Salmon Fishery in Crisis? South Island Sea-Run Salmon Numbers Down

Salmon Fishery in Crisis? by Allan Burgess

Massive 38lb salmon taken in the Waimakariri River “back in the day” when the fishery was in much better shape than it is now. We haven’t seen fish like this in a whole generation of salmon anglers!

I originally wrote and published this article Salmon Fishery in Crisis in July 2001. How much, if anything, has changed in the past seventeen years? How and why is it all going wrong? Here’s what I said then. The text in italics is updated as of September 2018.

“A recent meeting of interested parties has confirmed what many of us knew already. Our salmon fishery is in serious trouble!

The meeting, convened in Christchurch by Paul Hodgson, and attended by representatives of Fish & Game, NIWA, the Salmon Anglers Association, Rakaia River Promotions, fishing clubs, and several leading fishing tackle retailers, discussed the present poor state of the salmon fishery, possible causes for the rapid decline, and considered a range of options for its enhancement. 

The group, called the Salmon Action Group, met again in late May. This editorial does not necessarily reflect the views of the group as a whole.

Just how bad things are can be seen from salmon returns to the hatchery at Glenariffe, in the headwaters of the Rakaia River. The last three years have seen very poor returns. This year’s returns are looking a lot worse than last year. Just 80 fish have come back to Glenariffe as at 8 May 2001, of which 34 were females. By means of comparison with past years as many as 1,200 females have been caught in the Glenariffe trap!

(The Glenariffe hatchery isn’t operating anymore. The National Institute of Water & Atmospheric Research (NIWA) sold it to private interests in 1999 and it closed permanently around about the time this article was written originally. After that a trout and salmon hatchery was opened by Fish & Game at Montrose).

The boom years before hatchery releases in 1985/86 saw 7,288 salmon return to the Glenariffe trap. This indicates that from an anglers’ perspective, if not a scientific one, the current returns to the Glenariffe trap show a salmon fishery is in deep trouble.

The current state of our salmon fishery from the bumper returns of 93/94, 94/95, 95/96 and 96/97, anglers were catching far fewer fish by 97/98. Over the following summer of 98/99, the size and numbers of returning fish had dropped away markedly.

Then followed the dismal 99/2000 season. That year salmon were returning from the sea and entering our South Island East Coast rivers in appalling physical condition. Fish weighed only half of what they should have based on their length. There were by now far fewer salmon available to be caught, and sadly those that were caught were all ”slabby” under-weight fish. (Feeding conditions at sea must have played  a part in this – what do salmon eat at sea?). 

This last season 2000/2001 has been even worse with numbers of returning salmon believed to be only about 1/3 of the previous year. Many discussions early seasons were about when the salmon would arrive. The usual early season catches in November and December never took place with just the occasional salmon being caught. There were more being caught by late January — but still only in very low numbers! The situation didn’t improve during what are usually the best months of February and March.

The Rakaia, Hurunui and Waitaki River competitions turned up very few salmon for contestants. The numbers of anglers on the rivers had also declined noticeably for the time of year!

Though salmon this past season have been in excellent condition, they have been small in comparison with past years.

This season’s weights ranged between 10-20 pounds. A big salmon would have been a 22lb fish. There were none of the heavy four-year-old fish of previous years. The large quinnat salmon of even 26 lbs have become a fading memory, let alone the glorious specimens caught during the mid-90s that sent the scales as high as 38 lbs!

If you didn’t catch a salmon in Canterbury this season you share some illustrious company. Many leading salmon anglers didn’t catch a salmon this season either. To borrow from cricket, most salmon anglers experiencing “dot balls!

Salmon angler dissatisfaction is high with numbers of returning fish believed to be only around one-third of the previous season. In short, salmon were very hard to catch over this past season.

