Record month for Elver Trapping and Transfer
14 June, 2004
Record month for Elver Trapping and Transfer Programme
Over 107,000 elver (young native eels between 6 and 10 years old) were caught in January this year and transferred to Lakes Manapouri and Te Anau.
“This is fantastic news, it is the most elver we have ever caught in a single month which shows the eel population is thriving,” says Colin Sinclair, Natural Resource Advisor at Meridian Energy.
“February’s high rainfall meant we were unable to continue the programme but if we had, we have no doubt it would have been a record season.”
While larger elver and fish can successfully negotiate the fish pass at Manapouri Lake Control (MLC), small elver (those up to 80mm long) can’t.
Meridian funds the trapping and transfer programme which sees these small elver caught and transferred to Lakes Te Anau and Manapouri.
Colin Sinclair says the programme is an important means of restoring the natural balance of eels in the area.
-Waitaki River system
The Upper Waitaki system begins at Lake Tekapo, a storage lake with about 800 GWh of storage capacity, which represents about 22 percent of the country’s hydro storage.
Water passes through the Tekapo A power station and is diverted by a purpose-built hydro canal to Tekapo B station on the shores of Lake Pukaki.
Lake Pukaki has some 1600 GWh of storage capacity – about 44 percent of New Zealand’s total. Water is drawn by canal from both Lakes Pukaki and Ohau to supply Ohau A , B and C power stations, before being discharged into Lake Benmore.
After passing through the Benmore power station, the water flows down the Waitaki River through the Aviemore and Waitaki stations.
-Manapouri/Te Anau system
The combined storage of Lakes Te Anau and Manapouri is 380 GWh. The Manapouri power station lies 178m underground on the western shore of Lake Manapouri, and is accessed via a 2km road tunnel.
After passing through the station the water flows into Doubtful Sound via two 10km-long tailrace tunnels.
All of the stations are designed to be remote controlled from a control centre at Twizel.
Meridian Energy Australia Ltd owns the Southern Hydro power stations in Victoria.
The ten stations have a total generating capacity of 540MW, with about 940 GWh of output.
The company also owns hydro generation facilities at five small dams in New South Wales and Victoria, generating a total of 62 MW.
“The elver which do make their own way past the MLC tend to continue up the fast flowing Mararoa River instead of heading up the upper Waiau River to Lakes Manapouri and Te Anau.”
“The success of this programme is vital if we are to keep the number of native eels in our rivers and lakes up. The fish are significant to local iwi so this programme is both environmentally and culturally important,” says Colin Sinclair.
Each year, thousands of elver (young native eels between 6 and 10 years old) make their way up the river from the sea as part of their life cycle.
In 1998, Meridian Energy built a fish pass at the Manapouri Lake Control at a cost of $1.3 million dollars.
Smaller elver (those up to 80mm long) have difficulty negotiating the fish pass.
Meridian funds the trapping and transfer programme to help these smaller fish. Contractors set traps to catch the smaller elver at the MLC and then transfer them into Lakes Te Anau and Manapouri.
The programme, which began in 1998, is one of many mitigation measures Meridian Energy supports in recognition of its use of Lakes Manapouri and Te Anau.