This paper was written as part of the 2010 Alaska Oceans Sciences Bowl high school competition. The conclusions in this report are solely those of the student authors.

Managing walleye pollock (Theragra chalcogramma) and opilio crab (Chionoecetes opilio) fisheries under changing climatic conditions

Authors

Andrew Gregovich
Sarah Donohoe
Seth Brickey
Sam Kurland
Martina Miller

Team Hot Tropic

Juneau-Douglas High School
10014 Crazy Horse Dr
Juneau, Alaska 99801-8529

Abstract

Arctic ecosystems, marine and terrestrial, are changing as a result of climate change. Sea ice melt, caused by climate change, is an important factor in changing geological boundaries in the Bering and Chuckchi seas. The migration of species outside of traditional areas poses new and potentially difficult management problems. We show that if these migrations and trends associated with climate change aren't addressed rapidly, important commercial and subsistence fisheries may be at risk. Currently, sustainable fisheries models incorporate information regarding the individual species' life history, natural mortality, reproductive rate, and growth at age increments. We conclude that policy needs to be developed that incorporates changing ecosystem parameters such as climatic conditions. We discuss the possible consequences that climate change may have on the opilio crab (Chionoecetes opilio) and walleye pollock (Theragra chalcogramma), fisheries in the Bering Sea. Both are important economically to Alaska, and pollock constitute the largest U.S. fishery. Additionally, salmon bycatch associated with pollock is problematic to international and subsistence fisheries. Opilo and pollock have been shown to exhibit a northward shift in distribution, especially during warmer years. Moreover, opilio are calcifying organisms, and are negatively affected by ocean acidification, a process accelerated in the polar regions and accompanying climate change. Pollock juveniles are affected by warming sea water, possibly requiring more food to meet an increased metabolism. We conclude that it is possible that both pollock and opilio populations will decline in the Bering Sea. Thus, it is imperative that management of these fisheries accommodate for the changes induced by climate change. As the shifts in distribution bring international fisheries closer together, we recommend increased cooperation with neighboring countries—namely Russia, Japan, and Canada. The Bering Sea ecosystem can't be viewed as consisting of separate regions along national borders. We propose that international cooperation in forming new policies is vital for the health of the fisheries affected by climate change.

Introduction

The Arctic is a unique region encompassing land, ocean, wildlife, and eight separate nations that constitute its borders. One issue that links them all is climate change. Climate change is causing the Arctic sea ice to retreat at an accelerated rate; temperatures are rising twice as fast compared to other parts of the world (http://www.acia.uaf.edu/pages/scientific.html). The temperature rise has caused the main ice shelves to thin, split, and melt—freeing a large portion of arctic waters. This sea ice retreat, and the warming associated with it, has resulted in the migration of the ecotone that divides the arctic and sub-arctic communities in the Bering Sea (Mueter, 2008). Sea ice melt is affecting the distribution of Bering Sea marine life, which will affect the dynamics of commercial fisheries in the region. Two fisheries of particular concern to Alaskans are the walleye pollock (Theragra chalcogramma), and the opilio crab (Chionoecetes opilio) fisheries.

The largest concentrations of pollock in the Bering Sea are found in the U.S. federally managed eastern region, and in recent years (2001–2006) the average annual pollock catch in the eastern Bering Sea has been 1.45 metric tons (Ianelli, 2008). The federal pollock fishery was worth $322 million based on the five-year averages from 2000 to 2004 (http://www.cf.adfg.state.ak.us/geninfo/finfish/grndfish/pollock/pollockhome.php). Pollock are documented to migrate twice a year. Temperature has been found to be the main cause of this movement (Kotwicki, 2005). Changes in migration timing and direction may change or complicate commercial pollock fishing and fishery management.

The waters of the Bering Sea are under shared jurisdiction. The U.S. manages fishing in most waters east of the International Date Line. There is one small area of international water in the Bering Sea, known as the Donut Hole. Pollock were targeted in the Donut Hole during the 1980's and early 1990's. A fishing moratorium was enacted in 1993 due to depleted fish stocks (Ianelli, 2008). This ban serves as an example of what can happen in under-regulated fisheries in which multiple countries have claims.

