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The State of Our Fish

Fish are the most ancient of the five vertebrate classes. Their (and our) ancestors, the earliest vertebrates, were tiny eel-like animals called conodonts which first introduced teeth and backbones to the world during the Cambrian Explosion 520 million years ago (Janvier, 1995; New Scientist, 1995; Palmer, 1995c). Conodonts gave rise to the first true fish about 485 million years ago and these subsequently diversified into so many species that the Devonian period, from 355 to 410 million years ago, is referred to as 'the age of fishes' (Dayton, 1993).

Today, fish are by far the most diverse vertebrates on Earth with at least 20,000 species worldwide. They are also the most heavily harvested wild animals on Earth. According to the UN Food and Agriculture Organisation, 70 percent of the world's fish stocks are now 'either fully-exploited, over-fished, depleted, or are rebuilding from previous over-fishing' (FAO, 1995; Hagler, 1995; Pearce, 1995a).

Global fish and shellfish catches peaked six years ago, averaging 98 million tonnes per year through 1989-91 (plus about 27 million tonnes of discarded bycatch and about 13 million tonnes of farmed fish and shellfish). By 1993, the global catch had declined to just under 86 million tonnes, with marine yields falling by 6 percent to 78.8 million tonnes and freshwater yields falling by 52 percent to 6.9 million tonnes (Alverson et al., 1994; FAO, 1995; Welcomme, 1995). Most of the decline in marine catches occurred in northern oceans.

New Zealand's annual marine catch peaked in 1992 at more than 650,000 tonnes, made up of more than 530,000 tonnes of fish and nearly 120,000 tonnes of invertebrates, principally squid. This excludes discards, illegal catches, recreational catches and catches for customary Māori food-gathering. The year before, the total marine catch had been 608,000 tonnes and, the year after, it fell to 590,000 tonnes. Marine fish make up 99.8 percent of the total catch because we have only a small number of freshwater fish species. Apart from freshwater eels and farmed salmon, oysters and mussels, New Zealand's fisheries are almost totally based on wild populations of marine species.

Besides the commercial fish catch, a large number of inshore fish and shellfish are taken by non-commercial fishers and gatherers. About 390,000 people (16 percent of the population) engage in recreational sea fishing (Teirney and Kilner, 1995). An unknown number catch freshwater fish, both native fish fry (whitebait) and introduced trout and salmon. A smaller but unknown number of Māori engage in customary or cultural harvesting of fish, crustaceans and shellfish for household consumption and social gatherings.

Freshwater fish

New Zealand has 29 identified species of native freshwater fish. One of these, the grayling, became extinct earlier this century, and 10 of the remaining species are considered threatened. However, new species are still being identified (e.g. Mitchell, 1995). The number of identified species is expected to rise in the near future as a result of recent genetic research. Geneticists have found that some fish currently classified as sub-populations of a single species are really genetically distinct species that happen to look alike. As more 'new' species are discovered, or uncovered, the final species count could reach 35 or 36, and the threatened species count may, accordingly, rise to 15 or 16.

Although the total number of native fish is low compared to other countries, nearly 90 percent are endemic. Their Gondwana origins are obvious from the fact that most have close relatives at the genus or family level in other Gondwana countries, notably south-eastern Australia (McDowall, 1990). This is best reflected in the distribution of our most diverse genus, the galaxiids (Galaxias spp.) which are found not only in New South Wales, Victoria and Tasmania, but also throughout southern South America and even the southern tip of South Africa.

Table 9.15: New Zealand's native freshwater fish
Fish Description Indigenous Species Endemic Species Threatened Species
Grayling A trout or salmon-like fish up to 450 mm long. Colour variable, ranging from completely silvery or golden to red-brown with grey or yellow speckles on the back, and a yellow or golden belly. 1 1 Almost certainly extinct.
Galaxiids Mostly small with varied shapes, and leathery skin without scales. Nine threatened species include the giant kokopu, the short-jawed kokopu, the koaro, three mudfish, several Otago non-migratory galaxiids, and one inanga. 14 12 9
Torrentfish The only freshwater species of a family of marine fish (Mugiloididae). One of the few native species apparently unaffected by the clearance of riverbank forest cover. 1 1  
Bullies Mostly small, stocky fish with blunt round heads, noted for their rapid stop-start darting movements in the water. One freshwater species, the Tarndale bully (Gobiomorphus alpinus) is threatened. 7 7 1
Southern smelts Small, long, silvery fish. Some lake populations spend their entire life in freshwater, others spend much of their lives at sea. 2 2  
Black flounder A broad fish of typical even oval flounder shape, black to deep olive-green in colour with brick-red spots on the upper surface. 1 1  
Freshwater eels Two long-lived 'snake-like' species which return to the ocean to breed (probably north west of Samoa for the shortfinned Anguilla australis, and possibly east of Tonga for the longfinned Anguilla dieffenbachii). 2 1  
Lamprey Very primitive jawless 'sucker' fish, without scales or paired fins. 1    

Total

  29 25 10

About 20 alien species of freshwater fish have been introduced since European settlement. They include trout, salmon, koi carp, catfish, tench, rudd and perch. Another six marine species often stray into New Zealand rivers from the sea (McDowall, 1990). In all, this brings the number of fish species that either inhabit or visit New Zealand's rivers and streams to between 55 and 60.

Generally, New Zealand's indigenous fish are small, well-camouflaged, bottom-dwellers (Richardson and Jowett, 1994). Only 4 species (the 2 eels, the giant kokopu, and the extinct grayling) exceed 2 kg in body weight (McDowall, 1980). Although they are freshwater dwellers most of the time, many species have a marine stage in their life-cycles. This peculiarity may be related to New Zealand's long period of inundation during the Oligocene drowning.

One of the most distinctive of the sea-going freshwater fish is the torrentfish (Cheimarrichthys fosteri) - the 'black sheep' of a sea-dwelling family called the Mugiloididae. Other species in this family are exclusively marine dwelling, living in the oceans around Africa, Asia and various parts of the Pacific (McDowall, 1990). The wayward torrentfish, however, evolved into a freshwater species whose only acknowledgment of its oceanic heritage is a brief sea visit soon after hatching. Details are still sketchy, but it is believed that the torrentfish larvae are swept downstream to the sea where they develop into fry before returning to fresh water. On their way home, the maturing fry undergo an important rite of passage when they enter the river estuary. Vital developmental changes take place to equip them for freshwater life, including alterations to their body shape, colour, eating and escape behaviour and internal fluid regulating mechanisms (Glovaet al., 1995).

Though closely related to blue cod, torrentfish are much smaller, growing to about 10-12 cm. They live in open-bedded rivers and streams, using their large ventral fins, like hands and feet, to anchor themselves to the river or stream bed. Their pointed, flattened heads cut easily through fast-flowing water. Though rarely seen, the torrentfish is one of our more common species. Others have fared less well.

Today, a third of our native fish are threatened and several others are rare. A recent survey of the larger rivers found 16 native species and 3 introduced species (Richardson and Jowett, 1994). Only 8 native species were described as common. They included eels, torrentfish, various bully species and the common river galaxiids. Eels alone accounted for two-thirds of the biomass. The most abundant introduced species was the brown trout.

The National Institute of Water and Atmospheric Research (NIWA) maintains a freshwater fish database which now has about 13,000 records of fish sightings from all over the country (Richardson, 1993). The database gives some idea of the relative abundance of fish species. Whereas longfinned eels have been found at 48 percent of sites, the five migratory galaxiids are far less abundant. Inanga have been found at only 15 percent of sites, koaro at 10 percent, the banded kokopu at 8 percent, the giant kokopu at 4 percent and the short-jawed kokopu at a mere 2 percent of sites. All but the inanga were limited to heavily forested catchments.

The threats to our native fish come from introduced species and from human activities that have removed or altered their habitats. These activities include: forest clearance, pastoral farming, effluent discharge, nutrient pollution, water abstraction, barriers to migration, channels and drains and changes to river courses and banks, and possibly even whitebaiting.

No fish are known to have become extinct in the five or six centuries of Māori exploitation that preceded European settlement. For inland tribes in particular, freshwater fish were very important. Efforts were made to conserve and sometimes enhance fish stocks (McDowall, 1990). Eels, smelt, koaro and possibly bullies and banded kokopu were actively transferred to land-locked lakes to boost fish stocks (Strickland, 1993). One chief even tried to introduce 70 snapper to Lake Rotorua. A team of slaves carried the fish in a huge patua (a watertight vessel made of totara bark). A hundred more slaves were stationed along the way to replenish the saltwater from calabashes. Only one snapper survived the journey but died as soon as it was put in the lake (Mair, 1923).

