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Death of a fishery

Saturday, February 18, 1995
Okanagan Lake is in trouble.
Can we save it?

Frank Shannon of Summerland is deeply concerned the Okanagan Lake fishery is in imminent danger of collapse.

The 1992 kokanee catch in the big lake was only 10 per cent of the harvest in 1971. To make matters worse, the Fisheries Branch in Penticton says spawning kokanee numbers are at an all-time low.

There are fears a total collapse of the kokanee fishery will be followed a few short years later by the loss of the rainbow trout fishery.

Kokanee are now extinct in the South Arm of Kootenay Lake.

It could happen here.

Shannon is sounding a warning that must be heeded by all who care about the environment in general and Okanagan Lake in particular.

by Frank Shannon
B.C. Wildlife Federation
The Okanagan Saturday

THIS IS A STORY THAT IS IMPORTANT to every angler in southern B.C. It is the story of a major biological mistake.

Sadly, it took 15 – 20 years before the mistake was realized.

It is also the story of a political unwillingness to face the facts and do what is necessary to save our kokanee and rainbow trout fisheries in large lakes of southern British Columbia.

The story starts in Kootenay Lake where there once was a bonafide world-famous rainbow trout fishery. A whole tourist and recreational industry in the Kootenays was built up based on that fishery. Greedy and self-serving fishermen have their part in the story, too.

There were, at one time, many stories of washtubs full of rainbow trout over 10 pounds caught in weekend fishing expeditions. These fish were the famous Gerrard strain of rainbow trout.

In 1916, the provincial government, strapped for money, started selling and trading eggs from Gerrard (on the upper Lardeau River north of Kootenay Lake), the spawning area of the largest rainbow trout in the world.

Those eggs were sold all over! I have seen records where those eggs were shipped as far away as New Zealand and South America. They were also sent to a number of locations in the U.S. and other places I cannot remember.

In spite of the pressure put on the resource, those egg collections continued until 1949, when biologists were sent to find out what was wrong with the Kootenay Lake rainbow fishery! In 1949, spawners counted on the Gerrard spawning beds did not exceed 45 fish, and only 22 of those were female! This was a radical reduction from the hundreds which spawned there previously.

Concerned anglers had lobbied helplessly for years about the loss of this huge recreational resource. (Does that remind you of the Atlantic fishery?)

The late 1940s saw the dawn of biological research, such as it was, in B.C. There was a new crop of young biologists coming from the University of British Columbia and other Canadian universities. They had the courage of their convictions to order a stop to the sale of Gerrard eggs. That was a good thing, because if the sale had carried on much longer, Gerrard strain rainbow trout, the world record holder for size, would be extinct!

The biologists thought that if the trout’s early growth could be accelerated, the fishery would recover. To understand the biologists’ thinking, you need to know something about the life cycle of the Gerrard rainbow.

They are three years old before they attain 14 inches in length. At that age and size they become predacious and start feeding on kokanee. With this new source of protein. they grow very quickly to a large size. They don’t spawn for the first time until they are five, six or even seven years old.

The biologists had heard of a good rainbow population at Waterton Lakes in southwestern Alberta. These trout had good early growth. Their major food source was the mysid shrimp. Some of these shrimp were taken from Waterton lakes and released into Crawford Bay, on the Kootenay Lake, in 1949.

It was hoped, once they became abundant, the shrimp would spur the early growth of the Gerrard rainbow and speed up their recovery.

No evidence of the mysid’s progress was obtained until the late 1950s. The mysids had seemed to disappear.

In the late 1950s there appeared, in the west arm of Kootenay lake, near Balfour, an outstanding kokanee fishery. With daily limits of 25, and kokanee up to 10 pounds, Balfour was inundated with anglers from all over, particularly from Washington state’s Spokane area. The community of Balfour became very prosperous!

At this point, an explanation of mysids habits is in order.

They can feed not only on bottom-dwelling (benthic) animals, but also on swimming (pelagic) plankton. To avoid predation, the plankton feed mostly at night, rising to near the surface in the late evening, and retreating to the depths shortly after daylight.

Mysid shrimp follow the same pattern. The trouble is that kokanee alevin and fry (small recently-emerged kokanee) also feed on plankton.

There is strong evidence that the mysid are out-competing the kokanee alevin and fry for the same essential but common food source. This may be causing the young kokanee to starve, or at best grow so slowly that they are more vulnerable to predation.

There is a pressing need for more research. Unfortunately, research being done on Kootenay Lake does not address this situation. (That research is being funded by B.C. Hydro which has inherited the problems created by the Columbia River Treaty. That is another story in itself!)