Chinook salmon (Oncoryhnchus tshawytscha) bycatch is another major concern in the pollock fishery. An average of 50,000 chinooks have been taken each year by Bering Sea pollock trawl nets from 2000 to 2008 (Halflinger, 2008). Previous studies show that about half of the chinooks were from U.S. stocks and half from foreign stocks (Patton, 1998). Chinooks destined for western Alaska are essential for subsistence. Foreign chinooks are important for their respective countries of origin. With the passing of the 91st amendment to the Bering Sea Aluetian Islands Fisheries Management Plan, the North Pacific Fishery Management Council (NPFMC) is poised to implement new chinook bycatch regulations. Further changes in the Bering Sea ecosystem may warrant additional changes from the NPFMC.

The opilio crab fishery is not as lucrative as the pollock fishery, but it is still quite valuable. The total allowable catch (TAC) was 63 million pounds in the 2007/2008 season (NPFMC, 2009: King and Tanner Crab). The opilio crab season takes place from mid January to May. Opilio are fished on the Bering Sea shelf in both U.S. and Russian waters. The Russian area of the shelf is not fished due to the extent of the winter sea ice. Retreating winter sea ice extent may allow Russians to target the same crab stock that is currently targeted by U.S. boats.

Physical changes to the ocean could affect the accessibility and location of the opilio crab fishing grounds. The Bering Sea cold pool is a body of water created by melting seasonal ice that is about two degrees colder than adjacent Bering Sea temperatures, and creates an important habitat for opilio crab to settle and grow into maturity. (Orensanz et al., 2004). This cold pool has contracted northward 230 km since the early 1980's. The northward shift of the cold pool was accompanied by an increase in near-bottom temperature between 1975-1979, along with the northward contraction of the opilio crabs' distribution range (Orensanz et al., 2004).

Commercial fishermen may be affected by the changing climate and physical changes to the ocean as much as the fisheries themselves. Less sea ice may result in rougher seas due to increased fetch as the overall amount of ocean surface increases. The new open waters resulting from sea ice retreat may provide new fishing grounds in addition to changing water currents and biological dispersal patterns of the northern seas.

These changes to the Bering Sea fisheries warrant changes in marine policy. Management issues involving location, timing, sustainability, and participation in Bering Sea fisheries are going to arise. In this paper, strategies and policies currently in place will be discussed and amendments to these policies will be suggested. Sustainable management of the pollock and opilio crab fisheries is essential for the prosperity of commercial fishermen, subsistence users, and the seafood industry.

Changes in the Bering Sea associated with climate change

Arctic ice melt rate from 1981 to 2001 is eight times that of previous rates over the last 100 years. Arctic summer temperatures have increased an average of 1.22°C per decade. In some regions, the overall temperature has increased by 2.5°C per decade. Sea surface temperatures in the North American regions of the Arctic tend to be increasing more per decade then the other regions of the Arctic (NASA, 2003). Since the 1990's, the Bering Sea has shifted towards an earlier spring and later fall (http://www.pmel.noaa.gov/foci/publications/2002/mackS447.pdf). These changes have been accompanied by an increase in the amount of precipitation—about 5–10% per decade for the spring months and roughly 5% per decade for the summer months. In contrast, land masses have experienced a temperature decline in the fall and winter months (Adaption Advisory Group, 2009). The average temperature in the Bering Sea has also seen an increase. Between the two periods 1995–1997 and 2001–2003 the mean depth-averaged temperature in the southeastern Bering Sea has warmed by 2°C (Overland and Stabeno, 2004). In 2007 the ice extent reached a record low of 4.1 million square kilometers (http://www.pmel.noaa.gov/foci/publications/2002/mackS447.pdf). The albedo of ice is greater than liquid water. As the ice melts, the land or water underneath becomes exposed and absorbs greater amounts of light. Therefore, the rate of ice melt is accelerating and the amount of perennial ice is decreasing each year. Current predictions indicate that by the year 2037 there will no longer be perennial Arctic sea ice during the summer (Wang, 2009). This poses a critical threat to the global climate as a whole. Without the Arctic ice sheet to reflect solar radiation, global climatic warming will accelerate rapidly (http://earthobservatory.nasa.gov/Features/ArcticIce/). Changing pressure and wind patterns over the Arctic are other factors contributing to ice melt. The Arctic Oscillation (AO) is a pattern of non-seasonal sea level pressure (SLP) north of 20°N, characterized by warm periods of below normal SLP (high index) and cool periods of above normal SLP (low index) (http://jisao.washington.edu/ao/#analyses). During the high index stronger than average westerly winds in the upper atmosphere result in the cold air remaining near the Arctic. During the low index weaker high-altitude winds rotate counterclockwise about the pole in the high atmosphere. Weaker westerlies cause Arctic air masses to move further south and are associated with a dramatic drop in temperature and weaker subtropical trade winds in Asia and Europe (Martinson, 2000). The current high index of the AO has added to the already severe effects of global climate change.

