This paper was written as part of the 2000 Alaska Ocean Sciences Bowl high school competition. The conclusions in this report are solely those of the student authors.

Alaska Pacific Salmon Populations Analysis and Recommendations

Written in part by each of the following:
Margie Housley, team captain
Wesley Brooks
Sommers Cole
Colleen Dilts
Josh Passer

Team "Tsunami"
Juneau-Douglas High School
10014 Crazy Horse Drive
Juneau, AK 99801

Abstract

The most widely disputed human interactions are fishing and hatchery practices. Discussed in this report's management plan are recommendations that are crafted to protect and preserve the wild stocks of Alaska Pacific salmon, while concurrently continuing to benefit the fishing industry.

Hatcheries provide both positive and negative impacts to the Alaska Pacific salmon population. The commercial fishing industry relies heavily on hatchery produced fish for a substantial percentage of its total catch. However, hatchery fish are consuming resources that the wild stock may require. This leads to decreasing body mass measurements and declining health of wild Alaska salmon. In addition to consuming resources, hatchery fish reduce the genetic diversity of the overall population of salmon. The management plan proposed in this report analyzes the available data and makes the best use of salmon resources in southeast Alaska.

Salmon Life Cycles

The purpose of this report is to suggest a comprehensive management plan for Alaska salmon populations in SEAK. Due to the natural and socio-economic impact of fluctuations in salmon populations, it is important to create a successful fisheries management plan, a task that can be controversial.

Included in this report are possible causes for variations in salmon populations, including: climatic impacts, hatcheries/genetic diversity, commercial fishing, sport fishing, subsistence fishing, and indirect human interactions, as well as an effective plan to integrate controllable factors into an environmentally and economically feasible management plan.

Population Dynamics

Alaska Pacific salmon populations can be estimated by the total salmon landings in any given year, and other information is solicited from the average weight of the landed fish. For instance, the total of Alaska salmon landings in 1970 was 68,364,000. By 1998, that number had increased 222% to 151,820,000 fish (ADF&G, 1999). The preliminary year-to-date estimated total for 1999 is 212,791,700 fish, a 140% increase from 1998 and a 311% increase from 1970 (ADF&G, 1999) (Figure 1). It is important to recognize, however, that recent harvest data is a more accurate indicator of total salmon population.

The total weights have increased similarly, from 157,500 metric tons in 1970 to 323,300 metric tons in 1998, a 205% increase (ADF&G, 1999) (Figure 2). Although the average weights of Alaska salmon have remained relatively constant (Figure 3), the average weight does fluctuate, due to indirect factors, such as climatic changes and food-web variables. For instance, chinook, sockeye, and chum all experienced notable decreases in average weight in the early-1970s, before the climate regime shift of the mid-1970s (Beamish et al., 1998) (Figure 3). After the regime shift, average weights slowly increased, suggesting that the regime shift mostly affected the species' prey. Oil spills, as well, may affect weight of salmon (Geiger et al., 1996). Studies have suggested that low average weight caused by these oil spills may negatively impact spawning practices by reducing the general health of the adult population (Geiger et al., 1996).

When salmon spawn, they typically return to the same stream in which they were hatched. Due to these discrete separations of the salmon stocks, the species develop a strong genetic diversity which is essential to the long-term sustainability of the stocks. When a species is subject to phenomena that exert pressure on it, low genetic diversity will reduce the species' ability to respond to the phenomena, as each stock will be susceptible. In addition, low diversity will reduce the range of individuals able to respond to/survive the phenomena. Managing catch while protecting genetic diversity requires permitting an escapement large enough to maintain wild salmon populations. One major struggle in retaining genetic diversity is the hatchery program.

Climate

There are numerous ways that climate contributes to the fluctuations of the Alaska Pacific salmon populations. Among these factors are long term climate changes (regime shifts), short-term climate changes (El Niño Southern Oscillation--ENSO, and Pacific Decadal Oscillation--PDO), and long term human-induced climate changes (the greenhouse effect).

