00:07Every year during the peak season oyster farmers stop harvesting these waters in Smithdon for two weeks.
00:15We could harvest up to 18 to 20,000 dozen a week so there could be a lost opportunity of
00:25nearly half a million dollars worth of sales.
00:29The temporary pause is to protect oysters from nearby herbicide spraying to eradicate an invasive weed.
00:37Despite the financial hit the oyster grower is entirely on board.
00:41And we looked at what had happened in other estuaries. For my own business to survive we needed to make
00:49sure that the environment was looked after.
00:52Circular Head hosts Tasmania's largest coastal wetlands. In summer thousands of shorebirds feed here, some travelling from as far as
01:01Alaska or Siberia.
01:03But some of these estuaries and waterways have been completely taken over by rice grass, an invasive weed introduced to
01:11Tasmania in the 1930s.
01:13All of these little sheltered bays were full of rice grass which is a bright green wavy grass up to
01:20your knee height.
01:21About 15 years ago the local land care group, backed by industry, set itself the lofty goal of ridding it
01:28from salt marsh communities across a 120km coastline.
01:32Without intervention the weed would have further choked habitat and feeding grounds, encroached on oyster farms and impacted water flowing
01:40in and out of Duck Bay.
01:43Eventually it would have closed our farms down.
01:46Each year volunteers, with help from contractors, shower swathes of grass with herbicide.
01:52So it kills pasture grass and it kills rice grass, but it doesn't kill the salt marsh plants.
01:58So as we get rid of the rice grass the salt marsh plants start to recover on their own.
02:04They work on foot, quad bike and ute. And more recently they've used a drone.
02:11You've got the river and you've got mud and stuff so flying over the top of that is a lot
02:16easier than trying to hike through it.
02:17Scientists say the recovery has been remarkable.
02:21Vegetation has bounced back, fish are abundant and the number of species has more than doubled.
02:27The first year with the rice grass I think we caught two fish.
02:31After the rice grass was removed native salt marshes come back and we went back and did the fishing.
02:36In one net we had about 200 mullets and I've never seen anything like that in terms of the recovery.
02:42Pending weather and funding, Landcare hopes to attack the remaining rice grass meadows in the next two years.
02:49After that they're looking at 10 years of maintenance, using less and less herbicide as they go.
02:54We're incredibly proud. Our whole group, this is the most important environmental thing we will ever do in our lives.
03:00I also ate. I think about 1.000 people.
03:03Even more in
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