Table 9.16: Distribution of native fish in New Zealand lakes
Species Common Name Distribution
Geotria australis Lamprey Little known but probably widespread in tributaries of coastal lakes.
Anguilla australis Short-finned eel Widespread in coastal lakes and lagoons.
Anguilla dieffenbachii Long-finned eel Occasionally present in both coastal and inland lakes.
Retropinna retropinna Common smelt Common and widespread in coastal and tidal lakes, as well as in lakes of the North Island's Volcanic Plateau; populations in some coastal lakes of Northland and Wellington and some upland/alpine lakes of the eastern Southern Alps.
Galaxias maculatus Inanga Diadromous stocks in some coastal and most tidal lakes and lagoons; land-locked populations in Northland dune lakes.
Galaxias gracilis Dwarf inanga Coastal dune lakes of North Kaipara Harbour, and Kai Iwi Lakes near Dargaville.
Galaxias brevipinnis Koaro Diadromous populations in a few West Coast lakes; land-locked populations throughout New Zealand in cool upland/alpine lakes.
Galaxias argenteus Giant kokopu Often found in lowland lakes; widespread.
Galaxias fasciatus Banded kokopu Diadromous or landlocked populations in a few West Coast lakes; land-locked populations in Lake Okataina and Kaihoka Lakes, northwest Nelson.
Rhombosolea retiaria Black flounder Common and widespread in tidal lakes and lagoons.
Gobiomorphus cotidianus Common bully Widespread and abundant in tidal, coastal, upland and alpine lakes throughout New Zealand.
Gobiomorphus alpinus Tarndale bully Tarns of inland Marlborough.
Gobiomorphus beviceps Upland bully Upland and alpine lakes of the eastern Southern Alps.
Gobiomorphus huttoni Red-finned bully Tributaries of a few tidal and lowland lakes, e.g. Lake Wairarapa.
Gobiomorphus hubbsi Blue-gilled bully  
Cheimarrichthys fosteri

Torrentfish

 

Source: McDowall et al. (1975) updated by McDowall

Today, exotic species have displaced or become important predators of some of our native fish. The most widespread exotic intruders are brown and rainbow trout (Salmo trutta and Oncorhynchus mykiss) which were introduced, along with the closely related salmon (Salmo andOncorhynchus spp.), as sports fish and are still protected as such. Their introduction had a serious impact (see Box 9.9). As an example of the pre-trout abundance of native fish, Buck/Hiroa (1921) described a feast at Lake Ohinemutu in 1873 where the guests dined on 4,000 baskets of dried koura (freshwater crayfish) and inanga (a name then applied to several different galaxiid species). Such abundance apparently declined after trout entered the lake.

Māori tribes petitioned government on several occasions to stop further introductions of exotic fish, but without success (Strickland, 1993). However, not all fish introductions were unwelcome. Goldfish (Carassius auratus), which multiplied rapidly in some parts of the central North Island lakes, became a popular food fish with local Māori who protested when the Government temporarily prohibited the taking of goldfish in the early 1900s (McDowall, 1990).

A significant conservation problem continues to be the unauthorised liberation of fish. Current law requires, among other things, an environmental impact assessment before fish can be released or transferred. The requirement applies to both native and introduced species. Furthermore, some introduced species are designated as noxious and must be killed if caught. The noxious fish regulations were introduced in the 1970s after the deliberate release of exotic fish by irresponsible anglers (or 'biological hooligans' according to one commentator) who were trying to re-create an English-style 'coarse' fishery here (McDowall, 1990). Coarse fish are those with large scales compared to trout and salmon. Their release began in the upper North Island in the late 1960s with rudd. Then came tench and perch and, most recently, European carp and orfe. In the early 1970s, there were also misguided moves to introduce several smaller exotic species, such as European dace, minnow, roach and gudgeon as forage fish for trout.

The distribution of noxious coarse fish has gradually became more widespread. All are threats, not only to native fish and stream ecology, but also, in some cases, the waterways themselves. None is a greater problem in this regard than the European carp ( Cyprinus carpio) which is now well-established in the upper half of the North Island, particularly the Waikato catchment, despite firm Government policy to contain its spread. This fish is a native of Europe, the Mediterranean and western Asia but has become widespread throughout Asia where it is a popular aquaculture species bred for food and ornamental purposes. The brightly coloured variety living in New Zealand was developed by Japanese fish-breeders who refer to it as koi. European carp are closely related to goldfish and can hybridise with them. They are mud-feeders, which can undermine stream banks, turn clear waters muddy brown and cause significant damage to aquatic ecosystems. Controlling them is a priority for the Department of Conservation.

Other designated noxious fish which could cause damage if released here include three species of the ferocious and much feared South American piranha (Serrasalmus spp.), and the predatory walking catfish (Clarias batrachus), an African species which has been troublesome in Florida and is popular with anglers and fish fanciers. At present, the only known piranha in New Zealand are in captivity at the Napier Aquarium and Kelly Tarlton's Underwater World in Auckland. The only catfish species to have become established in the wild here is the North American brown bullhead (Ictalurus nebulosus). It is becoming more abundant in the lower Waikato and Lake Mahinapua, where it is accused by fishers of competing with the eel population (McDowall, 1990). Though not designated as noxious, it is considered to be a nuisance species. Another nuisance species is the mosquitofish ( Gambusia affinus), which preys on insect larvae.

Table 9.17: Alien fish which have been introduced to New Zealand
td>Catfish
Species Introduced Present Status
Atlantic salmon 1868-1911 Rare. Waiau River system (Southland).
Brook char 1877-1887 Very local: mostly South Island.
Brown trout 1867-1960 Abundant. Widespread except in far north.
1876-1877 Local: Northern and central North Island, especially Waikato; Lake Mahinapua.
Crucian carp 1864-1868 Unknown. May never have been introduced.
European (koi) carp 1960s North Island, mainly Waikato River and its lakes.
Golden orfe 1980s Very local: Broadmore's Pond, near Auckland, and probably Waikato.
Goldfish 1867-1868 Common and widespread.
Guppy 1920s Local: Reporoa, north of Lake Taupo.
Mackinaw 1906 Uncommon. Lake Pearson (Canterbury).
Mosquitofish 1930 Local northern half of North Island.
Perch 1868-1877 Widespread. Local in both North and South Island.
Quinnat salmon 1875-1907 Common in parts of South Island, mainly east coast.
Rainbow trout 1883-1930 Widespread; North and South Islands. Abundant in some areas.
Rudd late 1960s Local but widespread (e.g. populations around Christchurch).
Sailfin molly unknown Swamps around southern end of Lake Taupo.
Sockeye salmon 1902 Rare: Lakes Ohau and Waitaki.
Swordtail unknown Local: Waipahihi Stream, NE corner of Lake Taupo.
Tench 1867-1868 Local in North and South Island.

Source: McDowall et al. (1975); McDowall (1990)

Introduced plants have also had an impact on our native fish, altering their habitat and food distribution. At least 200 introduced wetland plants have been identified. In addition, nutrient pollution from run-off and waste discharges have caused algae and cyanobacteria to proliferate on stony river bottoms changing the invertebrate communities on which fish feed. Pressures on native fish have probably been mildest in north-west Nelson, Westland, Fiordland, and Stewart Island, where large river systems are still surrounded by unmodified catchments. Even there, however, most riverine plant and animal communities contain introduced species.

So far, only one native fish, the grayling (Prototroctes oxyrhynchus) has been exterminated by these pressures. It was abundant when Europeans first arrived, and died out in the 1930s. Forest clearance and pasture development probably contributed to its sudden decline, with trout giving it the final nudge (McDowall, 1990). Of the remaining 28 species, 10 (36 percent) are listed as threatened (see Table 9.18). Top of the list is the short-jawed kokopu (Galaxias postvectis), the only Category A fish on the Department of Conservation's threatened species list. Not much is known about this fish. It has been found at a small number of locations from Northland to Fiordland, suggesting a wide distribution in earlier times. Sightings have usually been made in smallish streams surrounded by unmodified broadleaf/podocarp forest, and in pools with very thick vegetation cover.

The brown mudfish (Neochanna apoda) and the Canterbury mudfish (Neochanna burrowsius) are also high on the threatened species list, but, fortunately, not as high as they were just a few years ago. Listed in 1992 as Category A species, the mudfish have now been downlisted to Category B, thanks largely to progress with habitat protection (Department of Conservation, 1994b). The mudfish are 10-15 cm in length and appear to be relic populations from former swampy wetlands and wet riverbanks. As the wetlands disappeared and the riparian tree cover was removed, the mudfish were relegated to weedy drains, irrigation ditches and shallow muddy creeks. They spawn in mud and, if this dries, the newly hatched mudfish wriggle down into the soil in search of moisture. They have sometimes been found more than a metre underground, to the amazement of early settlers.

Most of the other threatened fish are, like the short-jawed kokopu, galaxiids. Adult galaxiids are rarely seen, but the juveniles are familiar to most New Zealanders as whitebait - once readily available in fish shops, but these days an increasingly rare and expensive treat. Whitebait are caught in river mouths each Spring, as the teeming shoals of fry enter freshwater from the sea. Inanga (Galaxias maculatus) juveniles make up most of the highly prized catch, but on the West Coast of the South Island, up to 5 species are involved, including the koaro, the short-jawed kokopu and the giant kokopu. In the whitebait stage, koaro and short-jawed kokopu are difficult to distinguish from the other species, but the giant kokopu is more recognisable. Smelt fry may also occur in the whitebait catch.

As its name suggests, the giant kokopu (Galaxias argenteus) is larger than other galaxiids, with adults growing to half a metre in length. Loss of preferred habitat, nutrient pollution and competition with trout are some of the factors believed to have contributed to the decline in giant kokopu numbers. In 1994, the Government considered introducing regulations to reduce the whitebaiting pressure on the giant kokopu. Because the juveniles enter West Coast rivers in November, a little later than other whitebait, the regulations would have brought the 6 week season forward so that it ended on 31 October instead of 14 November. However, following submissions from West Coast whitebaiters on the timing of the juvenile giant kokopus' return to the rivers, the regulations were not introduced.