Some meteorologists predict that as Arctic sea ice melts and exposes more ocean surface, northeasterly winds over the Bering Sea will likely result in waves of an increased height and wavelength, due to an increased fetch and wind speed (Curtis, pers. comm.). Favoring a northeasterly direction, these winds could potentially drive an easterly current in regions newly exposed following sea ice retreat. We hypothesize that this will result in consistently earlier ice melts and result in an increase of years in which the phytoplanktonic bloom does not occur until May or June. A spring phytoplankton bloom in the Bering Sea typically occurs at the edge of seasonal sea-ice breakup (Alexander and Niebaur, 1981). In years when sea ice cover in the southeastern Bering Sea persists into the middle of March, an early bloom consumes many of the nutrients in the upper, mixed layer of the water column. However, in years where the ice melts before or not long after mid-March, the bloom is delayed until May or June when insulation causes the upper layers of the water column to become stratified. Recent Arctic winters have tended to be shorter, ending earlier than those historically observed (Overland and Stabeno, 2004). An overall ice retreat northward could result in the same effects, since the area would not be covered by sea ice in mid-March.

Increased ocean acidification is projected in the Bering Sea as sea ice retreats (U.S. Global Change Research Program, 2000) impacting organisms that form calcified shells. Ocean CO2 levels are predicted to rise to almost 500 ppm, and 800 ppm by the end of the century, reducing ocean pH by approximately 0.3 units (AAG, 2009).

Opilio crab biology

Opilio crab are distributed over the extensive shelf of the Eastern Bering Sea (EBS), where they have supported one of the biggest crab fisheries in the world (Otto, 1989). The male-only fishery conducted in winter months from mid January to May, is constricted by sea ice cover. Opilio crab, like every organism, are affected by the habitat they reside in. The location, changing temperature, water chemistry, predation, fishery, and biology of the opilio crab are all factors in developing well-managed policies.

Opilio are consumed by different predators at each stage of their lives. Larval opilio are prey for pelagic fish, such as pollock, salmon, and herring. Predators of juveniles and adults include a multitude of marine mammals, piscivorous fish, and cephalopods (http://www.nmfs.noaa.gov/fishwatch/species/snow_crab.htm). The movement of opilio may alter relationships in the food web. Pacific cod (Gadus macrocephalus) prey heavily on early benthic instars of opilio, and are likely to increase in abundance and expand northward with warmer seawater temperatures in the EBS (Webb, et al. 2007). The changing physical factors of the Bering Sea may also change the survival rate and predation of larval opilio. Peak abundance of opilio larvae occurs in April and is synchronized with the ice-edge associated phytoplankton bloom. Delays of the spring phytoplankton boom associated with mid-March ice retreat may affect larval survival for opilio in the EBS (Webb, et al. 2007). Since opilio crabs are calcifying organisms the pH change is also expected to challenge the crabs current survival as the observed trend of a drop in pH makes calcium carbonate ions more soluble, and harder for calcifying organisms to precipitate for formation of their exoskeletons. The Bering Sea has been identified as one of the most endangered areas for drastic pH changes to occur (Short, pers. comm.). Given that larvae and juveniles are usually the most sensitive to increased acidity, energy normally put into growth would have to compensate for the calcifying process. It is reasonable to conclude that the net effect on the crabs would be a lowering the survival of the species (Short, pers. comm.).

