A sea run salmon with a clipped fin that was caught at the Roxburgh Dam over the weekend shows that the programme of salmon smolt releases undertaken by Contact Energy is working, says Otago Fish & Game environmental officer Peter Wilson.
Mr Wilson says the fish - caught by a keen angler and weighing 6 pounds - would have come from the first release of 30,000 salmon put into the river in 2010. It would have headed to sea, and then using its natural homing instinct, returned to the river it knew.
"That’s an amazing natural characteristic of salmon," Mr Wilson adds.
Some fish make it back, whilst others don’t, and clipped fins are used as a marker to assess the success of the programme. On average, approximately 1% of salmon releases are expected to return.
“Contact Energy’s resource consents for their hydro scheme require them to boost the salmon fishery in the Lower Clutha to 5000 returning salmon per year," Mr Wilson points out. “Otago Fish & Game looks forward to Contact Energy ramping up their fish release and habitat enhancement programme to meet that target."
The salmon run in the Clutha was very significant before the construction of the Roxburgh Dam in the early 1950s, with adult salmon swimming upstream from the sea to spawn in lake tributaries such as the Matukituki and Hunter Rivers.
The natural run, estimated by some to be 50,000 returning fish at the time, dwindled quickly to less than 1000 returning salmon as the returning fish were cut off from their headwater spawning grounds.
“Restoration of the salmon run to 5000 returning fish per annum would be a major boost to angling in Otago and a significant visitor attraction,” Mr Wilson says.