This is a fibreglass replica of the winning fish from the 2000 Waitaki River Salmon Fishing Competition. This is a very slabby fish for its length. Feeding conditions at sea must have been the reason for its poor condition. Caught by S. Gregory it weighed 7.636kg (16.8lb). Whereas in 1994, 1995 and 1996 the winning fish all weighed in excess of 16kg (35lb). The winning salmon in 1997 weighed 14.005kg (30.8lb). Read more about past Waitaki River Salmon Fishing Contest Winning fish weights since 1984. Photo: Allan Burgess.

Possible causes for the decline

The Salmon Action Group discussed and considered a number of possible causes for the decline in salmon returns. They are as follows:

Low Flows

Lack of water in our rivers especially during the crucial period during which juvenile salmon go to sea could seriously affect survival rates.

Some scientists think that young salmon may suffer a sort of shock when entering saltwater for the first time. In Canada and Alaska the major rivers have broad intertidal estuaries which give the young fish a chance to acclimatise to saltwater, whereas in the Rakaia, Rangitata, Hurunui, and Waitaki, there are no estuaries for this to occur.

When there is a flood through the river, a big stream of dirty, brown, freshwater runs out into the sea where it gradually mixes and is diluted by sea water. This is thought to benefit the salmon smolt entering the sea. During low flow years, this doesn’t happen. So floods may, in fact, be a good thing for salmon!

Low river flows and poor water quality, for what ever reason, can only detract from the salmon fishery. Salmon spend their first year of life in the river before going to sea. It is at sea that they put on weight. But if conditions in the river were poor for the young salmon it can only decrease their survival rate before they even enter the sea.

Water abstraction for farming and pollution of our rivers by industrial and farming waste is disastrous for the salmon fishery. Any future enhancement plan for the salmon fishery must first address the dual problems of water quantity and quality before attempting to enhance the salmon fishery in other ways. Fish & Game are taking degradation of our rivers very seriously and I applaud them for this. (The appalling fish screen nonsense and obscene over-extraction of water from the Rangitata River needs to stop. Thinking that a screen of bubbles was ever going to stop fish from passing seems like a dumb idea to me! The once mighty Rangitata River renowned for its consistent salmon runs is fast headed the same way as the Opihi and Orari Rivers, where, for most of the year, the river mouths are closed).

(Fish screens are barriers designed to prevent trout and salmon, as well as native species, from being diverted from rivers and sprayed onto paddocks. Juvenile salmon are particularly vulnerable and have been destroyed in huge numbers by these poorly designed fish screens. There are many of these ineffective fish screens operating in Canterbury. It has only been relatively recently that Fish & Game and ECan have fully appreciated just how poorly these fish screens have performed. There must be no stalling on this issue).  

Extreme weather patterns

We have all heard about La Nina and El Nino weather patterns. There seems to be little effect from these on our east coast river flows from rainfall. But even a slight warming of sea temperatures could well have a serious effect on the food supply for salmon at sea.

Poor feeding conditions at sea, such as a lack of lobster grill, could well reduce survival rates for salmon. This would be particularly disastrous if such conditions prevailed for almost the entire time the salmon were at sea. It would not only decrease the chances of fish surviving to maturity then returning to our rivers, it would also explain the very poor condition of returning salmon during the 1999/2000 season. What do salmon eat at sea?

Weather patterns may well be a good blanket explanation for the decrease in overall salmon numbers, particularly when you consider that low returns have been reported over the whole of the East Coast from the Waiau River in North Canterbury, Otago Harbour, and all the way down to Bluff.

Commercial by-catch

Facts and figures were reported to the group by Ross Millichamp, manager of North Canterbury Fish & Game. Commercial by-catch was considerable in the six years between 1985 and 1990. It peaked at 60 tonnes in 1987. Without a doubt, the huge commercial by-catch over this period was disastrous for the fishery. The figure of 60 tonnes represents as much as one-third of the total salmon run. The figure of 60 tonnes was just the “reported” by-catch that year. There is little doubt that the “actual” by-catch was much higher. There was much hue and cry over this at the time with larger trawlers eventually being banned from the known salmon grounds off Banks Peninsula.