The spatial dynamics of female snow crabs have significant implications for stock dynamic models. Reproductive success is measured by the size of the spawning stock, the spatial distribution of mature male and female opilio crab, and the hatching location of the eggs in appropriate water circulation. Being slow moving benthic-dwellers, opilio crab's migration patterns were previously thought to be negligible. More recently, researchers have observed that female and male opilio crab migrate to deeper, warmer waters as they mature (Webb, et al. 2007). Surveys conducted between 1978 and 2001 by Ernst et al. (2005) indicate that there is a high concentration of mature female opilio crab in the Middle and Outer domains of the Central Shelf. Immature female opilio are found largely in the Middle Domain of the Central Shelf, with hot spots around St. Matthew Island. Recently, a northward shift in the opilio crab's distribution range has been observed (Ernst et al., 2005). Between 1978 and 1985 the center of geographic distribution of female snow crabs shifted to the north and west. In 1978, the centroid of female opilio was located at 58°N. From 1998 through 2000 the centroid shifted north of 60°N. The possible reasons for migration are near bottom temperature (NBT) and/or depth. Opilio respond to conditions in their immediate area, making it more likely that they will follow temperature gradients than depth gradients. Depth, however, may be related to other factors like sediment composition or temperature. Experiments conducted by Dionne et al. (2003) demonstrated that juvenile snow crabs move according to water temperature and substrate. The temperature gradient from the Coastal Domain to the Middle Domain is colder to warmer year-round. From the Middle Domain to the Outer Domain, the same gradient occurs; making the Outer Domain the area with the warmest NBT. The distribution of migration direction matches the distribution of NBT gradients better than it does the depth gradient template. Although the reason for migration is still unclear, there is strong evidence that opilio follow the temperature gradient to warmer, deeper water located offshore in the Outer Domain (Ernst et al., 2005). Organisms have a temperature range that is ideal for their growth, development, and reproduction. Opilio crabs have been observed to be extremely sensitive to temperature change. In 1984, the opilio crab fishery off the Avalon Peninsula in southeastern Newfoundland collapsed due to a drop in mean bottom temperature from -0.6°C to -1.4°C (David et al. 1993). It is possible that the same result may come from an increase in mean bottom temperature as is the trend in the Eastern Bering Sea.

Opilio crab fishery

The movements of opilio have been considered unimportant regarding policies and regulations in the past. Knowledge concerning the migrations of opilio and the importance of their location in relation to stock assessment should be used to develop new policies to improve the opilio fishery. As the migration trends show that mature crabs are shifting northward and westward, the area regulations may need to be updated. Historically, the Soviet Union and the Japanese fished tanner (Chionoecetes bairdi) and opilio stocks residing in U.S. waters but were ushered out of U.S. domestic waters in 1971. The Soviet Union stopped all fishing attempts for opilio in U.S. waters and Japan was given quotas in the years of 1973 and 1973; after which the U.S. began Bering Sea opilio crab landings in 1977. Subsequent legislation further reduced Japanese effort until it was halted after the passing of the Magnuson Act in 1976 that prohibited foreign fishers from domestic waters.

Opilio are harvested in the Bering Sea by the U.S. and Russia. Opilio crab have been the leading harvested crab species in Alaska following declines in king crab (Paralithodes camtschaticus) and tanner crab stocks. Opilio are caught by crab pot. U.S. pots differ from other countries in that the pot doors are designed to bio-degrade after six months in the water, allowing unwanted bycatch to be released. Russian Fishermen do not use this material.

Policy and the opilio crab fishery

Currently, the opilio crab fishery is open in all waters of the Bering Sea District west of 166°W long., except for Alaska Department of Fish and Game statistical area 695700 which lies between 169°W long. and 170°W long. and 57°N lat. and 57°30' N lat (Densby et. al 2009). Because of the sea ice retreat, waters may open up for opilio fishing that were previously restricted by the ice. This, along with the shift in the opilio's distribution range, may lead to the U.S.'s opilio stock gradually moving into waters governed by Russia. This raises policy issues about crab ownership.

In order to prevent a species collapse like those of the king crab and the opilio stock in Newfoundland, the Alaska opilio fishery management must be able to make quick policy changes to match the quickly changing fishery. The increased predation, decreased food supply, and increased acidity in the opilio's habitat call for flexible and adaptive fishery management. It is essential for the opilio fishery to be assessed considering these changing factors. A lower TAC should be considered for the long term health of the fishery and prevention of a species collapse.

