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:
AbstractThroughout Alaska, managing salmon resources can be controversial due to the critical socio-economic impacts on user groups, including commercial, sport and subsistence fishers. The necessity to remedy fluctuations in salmon populations requires that accurate data are gathered and that the interests of all are considered. Although some causes of population variations are disputed, possible factors impacting salmon populations include: long and short-term climatic changes, direct human interactions such as fishing and hatchery practices, and indirect human interactions such as habitat destruction. Some variables, including climatic impacts, are not controllable. Predictability and magnitude may be revealed with further research of these topics. Logging, mining, and pollution are human interactions that can be managed, and should be carefully researched and monitored to preserve and restore the habitat of the wild stocks.
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 CyclesIntroduction
Salmon is important to Alaska economically, historically, and culturally. Many communities in southeast Alaska (SEAK) rely on the fishing industry, directly and/or indirectly. In addition to commercial fisheries, many communities are involved with processing, as well as sport and subsistence fishing.
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 DynamicsPopulation dynamics of Alaska Pacific salmon are defined as the many different factors directly affecting populations and general health. This discussion includes total landings by commercial fisheries, total weight of those landings, and the subsequent average weight of each species. Also included is information about genetic diversity and its relation to hatchery practices and food-web interactions.
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.
ClimateAnother factor impacting salmon populations is climate fluctuation. Under the present circumstances, climatic change is not likely to reverse. The atmosphere has warmed approximately 0.5 ° C over the past century. Current social and population momentum produces a near guarantee that the atmosphere will continue this trend towards a warming climate. It is important to remember that when utilizing data concerning controversial topics such as climate, individual events can alter the overall data. One must differentiate between the relative and absolute (Friday, Keynote Lecture, NPAFC 1999) (Figure 4).
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 ShiftsA regime shift occurred in the mid-1970s that propelled salmon populations to a healthy standard, after a moderate decline prior to this event (Beamish et al., 1998). A regime shift occurs when many elements of an ecosystem undergo a change, usually resulting in physical alterations within the ecosystem. One of the best ways in which scientists determine the extent of these climate changes in Alaska is by using the Aleutian Low Pressure Index (ALPI). Decreasing ALPI levels indicate a warming trend, which alters the metabolic rates of salmon, as well as other plant and animal life within the ecosystem. Once the temperature rises, salmon require more nourishment to survive (Beamish et al., 1998). But due to the fluctuation, the usual food source for the salmon has grown scarce. This causes the salmon to expend more energy to look for their prey. Prior to the regime shift in the mid-1970s, the ALPI had reached extremely low levels, but then experienced a dramatic increase, possibly as a result of the regime shift. At the same time, salmon productivity also began to increase (Figures 1 and 5).
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).
PDOAnother, even more subtle, natural oscillation is called the Pacific Decadal Oscillation (PDO). PDO is an empirically-derived climate index that measures variations in sea surface temperatures (SSTs) over time. The results of PDO are much the same as the results of the short-term El Niño Southern Oscillation (ENSO), causing warmer SSTs. However, the natural cycle shifts from warm to cold approximately every 20-30 years. While the temperature fluctuation of ENSO occurs rapidly within a few years, the fluctuation of PDO takes many years to alter the SST a maximum of two degrees.
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)ENSO is an event that occurs approximately every two to seven years, and lasts one to two years. An ENSO event is generally followed by La Niña. A difference between these two weather patterns is that while ENSO warms the ocean, La Niña cools it. ENSO and La Niña are basically opposite ends of the equatorial easterlies. ENSO has abnormally weak trade winds, and La Niña unusually strong winds and high-pressure systems. Because of the common occurrence of ENSO, scientists have determined very efficient ways to measure some effects of this climatic change on an ecosystem. These effects are also less severe, because they are cycles with recurring patterns, and occur over a shorter duration of time. The most recent ENSO began in 1997, and was followed shortly by La Niña (Meyers et al., 1998).
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)The greenhouse effect, or global warming, occurs when the atmosphere is heated due to certain gases that are released in large quantities, such as carbon dioxide, methane, and chlorofluorocarbons (CFCs). The atmosphere heats up due to radiation from the earth's surface. The increasing temperature of the atmosphere, caused by the greenhouse effect, results in changing land temperature, weather patterns (such as wind speed, precipitation, etc.), and, more importantly, SSTs, which affect the availability of food sources for the salmon. Although global warming indirectly affects salmon, it still must be taken into consideration as a factor, because it is possible that in the future, global warming could become a large contributor to climatic stress of the Alaska Pacific salmon populations.
Human InteractionsHuman interactions with salmon populations may by direct or indirect. Direct human interactions are strongly affect salmon populations, and are comprised of two factors: positive impacts (those that increase population), such as hatcheries; and negative impacts (those that decrease population), such as fishing practices. These interactions are dynamic, and are often difficult to quantify. Quantification becomes the most difficult when the impacts are indirect, the most common form of which being habitat destruction. Habitat destruction is caused by logging and forestry practices, mining activities, and pollution such as oil spills and waste dumping. All of these factors may be controlled, but some with more difficulty, as many of these factors comprise a large part of Alaska's culture.