Long Term Climate Changes (Regime Shifts and PDO) Regime Shifts

During the year of 1989, the ALPI began to decrease again, placing further strain on salmon populations. Although not nearly as severe as the shift in the mid-1970s, scientists are beginning to suspect that another regime shift occurred in 1989, causing the reverse effect of the regime shift during the mid-1970s. It is unknown how much longer these negative impacts on the Alaska Pacific salmon populations will persist.

Regime shifts are known as long-term climate changes because they are erratic, consist of complex variables, and are hard to predict. Because they are hard to predict, it is more difficult to remedy population fluctuations. Also, the effect of these shifts occurs over a longer duration of time than short-term climate effects (Beamish et al., 1998).

PDO

PDO is known to alter freezing levels in the atmosphere, mountain snow packs, stream flows, and water supplies (Friday, Keynote Lecture, NPAFC, 1999). After the regime shift in the 1970s, PDO changed from a cold period to a warm period, causing higher than normal SSTs. Although the effects of these short-term climate changes do not largely impact salmon populations, it is essential to make sure that any natural climate occurrence which could possibly decrease the future Pacific salmon stock is researched and understood.

Short Term Climate Change (ENSO)

The ENSO that occurred in 1997 marked a fairly substantial change in sea surface temperature (SST) in the Bering Sea (BS) and Gulf of Alaska (GOA), in which many high measurements were recorded. This makes ENSO a good example of the effects of short-term climate change. The relationship between SST and Alaska Pacific salmon populations during ENSO was researched in great depth by fisheries biologists from the National Research Institute of Far Seas Fisheries (Ishida et al., 1999). Through this study, it was recorded that SSTs of the BS and GOA in 1997 were on average 1.01 ° C and 1.81 ° C warmer, respectively, than the previous six-year period (Meyers et al., 1998). The impact of these increasing temperatures on salmon populations is fairly insignificant because it occurs over a shorter period of time.

The relative abundance (catch per unit effort--CPUE) of Alaska Pacific salmon was compared between 1993-1996 (years not affected by ENSO), and the 1997 ENSO year. Sockeye salmon CPUE increased in the BS and the GOA, but decreased in the western and central North Pacific in 1997. Chum salmon CPUE increased in the western and central North Pacific in 1997. In the BS, chum salmon CPUE in odd years is usually lower than in even years; however, in 1997 chum salmon CPUE was higher compared to the previous odd-year data. During the same year, pink salmon CPUE increased in the western and central North Pacific and substantially increased in the BS, but decreased in the GOA. (Ishida et al., 1998) (Figure 6).

These data indicate that long-term climate changes have the greatest impact on salmon populations among the natural factors in salmon population fluctuation. Most likely this is because regular oscillations are constantly occurring and can be researched and predicted in-depth, as opposed to enigmatic regime shifts. Predictability allows scientists to make decisions about how to better manage the salmon stocks. It is challenging to see any true relation between changes in survival rates of Alaska Pacific salmon populations and ENSO (Friday, Keynote Lecture, NPAFC, 1999). However, the combination of a regime shift, PDO, and ENSO may be enough to cause serious damage to the Alaska Pacific salmon populations by altering the delicate balance of the ecosystem. However, PDO and ENSO are not completely separate events, but rather, are linked, with the severity of certain ENSO years are thought to be partly due to PDO, such as the extreme change marked by the 1997 ENSO. One of the possible effects PDO has on ENSO is a change in the trend of this occurrence, meaning that ENSO occurs more frequently, and possibly will continue this trend in the future, in which case salmon could suffer greater strain.