Until recently, the most resilient of the native fish were the eels. New Zealand has two native species. The larger of these, the longfinned eel (Anguilla dieffenbachii), is endemic, while the smaller shortfinned eel (Anguilla australis) is also found in South Australia, Tasmania and New Caledonia. Although longfin and shortfin habitats overlap, longfins predominate in stony rivers and high country lakes, while shortfins are more abundant closer to the coast in the lowland lakes (e.g. Ellesmere or Waihora) and muddy rivers.

Table 9.18: Conservation status of threatened native freshwater fish

Category A: Native fish facing extinction and with the highest conservation priority

  • Short-jawed kokopu (Galaxias postvectis)

Category B: Seriously threatened native fish with the second highest conservation priority

  • Giant kokopu (Galaxias argenteus)
  • Dwarf inanga (Galaxias gracilis)
  • Brown mudfish (Neochanna apoda)
  • Canterbury mudfish (Neochanna burrowsius)

Category C: Threatened native fish with the third highest conservation priority

  • Koaro (Galaxias brevipinnis)
  • Banded kokopu (Galaxias fasciatus)
  • Long-jawed kokopu (Galaxias prognathus)
  • Tarndale bully(Gobiomorphus alpinus)
  • Black mudfish (Neochanna diversus)

Source: Department of Conservation (1994b)

Average eel life-spans are almost the same as the pre-industrial human life-span - in the 20-40 year range - and, as with humans, very old individuals have been recorded. Female eels are longer-lived and bigger than the males, with the oldest on record being a 60-year-old shortfin and a 106-year-old longfin. They breed only once and leave New Zealand to do it. Their spawning grounds appear to be several thousand miles away, in the tropical waters to the north of Fiji and Western Samoa (Castle, 1995).

After spawning, the parent eels never return, but their tiny young elvers drift back on the ocean currents that sweep in an arc through the western Pacific, past New Caledonia and Australia and on to New Zealand. Once in our waters, the elvers randomly enter rivers as they encounter them. Recently the Australian longfinned eel (Anguilla reinhardtii) has been discovered here, presumably because its elvers were swept down on the same currents and missed their usual stop. Our native shortfin probably arrived here in a similar way thousands of years ago.

Though still abundant, eel biomass has fallen in some areas, particularly Lake Ellesmere and the lower Waikato River, as a result of habitat decline (i.e. pollution, wetland drainage) and human predation (i.e. commercial fishing). Eels are the only commercially significant native freshwater fish. Although they have always been harvested for food by Māori communities, commercial harvesting for export markets by Europeans only began in the late 1960s.

Figure 9.4: Estimated eel catch, 1965-96
Textual description of figure 9.4

Data for this figure relates to the period between 1965-96. The estimated eel catch peaked between the 1970s and 1980s with between 2000 and 2500 tonnes annually. Since the 1980s the estimated catch has been around 1500 tonnes annually.

Source: Ministry of Fisheries

The estimated annual catch peaked in the 1970s, exceeding 2,000 tonnes several times. Since the early 1980s, the catch has settled to an average of just under 1,400 tonnes (see Figure 9.4). Concerns about declining biomass in Lake Ellesmere (Waihora) led to it being declared a controlled fishery in 1978. The number of eel fishers was cut from 30 to 17, and the total allowable catch (TAC) quota was set at 256 tonnes. In following years, both the fishers and TAC quota were progressively reduced to the current 136.5 tonnes distributed among 11 fishers.

Consideration is being given to bringing all eel fishing under the Quota Management System. Regulation at present is through restrictions on entry, gear limitations and a minimum size limit on eels caught. Amateur fishers are restricted to six eels a day, regardless of size. For commercial fishers, a new national minimum size of 220 g took effect in April 1993, replacing the previous 150 g size limit. However, the minimum size for eels in Lake Ellesmere was set at 140 g, reflecting the extent to which the lake's large old eels have been reduced. The Lake Ellesmere limit will be incrementally raised each year to bring it into line with the national size limit.

Ironically, the minimum legal size limit is probably threatening the sustainability of the eel stocks rather than helping them. It offers total protection to shortfinned males, which normally migrate when they weigh between 140 and 160 g, and has redirected the fishing effort onto the rarer longfins and the female shortfins. To counter this, a maximum legal size of 4 kg now covers the whole of the South Island. This was introduced to offer some protection for the larger longfin females, which are at the greatest risk because they remain in the river systems the longest.

One obstacle to successful eel quota management is the lack of good data. Eel stock size and levels of exploitation cannot be assessed accurately for several reasons: stocks are replenished from the ocean rather than from resident populations; commercial catch data are of poor quality; and non-commercial catch data are nonexistent.

Besides fishing, eels, like other native fish, are affected by environmental pressures, such as pollution, loss of overhanging vegetation, river straightening, lake lowering and wetland drainage. Another source of pressure is the increasing number of river obstructions impeding their migrations. With more than 400 dams of 1.8 m or more in height and thousands of smaller dams and weirs, returning elvers now run a formidable obstacle course. The Electricity Corporation (ECNZ) has assisted with feasibility studies on installing passes for incoming elvers in the Waikato, Waitaki, Clutha, and Waiau rivers.

Sometimes, Government, industry and iwi have cooperated to physically transfer elvers to headwaters, lakes or farm dams. This can involve up to a dozen people working over several consecutive nights with boats, buses, tankers and collectors. When eels are transferred to landlocked waterways they are effectively taken from the ocean-going breeding population so a special permit from the Ministry of Fisheries is needed for transfers, even small ones. Freshwater fishing regulations now prohibit the taking of more than six eels (of any size) per person per day. Technically this applies to elvers, 1,000 of which weigh less than a kilogram.

Box 9.16: Eel fishing, past and present

Freshwater eels (called tuna in Māori) are prized as taonga (treasures) in Māori culture (Taylor, 1992). Eels are important for hui (gatherings), tangi (funerals) and other social activities, including gift exchanges. They also feature in tribal traditions and mythology. More than 160 names for eels have been recorded, reflecting the diversity of local traditions and the significance attached to variations in size, shape, colour, taste, behaviour and habitat (Best, 1929). Eel fishing took many forms, varying according to tribal tradition, location, season and habitat. The main fishing methods included hinaki (eel pots), pa-tuna (eel weirs), toi (eel bobbing without hooks), korapa (hand netting), rapu tuna (feeling with hands and feet then catching with hands), rama tuna (by torch light) patu tuna (eel striking), mata rau (spearing) and koumu (eel trenches). During the annual tunaheke (eel migration) channels were dug into stream banks and lake shores, trapping vast numbers of eels on their way to the oceanic breeding grounds. The returning elvers (baby eels) were taken by placing bundles of bracken fern at the top of falls or at known congregation points during their upstream movement.

Māori communities regulated eel harvests and controlled access to fishing areas through a system of tapu (sacred) rules, usages, beliefs and ceremonies whose violation could bring retribution from both supernatural and human agents (Habib, 1989). Individual iwi (clans or tribes), hapu (septs or sub-tribes) and whanau (extended families) were restricted to fishing specific waters. Examples of traditional practices include: transferring juvenile eels to land-locked waters with no eels; refraining from fishing during the first three days of the migration (which, it is now known, protected mostly the male eels which migrate first); releasing the largest of the migrating eels (which are now known to be older females); imposing rahui (temporary bans) on fishing in particular areas; and minimising wastage of eel carcasses (Butler, 1993; Carkeek, 1989).

Although eel use has declined, it is still important to Māori as shown in various protests, petitions and court cases, including submissions to the Planning Tribunal and the Waitangi Tribunal. Eel fishing is still seen as a part of the traditional dimension of people's lives (Todd, 1978). Although modern technology is now used, the aim is not to increase catches but to reduce catch effort and time spent on equipment maintenance. In adapting new technology, key elements of traditional design and ritual have often been retained. Despite the social changes of the past 150 years, and the movement of people away from their family lands, many customary practices continue. Traditional 'gathered' foods are preferred to 'bought' foods on ceremonial and festive occasions, such as hui and tangi where the serving of traditional food upholds the mana (prestige) of the marae (tribal gathering place) (Butler, 1993; Marshall, 1987).

Eels were particularly important in the South Island where climate prevented kumara from being a staple food. The two most favoured eel fishing lakes were on the southern side of Banks Peninsula - Waihora (Lake Ellesmere) and Wairewa (Lake Forsyth). Waihora had a reputation as a food basket throughout the country. The Ngai Tahu people at Taumutu on the southern end of Waihora were renowned for taking large quantities of eels to hui throughout New Zealand. Today tribal members believe the polluted and overfished lake can no longer sustain this practice, causing them to suffer a loss of mana (Jull, 1989). According to Don Brown:

The eel fishery right up to 1960 would have been considered a Māori fishery in Waihora because only the Māori used the reserve... Generally speaking it was no trouble to catch a good feed of eels within a short time. I mean a sugar bag of eels in about half an hour would have been normal. That would have been around Spring or Christmas time, not at the migration time. Today that would be an impossibility... There's a strong possibility in Waihora that things that happened traditionally with catching and processing eels ... and storing them ... are all going to be lost to that hapu. But as long as Wairewa keeps going I guess Ngai Tahu won't lose that great tradition. (Butler, 1993).

