The darkening future of our indigenous freshwater fish.

Having recently moved to the Eastern Bay of Plenty from Auckland earlier this year, this is the first time I have witnessed the ritual of cars pulled up by the side of the road, with people hanging their nets in the river, eagerly partaking in the whitebait harvest taking place at rivers and coasts all over the country.

Whitebait season, Waioeka River,

Ōpōtiki

Much has been made in the lead up to the election about the degraded quality of our freshwaters and how swimmable they are or should be for people. But people are not the only ones suffering from our degraded waterways, our country’s once rich and diverse indigenous freshwater species are in a parlous state, and could be considered the canary in the coal mine.

The diminishing numbers of juvenile fish that are unfailingly caught this time every year as whitebait, are facing a tougher and tougher time to get past the nets and live out their full natural life cycle. Whitebait is the collective term given to the juveniles of five of our native freshwater fish species belonging to the group galaxiids: banded kōkopu, giant kōkopu, īnanga, kōaro, and shortjaw kōkopu. These five species are the only migratory species of galaxiid out of approximately twenty, and this aspect of their life cycle sees juveniles running the gauntlet of nets every year. If a juvenile of any of these species makes it past the waiting nets, they can grow into beautiful fish up from 9cm up to 25cm in the case of the giant kōkopu pictured below, netted during fish monitoring at Paekakariki.

Galaxias arganteus Giant kōkopu approx. 25cm in length netted during monitoring at Paekakariki. Source: Stella McQueen.

Galaxias brevipinnis kōaro juvenile photographed in aquariam. Source: Stella McQueen.

Mature kōaro in Taranaki stream. Source Stella McQueen.

Breeding season is autumn. Inanga migrate downstream to estuaries and lay their eggs among plants and grasses, whereas kōaro and kōkopu stay put and spawn on leaf litter and forest plants. This provides one more clue to the hurdles faced by our native fish: rivers and streams straightened, modified, and blocked by impassable barriers; stripped of their native vegetation; turned into irrigation canals or drainage canals; and loaded with sediment and nutrients washing off our highly intensively farmed and deforested catchments. Quite simply, there are less and less suitable spawning grounds for fish, and less suitable habitat for those that grow to maturity. 

 The eggs stay out of water for several weeks, and need to stay moist which is why vegetation and shade is so important. They hatch when they become immersed, either by spring tides or floodwaters, and the larvae float out to sea, maturing over winter. Come spring, they face the gauntlet once more and migrate upstream, to grow to maturity and breed. However, thriving and breeding is no doubt becoming more and more of a challenge in a world of decreasing habitat. Many of our native fish prefer cool streams shaded by vegetation, with insects from the vegetation providing a valuable food source. Unfortunately, this is the exact opposite of what many of our lowland streams and rivers have become.

Not perfect, but cool clear running water, shade, suitable spawning area and stones for shade and refuge.

The same stream downstream, high sediment load, no shade, and barriers to migration.

Given that fishing for whitebait is not regulated, and in fact it can be sold commercially, one would be justified in thinking that there are plenty of fish in the sea, so to speak. The giant, shortjaw, and banded kōkopu are endemic to New Zealand, the giant has a threat status of declining, and the shortjaw has a status of threatened. To date, there is still much to be learned about these fish; little quality data on numbers and breeding habits; and no quota on allowable catch. The status of the whitebait species is reflected in the poor statistics for our freshwater fish in general. Seventy four percent of our native fish species are listed as Threatened or At Risk, due to reasons such as declining water quality, water extraction, loss of habitat, and modification of waterways. Between 2009 and 2013 this figure increased from 65% according to the Department of Conservation.One species, the New Zealand grayling, is classified as extinct. Remember that fish, because it has an honorary position in freshwater fish legislation, a situation described by freshwater ecologist Dr. Mike Joy as "pythonesque".

New Zealand’s indigenous freshwater fish are covered by the Freshwater Fisheries Legislation 1983.  Only one species is specifically mentioned in the act, in part 10 section 69 "no taking of grayling". All well and good you may think, except this 1983 legislation applies to a fish that was extinct by 1930! Section 70 seemingly gives blanket protection for our native fish species by stating “no person shall in any water intentionally kill or destroy indigenous fish”.And yet, with one more sentence in section 71 this protection is totally removed where it states “Nothing in regulation 70 shall be construed as a restriction on the taking of whitebait, or eels, or other indigenous fish for the purposes of scientific research or for purposes of human consumption”.  

So, if you are thinking, it doesn’t matter how rare or threatened a species is, if you are going to eat it that’s ok, you would be right. The inevitable consequence of this twist in the regulations is a recreational pursuit, and commercial industry, based on an ever-diminishing ecological resource, where the juveniles are harvested before reaching breeding age which is essential for replenishing stocks. Quite simply, our freshwater fish legislation gives more protection to introduced game species such as trout and salmon which are prohibited from sale or trading, while our threatened native species such as whitebait and eels are subject to commercial pressures. As if to add insult to injury, predation by those very same introduced game fish that receive such a high level of protection is one more factor hastening the decline of our native species.  

Whitebait stand for sale, $30000. Source: https://www.trademe.co.nz/sports/fishing/other/auction-1422795615.htm

New Zealand whitebait for sale online, $100 per kilo. Source: http://nzwhitebait.co.nz/products/

In the lead-up to the 2017 election the state of our freshwater rivers, lakes, and wetlands was given a rightfully deserved place as one of the most concerning issues confronting voters. However, by singularly focusing on the benchmark of swimmable for humans, we risk losing sight of the bigger picture where we are just one part of the interconnected ecosystems facing losses brought about by the current state of our waterways. A river choked with algae is likely to be unattractive, and possibly lethal, to humans as much as it will have the same effect on fish when waters reach the stage of eutrophication. This occurs as the end stage of a series of events started by excessive nutrient run-off into water, primarily resulting from nitrogen based fertilizers and cow-urine from surrounding land. Increased nutrients in the water encourage increased growth and decay of algae and invasive weed species, in turn using up dissolved oxygen in the water which fish require to breathe. 

Whatever the outcome of the 2017 election, it would be a brave government to tackle the issue of regulating the whitebait fishery, an activity that some consider as a cultural birthright, rather than a privilege.  Nonetheless, it is high time our freshwater fish regulations were brought up to date to truly protect our threatened and critically endangered species, as no amount of improvements to water quality and habitat will make a difference to an extinct species.  In a recent case in Christchurch, $3million dollars was budgeted to change the design of an intersection due to the presence of threatened Lamprey fish. While the outcome is laudable, it also demonstrates the increasingly drastic measures that must be taken to preserve diminishing populations. In the meantime, while we still have the privilege of sharing the waterways with our native freshwater species, and in the search for acceptable standards, let’s remember that swimmable rivers for humans must also mean swimmable rivers for our native fish. 

If you would like to learn more about our indigenous freshwater species, check out A Photographic Guide to Freshwater Fishes of New Zealand, by Stella McQueen, self- confessed “nativefish geek”,  and follow her facebook page New Zealand Native Fish here. 

You can keep up to date with my fossickings and musings at Mangere Bridge Rocks fb page