A short explanation of Kootenay lake history is needed here to explain what happened following the introduction of the mysid shrimp into Kootenay Lake.

At one time in past geological history, Kootenay Lake and Kootenay River flowed southward into Pend Oreille Lake near present-day Sandpoint, Idaho, then westward to a confluence with the Spokane River finally joining the Columbia east of the present site of the Grand Coulee dam.

Volcanic eruptions about 250,000 years ago covered the Spokane area and created a mountain which dammed the river about five miles west of Bonners Ferry, Idaho. This, and subsequent glacial events caused the Kootenay River to back up and become a huge lake, which formed a new outlet over a low summit west of Balfour, near Nelson, B.C.

Years of water erosion have worn the summit down to its present level. Kootenay lake is over 300 feet deep just eat of Balfour, but less than 60 feet deep at the Balfour outlet.

As the mysid shrimp rise to the surface at night to feed on the plankton, they are swept over the bench at Balfour and into the west arm of Kootenay Lake. As the mysid are unable to retreat to great depths in the shallow west arm, they become an excellent food source for trout and larger kokanee. This situation resulted in the tremendous fishery which occurred in the early 1960s.

That fishery attracted the attention of biologists all over the world, particularly in the whole of the Pacific Northwest, which had many large lakes with co-existing rainbow trout and kokanee populations.

Biologists became elated over this method of creating a world-class recreational fishery. As a result, mysid shrimp were planted in nearly every large lake in the Pacific Northwest which contained rainbow and kokanee populations. Some mysid were even released in Sweden and probably other locations world-wide.

The sequence of events following the release of the mysids into Kootenay Lake probably went something like this: When the first mysids were introduced into Kootenay Lake, there was a good population mix of all generations of kokanee. Larger kokanee happily gobbled the swelling mysid population and grew tremendously large. This resulted in the fabulous kokanee fishery a few years after the mysid plant, and the record-breaking size of kokanee in lakes where there were already a number of near mature kokanee available.

In most lakes where the mysids were planted, there was initially a short lived “bonus” fishery, followed by a slow decline to alarmingly-low levels.

All kokanee populations in the south arm of Kootenay Lake are now considered extinct!

Most, if not all large lakes, where mysids were planted are showing similar experiences with declining kokanee stocks.

The problem is young kokanee also use plankton as a critical food item during their first years in lakes. As previously stated, mysids use plankton, too. As a result, there is competition for this common critical food source.

Apparently, mysids are winning the food wars!

In Flathead Lake in northern Montana, the same sequence has happened. Historically there has been a major migration of eagles through the Kananaskis Park area in Alberta into the Flathead in the early fall. The eagles rested there and fed on spawning kokanee.

Now that the kokanee runs are sadly depleted, there is a great concern as to what will happen to that eagle migration. The declining kokanee problem can have a domino effect throughout the environment.

In the Okanagan, there were historically large spawning populations of kokanee consisting of both creek and shore spawners. They were small fish, mostly in the six-to-eight-inch range at maturity.

Every creek and suitable shore area was populated by kokanee in the late summer and early fall. Pioneer farmers raked them out and used them for fertilizer! There was also a commercial kokanee fishery. For generations, the natives dried kokanee and stored them for their winter food supply.

Rainbow trout were also numerous. Early settlers had no problem catching a feed of rainbow trout for the family. The larger Mission Creek strain was sometimes called salmon because most settlers didn’t believe trout could grow that big.

With the arrival of more settlers came the need for more dependable water supplies for both domestic and irrigation use. Creeks were dammed and water was cut off during the critical kokanee spawning periods in the fall.

It took a long time before declining kokanee populations caused any comments, probably because shore-spawning kokanee helped to partially maintain their numbers. However, shore spawning can be precarious when water levels are relatively high, but the eggs hatch in February and March when water levels are relatively low.

The Okanagan wasn’t exempt from the mysid transplants, which only compounded the problems for the kokanee.

The biologists believed (at the time) that the mysids would give a boost to the Okanagan’s fishery just as they had given a boost in the Kootenay. The shrimp were planted in Okanagan and Christina lakes, along with other large lakes in southern B.C. during the mid-1960s.

There followed in the mid-to-late 1970s a “bonus” kokanee fishery in these lakes. Okanagan Lake’s “bonus” kokanee fishery extended into the early 1980s, when a small hatchery was activated near Okanagan Falls.

Kokanee were raised to about three inches in size and released into Skaha Lake as an experiment. They prospered for about two years, then disappeared!