Pollock biology

Pollock are a member of the Gadid family. Like cod, they are fast to reproduce and grow, and swim in large schools. They are a cannibalistic species. Adult pollock feed on juveniles; therefore a higher concentration of juveniles and adults results in a lower recruitment of the pollock. The opposite is also true. Wespestad et al. (2000) assumes that juvenile pollock are distributed away from adults primarily by passive transport in the egg and larval stages of development. The distribution of pollock larva is largely dependent on current velocity and direction. Surveys suggest that larval pollock use the stratified warmer upper waters of the mid-continental shelf to avoid predation from the adult pollock that lurk below (NPFMC, 2009). Warm years are characterized by an increased transport of eggs and larvae away from adults, and lesser cannibalization as a result, possibly leading to improved recruitment to the fishery (Wespestad et al., 2000). Thus, barring other biological factors (food availability, other predation eggs/larvae, etc.) warming waters could improve recruitment to the pollock fishery. However, increased temperature will result in an increased metabolism that requires greater food intake. Additionally, it is likely that other changes to the ecosystem will reduce any recruitment gains.

Three distinct stocks of pollock are identified in the U.S. (EEZ) portion of the Bering Sea: the Eastern Bering Sea (EBS), Aleutian Island, and Central Bering Sea stocks (Ianelli et al., 2008). The largest stock of pollock is found in the EBS, located over the outer continental shelf (NPFMC, 2009). There are also two stocks in the Russian EEZ. One stock (the Central Bering Sea stock) is believed to migrate from U.S. and Russian shelves to the Aleutian Basin around the time of maturity (ACIA, 2004). Spawning aggregations occur on the southeast region of the Bering Shelf from February to May, peaking in mid March. Smaller spawning aggregations occur north of the Pribilof Islands later in the year—from April to May. Pollock reach reproductive maturity between the ages of three and four years. Pollock migrate twice a year—to feeding areas in the spring and breeding grounds in the winter. Kotwicki et al. (2005) showed that pollock of all sizes moved northward and inshore during warmer years.

Pollock fishery

Pollock are the most abundant species of fish in the Bering Sea (Woodby et. al., 2005) and the pollock fishery is the largest in the world with almost all of the world's harvest coming from Alaska and Russia. Two million metric tons of fish are taken annually (Kurland, 2009). Over the past twenty years an annual average of 1.22 million metric tons of pollock have been harvested in the Bering Sea, comprising over half of the annual seafood take in the Bering Sea.

The federal fishery had 180 permitted vessels in 2004 and the catch yielded an average exvessel value of almost $322 million (Woodby, 2005). Harvests of pollock in the Gulf of Alaska and Bering Sea are primarily by pelagic trawls with 90% of pollock caught in the Gulf of Alaska, and 95% in the Bering Sea. (Dorn et al., 2002). Recent catch reports have reflected that the pollock fishery has accounted for approximately 30% (GAPP, 2009) of the total U.S. seafood harvest by weight. While low, the bycatch of endangered species such as sea lions (Eumetopias jubatus) and species important in both subsistence and commercial fisheries such as chinook and chum salmon is of concern. Precautionary steps to protect these species including sea lion exclusion zones and salmon saving areas have been put in place. The first pollock season of the year takes place from January 20 to June 10 and targets pollock roe. It accounts for 40% of the TAC allocation. Currently, the pollock fleet's fishing is restrained by sea ice and weather conditions during this season. The second occurs from June 10 to November 1 and makes up the remaining 60%. A decrease of the winter sea ice extent in the may change the amount of pre-spawning female pollock that are removed from the Bering Sea. This could in turn affect pollock spawning when it occurs later in the year.

The EBS fishery primarily harvests mature pollock, with fish aged 6–8 most often caught (NPFMC, 2009). The reason that older pollock do not make up more of the total catch is that they become increasingly demersal with age. Younger aged pollock are not fished as frequently in U.S. waters due to the fact that fishing is mainly concentrated on the SW area of the shelf, whereas young pollock typically reside on the NW portion. The SW portion is targeted more heavily it the winter and spring, with the fleet expanding northward as the ice retreats. This may imply a fishery problem in the future, if ice retreats and the fishery moves farther north.

