Last year as part of the South Cornwall River Improvement Project (SCRIP) a significant barrier to fish migration was removed on the river Lerryn, a tributary of the Fowey that rises near East Taphouse and flows through the historic Boconnoc estate, before flowing into the Fowey estuary near Golant.
The weir historically served a leat, although over time the majority of the leat has been taken out of use. It was important however, given its historical significance that there was detailed consultation with Cornwall archaeology regarding its value.
This year the area upstream of the barrier was surveyed for juvenile fish to assess the number and presence of fish following the removal of the weir. During the short timed survey, several brown trout fry were caught along with juvenile eels and bullhead. However, of significant interest was the presence of salmon fry (one-year-old), that indicates salmon spawning in the previous autumn, upstream of the weir. There has also been a recovery of the river channel and natural habitat upstream with the re-creation of riffles, glides and gravel spawning areas.
This provides compelling evidence of the rapid benefit that removing such obstacles can have to migrating and spawning fish. Previously, salmon fry have either not been found or only in very low densities above the weir. It is hoped that future surveys will provide more compelling evidence of the benefits to removing barriers to fish.