In 1868, the Government established several Māori fishing reserves in Canterbury to honour a promise made in the Kemp Deed when the land was purchased from Ngai Tahu. However, the effectiveness of the reserves was limited by the Government's insistence that eel weirs and fisheries should not interfere with the general settlement of the country (Law Commission, 1989). In 1873 the Timber Floating Act was passed over protests from several Māori Members of Parliament that it would permit damage to Māori eel weirs (Law Commission, 1989). Nationally, 10 eel fishery protests were registered from 1881 to 1895. The main concerns were: reserving eel fishing areas; protecting traditional fishing rights and eel weirs; and wishing the return of various lakes and rivers (Waitangi Tribunal, 1988). Evidence was given that access to eel fisheries had been denied by land settlement, insufficient reserves, drainage of wetlands, river straightening, acclimatisation regulations and diversion of water from rivers for power-supply dams (Waitangi Tribunal, 1991).

Drainage pressures were particularly acute in Waihora and Wairewa. Both lakes are kept at low levels by the periodic opening of cuts to the sea through Kaitorete Spit (Waihora) and Pourinui Spit (Wairewa). As a result, Waihora is only two-thirds its original area and the surrounding wetland has been reduced by 80 percent. Until the late 1960s lake levels were set solely to meet the needs of surrounding farmers. The local iwi, Ngai Tahu, was not consulted about drainage, irrigation or reclamation. This has changed in recent decades, particularly since the passing of the Resource Management Act 1991, which requires local authorities to consult with iwi on issues affecting traditional resources and food gathering areas. In 1993, for example, the Taumutu runanga was able to stop a bid by local farmers to have Waihora opened to flush out decomposing weeds. The runanga argued that lowering the lake further would interfere with the eel migration.

In the 1960s an additional threat to the traditional eel fisheries emerged with the development of export markets for eels. Māori concerns were overlooked in the rush to meet export orders from Europe and Japan. The fishers were mostly pakeha labourers who caught eels for seasonal employment, though some were farmers whose land bordered fishable waters. Initially the industry was centered in the South Island with Waihora providing more than half the national eel catch in the early 1970s (Jellyman, 1992). By 1978, the North Island had become more important and Waihora's share of the national catch had dropped to 12 percent. For most of that first decade the export demand was for short-finned eels rather than the larger longfins. Longfins were often killed as pests when fishers found them crowding and sometimes tearing nets. Meanwhile, the largest shortfins (mostly females) were fished so heavily that, between 1974 and 1977, the average length of Waihora's shortfins declined by 20 percent from 474 to 375mm. Today longfins are almost absent from Waihora and male shortfins vastly outnumber females (Jellyman, 1992).

In some areas traditional eel fisheries have been protected by conservation legislation (which bars commercial fishing in all national parks and reserves but permits customary fishing subject to the Minister's approval) and fishery regulations (which reserve some areas, including an arm of Waihora, exclusively for traditional and recreational fishing). Most of these protected areas are controlled by the Department of Conservation and the Ministry of Fisheries and are accessible to all Māori fishers, but two (Wairewa and Lake Horowhenua near Levin) are directly controlled by the local runanga. Wairewa's eel fishery was reserved exclusively for the Ngai Tahu people in the 1960s. The runanga operates a permit system to preserve its mahinga kai (food source) and to set a general code of conduct for catching eels. The eels are bigger than in Waihora, partly because commercial fishers have been kept from the lake, and partly because big eels were considered kaitiaki (food guardians). When the "big eel broached fishing stopped" (Butler, 1993). However, the runanga had little control over the tributary streams where eels were still exposed to commercial fishing and habitat loss (Tau et al., 1990). In 1993 the annual eel migration failed to occur at Wairewa and the following year regulations were brought in to close commercial fishing in the lake's tributaries. Commercial eel fishing has also been brought to an end in the Chatham Islands where the Ministry of Fisheries has decided not to issue any more permits.

Recent developments in the South Island suggest the tension between commercial and traditional eel fishers may soon become a thing of the past. In 1991 the Waitangi Tribunal recommended that fisheries in Waihora and Wairewa be jointly managed by Ngai Tahu and the Department of Conservation. Ngai Tahu and the commercial fishers were strongly opposed to this and, instead, continued to deal with the Ministry of Fisheries. After much discussion and negotiation all South Island iwi entered a joint accord with the South Island Eel Industry Association. One result of the accord is the formation of a Waihora Eel Management Committee, with equal representation from Ngai Tahu and the Ellesmere eel fishers. Another result is that the Wainono coastal lagoon near Waimate (one of the 1868 eel reserves which has been heavily fished by commercial fishers) is now closed to commercial eel fishing. Many other non-commercial fishing areas are likely to be agreed in the future. It may only be a matter of time before North Island fishers follow the South Island example.

Taken together, the Resource Management Act, the Conservation Act, the fishery regulations and the South Island Eel Accord provide a range of safeguards for traditional eel fisheries which should enable them to withstand the pressures from commericial fishing and surrounding land and water uses. The settlement of Māori land claims also contributes to this process. Landowners can bar anyone from crossing their land, including commercial fishers wishing to access streams and lakes. By regaining control of alienated lands, therefore, iwi can also regain some control over their waterways and traditional fisheries, as well as land uses which may affect them. While most of these measures have been slow in coming, it seems that they have not been too late, and the credit for that must go largely to the resilience of the eels themselves.

Marine fish

More than 1,000 species of fish have been identified within 200 nautical miles (320 km) of our coast - our Exclusive Economic Zone (EEZ) (Paulin et al., 1989). A further 200 or so have yet to be formally identified. Each fortnight another unidentified species is added to the list. About 110 marine fish (11 percent) are endemic to New Zealand waters, but less than half of these live in the open sea. Most of them (61) are confined to coastal rockpools where 62 percent of species are endemic. The most diverse rockpool species are the triplefins (or cockabullies) with their distinctive line of three fins on the back. New Zealand's rockpools have 21 species, accounting for a third of the world's known triplefins and making our region a biodiversity 'hotspot' for cockabullies (Paulin and Roberts, 1993; Roberts, 1994).

Although little is known of the status of most marine fish in the EEZ, an assessment has been made of the rockpool fishes. Eleven are listed as threatened, all of them endemic (Paulin and Roberts, 1994). None are endangered, but they are rare and vulnerable to habitat disturbance (see Table 9.18). The threatened species represent 12 percent of all rockpool fish and 18 percent of the endemic ones. Away from the coastline, only two of the sea-dwelling fish species are known to be threatened and neither is endemic. The great white shark (Carchardon carcharias) and the basking shark (Cetorhinus maximus) are threatened in all oceans (Department of Conservation, 1994e; IUCN, 1990).

Only 5 percent of the marine fish living beyond the rockpools are endemic (50 out of about 1,100 species). Most, nearly 60 percent, are found throughout the world and a further 30 percent are found elsewhere in the Southern Hemisphere. Many arrived here by a gradual process of migration and expansion over long periods of time, while others are recent or intermittent arrivals. Orange roughy, for example, have probably been here for a long time. They are also found as far away as the North Atlantic, where they were first discovered. Peruvian jack mackerels, however, are recent immigrants. They were first noted in 1987 and now are caught far more frequently than the two endemic jack mackerels. Tuna are migratory visitors which come and go every year, covering vast areas of ocean. In many cases, 'foreign' fish arrive as stragglers which remain rare in our waters but abundant elsewhere.

Table 9.19: Threatened rockpool fish in New Zealand's coastal waters.
Taxonomic name Common name
Parma kermadecensis Kermadec damselfish
Cologrammus flavescens Clinid
Blennodon dorsale Giant triplefin or cockabully
Gilloblennius abditus Obscure triplefin or cockabully
Ennapterygius new species Kermadec triplefin or cockabully
Odax cyanoallax Bluefinned butterfish
Congiopodus leaucopaeilus Southern pigfish
Gastrocymba quadriradiata Subantarctic clingfish
Bovichtus psychrolutes Subantarctic thornfish
Priolepis psygmophilia Kermadec goby
Forsterygion jenningsi Jenning's triplefin or cockabully

Source: Paulin and Roberts (1994)

Most fishing in New Zealand is confined to places where the water is less than 1 km deep. Such areas cover approximately a third of the EEZ. Scientists and fishing companies are continually exploring these waters to find new stocks and new species which may be exploitable. Trawl surveys have found more fish species in the north than in the south and more species in deep rather than shallow water. The areas of greatest species diversity are concentrated along the margins of the Chatham Rise and are associated with the subtropical convergence of cold and warm waters (McClatchie, 1995).

Two-thirds of our fishing zone is considered commercially barren, consisting of deep low-nutrient waters which plunge more than a kilometre down. Though many species live in the deep water, few are considered fishable at present, with the significant exception of orange roughy. Few surveys have been done to identify species living at depths greater than 1.5 km, which is roughly the lower limit of the orange roughy trawl. In some areas, such as the subduction zone of the Kermadec Trench, the water is more than 10 km deep and its inhabitants are unknown.

A little over 100 marine fish species are harvested commercially - 10 percent of our known fish species. Stock assessments are made on the 42 species harvested for Maximum Sustainable Yield (MSY) under the Quota Management System (QMS). Stock assessments are also made on species such as Southern Blue Whiting, which are fished commercially, although they are not part of the QMS. Provision exists for a further 117 species to be brought into the system.

