National Parks’ Challenges

Case Study 7: The Fishy Disappearance of Kokanee Salmon in Kluane National Park and Reserve of Canada

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Contents:

1. Issue overview
2. Park overview
3. Detailed issue information (kokanee salmon, decline of kokanee salmon, questions about kokanee decline, research studies and findings)
4. Stakeholder descriptions
5. Supplementary information

1. Issue overview

Kluane National Park and Reserve (KNPR) is Canada’s only national park with a naturally occurring population of kokanee salmon (Oncorhynchus nerka).  For reasons yet to be understood, the spawning numbers of this population have dramatically decreased over the past few years.  Fish are a vital part of the aquatic ecosystem, they play an important role in First Nations cultures, and fishing is an important part of a national park experience for many people.  The potential loss of the kokanee salmon in KNPR and the lack of definite answers as to the cause of this disappearance present an intricate and complex issue for park managers. 
                  
2. Park overview: Kluane National Park and Reserve of Canada

• Located in the southwest corner of the Yukon Territory, bordering both British Columbia and Alaska.
• Established in 1976
• Representative of Northern Coastal Mountains Natural Region (Region 6)
• Area: 22 016 km2
• UNESCO jointly declared KNPR and its American counterpart, Wrangell-St. Elias National Park, a World Heritage Site in 1979.  Glacier Bay National Park in Alaska was added in 1992 and Tatshenshini-Alsek Provincial Park in BC, in 1994.  The combined total of 98, 340 km2 forms the largest international terrestrial world heritage site and protected area on earth.
• KNPR features the highest mountains in Canada, including Mount Logan, Canada's highest peak.

The Kluane National Park and Reserve Fact Sheet (located in Printable Version) will provide you with more information on this park.  You can also consult the National Park System Plan; look up Region 6.

3. Detailed issue information

3.1 Kokanee salmon

Kokanee salmon are landlocked salmon that live out their entire lives in freshwater. This is different from regular, ocean-going salmon. While regular salmon are born in fresh water, they eventually leave to spend most of their lives in the more productive salty waters of the ocean, returning to fresh water only as reproductively mature adults to spawn.  Sometimes, when ocean-going sockeye salmon are using a lake system as their spawning area, a new strain of landlocked salmon develops.  Instead of migrating hundreds of kilometres from their birthplace to the sea, and then back again to spawn, these new salmon (kokanee salmon) complete their entire life cycle within a lake system.  Such is the case with the kokanee salmon of KNPR, which complete their entire life cycle in the fresh water of the Kathleen Lake watershed.

Life Cycle

As adults, the kokanee of KNPR spend most of their time in Kathleen Lake.  They are silver in colour, much like their ocean-going cousin the sockeye salmon.  The kokanee are much smaller than the sockeye, though, normally weighing less than one kilogram and measuring approximately 20-30cm long. 

At 3-5 years of age, kokanee become reproductively mature fish known as spawners. At this point in their life cycle, they undergo dramatic physiological changes.  The males turn bright red with a green head; they develop a slightly humped back and an elongated, hooked jaw. The females turn a darker shade of red with a green head.  In July, both male and female spawners stop eating and devote all their energy and fat reserves to migrating upstream to their spawning beds at Sockeye Creek (a journey of about 20 km).  When they reach the spawning beds in mid- to late-August, they are ready to reproduce.  The female uses her tail to dig a nest in the gravel called a redd. She then releases bright red eggs into the redd while the male releases sperm to fertilize the eggs.  The female once again uses her tail to bury her fertilized eggs beneath the gravel.  She will dig two or three redds, filling each with as many as 1000 eggs.  Once this process is complete, the adults die, adding nutrients to the streambed and providing food for scavenging wildlife.

Spawners © Alida Allison, 2006 Parks Canada	Eggs © Alida Allison, 2006 Parks Canada
Alevins © Alida Allison, 2006 Parks Canada	Fry © Alida Allison, 2006 Parks Canada

In February, the eggs hatch out as alevin. The alevin stay in their redds under the gravel for protection and are nourished by egg sacs attached to their bodies.  In a few months, the alevin develop into kokanee fry that measure about 2-3 cm long.  Most fry will ride the current downstream to Louise and Kathleen Lakes, but some will fight the current to reach Sockeye Lake.  The kokanee will grow to become silvery adults and then the whole cycle will repeat itself.

3.2 Decline of the Kokanee

When KNPR was established in the early 1972, a fish specialist did an inventory of all the lakes and rivers in the park.  This specialist described the kokanee salmon in Kathleen Lake as having special significance.  The original sockeye salmon population that gave rise to the kokanee population was no longer present in Kathleen Lake. The specialist noted that this was probably because their migratory routes to the ocean had been cut off periodically in the past by surging glaciers.  The kokanee’s adaptation to living exclusively in freshwater, however, meant that they were not affected by such glacial activity, and they continued to survive in Kathleen Lake.  This was a very unique and important story.