Since 1992 the commercial by-catch has been quite low. Total reported by-catch last season (2000/2001) was just 450kg. This represents about 76 to 80 salmon. Commercial fishermen have reported seeing, or catching very few salmon this past season.

Interestingly red cod catches have also been poor. There seems to be some correlation between good years for salmon and red cod. The red cod fishery has always gone in cycles. There are so many good years followed by so many poorer years. The same can also be said for the salmon fishery which seems to revolve in an eleven-year cycle – possibly this may have something to do with the earth’s magnetic field.

My personal opinion is that any large commercial by-catch can quickly destroy our salmon runs, which are relatively small compared to those of the Pacific Coast of North America. In my view, it should be totally illegal for a commercial fishing boat to have a quinnat salmon on board in New Zealand waters!

This big red cod was caught near Bluff, Southland. Some years are very good for red cod commercial fishing catches, and other years not so good. It is thought this is related to sea temperatures and the abundance or otherwise of prey species like whale-feed (krill). Good years for red cod and barracouta are often good years for salmon too!

Wild or Hatchery Salmon

For the benefit of younger anglers, there are two sorts of returning salmon: wild fish and hatchery fish. Both are the same Quinnat salmon species. The only difference is in the way they are raised.

Wild fish return to the streams from which they hatched as ova. Hatchery fish return to the stream where they were released as smolt (juvenile salmon). These hatchery-reared fish hatch from ova into the protection of tanks were they are fed and cared for protected from predators. The whole object of the exercise is to increase the survival rate above that in the wild.

Egg to smolt survival in a South Island hatchery situation is quite high at about 50 per cent. A mature female produces around 5,000 eggs. It isn’t all plain sailing, however. Raring salmon in a hatchery situation is expensive. You also have to know what you’re doing. A wrong move and the young salmon can easily die!

There are other factors to consider also. Hatchery fish tend to return to our rivers to spawn earlier than wild run fish. As most of the feeding and subsequent weight gain takes place at sea hatchery fish tend to be smaller than wild salmon. This explains the reason that returning salmon have been generally much smaller over the last five years. You just don’t see the big salmon weighing thirty pounds or more caught at the mouth of the Rakaia River the way we used to! These big salmon were wild run fish that had been spawned naturally.

The biggest problem with hatchery salmon is that they tend to join with the wild run. This is great, to begin with. In initial years the two combine together to produce a greatly increased overall run of salmon to our rivers.

The drawback is that the hatchery fish interact with the wild fish over the following years to the extent that overall returns decline. Eventually, the fishery becomes dependent on hatchery releases to sustain it.

From 1985 to the early 1990s commercial hatcheries released as many as 6 million smolts annually. These releases have now almost stopped. Many of the companies, some of which were listed on the New Zealand stock exchange, went belly-up! In hindsight, it can be said that these massive releases of hatchery-bred smolt have at least been partly responsible for the overall decline of the salmon fishery.
It was great while these huge commercial releases were taking place. Returns in the mid-90s were excellent. But it now seems that the fishery had become dependant upon such releases.

A notable side effect of releasing millions of smolt annually is that the releases were staggered. The aim is to generate returns over a longer period than that which occurred naturally. Hatchery salmon returned from early November through to mid-winter. While the wild run salmon didn’t start to run until late January and peaked in Late February and early March.

The best salmon fishing this year in the Waimakariri River, at Mclntoshes Hole, was during the month of March. By this stage, with the poor season so far, many had pretty much given up and put their rods away for the winter!

Keith Reinke is one of the best salmon anglers around and a Waitaki River stalwart. Here Keith has landed a hefty 35 pounder together with a 15-pound fish. The size difference is amazing!

Angler Catch

According to Fish & Game, the figure for angler catch is estimated to be in the region of 40 per cent of the total salmon run returning to our rivers. Interestingly Fish & Game have no data for the actual total numbers of salmon caught by anglers going back 20 years or more.