Human-Induced Climate Changes (The Greenhouse Effect)

Human Interactions

Hatcheries

Throughout Alaska, hatcheries produce many salmon. Although other salmon stocks in the Pacific Ocean are declining, Alaska Pacific salmon stocks remain steady. However, there are still concerns about genetics regarding hatchery fish. Fish hatched artificially usually do not have as diverse a genotype as the wild fish they supplement. Small differences in such variables as genotype can create large problems for Alaskan salmon.

There have, however, been many positive effects as a result of Alaskan Hatchery programs. Hatchery fish make up for much of the commercial fishing industry catch numbers. In Southeast Alaska (SEAK) 87% of the chum salmon harvested in Lynn Canal are products of the DIPAC hatchery, and 50% of all chum salmon caught in Southeast Alaska's waters are products of hatcheries (ADF&G Salmon Enhancement Program, www.cf.adfg.state.ak.us). In addition, 21% of SEAK's troll-caught coho are hatchery fish and 19% of the region's total fish harvest is a product of hatcheries. If these fish were to cease being produced there could be a drastic reduction in salmon populations across the state, therefore reducing the entire fishing industry. Because so much of Alaska's economy is based on fisheries, this could cause severe economic hardships.

Yet despite this positive aspect, there are some negatives. One argument often used is because historical salmon population statistics are unavailable, the populations may be stressed at an unnaturally high level. This upper limit on the ocean and river carrying capacity is draining other natural resources to a degree in which the surviving salmon are not abundant. Researchers have found an inverse relation between the number of fish and their size (Volobuyev, 1999). The study also indicates that a long-term overabundance of salmon may change the biological structure of the stocks. This change in biological structure translates into lower commercial value and fish quality. The study states that the North Pacific Ocean may have reached its carrying capacity for salmon, and any further increases in stock levels could be harmful to the species as a whole. "We presently observed a significant allogenic influence of hatchery fish to the environment of the North Pacific Ocean." The ocean appears to be nearing its limitations for production of food for fish. This limited food is shared by hatchery and wild fish, which results in direct competition for food resources. The wild fish reach their spawning grounds with less body mass and with fewer caloric resources to last through spawning, resulting in a lower spawning success rate.

Commercial Fishing

Currently, the commercial salmon fishery is Alaska's largest non-governmental employer (NOAA Tech. Memo., 1992). There are three main methods of harvesting salmon commercially. These include seine, troll, and gill/drift net fisheries. In 1998, from these fisheries, approximately 151,820,000 fish were landed, weighing about 284,000 metric tons (NMFS Statistics, 1999). Statewide, the commercial salmon fisheries generated an ex-vessel value of $262,720,000 for that year (ADF&G, 1999).

However, these statistics are not an accurate measure of more recent years' salmon harvests. 1998 was the year in which the Governor of Alaska, Tony Knowles, declared some fisheries to be in a state of crisis. Along with a lack of fish, market prices decreased significantly (ADF&G, 1999). For a more accurate example of how much Alaska relies on the commercial salmon industry, a year with fairly average statistics should be examined. In 1994 about 195,861,000 salmon were landed, weighing roughly 392,900 metric tons. The total ex-vessel value of these fish in 1994 was $489,130,000 (ADF&G, 1999). This can be compared to an average of the past ten years, to better portray the statistics of this volatile industry. From the years of 1989-1998, an average of 169,237,000 fish were harvested each year. The average total weight of the fish from those years were 352,177 metric tons (ADF&G, 1999); with an average ex-vessel value of $372,800,000.

Commercial fishing of salmon stocks is also one of the few variables relating to salmon population changes that people have direct control over, the others being habitat destruction/rehabilitation and hatchery practices. Commercial fishing is also where the most visible population impacts occur. Because of this industry's value to the State of Alaska, and the ease of which wild salmon stocks can be exploited by fisheries, the state has delegated a great deal of authority to the Alaska Department of Fish and Game to regulate commercial salmon fishing. This department must set regulations regarding the commercial fisheries. For example, the agency has the power to set fishing boundaries around stream mouths and to set openings, or days in which a certain fishery is open. ADF&G also regulates gear types and the total allowable number of fish to be caught in each region.