The specialist conducted various tests regarding the physical, chemical and biological aspects of the kokanee’s lake habitat.  The specialist also designed a long-term program to monitor the spawning kokanee.

The kokanee monitoring program involved counting the number of adult spawners showing up on the spawning beds over a certain period each August.  The average number of spawners counted each year from 1976 to 2001 has fluctuated considerably, but wildlife populations typically show this kind of variation when monitored for extended periods of time.  Over the last 30 years, there have been as many as 8000 or as few as 1000 kokanee on the spawning beds, with the average number of kokanee appearing on the spawning beds each year being about 2800.  This has been taken to be a healthy average for the Kathleen Lake system. 

In 2002, however, the number of kokanee counted on the spawning beds dropped to an all-time low of only 730 fish.  Though this was a concern, everyone was hopeful the kokanee would bounce back as they had in the past.  The next 5 years, however, saw an overall decline in the numbers of fish showing up on the spawning beds. 
2003 – 160 kokanee
2004 – 53 kokanne
2005 – 66 kokanee
2006 – 94 kokanee
2007 – 88 kokanee
This drop in numbers is what ecologists call a massive decline.  A major drop in population numbers of any native species within a national park is cause for concern and investigation.  

3.3 Questions about the Kokanee Decline

No one knows why the kokanee numbers have plummeted over the last few years.  Since the 2002 survey count of only 730 kokanee, park wardens have been taking various steps to try to understand the decline in hopes of mitigating it.  KNPR has organized kokanee salmon workshops, working groups, and research initiatives. 

The investigation into the reasons for the decline of the kokanee began with asking questions and identifying knowledge gaps.  Below are some of the major questions and hypotheses that KNPR, along with diverse stakeholders, have come up with regarding the decline of this special fish population.

Questions about Abundance

• What have fish numbers been in the past (prior to the monitoring that started in the 1970s)?  Are the fish surveys that have been done since accurate?  Are there other methods to estimate the fish population?

Questions about Habitat Loss

Changes to spawning habitat

• Kokanee are only known to spawn in water that is less than 15 degrees Celsius; their eggs will not survive in warmer water.  Are warmer temperatures in the creek causing kokanee eggs to die?
• Kokanee salmon are sensitive to flow rates because they cannot swim against powerful currents.  Are flow rate stress and water temperature stress combining to cause population decline?
• Have changes to the water temperatures or flow volumes caused kokanee to abandon the Sockeye Creek streambed as a spawning site altogether?  Are kokanee still spawning in good numbers in another location?
• The timing of the emergence of fry from their redds (the gravel nests) is temperature-dependant. Are warmer, earlier springs causing fry to emerge earlier than usual, before plankton is available for them to eat? (Plankton are micro organisms  that comprise the bulk of the kokanee’s food.)
• Is winter and spring snowmelt more erratic, causing abrupt changes to stream flow and depth in Sockeye Creek?

Changes to lake habitat

• Are warmer temperatures close to the surface of the lake forcing kokanee to cooler depths, where there are more predators?
• Has the shedding of needles from beetle-killed spruce trees in the area altered the pH levels (acidity) of the water in the lakes or on the spawning beds?  If so, has this change in water chemistry made the water too acidic for the kokanee and/or their eggs to survive?

Questions about other Limiting Factors

Food availability

• Plankton are the major food source for kokanee in Kathleen Lake. Plankton numbers in Kathleen Lake probably go up and down cyclically. Has the plankton population changed in a way that is negatively affecting the kokanee? Is there less plankton? Is there less plankton at times when kokanee need it most? 
• There are various other small fish in Kathleen Lake.  Is competition with other fish for limited food sources becoming a problem for the kokanee?

Predation

• There are many larger lake trout in the Kathleen Lake watershed; these fish prey on kokanee salmon.  Are these large trout eating too many kokanee adults and young for the kokanee population to survive?
• Have the kokanee salmon been over-fished by people?

Disease

• Cold northern lakes like Kathleen Lake don’t typically host many parasites. Have water temperatures warmed, favouring parasite survival and leading to disease and death in the kokanee population?

3.4 Research studies and findings

Using the above questions and knowledge gaps as a kind of road map, KNPR, researchers and local residents have begun investigating possible reasons for the decline of kokanee.  Some questions have been answered and some knowledge gaps have been narrowed.  Results from various research projects are summarized below.  Unfortunately, many questions still remain and the reason for the decline is as much a mystery today as it was in 2002.

