The spin-off for locals was that fish screens constructed at the end of the lake to prevent eels and other species from entering the hydro canal meant a plentiful supply for eating.
The eels that end up in the screens within a fenced-off restricted area are channelled through a concrete chute to a holding trough outside the fenced area, making for easy pickings.
Mr Morgan says in those days little was known about the migratory habits of eels. "I always thought they were breeding in the lake and didn't know the science or that they needed to go to salt water to breed."
He says many people still believe the adult eels are able to spawn in Lake Otamangakau and have no idea the stocks are being depleted to the point of no return.
The Morgans say although Genesis Energy has no legal obligation to assist their efforts to restore the eel stocks, the company has been of huge assistance with the restoration project - funding their efforts for the past three seasons and providing them with the services of Niwa scientist Jacques Boubee, whose specialist knowledge has been invaluable.
The couple say the biggest challenge is educating locals who have traditionally caught and eaten the eels about the need to make sure at least some breeding stock are caught and released back into the Whanganui headwaters to give them a chance of making it to Tonga to spawn.
"Our motto is that even if people let one big migrant female go, it is better than zero."
The couple say some people go to extreme and dangerous lengths - even getting children into the restricted fenced-off area - to try to gaff the eels in the fish screens.
"We get 26lb eels that are injured (by the gaffs) which is really sad when I think how hard it is for them to get where they are," says Mrs Morgan.
The couple tag and measure the eels before release.
This season, they have also re-stocked the Whanganui River upstream of the intake and Lake Otamangakau with more than 5000 elvers.
While the benefits of that might not be seen for 20 years, Mrs Morgan says their children and mokopuna will hopefully reap the benefits of having a sustainable kai (food) source again.
Their children are already champions of the eel restoration project.
"The kids think the eels are really cool," says Mrs Morgan.
The eel migration is triggered by rain in the spring and autumn and the couple have spent the past three seasons working at night in the rain catching and releasing as many eels as they can.
So far this season, they have released 27 migrant eels into the headwaters, which is an increase on last year.