Back during the big runs angler surveys were not carried out so it isn’t possible to gauge the true extent of angler catch as a percentage of returning fish over time.

Fish & Game can argue, correctly, that it makes good sense to restrict angler catch in poor years so as to maximise the numbers of salmon surviving to spawn. Conversely, in years when salmon are plentiful, most restrictions on angler catch could be lifted. For example, in poorer years catches could be limited to one fish, per angler, per day, whilst in good years the bag limit could be raised to four fish, per angler, per day without a negative impact on the fishery! 

This sort of scheme, which operates in Canada, would require closer monitoring of the numbers of returning fish by Fish & Game. The argument against this is that because the period of the main salmon run is quite short, and returning fish numbers can only be monitored above the gorge, by which time it would be too late to make any difference. Also because fewer anglers would catch their current limit of two fish in a poor year anyway it would make more sense to close the salmon fishery entirely by, say mid-February, if any substantial benefit was to be gained.

Although most anglers would understand the logic of closing the salmon fishery early in very poor seasons, I doubt that this option would be a runner with many. It would certainly reduce angler enjoyment of the fishery. I suspect that it would also impact on fishing licence sales if anglers were made aware that the fishery might be closed at any moment.

Another possibility that has been discussed is limiting the total catch per angler per season. This is something else that is done in Canada. It works on a tag system where an angler gets so many tags with his licence and must attach a tag to the head of a captured salmon – get caught by Fish & Game with an untagged salmon and you are in big trouble even if you do have a fishing licence.

With this tag system, it would be possible to limit the total number of salmon an angler can catch in a season. The object is to allow more fish to survive to spawn, and so replenish the fishery.

About 100 anglers catch most of the salmon

In Canterbury, roughly 100 anglers catch as many salmon as all the other license holders combined. The old fishing rule about 10 per cent of the anglers catching 90 per cent of the fish is very much alive and well when it comes to salmon fishing. The great majority of salmon anglers catch between zero and two fish per season. This applies even in the very good years.

Salmon is always a difficult fish to catch! Limiting the number of fish an angler can catch per season would be very unfair on those anglers who live at South Rakaia Huts, for example. It would diminish their fishing enjoyment considerably.

So why do so few anglers catch so many salmon?

The first thing you need is time on your hands. I spoke to one bloke recently who had caught 11 salmon this season at Mclntoshes Hole on the Waimakariri River. A remarkable feat I’m sure you‘ll agree! However, he told me that he had averaged 65 hours per fish with about five salmon being caught during a four day period in mid-March. This short burst of success had improved his average considerably. That totals 715 hours. Which, if my math is correct, equals 17 x 40 hour weeks. That’s something like a forty hour week, every week, during the four months December – March. Most people just can’t afford that sort of time to go fishing. I know I can’t.

Live close to the river

Many of the anglers who catch a large number of salmon live close to the river. They often have a bach at the river mouth and can ride down every morning of the week for a “look” at first light, and then again in the evenings. (They are also well placed to fish the surf from low-tide, and then drop back to the gut and lower braids as the tide rises). This gives them a big advantage over most anglers who can only fish at weekends. I have often caught salmon within the first few casts upon arrival at a likely spot. The more times you can “arrive” the greater your chances.


These days it seems everyone has a four-wheel-drive vehicle. But not everyone has a jet boat. A jet boat and the time to go out in it is a massive advantage when it comes to salmon angling. At the Rakaia and Waitaki Salmon Fishing Contests, the majority of fish are caught from jet boats.

I suspect improved mobility for a greater number of anglers has meant that more salmon are caught these days as a percentage of the total run than was the case in years gone by. Although as mentioned earlier Fish & Game have no figures on this (fishing for salmon above the gorge bridges on the Rakaia River was almost unknown before the 1980s. In general, anglers are now much more mobile than they once were and are better able to get a shot at the salmon).