Sport Fishing

However, the fact remains the sport-fishing take of Alaskan salmon is much smaller than the commercial take. Despite this, some of the most effective conservation efforts are made in the sport-fishing arena. Because most sport harvest of Alaskan salmon is done near the mouth of or on the actual river that the salmon are returning to, stringent restrictions are placed on the number of fish an angler is allowed to keep each day, and on many rivers and streams, the days that the waterway is open to fishing.

For example, Windfall Creek in Juneau, Alaska, has a month long opening of the sockeye fishery in June. Only one fish, 16 inches or more, may be kept per person, per day. Additionally, there is a city-wide limit of five sockeye salmon per season (ADF&G, 1999). These restrictions were implemented largely due to the dramatic decrease in sockeye populations in Juneau over the past twenty years. Decreases in population, such as those observed in Juneau's sockeye, can be traced back to overfishing in the spawning grounds. In this sense, sport fishing regulations are very important to the maintenance of strong salmon populations.

Subsistence Fisheries

In July of 1990, the Federal Government assumed management of Alaska's subsistence usage of fish and wildlife. This was done in response to an Alaska Supreme Court ruling which states that it is against the Alaskan Constitution to provide a subsistence priority for rural Alaskans. The Federal Government is required by Title VIII of the Alaska National Interest Lands Conservation Act (ANILCA) of 1980 to give a subsistence priority to rural Alaskans unless otherwise provided by the State through its laws (US Fish and Wildlife Service Report, 1993). Subsistence fishing does not contribute substantially to the total harvested salmon, yet it is vital to people in remote areas which often lack cash economies.

Culture and tradition are also reasons for subsistence fishing. Fishing is a part of native Alaskan culture. If Alaska natives were not able to subsistence fish, they would lose a major part of this tradition. As the laws currently in effect are working well, there is no need for present changes in subsistence management.

Indirect Human Impacts—Habitat Destruction

Logging

The primary effects of logging may take twenty to thirty years to be noticed in the returning Alaska salmon stocks and in the general health of the fish (Casipit, pers. comm.). Fallen logs and trees create ideal spawning habitat for salmon, and clearcuts remove trees near the water. Years later, when the material in the stream has rotted away, it is nearly devoid of natural spawning habitats. Further, the forestry waste clouds the water, and sediment and runoff from construction roads settle in the gravel. Salmon spawn only in clear streams and gravel beds for maximum oxygenation of their redd (USFWS, 1993). Another major effect of clearcutting is that it exacerbates the extremes known as peak flow and base flow of a river, and can affect salmon populations in a stream by decreasing suitable spawning habitat (Casipit, pers. comm.). When clearcutting of larger trees occurs near a river or stream bed, small and fast-growing vegetation grows on the banks of streams during periods of minimal rainfall. Later, when the water level rises, the vegetation decreases the amount of suitable spawning habitat. Conversely, when there are periods of plentiful rainfall, the lack of stable vegetation on the banks may cause the waterway to erode the banks and run over, causing the channel to become over-fit, or excessively wide and shallow. In this case, much of the salmon habitat is washed away (Casipit, pers. comm.).

The Tongass National Rainforest is the largest National Forest in the United States (USFS, 1997). Covering most of Southeast Alaska, much of the forest has been logged, endangering salmon habitats in pristine environment (Figure 7).