Netting a spawner © R. Staley, Parks Canada

Warden collecting weather data © L. Gorecki, Parks Canada

Investigations into Abundance

• Kokanee salmon are known to have a boom/bust cycle; the population reaches very high numbers, and then “crashes” to lower numbers, only to rebound back to very high numbers again.  However, the ecological integrity indicator range (the range within which a healthy population is expected to cycle) is between 1507 and 3849 fish.  Current numbers fall far below this range.
• Kokanee salmon surveys have been conducted since 1976 (with the exception of 1977, 1983, 1986, 1987, and 1988). The area surveyed, the time of year, and the techniques used were consistent from year to year.  This survey is an accurate count of the kokanee spawners and confirms that kokanee are in massive decline.
• If the fish were spawning in areas other than the survey location, it is possible that there may in fact be more fish in the Kathleen Lake system.  A hydro-acoustic survey of the Kathleen Lake water system was completed in 2005 to determine how many juvenile kokanee salmon could be detected throughout the entire water system.  Transects of Kathleen Lake, Louise Lake and Sockeye Lake were surveyed using echo sounds.  When a group of fish was located at a depth of 30m or less, a sample was netted to check the species type.  This hydro-acoustic survey turned up plenty of fish in the lake system, but no kokanee were found. These results do not indicated with certainty that the kokanee population is not in Kathleen Lake.  More studies are needed to determine the actual population number as kokanee could be living at water depths deeper than 30 meters.

Investigations into Habitat Loss

Changes to spawning habitat

• Wardens and researchers have looked for other potential spawning sites during the annual survey; none have yet been found.  More surveys are also being completed throughout the entire month of August in case the kokanee are spawning at a different time than in the past.
• A weather station was set up in the spawning bed to collect temperature and precipitation data at the site.  Habitat requirement for kokanee is between 2-15 degrees Celsius; there is 100% mortality of kokanee eggs at approximately 17 degrees Celsius.  It was found that water temperatures were 14.4 degree Celsius, which is close to the maximum preferred temperature for kokanee to survive. 

Changes to lake habitat

• Water tests show that the pH values of the lake and stream have not changed since the 1970s.

Investigations into other Limiting Factors

Food availability

• While there have been numerous plankton hauls and samples taken in the watershed since the kokanee went into decline, no link between plankton abundance and kokanee has yet been established.  Results from the recent studies are pending.

Predation

• Lake trout stomachs collected from local ice fishers have revealed little evidence of kokanee predation by lake trout.  These results are not scientifically significant though, as very few stomachs have been turned in.

Disease

• A veterinarian examined 16 kokanee for evidence of disease or parasites, but found that the fish were clean and healthy. While the veterinarian reported that disease or parasites were not likely to be a major factor in the kokanee’s decline, he did not rule out the possibility, and has suggested further study into the matter.

Other Information to Consider

• Other kokanee populations in the Yukon (outside KNPR) appear to be stable.  This suggests that whatever factors are influencing the kokanee inside KNPR are regional.
• Interviews with First Nation Elders have been conducted to find out what they know about kokanee and how the Kathleen Lake watershed was used in the past.  This is an on-going project.

3.5 Management Action Taken

In 1980, the kokanee salmon spawning area was set out as a Zone 1 special preservation area.  This means that there is a special feature (the kokanee salmon) that may need special protection and gives the park the authority to take management action in these areas. 

Prior to the decline of kokanee on the spawning beds, management actions taken to protect the fish included certain boating and hiking restrictions. While motorized boats have always been allowed on Kathleen Lake, they are not allowed on Louise or Sockeye Lake to protect the spawning beds.  Hiking and camping are not allowed in the Sockeye Lake area (the spawning grounds) between July 15-October 30   as not to disturb the fish at this important time. Since the decline of kokanee on spawning beds, KNPR has gone from setting a daily catch limit for kokanee to shutting down the fishery altogether in March 2004.

Kokanee eggs from KNPR were taken in 1990s to test the health of the fish population and to populate other lakes in the Yukon.  Tests showed that these fish were the very clean of disease or parasites.  These fish populations are doing well in these lakes.

4. Stakeholder descriptions

Stakeholder Profiles

First Nation Member

As a member of the Champagne and Aishihik First Nations, you have the right to harvest (gathering, hunting, fishing and trapping) for subsistence within park boundaries, all species of fish and wildlife, in all seasons of the year (“taking only what you need and not taking more than you can use”).  Elders in your community are concerned about the effects of global climate change.  Warmer water temperatures may be decreasing the amount of oxygen in the spawning stream.  Spruce beetles that are favoured by the warmer weather have killed the spruce trees beside the spawning stream, so the trees have lost their needles and do not provide shade like in the past – making the stream even warmer.  A warmer climate could also contribute to spring run off, because beetle-killed trees are not absorbing water directly into their roots.