The QMS species are not all assessed separately. Some are lumped together into groups (such as the jack mackerels, the oreos, and the flatfish) bringing the number of assessed fish 'species' down to 30. These are subdivided into 179 stocks (150 if the little-fished Kermadec area is excluded). Large amounts of data on many other species have been collected in trawl surveys. The information is stored in huge databases, but has not been analysed because a limited number of fishery scientists are available to do the work. As a result, low priority species and those which are only lightly harvested are not assessed.

Migratory species, such as tuna and billfish, are also fished commercially, but they are not covered by the Quota Management System. Because they range so widely across the world's oceans, these fish are caught in many different waters and need to be managed under an international system, rather than by different sets of national regulations. So far, the only such system in operation is the Convention for the Conservation of Southern Bluefin Tuna (CCSBT). Under this trilateral agreement between New Zealand, Australia, and Japan, separate southern bluefin quotas are set for each nation (see Table 9.23). Management regimes for other migratory species have recently been the subject of a United Nations-brokered agreement on the management of straddling stocks.

Because fish stocks are wild populations living in inaccessible environments, population data and models are often uncertain or inadequate. This is particularly true for species living in areas not suited to trawling. Data for these species are sparse and often limited to commercial catch/effort data. However, in areas that are more suited to trawling, good quality data are collected from regular trawl surveys by NIWA's fishery research vessels. This information, along with data derived from the commercial fishery, is used to make assessments on 74 of the 161 QMS stocks. Sufficient data are also available to assess many non-quota stocks, but resource constraints have prevented this to date.

Figure 9.5: Quota Management Areas (QMAs) for commercial fish stocks within New Zealand's Exclusive Economic Zone (EEZ)
Textual description of figure 9.5

There are 10 quota management areas:

  1. Auckland (East), north between Northland and Bay of Plenty.
  2. Central (East), off the east coast of the North Island.
  3. South East (Coast), east of Christchurch.
  4. South East (Chatham), Chatham Rise.
  5. Southland, east, west and south from the lower South Island.
  6. Campbell Plateau and Bounty Platform, around Campbell, Auckland and Bounty Islands.
  7. Challenger Plateau and Hokitika Trench, west of the South Island
  8. Central (West), off the lower west coast of the North Island.
  9. Auckland (West), off the upper west coast of the North Island.
  10. Kermadec, around the Kermadec Islands.
Table 9.20: Commercial fish and invertebrate stocks and the Quota Management Areas in which they occur (see Figure 9.5)
Species and stock designation QMA1 QMA2 QMA3 QMA4 QMA5 QMA6 QMA 7 QMA 8 QMA9 QMA 10
Alfonsino (BYX) BYX1 BYX2 BYX3 BYX7 BYX8 BYX1 BYX10
Barracouta (BAR) BAR1 BAR4 BAR5 BAR7 BAR10
Blue cod (BCO) BCO1 BCO2 BCO3 BCO4 BCO5 BCO7 BCO8 BCO1 BCO10
Bluenose (BNS) BNS1 BNS2 BNS3 BNS7 BNS8 BNS1 BNS10
Blue moki (MOK) MOK1 MOK3 MOK4 MOK5 MOK1 MOK10
Blue warehou (WAR) WAR1 WAR2 WAR3 WAR7 WAR8 WAR1 WAR10
Elephant fish (ELE) ELE1 ELE2 ELE3 ELE5 ELE7 ELE2 ELE1 ELE10
Flatfish (FLA) FLA1 FLA2 FLA3 FLA7 FLA2 FLA1 FLA10
Gemfish (SKI) SKI1 SKI2 SKI3 SKI7 SKI1 SKI10
Grey mullet (GMU) GMU1 GMU2 GMU3 GMU7 GMU2 GMU1 GMU10
Groper/Bass (HPB) HPB1 HPB2 HPB3 HPB4 HPB5 HPB7 HPB8 HPB1 HPB10
Hake (HAK) HAK1 HAK4 HAK1 HAK7 HAK1 HAK10
Hoki (HOK) HOK1 HOK10
Jack mackerel (JMA) JMA1 JMA3 JMA7

JMA10

John Dory (JDO) JDO1 JDO2 JDO3 JDO7 JDO2 JDO1 JDO10
Kahawai (KAH) KAH1 KAH2 KAH3 KAH9 KAH10
Ling (LIN) LIN1 LIN2 LIN3 LIN4 LIN5 LIN6 LIN7 LIN1 LIN10
Paua (PAU) PAU1 PAU2 PAU3 PAU4 PAU5 PAU6A PAU7 PAU2 PAU1 PAU10
Red cod (RCO) RCO1 RCO2 RCO3 RCO7 RCO2 RCO1 RCO10
Red gurnard (GUR) GUR1 GUR2 GUR3 GUR7 GUR8 GUR1 GUR10
Rig (SPO) SPO1 SPO2 SPO3 SPO7 SPO8 SPO1 SPO10
Scampi * (SCI) QMA1 QMA2 QMA3 QMA4 QMA5 QMA6 QMA7 QMA8 QMA9 QMA10
School shark (SPO) SCH1 SCH2 SCH3 SCH4 SCH5 SCH7 SCH8 SCH1 SCH10
Silver warehou (SWA) SWA1 SWA3 SWA4 SWA1 SWA10
Snapper (SNA) SNA1 SNA2 SNA3 SNA7 SNA8 SNA10
Stargazer (STA) STA1 STA2 STA3 STA4 STA5 STA7 STA8 STA1 STA10
Tarakihi (TAR) TAR1 TAR2 TAR3 TAR4 TAR5 TAR7 TAR8 TAR1 TAR10
Trevally (TRE) TRE1 TRE2 TRE3 TRE7 TRE10

Source: Annala (1995a)

* The stock structure for scampi is not well known. At present, quotas are set for each QMA, though preliminary studies suggest that scampi in QMA 6 are genetically distinct from the rest and that stocks in QMA 1 and QMA 2 are also different.

Table 9.21: Commercial fish and invertebrates with non-standard stock boundaries (see Figure 9.5)
Orange (ORH) roughy ORH1 ORH2A 'North' ORH2A, ORH2B, ORH3A 'East Coast' ORH3B 'Chatham' ORH3B 'Puysegur' ORH3B 'Other' ORH7A ORH7B    
(See Figure 9.5) QMA 1, 9 (northern Nth Island) QMA 2 (north of East Cape) QMA 2, 3 (East Cape to Christchurch) QMA 4 (Chatham Rise) QMA 5 (south of Fiordland) QMA 6 (southern oceans) QMA 7 (Challenger Plateau) QMA7 (Sth Island West Coast)    
Oreos (OEO) OEO1     OEO3A, OEO4     OEO6      
(See Figure 9.5) Otago-Southland coast and Puysegur     Chatham Rise     Campbell Plateau and Bounty Platform      
Oysters (OYS)   Challenger       Foveaux Strait        
    Part of QMA 7: Golden Bay, and Tasman Bay except for an area of outer Tasman Bay       Part of QMA 6: Foveaux Strait        
Packhorse (PHC) rock lobster     PHC1              
     

(Managed as a single stock throughout New Zealand)

             
Scallops ((SCA)                    
    Northern       Southern        
(See Figure 9.5) Area 1 East Northland Area 2 Hauraki Gulf-Coromandel Peninsula       Nelson and Marlborough        
Southern (SBW) blue whiting   Bounty Platform Campbell Island Rise       Pukaki Rise/Auckland Islands      
      All these stocks are within QMA 6              
Squid (SQU)   SQU1T SQU1J SQU6T            
Red rock (CRA) lobster CRA1 (NTH) CRA2 (BOP) CRA3 (GIS) CRA4 (WHB) CRA5 (CBM) CRA7 (OTG) CRA8 (STM) CRA9 (WKI) CRA6 CRA10
(See Figure 9.5)         North and South Islands (including Stewart Island) (NSI)       Chatham Is (CHI) Kermadec Is (KER)

Source: Annala (1995a)