Internationally, the main contenders for the global pollock fishery are the U.S., Russia, Japan, China, and South Korea. In a research study published by the United Nations Food and Agricultural Organization the pollock harvest numbers for these five countries in a 6-year observation period were recorded. The data yielded a global landing average of 3,380,099 metric tons per year in the northern Pacific. By itself the Russian pollock industry fished about 1,924,549 metric tons operating mainly in the Sea of Okhotsk and in the Donut Hole. The U.S. had an average landing of 1,182,176 metric tons. Other countries including Japan, China, and Korea had a combined average of 801,624 metric tons per year. In the Russian portion there are two stocks; one located from 171°E to U.S.-Russia Convention Line, straddles the U.S. EEZ (Ianelli et al., 2008). Contiguous surveys reveal that this stock is predominantly composed of EBS pollock (Ianelli et al., 2008). Furthermore, juveniles which are primarily located in the northwest region of the EBS have been found to make up a major portion of the Russian catch (NPFMC, 2009).

As the ecosystem of the Bering Sea shifts northward, fishing effort will probably follow. The cruise report from the 2008 Beaufort Sea Survey reveals that pollock can already be located in the Chukchi Sea. Precautionary measures have already been taken to avoid premature exploitation of these Arctic stocks by the U.S. and an area of the Northern Bering Sea, (dubbed the Northern Bering Sea Research Area), has been closed for bottom trawling until sufficient research has been conducted (Kurland, 2009). Management policy regarding the research area will be developed further following the completion of a research plan in 2010 (Kurland, 2009). The waters within the U.S. EEZ to the north of the Northern Bering Sea Research Area, known as the Arctic Management Area, have been closed to commercial fishing until further research has been conducted.

The EBS total allowed catch is divided up among inshore catcher vessels, offshore catcher/processor vessels, motherships, and community development quota (Mecum, 2008). Community Development Quotas, or CDQs, were created in order to facilitate western Alaskan community's participation in Bering Sea/Aleutian Islands (BSAI) fisheries (Mecum, 2008). The program includes native Alaskan villages designated under the Alaskan Native Claims Settlement Act (Ginter, 1995). Currently the NPFMC allocates 10% of the pollock TAC, and 7.5% chinook prohibited species catch to the CDQ Program (Mecum, 2008). The economic stimulus that the CDQ program provides these communities is essential for their well-being (Ginter, 1995).

Pollock biomass has been on the decline since 2003 due to a period of below average recruitment levels and research suggests that biomass will further decline through 2009 (Ianelli et al., 2008). The 2008 total EBS biomass estimate was 3.0 million tons, down from 4.3 million in 2007 (Ianelli, 2008). As broadcast spawners, pollock's reproductive success is heavily influenced by environmental factors and changing conditions in the Bering Sea may already be affecting recruitment success of pollock.

Pollock and opilio fisheries and the Alaskan people

In addition to affecting the pollock and opilio fisheries, Arctic ice retreat also directly affects the Alaskan residents. It is predicted that as Arctic sea ice melts and exposes more ocean surface, winds could potentially drive an easterly current in regions newly exposed following sea ice retreat (Curtis, pers. comm.). Rural communities that rely on ocean travel for food are threatened by these changes because small seafaring craft have difficulty operating in high seas. Moreover, the ocean level is rising from thermal expansion (AAG, 2009) and by the year 2100 is expected to rise almost one meter. This will exacerbate erosion problems in coastal Alaskan villages (http://earthobservatory.nasa.gov/Features/ArcticIce/). Shorelines have already retreated nearly 400 meters in some places (http://www.usgcrp.gov/usgcrp/Library/nationalassessment/overviewalaska.htm).

Alaska residents make up two-thirds of the fishermen out on Alaskan water, and account for one-third of the seafood processing jobs that were offered. Approximately $72 million was paid to Alaska residential seafood processors (MCA, 2009). A greater amount of $92.4 million was paid to residential fishermen. Russia's pollock catch is another concern to Alaskans. "We think, depending on the year and conditions, that roughly 10–20% of the stock goes over to the Russian side," said James N. Ianelli, a NMFS scientist, in an interview with the LA Times. This is a huge loss to the Alaskan pollock fishery. If our stocks spill over into foreign waters our profits and harvests may be cut accordingly. If this rate continues our seafood industry may suffer and the species may become increasingly absent from our waters.

Pollock stocks are moving in a northeastern trend towards the pole (Ianelli, 2008) but U.S. vessels are restrained by the EEZ border. The industry can't be maintained if fishermen are separated from the resource.

