Up to 100% of breeding female eels dying in drainage pumps
Documents obtained by Forest & Bird show that for decades, regional council drainage pumps have been brutally killing native eels as they attempt to swim to the ocean to breed.
The reports, created for Waikato Regional Council, contain grisly images of dead eels, many decapitated, with internal hemorrhaging due to high speed spinning, or with extensive spine damage.
At the time of its publication in July 2017, one report concluded that “currently … no pumps in NZ are likely to be ‘fish friendly’”, or safe for fish to pass through.
Forest & Bird’s Fresh Water Advocate Annabeth Cohen says the reports makes grim reading. “The potential scale of the crisis is horrifying. In some cases, all breeding female eels died as they passed through the drainage pumps."
A second document, also from Waikato Regional Council says: “The larger female eels in the catchment, which were migrating to reproduce, were completely annihilated. None survived.”
“Sadly, the heavy rain that triggers eel migration, also triggers the pumps. And it’s the larger breeding females - essential to the ongoing survival of these species - that have the least chance of surviving,” says Ms Cohen.
“Seventy four percent of our freshwater fish, including longfin eels, are heading towards extinction because of water pollution and habitat destruction. We can now add publicly owned drainage pumps to their problems.”
“These reports show that regional councils all over the country are operating machinery that is deadly to our treasured eels, and yet there appears to be no urgency or coordinated management of the situation.”
Ms Cohen says “The Resource Management Act requires that regional councils “ensure that fish passage is provided … where it would otherwise exist”, but it appears most councils are failing to do so. Instead they are helping drive these and other freshwater species closer to extinction.”
“With 90% of New Zealand’s wetlands having been destroyed, many regions are now dependent on pumps to keep these areas drained for agriculture.
“Draining wetlands is bad enough, but the very pumps used to do it are actively killing some of the few native species that have managed to survive the consequent habitat destruction and water pollution.”
Ms Cohen says “The pace of change is too slow. While some councils are taking steps towards ending this horrifying massacre, there is little sign of the urgency that the situation requires.
“Meanwhile, migrating eels, which breed only once in their lives, are being pulped by drainage pumps around the country.”
“Regional Councils must act urgently to ensure native fish and eels can safely swim both in directions along rivers and streams. They must start replacing existing pumps with proven fish friendly versions, and returning ecologically significant areas to wetlands. This will mean a managed, long term project of returning waterways and wetlands to their natural state.”
There are two main types of eel in New Zealand – the shortfin, and the threatened longfin. Loss of wetlands and historical commercial fishing practice has impacted heavily on their populations.
New Zealand freshwater eels breed only once at the end of their lives. In order to breed, they migrate en masse, leaving New Zealand’s lakes, rivers and wetlands to swim all the way up to the subtropical Pacific Ocean, where they spawn in very deep water.
The longfin eel is one of the largest eels in the world and it is found only in the rivers and lakes of New Zealand. The longfin eels population is declining. They can live up to 100 years.