Table 9.22: Recent quotas, catches and status of commercial fish stocks.
Species   1989-90 1991-92 1993-94 1995-96 Stocks Status 1995-96
    (tonnes)  
Alfonsino (Beryx splendens; B. decadactylus) Quota 2,422 2,648 2,718 2,721 A (BYX3)
C (BYX2)
D (BYX1,7,8,10)
Catch 1,688 1,641 2,001 2,865  
Barracouta (Thrysites atun) Quota 33,073 34,190 33,202 33,202 C (BAR1,4,5,7)
D (BAR10)
Catch 23,568 22,212 19,345 26,258  
Blue cod (Parapercis colias) Quota 2,666 2,722 2,689 2,665 C (BCO1,2,3,4,5,8)
D (BCO7,10)
Catch 1,527 1,480 1,812 2,106  
Blue moki (Latridopsis ciliaris) Quota 299 306 404 604 C (MOK1,3,4,5)
D (MOK10)
Catch 303 355 476 507  
Blue warehou (Seriolella brama) Quota 5,459 4,499 4,512 4,512 C (WAR1,2,3,7,8)
D (WAR10)
Catch 1,696 3,905 1,500 2,901  
Bluenose (Hyperoglyphe antarctica) Quota 1,765 1,847 2,033 2,170 C (BNS2)
D (BNS1,3,7,8,10)
Catch 1,541 2,031 2,325 2,290  
Elephant fish (Callorhynchus milii) Quota 623 636 639 715 C (ELE3)
D (ELE1,2,5,7,10)
Catch 510 597 568 855  
Flatfish (flounders, soles etc.) (8 spp.including 4 Rhombosolea ) Quota 6,568 6,670 6,671 6,670 D (All 5 stocks)
Catch 3,482 3,202 4,605 4,456  
Gemfish (Rexea solandri) Quota 7,218 7,350 7,470 7,480 D (All 5 stocks)
Catch 4,369 3,096 2,616 1,701  
Grey mullet (Mugil cephalus) Quota 1,070 1,086 1,086 1,086 C (GMU1)
D (GMU2,3,7,10)
Catch 913 852 706 828  
Groper (Hapuku) / Bass (Polyprion oxygeneios/ P. americanus) Quota 2,117 2,163 2,167 2,179 C (All 8 stocks)
Catch 1,098 1,319 1,525 1,437  
Hake (Merluccius australis) Quota 6,930 13,780 13,847 13,997 A (HAK1,4)
C (HAK7)
D (HAK10)
Catch 7,783 8,196 7,363 15,809  
Hoki (Macruronus novaezelandiae) Quota 251,884 201,897 202,155 240,010 A (Entire stock)
Catch 209,000 215,000 190,000 208,753  
Jack mackerel (Trachurus spp . - 3 species ) Quota 40,707 40,749 49,546 32,547 A (JMA7)
C (JMA1,3)
D (JMA10)
Catch 30,102 38,676 45,498 12,268  
John Dory (Zeus japonicus) Quota 1,094 1,102 1,106 1,107 C (JDO1)
D (JDO2,3,7,10)
Catch 701 837 864 864  
Kahawai * (Arripis trutta) Quota none 6,500 Includes 10% Māori allocation of kahawai and 15% acceptable bycatch. 4,390 Includes 10% Māori allocation of kahawai and 15% acceptable bycatch. 4,390 Includes 10% Māori allocation of kahawai and 15% acceptable bycatch. A or C (All 5 stocks)
Catch 8,466 5,018 5,164 4,365  
Ling (Genypterus blacodes) Quota 19,672 19,711 19,741 22,111 A (LIN3,4,5,6,7)
C (LIN1,2)
D (LIN10)
Catch 9,028 17,778 15,961 21,084  
Orange roughy (Hoplostethus atlanticus) Quota 47,537 38,117 35,490 21,330 A (ORH1; ORH2A "North")
B (ORH3B - Chatham Rise)
(ORH3B - Puysegur)
(ORH7A - Challenger Plateau)
(ORH7B - Sth Is. West Coast)
C (ORH2A/2B/3A - East Coast)
D (ORH3B - Other)
Catch 48,312 37,012 29,688 20,700  
Oreos (Allocyttus niger; Neocyttus rhomboidalis; Pseudocyttus maculatus) Quota 25,139 25,139 26,160 26,160 D (All 5 stocks)
Catch 18,703 21,718 23,318 23,571  
Red cod (Pseudophycis bacchus) Quota 16,537 15,840 15,930 16,066 D (All 5 stocks)
Catch 7,502 9,104 11,508 15,295  
Red gurnard (Chelidonichthys kumu) Quota 4,730 4,975 4,978 4,982 C (GUR1)
D (GUR2,3,7,8,10)
Catch 2,745 3,390 3,141 2,879  
Rig (Mustelus lenticulatus) Quota 1,727 2,070 2,097 2,098 D (All 6 stocks)
Catch 1,514 1,770 1,619 1,829  
School shark (Galeorhinus galeus) Quota 2,996 3,086 3,093 3,105 D (All 8 stocks)
Catch 2,377 2,508 2,607 3,353  
Silver warehou (Seriolella punctata) Quota 9,133 9,509 9,514 9,884 D (All 4 stocks)
Catch 8,625 7,066 8,647 9,327  
Snapper (Pagrus auratus) Quota 7,932 7,962 6,884 6,893 B (SNA1,7,8)
D (SNA2,)
Catch 8,034 8,191 6,835 6,838  
Southern blue whiting * (Micromesistius australkis) Quota None None 32,000 32,000 A All 3 stocks
Catch 24,514 83,427 13,300 Preliminary estimate for 1993-94 southern blue whiting catch from Licensed Fish Receivers 15,625  
Stargazer (Kathetostoma giganteum) Quota 4,502 5,296 5,329 5,353 A (STA4)
C (STA1,2,3,5,7,8)
D (STA10)
Catch 2,763 3,239 3,097 3,243  
Tarakihi (Nemadactylus macropterus) Quota 5,873 5,953 5,990 5,992 A (TAR4)
D (TAR1,2,3,5,7,8,10)
Catch 4,473 5,417 4,876 5,249  
Trevally (Pseudocaranx dentex) Quota 3,906 3,921 3,932 3,932 C (TRE1,7)
Catch 3,122 2,733 3,620 3,368 D (TRE2,3,10)

Source: Ministry of Fisheries

Stocks Status Key

A = Above Maximum Sustainable Yield (MSY) and being "fished down".

B = Below MSY level.

C = Currently at or near the MSY level.

D = Data deficient.

* Commercially important fish species not included in the Quota Management System (QMS).

Table 9.23: Reported catches (greenweight tonnes) of non-Quota Management System fish.
Species   1989-90 1991-92 1993-94 1995-96 Stocks Status
  (tonnes)     1995    
Blue mackerel (Scomber australisicus) No quota         D
Catch 5,673 15,279 6,093 5,646  
Cardinal fish (Epigonus telescopus) No quota         D
Catch 2,374 1,651 3,793 4,565  
Frostfish (Lepidopus caudatus) No quota         D
Catch 2,536 3,298 2,964 1,575  
Ghost shark (Hydrolagus novaezelandiae) No quota         D
Catch 903 1,264 1,591 1,927  
Skate (Squalus acanthias) No quota         D
Catch 1,330 1,879 2,022 1,456  
Spiny dogfish (Squalus acanthias) No quota         D
Catch 2,952 3,274 6,151 5,974  
Swordfish (broadbill) (Xiphius gladius) No quota         D
Catch 200 8 1 22  
White warehou (Seriolella caerulea) No quota         D
Catch 1,286 2,419 1,719 1,901  
Albacore tuna (Thunnus alalunga) No quota         D
Catch 3,144 3,417 5,315 6,259  
Skipjack tuna (Katsuwonus pelamus) No quota         D
Catch 3,972 988 3,136 4,105  
Southern bluefin tuna (Thunnus maccoyi) CCSBT quota *         D
Catch 529 60 277 133  
Other tuna (5 Species) No quota         D
Catch 161 105 146 303  

Source: Ministry of Fisheries

* The Global Catch Limit for Southern bluefin tuna agreed to under the Convention for the Conservation of Southern Bluefin Tuna (CCSBT) for the 1993-94 was 11,750 tonnes (6,065t. for Japan, 5,265t. for Australia, and 420t. for New Zealand).

Many of the stocks whose status is unknown are either unexploited or only lightly exploited and are assumed to be in the fishing-down phase or fluctuating within natural limits. What is unknown, however, is whether those natural limits are changing in response to fishing activities and other environmental disturbances. Commercial fishing can alter predator-prey relationships and habitat quality through such practices as: significantly reducing the biomass of prey or predator species; dumping waste; stirring up sediment clouds; and killing non-target species of fish, marine invertebrates, seaweeds, seabirds and marine mammals through bycatch, bottom trawling or dredging.

There is often a noticeable decline in the invertebrate animals brought up by trawls when new deep-water fishing grounds are exploited. Because no records are kept, the extent of these effects has not been quantified and their possible contribution to fishery declines has generally been ignored in fisheries management literature. Some marine biologists believe there is an urgent need to carry out trawling impact studies in water deeper than 500 m because this is where the effects could be severe with flow-on impacts on the fisheries themselves (Jones, 1992).

Non-commercial fishing can also be a source of pressure on commercial species, such as snapper and blue cod, and non-commercial species, such as red moki. As much as a third of the annual snapper catch is taken by recreational fishers. Set-netting and spear-fishing have forced some stocks of reef-dwelling red moki (Cheilodactylus spectablis) into a decline. On some Northland reefs, stocks have been almost wiped out. Because they are long-lived (60 years) and slow-growing, their recovery is likely to be slow.

Of the 74 QMS fish stocks which have been scientifically assessed, most are thought to be near or above the level of Maximum Sustainable Yield (MSY) and still in the fishing-down phase (e.g. all stocks of hoki). Among those thought to be at or near the MSY level are most stocks of barracouta, blue moki, blue warehou and groper. Other species with at least some stocks above, at or near, the MSY level are alfonsino, blue cod, bluenose, hake, jack mackerels, ling, orange roughy, red gurnard, southern blue whiting, stargazer, tarakihi and trevally.

Two QMS species (blue moki and elephantfish) have stocks which are believed to be recovering from previous over-fishing and may be below the MSY level. Several other species (gemfish, grey mullet, rig) have one or more stocks whose catches are declining or are well below the allowable quotas. It is unclear whether the low catches are caused by economic or biological factors. Two species (smooth oreo and snapper) have one or more stocks which may be at risk of depletion given 1995 catch rates. Overall, only 7 of the 74 assessed fish stocks (10 percent) are considered to be below the MSY level. Four of these are orange roughy and 3 are snapper (see Table 9.23).