Is the Salmon Fishery in Crisis?

Is the fishery in serious danger of total collapse through insufficient natural recruitment to sustain itself into the future? Probably the answer is no. From a scientific viewpoint, the fishery will recover. But will there be a worthwhile experience for anglers in the meantime?

Have we reached a point where there are so few fish returning to spawn in the headwaters that the whole viability of salmon fishing in Canterbury as we have known it is under serious threat of extinction? I hope not. But this is a very real possibility. I believe it will recover on its own eventually – but it could take a few years. (One thing that has certainly changed since the mid-1990s is the size and weight of returning salmon. In those days fish weighing in excess of 25lb, and all the way up to and exceeding 35lb were not uncommon. We haven’t seen salmon that size caught in Canterbury in a generation).  

As Ross Millichamp from Fish & Game wrote in an article in the salmon angler’s newsletter a decade ago it took just fifteen years for salmon to become widespread in Canterbury rivers following their introduction in the early 1900s.

Salmon fishing is part of our heritage and tradition in Canterbury. It is a unique South Island fishing experience. The knowledge of how to catch salmon is often handed down from father to son. 

What can we do to enhance the fishery?

According to Fish & Game hatchery releases do improve salmon runs, however, the greatest improvement comes in the good years. Smolt releases may not substantially improve returns in poorer years.

Releasing smolt is an expensive business. The cost of providing an extra salmon to the angler varies with the cost of smolt and the percentage that return.

NIWA’s Martin Unwin, a respected expert in hatchery management, believes that a return of one per cent to the river can be achieved most years.

The commercial cost of 10,000 smolts from NIWA would be $10,687. The number of these returning to the river is just 100 fish. Number caught by anglers is about 40 fish. Hence the cost of each additional angler caught fish would be $267 each!

According to NIWA 300,000 to 500,000 smolt would need to be released to have a significant impact on the numbers of returning salmon in the Rakaia River alone. A half million smolt would cost half a million dollars. Even if it could be done for a bit less it would still be a very significant figure.

A less expensive option might be to plant eyed ova into stream beds. The survival rates may not be as high as smolt releases but it is also technically less demanding so that salmon anglers would be able to help out with planting the eyed ova.

At this stage, there are no firm plans in place to conduct large-scale smolt releases, although some work is being done to release eyed ova.

(I see in Special Issue 47 of Fish & Game magazine – September 2018, which is free to all licence holders, that North Canterbury Fish & Game are “strongly encouraging” anglers to limit their salmon catch to just four salmon for the whole season. Fish & Game are considering “further restrictions” if harvest and spawning number ratios do not improve and the salmon fishery begins to show signs of recovery. They are even ser5iously considering reducing the daily bag limit from two fish to one! 

Following on from the Sea-Run Salmon Symposium “Turning the Tide”, held in 2017, you can read the 23-page outline on what is being done to restore the ailing Canterbury salmon fishery produced by Steve Terry of North Canterbury Fish & Game, dated June 2018. 

Also in the 23-page outline, is this little snippet from Central South Island Fish & Game which provided a summary of their 2010 salmon catch below. This also highlights the need for a conservative limit bag to have any significant difference in the number of salmon saved.
8873 licence holders
6418 did not go salmon fishing
Of 2455 who fished for salmon 1834 caught nothing
621 fished for salmon and caught 1623 fish average 2.6 per successful angler
253 caught 1, 166 caught 2, biggest catch 29.
Interesting that 14 anglers caught more than 10 (poor season or not 14 anglers caught more than 10. One of those anglers catching 29 salmon). Even in a poor season, the top anglers are still going to catch a lot of fish compared with the majority. 

If you are a Canterbury salmon angler I strongly recommend you download Steve Terry’s report and digest as much of it as possible. In this matter knowledge is power).

Is the Salmon Fishery in Crisis? Yes, it is. We’ll keep you posted on developments.

This post was last modified on 16/01/2021 8:43 am

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