Mike Joy and Amber McEwan of Massey University say our native fish will disappear forever if we don’t act now to save them.
It’s tough being a native freshwater fish in New Zealand. The unique features that make them special on the world stage and allowed them to survive the geological upheavals that formed this landscape make them particularly vulnerable to the multiple blows we are throwing at them now.
New Zealand indigenous fish are highly affiliated with native forest and we’ve chopped down about 70% of our forests. Many of them are wetland specialists and we’ve drained more than 90% of our wetlands to create more and more pasture. A large number of them need to migrate between freshwater and the ocean and we’ve blocked these passageways with dams, culverts and chemical pollution barriers. Perhaps most obvious of all, our native fish evolved to live in clean, cold water — historical waterscapes that have now been largely replaced with streams full of mud, municipal effluent, factory by-products, nutrient run-off and the agrichemicals and waste products associated with 5.3 million dairy cows.
Our unique fish fauna is naturally specialised to suit the waterways of pre-human New Zealand conditions but our land and waterways were turned by the colonisers into replicas of their home countries. These changes are now accelerating exponentially as industrial farming becomes the norm and dairy companies require unsustainable annual increases in production.
It is little wonder that the many freshwater invaders from Europe and Asia such as koi carp and perch are doing so well here — we have recreated the warm, nutrient-rich soups they evolved in. As well as being a symptom of the degraded conditions they thrive in, these invaders provide yet another nail in the coffin for native species.
Recent research using transponder tags in native fish has revealed previously unknown aspects of the secret lives of these animals in streams where there is little impact from human-induced changes. Koaro, shortjaw kokopu and redfin bullies, formerly stalwarts of most of New Zealand’s middle catchment streams but now only found in catchments with low intensity or no farming, were found to spend much of their lives deep down in the stream substrate. This daytime refuge is the labyrinth of tunnels and gaps between rocks and boulders on the stream bed which offers fish a safe haven and effectively forms a third dimension of native habitat - allowing many more fish to exist than if it was not available. This crucial third dimension has now disappeared from most of our waterways, with the spaces filling up with sediment from geologically unprecedented levels of hill country erosion.
Already, around two thirds of our native freshwater fish are on the threatened species list and populations continue to nosedive as we labour to produce more and more milk from our already choking lowlands. The dairy boom has resulted in massive areas of unsuitable land being forced into apparent suitability by industrial processes. On the West Coast of the South Island huge machines are used to dig through wetland iron pans, turning over millions of cubic metres of earth in a process known as “humping and hollowing”. This process alters groundwater hydrology and subsequently requires massive fertiliser inputs.
On the other side of the South Island unsuitable land is made “suitable” using irrigation, requiring huge energy inputs to power pumps and sucking the life blood out of rivers to supply the water. Whenever these impacts of farming on freshwater make the news, Federated Farmers representatives leap in with either absolute denial or they point out the economic value of farming to New Zealand, as if this somehow justifies the impacts and that this is a trade-off we all must accept. The irony of course, is that it is our “clean green” image that underwrites the economic viability of primary producers, and the trashing of our waterways will inevitably mean the loss of this selling point.
The solutions are never easy, they take time and effort, and there must be an economic incentive for farmers to do it right. This is already happening to a limited extent with organic farming and the premiums available for sustainable low-input farming. Because of the extent of changes required to make conventional farming sustainable and to rescue our native fish we need much stronger incentives to motivate change.
Due to discrepancies in legislation, our freshwater threatened species, with equal threat ranking to their feathered contemporaries, have no statutory protection whatsoever. Moreover, many are actually exploited for economic gain. Amazingly, the Freshwater Fisheries Act only specifically protects grayling, an endemic freshwater fish species that went extinct 40 years before the Act was passed. The endemic and threatened longfin eel, shortjaw kokopu and giant kokopu are commercially harvested. Whilst the two threatened kokopu species are found on the plates of New Zealanders in whitebait fritters, the eels are predominantly eaten by Northern Hemisphere diners who buy from New Zealand because they have driven their own native eels to the verge of extinction.
We are living in a time of unparalleled environmental destruction: in one generation most of our freshwater fish have made the threatened species list and unless we act quickly they will be all but gone in another generation. As with most other environmental problems there is a lag period and we are now seeing the impacts of previous decades of unsustainable land-use hit home. Even if we stop the destruction right now and start protecting our freshwater ecosystems, these species’ declines will continue for some time.
To save our freshwater heritage we need amendments made to the freshwater fisheries regulations and to the Wildlife Act, and we must have effective regulations put in place in the agricultural sector. Government-employed and funded freshwater scientists’ hands are tied with political tape, meaning these changes must come from the people.
So rise up all those who want their grandchildren to see native fish and have swimmable rivers. Target the environment, fisheries, State-owned enterprises and conservation ministers, councils and Fonterra and tell them we refuse to accept the loss of our fish and our rivers.
We can have a strong farming industry and clean waters but not when the emphasis is on unlimited increases in production. There is a limit to what the land can produce sustainably and what waste the rivers can assimilate and that point has long since been passed in many parts of New Zealand.