HatcheriesModern hatcheries were originally thought to be a viable solution to the problem of the dwindling fish numbers (Beckman et al., 1999). Now they are under question from scientists for their effectiveness in replenishing fish stocks (Beckman et al., 1999). Presently this is a global problem, with some fish stocks nearing extinction. The technology used in hatcheries has gone from being a solution to a possible contributor of the decline. It has been known since the institution of hatcheries that they would not be the only answer to the problem. During a hearing on artificial hatching held in 1902 one of the contributors said, "There is no example of the establishment or maintenance of a commercial salmon fishery upon any river in North America which has depended for its yield upon artificial culture, unsupported by restrictions upon netting or by accessibility spawning grounds" (Beckman et al., 1999).
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 FishingAlaska's Gross Domestic Product for 1998 was $24,494,000,000 according to the U.S. Bureau of Labor Statistics. In the same year, the commercial fishery of Alaska's salmon stocks earned net ex-vessel value of $262,720,000, meaning that approximately 1% of Alaska's total income has its source in commercial salmon fisheries. Though seemingly a small percentage, the reality is that the industry has a major impact on Alaska's overall economy. No matter how the data is presented it is evident that the commercial salmon industry has an important impact on the lives of many Alaskans.
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 FishingAlthough sport fishing makes a much smaller impact on salmon populations than the commercial fishing industry, it can add pressure to accessible runs in urban areas. Sport fishing pressures are increasing overall. With each passing year, sport fishing becomes a more popular past-time, in a large part due to the charter boat industry, which has grown because of increased tourist marketing. In 1998, 1,657 king salmon, and 4,710 coho salmon were landed by Juneau-area charter fishing businesses. Currently, the charter boat industry's status as a sport fishery is being disputed. In Juneau, the charter fishing industry, amongst the approximately 60 active operations, makes approximately $3-4 million a year. This is a fraction of the statewide total, which is estimated to be near $60 million annually (Preston, pers. comm.). Most charter boat owners argue that their businesses should continue to be considered part of the sport fishery on the grounds that "The charter boats don't catch the fish; sports fishermen catch the fish on the charter boats." (Preston, pers. comm.). However, skeptics of this reasoning argue that fish are still being sold. Because the takes are becoming noticeably large. Charter boats should have separate licenses instead of the current sport fishing license. Every year, mostly between May and September, approximately 600,000 tourists visit Juneau, a city of less than 40,000 people. It is many of these people that hire charter boat operators, in search of an Alaskan salmon fishing experience.
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 FisheriesSubsistence fisheries are a vital part of many rural Alaskan communities. These communities are usually isolated and cannot rely completely on outside sources for food. Therefore, they must get some or most of their food from the area around them. Many coastal villages and small communities throughout the state utilize subsistence fishing as a food source.
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
LoggingLogging and road construction are the causes of the most severe destruction by indirect impact of forested watersheds. The main cumulative effect of long-term logging activities is a substantial reduction in water quality of freshwater salmon habitats, even when a buffer zone is left along fish-bearing rivers or streams (Casipit, pers. comm.). In addition to direct water-quality disturbances, forestry practices, especially road construction, also cause secondary damages to streams and rivers. These secondary effects include the following: runoff from roads; washouts; hydrocarbons due to incidental pollution from traffic; and incidental damage from traffic accidents along the stream. Washouts can conduct synthetic and toxic chemicals to freshwater salmon habitats, even if buffer zones are present (Kirkpatrick, pers. comm.).
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).
MiningThe damages salmon habitats and populations caused by mining, although important, are more site-specific than those of logging (Kirkpatrick, pers. comm.). One of the most prevalent dangers to affected watersheds and therefore salmon stocks associated with mining is Acid Mine Drainage (AMD). AMD occurs when sulfide-bearing ores are exposed to the air and water. This exposure causes a reaction to turn sulfide to sulfuric acid, which dissolves the heavy metals from the ores. If these metals seep through the ground or otherwise enter spawning streambeds, they act as a toxin to salmon stocks in the affected water. Mining practices further compound the pressures of logging by requiring roads and other logging practices in the area, in addition to associated urbanization due to jobs provided by the mines.
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 largest oil spill in Alaskan history occurred at Prince William Sound in 1989, where its effects can still be observed. In a study of Prince William Sound pink salmon, researchers found that the presence of oil reduced survival at any life stage, and the reduced survival was translated at the adult life stage (Geiger, 1996). However, the final returns of adult salmon have remained largely unaffected. This appears to be due to compensatory mortality, mortality that increases when density is high and decreases when density is low. Perhaps due to this effect and because they affect a discrete group of salmon stocks, oil spills are one of the smallest contributors to salmon mortality, but are also one of the most easily prevented.
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* Although the effects of short-term climate changes cannot be discounted, it is the long-term climate changes (such as regime shifts) that have the largest effects on the ecosystem, for instance, altering the metabolic rate and reducing the food source of Pacific salmon stocks.
* 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 research of correlations between long-term climate changes and Pacific salmon populations.
* 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.
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