Box 9.17: Our changing fishing industry

Before the 1960s, New Zealand's fishing industry was confined to the coast and the 12-mile territorial sea limit, and was restricted to a small number of licensed commercial fishers. In the mid-1960s, the Government removed entry restrictions and began to actively encourage new entrants and investment in the industry through subsidies, grants and incentives. The fleet and the catches grew accordingly, but the fishing effort was still concentrated entirely on the fishery within the territorial zone. The deep water beyond this territorial limit was left to the large Japanese, South Korean and Soviet fleets.

During the 1970s, pressure intensified on the limited inshore species such as snapper, tarakihi, trevally, gurnard, rock lobsters and scallops. The lucrative snapper catch, for example, peaked at 18,000 tonnes in 1978 but had fallen to 9,000 tonnes by 1983 and has remained below this level since (Annala, 1995b). Just as the inshore fisheries were reaching their limit, however, the world's governments agreed to set up Exclusive Economic Zones (EEZ), giving each country exclusive control of the marine resources within 200 nautical miles of their coastline. With the fourth largest EEZ in the world, New Zealand now had the opportunity to reduce pressure on the inshore fishery and begin exploiting deep water species such as hoki, orange roughy and squid.

Realising that the inshore fishery was over-capitalised (i.e. had too many boats, nets and fishers) the Government restricted permits for new entries in 1980 and developed plans to restructure the fishing industry. By 1986, the Quota Management System (QMS) was in place and the coastal fishing fleet was in the process of being reduced by 40 percent. Small and part-time fishers almost disappeared, while the larger companies invested in deep-water vessels and technology. Today, the vast bulk of the catch consists of deep-water species and 60 percent of the quota is owned by the three largest companies, Sealord, Sanford and Amaltal. Ninety percent of the catch is exported.

The growth of the domestic deep-water fishery since 1980 is revealed in the total tonnages of fish landed. In 1980, New Zealand companies caught nearly 77,000 tonnes of fin-fish, including tuna, while licensed foreign vessels caught more than twice this. By 1992, the domestic catch had risen to an all-time high of 536,000 tonnes and the foreign catch had declined to 1,300 tonnes. (Both catches receded the following year with 495,000 tonnes landed by domestic vessels and 400 tonnes landed by foreign boats.) Similarly, the catch of invertebrates, mostly squid, rose from about 24,000 tonnes in 1980 to almost 120,000 tonnes in 1992 receding to 96,000 tonnes in 1993. The industry's growth is also reflected in its export receipts which totalled $162 million in 1980. By 1992-93 they had reached $1,200 million, 10 times the value of domestic sales. They have remained at about that level through recent seasons, but the industry is aiming for $2,000 million by the year 2000, mainly through improved processing and marketing, and the growth of aquaculture, assisted by the introduction of a further 117 species to the QMS.

Despite the growth in catch and income, the industry is not a large employer, providing about 9,000 full-time equivalent jobs, nearly half of which are in the processing sector (Ministry of Fisheries, 1996). With low labour costs and few costs for stock replenishment or maintenance, other than some research and monitoring, the industry has ploughed its capital into highly mechanised catching and processing equipment, making the New Zealand industry one of the most economically efficient in the world. The last decade has involved the refinement of the QMS system, the clarification of Government and industry roles in research, monitoring and stock assessment, and the introduction of laws to enact Māori fishing rights which include: a guaranteed percentage of the total quota (10 percent of existing QMS species, 20 percent of future ones); customary food-gathering rights; a half-share in Sealord Fisheries; and provisions for iwi to manage fisheries of tribal significance (taiapure and mataitai).

The culmination of this reform process was the passing of the Fishing Act 1996. It has an explicit requirement to sustain not only the fisheries, but also associated and dependent species, aquatic biodiversity, and any habitats significant to fisheries. The Act also contains provisions for dealing with bycatch, or 'fishing induced mortality' of protected species and for bringing new species into the QMS. The 1996 Act consolidated a series of amendments to the previous legislation under which user charges for fisheries administration and research were introduced (e.g. the Conservation Services Levy, which enables the Department of Conservation to undertake research on fishing related mortality). The earlier amendments also split the former Ministry of Agriculture and Fisheries (MAF) into two separate ministries, one for agriculture (which has retained the acronym MAF) and one for fisheries (which is now known as Mfish). Following these amendments, MAF's fisheries research facilities and vessels were sold to the Crown Research Institute, NIWA, which now undertakes fish stock analysis and assessment, and other fisheries-related research, under contract to MFish.

Snapper

Snapper (Pagrus auratus) are the dominant inshore species in the warmer waters around the North Island and the top of the South Island. Although several species occur in temperate and tropical coastal waters in all oceans, only one is known in New Zealand. They eat invertebrates, squid and small fish at, or near, the sea bottom and rarely go deeper than 200 m. They are most abundant above 60 m. Unlike orange roughy, they were already depleted before they came under the QMS. However, they do share some traits with their deeper-water cousins. They are long-lived (up to 60 years), have low natural rates of birth and death and, like roughy, their flesh commands high prices, particularly in Japan.

Snapper have been caught commercially for many years, and the fishery is one of the largest and most valuable coastal fisheries in New Zealand. It is also one of the largest recreational fisheries. Recent surveys indicate that up to one-third of all snapper caught are taken by amateurs (Teirney and Kilner, 1995). Snapper are also part of the bycatch taken by the tarakihi, gurnard and other inshore fisheries. The customary Māori catch is unknown.

Three of the four snapper stocks (SNA1, SNA7 and SNA8) have been reduced below the MSY level (see Table 9.22). These stocks surround the top and west coast of the North Island. The fourth stock (SNA2) extends along the east coast of the North Island from Gisborne to Wellington. Its status is unknown, but its TACC has constantly been exceeded since 1987-88 because of bycatch losses to the tarakihi and red gurnard fisheries.

The largest snapper stock (SNA1) consists of two separate populations, both of which have been heavily reduced. The east Northland population is now close to the MSY level, while the Hauraki/Bay of Plenty population is well below it (see Figure 9.6). In 1995, scientists predicted that, at prevailing catch rates, both sub-stocks would decline further over the next five years (Annala, 1995b). The Fisheries Minister responded to this new information by announcing quota reductions for SNA1 (Minister of Fisheries, 1995). A year earlier, the Minister had accepted proposals by the Recreational Fishing Council to reduce the take of juvenile snapper in SNA1 through measures other than quota reductions. These had included an increase in the minimum legal size from 25 cm to 27 cm for recreational fishers and a cut in the daily bag limit from 20 fish to 15.

Based on the new evidence, however, the estimated recreational catch was reduced to 2,300 tonnes by lowering the daily bag limit from 15 fish to 9. The commercial quota was reduced from almost 5,000 tonnes to 3,000, and an allowance was made for a Māori customary take of 300 tonnes. Additional measures, to reduce snapper bycatch, included a year-round minimum net mesh size of 12.5 cm in shallow waters and a six-month closed season to commercial fishing in the inner Hauraki Gulf. No changes were made to management controls for the other snapper stocks. Catch levels for the other depleted stocks (SNA7 and SNA8) were considered to be sustainable and at levels that would allow them to rebuild to the MSY level. A year after these measures were implemented, the catch limits for Hauraki snapper had to be reduced yet again.

Figure 9.6: (a) Estimated biomass changes in the Hauraki Gulf/Bay of Plenty snapper sub-stock (SNAI). (b) Estimated biomass changes in the East Northland snapper sub-stock (SNAI)
Textual description of figure 9.6 (a & b)

Figure 9.6a

The estimated biomass of the Hauraki Gulf / Bay of Plenty snapper sub-stock has been dropping since the 1850s with a particularly steep drop between 1915 and 1940 (approximately 225 thousand to 75 thousand tonnes). It has dropped further since then, to around 35 thousand tonnes in 1990, but is predicted to slowly rise. The maximum sustainable yield is around 65 thousand tonnes.

Figure 9.6b

The estimated biomass of the East Northland snapper sub-stock has been dropping since the 1850s with a particularly steep drop between 1920 and 1940 (approximately 55 thousand to 25 thousand tonnes). It has dropped further since then to around 15 thousand tonnes in 1990 and is predicted to keep dropping. The maximum sustainable yield is around 15 thousand tonnes.

Source: Annala (1995b)

Orange roughy

Orange roughy (Hoplostethus atlanticus) has been heavily fished since 1982. It is one of five roughy species found in our waters and is by far the most valuable. The first known New Zealand specimen was netted at the bottom of Cook Strait by scientists in 1957, but it was not properly identified until 1979. Adults range between a third and half a metre in length, and are highly valued. Although they make up less than 5 percent of the total marine catch by weight, orange roughy account for nearly 17 percent of the fishing industry's income - about $200 million.

Living at depths of 700 m to at least 1,500 m, the orange roughy's life is still somewhat mysterious. From gut contents, it is known to eat squid, crustaceans and other fish. It is also known to be eaten by larger species, such as sperm whales. Those that avoid being eaten are long-lived. Individuals can survive for up to 120-130 years and many which end up in fish fillets are far older than the people consuming them. They also have one of the longest childhoods of any species, not reaching sexual maturity until they are about 33 years old. By fish standards, they produce relatively few eggs each spawning season (40,000-50,000). The eggs are large and drift upward. Those not eaten by predators hatch after 10 days and begin the slow process of growing up in the ocean depths.