Mining

An example of the potential effects on Alaska salmon habitat and stock-specific population is the Tulsequah Chief Mine (TCM), a proposed underground base/precious metals mine located forty miles from Juneau in the Tulsequah River Valley, Canada (U.S. Forest Service, 1982; Paez, pers. comm.). Harry Carlick, a clan leader of the Taku River Tlingit First Nation (TRTFN), commented on the condition of the river when the original TCM was operating: "There were no fish in the Tulsequah and on the side creeks when the mine was operating. There was nothing there." (B.C. Wild, 1997). Salmon stocks from the Taku System provide 2.7 million dollars annually to Alaska's economy, with its nearly pristine watershed, is a significant producer of all five species of Pacific salmon (Knowles, 1999). The Taku River is also a trans-boundary river, under the Pacific Salmon Treaty, between the United States and Canada fisheries. The State of Alaska presently has continuing concerns about the TCM regarding such issues as effluent mixing zones, tailings pond seepage, and road construction and maintenance (Knowles, 1999). Alaska salmon habitat could be affected by the proposed ninety-nine mile road and the sixty-nine stream crossings that would be necessary to reopen the mine. Further, draft reviews of the mine proposal suggest that reopening the TCM would cause effluent discharge of acids, heavy metals, petroleum products, or toxic reagents (American Rivers, Information Services; http://www.amrivers.org).

Pollution (Oil Spills and Waste Dumping)

The other notable form of pollution in Alaska is waste dumping: the dumping of waste waters, such as bilge oil, human waste, chlorinated dry cleaning waste, and chemical deposits, off Alaskan shores. International dumping standards state that vessels must be at least twelve miles from shore when disposing of "black water" (untreated sewage) and special waste, but may be anywhere within the exclusive economic zone (EEZ) to dump "grey water," or treated waste. Although this usually prevents waste materials from falling on the continental shelf, in an archipelago such as that of Southeast Alaska, "doughnut holes" are formed--areas three miles from any shore and enclosed by the three-mile buffer zone (NMFS, 1996). Materials dumped in these areas may have unknown, more concentrated effects on salmon populations, as the doughnut holes are closed systems.

In December 1999, the Alaska Department of Environmental Conservation and the EPA began meeting with tour-ship officials to discuss the laws in Southeast Alaska regarding cruise ship dumping. Due to the doughnut holes in the Alexander Archipelago, the closed systems cause the vessels to dump in areas that may not have the capacity to manage such large amounts of waste. Therefore, talks have commenced which may result in efforts to change the dumping laws in Southeast Alaska or statewide to counter the dumping in the restricted waters of closed systems.

Conclusions

* Hatcheries have had both positive and negative effects on the Pacific salmon stocks of Alaska. Their contribution to commercial fisheries is important. However, hatchery fish take away needed resources from natural salmon, while diminishing the overall genotype diversity of the wild salmon.

* Commercial salmon fishing is currently Alaska's largest non-governmental employer. The greatest visible human impacts on salmon in Alaska are made via the commercial salmon industry. Because of the major economic implications of this industry, any changes made in fisheries management must necessarily be well-planned.

* Subsistence fishing remains a way for remote coastal towns and villages to receive food. Heritage is a reason for native people to continue in their current practices.

* Human activities such as logging and mining can degrade habitat, making streams unsuitable for spawning salmon. Waste dumping in coastal waters, especially the doughnut holes of island formations, indeterminably affect salmon stocks.

Recommendations

* Continued study of the impacts of global warming on Alaska's salmon stocks and ways to reduce man's contribution to the greenhouse effect.

* Institute habitat restoration programs in order to increase wild salmon populations, while simultaneously reducing the total number of hatcheries and hatchery-produced salmon, in order to maintain the same total salmon populations.

* No changes in the current commercial salmon fisheries' regulations need to be made at this point in time, unless it is obvious that large numbers of salmon from threatened wild runs are being caught. If this incident occurs, harvests should be reduced specifically.

* Institute and enforce mandatory buffer zones on the banks of all spawning streams and connected waterways.

* Institute and enforce sanitation regimes in areas where Acid Mine Drainage is prevalent.

* Ban the diversion of mine tailings and logging by-products into spawning streams, and enforce waste-management plants in areas of mining and logging activities.

* Continued research regarding the environmental impacts of waste dumping in doughnut holes, and recommend enforcement of maximum dumping laws in these areas.

References

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