Many native Alaskans also rely heavily on subsistence fisheries. These fisheries are estimated to provide an average of 104 kg to each person in rural Alaskan communities (Fall, 2007). Subsistence comprises 2% of Alaska's wild resource harvests, compared to the 97% taken by commercial fisheries (Fall, 2007). Chinook salmon bycatch is thus of concern for subsistence users as well as our international neighbors. In a radio tagging survey conducted by the Alaska Department of Fish and Game, half of the Yukon River chinook returned to Canadian waters (Eiler, 2009). Since 1992 chinook bycatch has averaged approximately 48,000 fish in the BSAI groundfish fisheries, removing fish prior to returning to rivers (NOAA, 2009). Bycatch reached a peak of nearly 130,000 salmon in 2007 (NOAA, 2009).

The increase in bycatch prompted regulations to help curb bycatch numbers. The 91st amendment to the BSAI fisheries management plan will set a cap on the number of chinook that would be allowed to be caught when it is implemented in 2011. The amendment calls for a hard cap of 60,000 chinooks per year. Chinook incidentally caught are considered prohibited species; they must either be discarded or donated via the Prohibited Species Donation Program.

Summary of recommendations

Flexibility and international cooperation are key in order for the complex management system to work effectively. Currently the NPFMC is comprised solely of U.S. members. Two voting members of the NPFMC are from Oregon and Washington; these states are located further from the Bering Sea than some foreign nations—specifically Russia. While the U.S. conducts a majority of the fisheries in the Bering Sea, other countries are affected by decisions made by the NPFMC. International involvement will be important when implementing new management policies in the future. Stocks of commercially fished species in the Bering Sea are greatly interconnected with Russian stocks. In the future, streamlined management by the two countries would be beneficial to the sustainability of the Bering Sea ecosystem. Increased cooperation will become even more important as the Bering Sea Ecosystem shifts northward. The distance between the U.S. and Russia decreases with increase in latitude, and thus the rate of stock mixing increases. The two countries will need to work together in order to sustain the fisheries in the future.

Walrus (Odobenus rosmarus), used for subsistence by Alaskans, have been noticeablly absent to native Alaskans as of late (Mattlin, 2000). Whereas walrus are not harvested in a fishery, they do serve to illustrate that multiple species, many of which are commercially or subsistence harvested, are likely to cross international boundaries. The walrus is protected in the U.S. under the Marine Mammal Protection Act, but Russia's policies may differ. Nations need to discuss and develop mutual policies that are in place if management is to be effective.

Future management plans will need to be flexible in order to effectively deal with the Bering Sea's rapidly changing ecosystem. The NPFMC will be better able to mitigate future problems if they are able to react to changes quickly. Current outlooks suggest that U.S. stocks of pollock and opilio are unlikely to significantly shift into Russian and international waters in the near future. Nevertheless, plans should be put in place in order to deal with shifts in population due to further ice retreat.

In order to keep up with the changes on our planet, we have to have a system where all of the different organizations involved in ocean policies can communicate, and delegate important issues, and most of all allow for regulations to go into effect and be enforced.

Modifications to current policy won't stop the physical change that is already occurring. Yes, fisheries will benefit from altering regulations to match the current trends, but the policies would constantly need to be reassessed unless the accelerated change is stabilized. Arctic ice melt in the Bering Sea is directly related to global climate change associated with anthropogenic carbon emissions. The long-term goal for fisheries management is to maintain populations for sustainable harvest. Therefore, a policy goal should be to get a handle on carbon missions so that fisheries management programs can be effective. If the accelerated state of change continues in the Bering Sea, few species will be left unaffected by factors like changing habitat, food web, predation, or overfishing. Careful management can only benefit the health of ecosystems so much. There is a point where it moves past management and into social change. Even within the fisheries themselves we see very old, inefficient boats and processing plants. Updating technology to be cleaner and discouraging the use of boats and plants that release excess carbon can be a step that fisheries management can take toward protecting the fisheries. In relation to Arctic sea ice melt, and the changing fisheries that will follow, it is important that our nation deal with the issue directly. By outlining threats and trends of two valuable fisheries for the U.S., and highlighting the need for new policies and increased international communication, we hope to convey that Arctic sea ice melt cannot be ignored.

References