The decline of the kokanee may be a result of global warming, but it may be a totally natural decline in the kokanee population, and the spawning numbers may return to normal on their own. Any response to the kokanee salmon decline must show respect for the fish.  Elders feel that “catch and release” fishing stresses fish and is the equivalent of “playing with your food”. Though many anglers exercise good practice in catch and release, it is still viewed as disrespectful. The elders would like to see “catch and release” fishing discontinued.

Local Fisher

You have fished in KNPR for many years and believe sport fishing contributes to many people’s enjoyment of being in a national park.  You notice there have been many more large lake trout in Kathleen Lake ever since slot limits  were introduced about 15 years ago.  (The slot limits require fishers to release any larger fish they catch.) You have seen kokanee in the stomachs of lake trout, and believe the increased number of lake trout is the main contributor to the kokanee’s decline.

Fishing regulations should be changed to allow more fishing of large lake trout- this will decrease predation of kokanee and allow the kokanee population to rebound.  The Whitehorse Fish Hatchery raises kokanee of the same genetic stock as the naturally occurring population (originally from Kathleen Lake).  Plans should be made to stock Kathleen Lake with these kokanee if numbers do not rebound soon. 

Park Warden

Part of your job is to carry out the park’s mandate to preserve the ecological integrity of the park’s ecosystems.  It is difficult to understand what’s happening to a single fish species in isolation, without understanding what’s happening in the Kathleen Lake ecosystem as a whole.  Yet, you are forced to make management decisions before you have all the information.

You supported closing fishing for kokanee and believe it should remain closed until it is clear their numbers are back to normal levels.  The area around the kokanee’s spawning grounds will continue to be given special protection by the park’s zoning policy, and research into the decline of kokanee will continue.  You would not support stocking the lake with hatchery fish because of the danger of introducing new diseases to the ecosystem, or the chance that the stocked fish could out-compete the natural population.

Fisheries Biologist:

You have participated in several studies of kokanee in KNPR. You have found that there have been very low water levels in the spawning stream in some years, and that water temperatures were quite high in other years.  You know that spawning kokanee can be sensitive to water level changes and that kokanee eggs cannot survive in water above 17 degrees Celsius. You feel that more research needs to be done, especially to check if anything is out of balance in the kokanee’s food supply. 

You are cautious about focusing on only one possible cause of the kokanee’s decline.  You think it’s important to have as much scientific data as possible to understand what’s happening to the kokanee salmon.  You have also read reports of other kokanee populations that appeared to “disappear” only to rebound several years later. 

Local Environmentalist

You note that climate change has created warmer water temperatures in the spawning stream, warmer winters and earlier springs.  These changes may be affecting kokanee eggs as well as kokanee’s main food source: plankton (microscopic organisms).

You are a proponent of “letting nature take its course” in national parks.  The kokanee salmon have cycled up and down in the past, and you think they should be allowed to rebound on their own, without any human intervention.  Researching (tagging fish, disturbing spawning sites) can be very invasive to wildlife species.  You wonder whether researching the decline should stop altogether.  You also wonder whether the kokanee salmon were over-fished in the past, and you question whether fishing should be allowed in national parks at all.

5. Supplementary Information

Kluane National Park and Reserve hosts a Web site featuring additional information and current updates on kokanee salmon in the Kathleen Lake watershed.
http://www.pc.gc.ca/pn-np/yt/kluane/natcul/natcul4_E.asp

Visit the Web site of the Living Landscapes to learn more about the biology of kokanee salmon.
http://www.livinglandscapes.bc.ca/thomp-ok/kokanee-salmon/view-life.html

References

DeGraff, Nick.  2004 Sockeye Stream Analysis Report.  Unpublished report (2004).

DeGraff, Nick.  2006 Sockeye Creek Stream Monitoring Report.  Unpublished report (2006).

Hall, P.  Kluane National Park and Reserve Hydroacoustic Survey Trip Report.  Unpublished report (2005).

Marty, Gary.  Draft Histopathology Report.  Unpublished report (2006).

Morbey, Yolanda  Report on kokanee (nonanadromous Oncorhynchus nerka) in Kluane National Park & Reserve.  Unpublished (2005).

Parks Canada.  2006-2007 Funding Application Update and 2005-2006 Progress Report- Parks Canada Ecological Integrity Innovation and Leadership Fund.  Unpublished report (2006).

Parks Canada.  2006-2007 Funding Application Update and 2005-2006 Progress Report-Parks Canada Ecological Integrity Innovation and Leadership Fund.  Unpublished report (2006).

Parks Canada.  Kluane National Park and Reserve Resource Description and Analysis Volume 2.  Unpublished (1985).

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