Nobody knows where they went, but coincidentally there was a good kokanee fishery in Osoyoos Lake. During the next few years, the hatchery kokanee were planted in Okanagan Lake.

A research project was commenced in conjunction with the kokanee fingerlings’ release into Okanagan Lake. Among other things, the research was going to study the kokanee-mysid relationship. The biologists were curious as to why the kokanee grew to such an unusually-large size.

There was a theory that only larger kokanee would feed on the mysids, and the small kokanee would not. Mysids, being an excellent food source, might explain why nine- and 10-pound kokanee had been caught in Kootenay Lake.

An excellent kokanee fishery resulted allover Okanagan Lake with many large fish being taken.

A record kokanee, 10 3/4 pounds was caught near Okanagan Centre in 1988. Biologists believed they were finally finding the answers to the kokanees’ larger sizes. Apparently the kokanee fingerling were consuming mysids and growing to a large size because of improved nutrition.

This had two positive results: it improved the kokanee fishery which in turn reduced the mysid population, thereby helping the kokanee alevin emerging from their natal creeks by reducing the competition between the young kokanee and the mysids for their common food.

The good fishing continued for a few years and then the Okanagan Falls hatchery was closed and the on-going research was terminated, all due to lack of funding. Many organizations — both political and non-political — private citizens, and the Okanagan Region of the B.C. Wildlife Federation, have fought long and hard to have that hatchery reopened, but to no avail. The provincial government has turned down all requests for funding of the hatchery even though the statistics have proven reopening it is economically viable.

The biologists have stated that the rejuvenation of Okanagan Lake’s kokanee stocks rests with stream rehabilitation, such as at Deep Creek near Peachland, Penticton Creek in the Peach City, and Mission Creek at Kelowna.

Most of this work has been done by the Okanagan’s sportsmen’s clubs. Some of the enhancement projects have been done by local native bands on creeks running through their reserves. Most of the financing has come from the Habitat Conservation Fund. (The main source of funding for which is the surcharge paid on every hunting and fishing licence.)

Also, the biologists are waiting for the results of the studies presently being conducted on Kootenay Lake.

However, the local clubs are afraid of the possible results of any delays. What if the mysids are winning the food wars in Okanagan Lake also?

Then the question must be asked, would there be any point reopening the hatchery to increase the numbers of young kokanee in Okanagan Lake, only to have them starve? The answer to this question is “yes,” if the kokanee research which was cancelled is restarted and funded until its completion.

In our opinion, the Okanagan Falls hatchery experiment was a win-win situation. Anglers got good kokanee fishing and the larger kokanee were feeding on the mysids.

Yet the biologists say that three-inch kokanee don’t feed on the mature mysids. They say the kokanee fingerlings must survive on some other food source until they become mature mysid-eaters. The excellent fishery of the late 1970s proved that the kokanee fingerlings were feeding on something favorable. Could they have been feeding on juvenile mysids? Unfortunately, juvenile mysids are difficult to identify in kokanee stomach samples. More research is required to determine just what the young kokanee are feeding on.

The problem today is that we are never going to get rid of the mysids. Research must find some way to control the mysid population and find a way to help the young kokanee populations recover if we are ever to have a decent kokanee fishery in Okanagan Lake (or any other lakes with similar problems) again.

Biologists don’t necessarily agree with this. What they do agree on is that more basic research must be done if we are ever to know the answer to the kokanee’s problems.

Next we must trace the history of the large kokanee-eating rainbow trout in the Okanagan.

There are as many races of rainbow trout as there are of kokanee. Minor biological work but no long-term studies have been done on the Okanagan Lake rainbow trout.

Most of our knowledge is gleaned from work done elsewhere, mainly Kootenay Lake. The two major kinds of rainbow in Okanagan Lake are the Pennask and Mission Creek strains.

Pennask fish prefer to feed on insects. Any hatchery rainbow in the lake have come from accidental releases of Pennask trout. Also, Pennask rainbow enter the lake from creeks during freshets. Those, plus native stocks from the smaller creeks, are the main source of insect-eating rainbow in Okanagan Lake. The Mission Creek trout is similar to the large Gerrard strain of Kootenay Lake rainbow.

These fish feed on plankton and insects until they reach about 14 inches in size, when they become predacious and start eating kokanee. This extra protein source makes them grow quickly to a large size.

While the Pennask strain spawn at three or four years of age, the Mission Creek strain — like the Gerrard strain — doesn’t spawn for the first time until they are five, six or even seven years of age.