In just 15 years, from 1978 to 1993, the total biomass of known orange roughy stocks was reduced to an estimated 15-30 percent of its original size. The decline was greater for some stocks than for others, depending on their initial size and the intensity of the fishing. Some stocks live as isolated populations on underwater plateaus or in deep-sea canyons and valleys, while others are spread over wide areas. It is now clear that the actual stocks do not always correspond to the fishery stocks for which TACCs have been set in the past. At present eight stocks are recognised, four of which are below the MSY level.

The four depleted stocks are around the west, south and lower east of the South Island. They are: the Challenger Plateau stock (ORH7A); the West Coast stock (ORH7B); the Puysegur stock (ORH3B Puysegur); and the Chatham Rise stock (ORH3B Chatham). A fifth southern 'stock' (ORH3B Other) consists of separate populations which may be one stock and which are too poorly known to make an assessment (Annala, 1995a).

The two stocks still above the MSY level and being fished-down are the Northern stock (ORH1) to the north and west of the North Island, and the East Cape stock to the north of Gisborne (ORH2A North) (Annala, 1995a).

The only stock which is currently at the MSY level is the 'East Coast' stock extending from Cape Runaway in the North Island down to Banks Peninsula in the South Island. It was originally classified as three separate stocks (ORH2A, ORH2B and ORH3A) but is now assessed as a single stock. Since 1986, catches and quotas for this stock had averaged almost 10,000 tonnes. Following scientific advice, the TACC was reduced to 6,660 tonnes in 1994 and then 2,100 tonnes in 1995, barely a fifth of its original level (Annala, 1995a; Minister of Fisheries, 1995).

Because of its extremely slow growth, very high economic value and ecological remoteness, orange roughy has been a difficult test case for the Quota Management System, embodying some of the biological and economic extremes that make quota decisions difficult for scientists and politicians. The entire history of the fishery represents less than a fifth of one fish's lifespan. So far the QMS has not emerged with flying colours. The four depleted stocks were all driven below the MSY level under the QMS regime. The challenge now is to achieve stock recoveries while avoiding the same mistakes with the remaining stocks.

Recent quotas reflect this goal. Although the two 'new' northern stocks have had their quotas increased, all other stocks have had substantial quota decreases. The overall orange roughy TACC for 1995-96 was just over 21,000 tonnes, one third of its peak in 198889 when it exceeded 62,000 tonnes. However, stock sustainability is only part of the challenge facing the orange roughy fishery in this era of ecological sustainability. Trawler impacts on deep-sea ecosystems, such as seamounts and coral communities, also need to be assessed and addressed before it can be considered to be truly sustainable (Jones, 1992; Fisher, 1995; Probert, 1996; Probertet al., in press; Raloff, 1996).

Hoki

In contrast to snapper and orange roughy, hoki (Macruronus novaezelandiae), which is fished as a single widespread stock, is under no stress. In fact, it is the most abundant of our commercially fished species. Foreign vessels began catching hoki in the 1970s, and today it makes up nearly one-third of the industry's total catch of all species. The hoki stock is well above the MSY level and is still being 'fished down'. The TACC was reduced from more than 250,000 tonnes in 1989 to just over 200,000 the following year. Since 1994, it has been cautiously increased and, for the 1995-96 season, was 240,000 tonnes (Minister of Fisheries, 1995).

While scientists believe the current hoki catch and quota levels are sustainable during the fishing-down phase, the catch has a significant impact on other species which may be less sustainable. Some stocks of ling, hake and silver warehou have had their quotas exceeded because too many are taken as bycatch in hoki nets. The hoki fishery also has a significant effect on non-fish species, such as seals and sea lions (see Box 9.18) and on mud-dwelling corals and other sea-floor invertebrates (Grange, 1993).

Box 9.18: The non-fish bycatch problem

Nets and baited hooks do not always discriminate in the species they catch. Besides the fish intended for the table, many other species also get caught, including protected species, such as corals, marine mammals and seabirds. One of the worst offenders was the 65 km 'wall of death' drift-net which New Zealand played a key role in getting banned from the South Pacific six years ago. But less notorious examples are commonplace. Trawler nets can kill corals and other sea floor dwellers as well as marine mammals near the surface. Poorly secured inshore setnets (or gill nets) can billow in the water, entangling anything that encounters them - mammal, fish, or bird. Even when properly set and securely anchored to keep the mesh taut and open, they can entangle dolphins. And nets are not the only threats. Tuna boat longlines are well-named. Each 135-km line carries up to 3,000 baited hooks, which often attract and catch hungry seabirds.

Coral and other inveretbrate bycatch is not monitored but marine mammal and seabird bycatches are. By law, all marine mammal captures must be reported and similar legislation is proposed for protected species of seabirds. Up to 1993, most data came from Government observers on board joint venture and foreign licensed vessels. They covered about 20 percent of the squid trawlers and less than 10 percent of the tuna longliners. Few observers were on domestic boats. As foreign boats declined and were replaced by domestic vessels, Government observers decreased and the fishing industry assumed a greater observer role on domestic, joint venture and foreign boats. Aside from the standard observer duties of recording fish species and catch effort, a strong emphasis is now placed on recording and reporting non-fish bycatch.

Estimates from Government observers for the period 1988-95 show that the seabird bycatch from Japanese longliners has declined from several thousand per year to several hundred (Baird, 1996). This reflects the sharp reduction in the Japanese fleet. The seabird bycatch from domestic longliners is not known but is believed to be less than the Japanese toll (see discussion later in this chapter).

Official estimates also show that about 950 New Zealand fur seals and nearly 70 New Zealand sea lions are drowned in trawl nets each year (see Tables 9.34 and 9.35). The fur seals are caught mainly in the southern blue whiting and West Coast hoki fisheries and also in the hake and southern squid fisheries. Some are hooked on longlines. The sea lions are mostly taken by southern squid trawlers operating within an 80 km radius of the Auckland Islands marine mammal sanctuary (where the sea lions breed). Both sea lions and fur seals were almost wiped out last century and are still only a fraction of their former population sizes. As they recover, their soaring birth rate may lead to more frequent encounters with trawlers near rookeries, haul out sites and feeding grounds. Dolphins are also bycatch victims. Common and bottlenose dolphins are sometimes trapped in jack mackerel nets off the west coast of New Zealand, usually one or two at a time, but multiple catches do occur, perhaps averaging 70 a year (see Table 9.36). Because these dolphins are abundant the bycatch is unlikely to threaten their populations. A far more serious threat, however, is the impact of inshore setnets on the rare Hector's dolphin.

Hector's dolphins are not the only setnet victims, but they are the most endangered (see discussion later in this chapter). Other setnet victims include: Dusky dolphins (near Kaikoura), fur seals and seabirdsespecially shags, yellow-eyed penguins, shearwaters, gannets and diving petrels. Most of these are protected species and several are threatened. The areas most at risk of setnet bycatches are: (a) those near the populations or feeding areas of vulnerable species; (b) areas of deep water close to shore (e.g. Kaikoura); (c) the Tamaki Estuary and Panmure Basin; and (d) Banks Peninsula. Although setnets now account for barely 5 percent of the overall domestic fish catch, the setnet fisheries still involve more than 600 vessels seeking the following species: rig and other sharks, butterfish, mullets, moki, flatfish and Kaikoura groper. A 1987 national survey found that setnets are also used by some 66,000 recreational fishers, accounting for about 7 percent of the national marine recreational catch. A survey of 647 recreational setnetters found that 30 percent had come across birds or marine mammals in setnets at some time (Taylor, 1992). Nationally this represents at least 19,800 recreational bycatch incidents over an unspecified period.

Government and the fishing industry are taking steps to reduce the protected species bycatch. In December 1988, a marine mammal sanctuary was established around Banks Peninsula to protect the local Hector's dolphins from setnets. Commercial setnets are banned, and amateur setnets are only permitted, subject to restrictions, from March to October. In 1993 the Marine Mammals Protection Code of Practice was introduced. That same year, fisheries regulations were amended to require bird-scaring devices, such as tori lines, on all tuna longliners. These measures have had some impact on the bycatch rate, but are far from a total solution (Mattlin, 1994a, 1994b; Duckworth, 1995).

Because zero mortality is seen as an unattainable goal, the Minister of Conservation has set marine mammal bycatch limits which the industry must not exceed. In future, the Maximum Allowable Fishing Related Mortality (MALFIRM) for all protected species will be determined through a consultative process set down in the new fisheries legislation and consequent amendments to the Marine Mammal Protection Act 1978. Setting MALFIRMs will require high quality population and bycatch data.

Other efforts to resolve the bycatch problem include a slight expansion of the Ministry of Fisheries Observer Programme. Bycatch assessments will continue to be made by the Non-fish Species and Fisheries Interactions Working Group, which is made up of Government, industry and environmental group representatives, and is convened by NIWA for the Ministry of Fisheries. Other research on bycatch species and mitigation techniques is being carried out by NIWA, the Department of Conservation and the fishing industry, with funding coming from the Ministry of Fisheries and from a Conservation Services Levy which is paid to the Department of Conservation by the fishing industry (Baird, 1996).