of its aims is to find ways to recycle all the recovered plastic including the discarded nets, large numbers of which also litter Finland's harbour sides.
Markku Saiha, of the Finnish Fishermen's Association, says that people need to be made more aware of the impact of their lost nets.
"We have to tell people that the risk is there all the time if they abandon their nets in the archipelago or on the coast," he tells AFP.
Nets are also a safety risk for small boats, and fishermen are losing money by discarding their nets, says Saiha.
"It's money. No one wants to leave money in the sea."
But, despite the dire warnings of Baltic pollution, he sees reason for optimism.
"This is one starting point," Saiha says.
"After 10 years, maybe it'll be a better situation, I believe that strongly."
Finland is tackling the problem of plastic "ghost nets", old fishing nets abandoned or lost in the water but which still catch fish and other wildlife
The submerged plastic of the ghost nets is gradually worn down by the sea's currents, releasing harmful microplastics into the ecosystem
The UN's environmental and food agencies estimate that ghost nets account for one tenth of all the plastic waste in the world's oceans
The Baltic Sea has been singled out by the European Union and environmental charities as in urgent need of action over high pollution levels