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8 Gaps in Knowledge and Recommendations Both the gaps in our knowledge about the Bering Sea ecosystem and the research required to fill those gaps are so extensive that a detailed elaboration could be a report in itself. However, characterizing the general shortcomings of our past perspectives that contribute to our present lack of understanding and specifying a list of priority research needs could help address some of the most pressing issues concerning the Bering Sea ecosystem. The biggest single impediment to understanding the causes of change in the Bering Sea ecosystem (as well as in many other ecosystems) is the absence of an ecosystem viewpoint in research and scientific analysis. Previous research has typically focused on individual species populations, small subsets of the ecosystem, or short time periods. Such approaches have reflected the narrow ecological and temporal focus and responsibilities of the individual management agencies responsible for specific subsets of resources in this ecosystem. Such partitioning of an ecosystem into separate species, or subsets of species, does not allow the broad synthesis of information across all interacting and interdependent components of the ecosystem. Such synthesis is required to properly interpret the dynamics of the system. The most significant research recommendation that emerges from this study is to adopt a broader ecosystem perspective in both science and management of the natural resources of the Bering Sea. Such an approach makes sense scientifically and holds the greatest promise for unproved management and understanding. Even with adoption of an ecosystem perspective to synthesize information, ecological science will never achieve complete understanding of what controls the dynamics of distributions and abundances of species in any ecosystem. Gacs in knowledge will always be present and , ~ ~ a- -- r--~-~~~ if--- unexpected phenomena will continue to arise. Such changes, if deemed important, will stimulate demand for additional research, enhancing our understanding of causation and consequences. The challenge to management and stewardship of ecosystems is therefore how best to manage human activities given substantial uncertainty in the scientific understanding of the causes of dynamic change in those ecosystems. ~ , ~ r ~ ~. in part Because or uncersamplmg of marme ecosystems, there is probably greater uncertainty about the causes of dynamic changes in ecosystems in the ocean than on land. The vastness' isolation from human habitation, and large' three-dunensional domain of the open oceans create an overwhelming problem in simply knowing the abundances and distributions of species in the ecosystem. Although physical oceanographers have the technological capacity to 250
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Gaps In Knowledge and Recommendations 251 characterize ocean currents in three dimensions by use of acoustic Doppler current profilers, for example, the development of analogous biological samplers (even those exploiting the same acoustical principles) is in its infancy. Nonetheless, despite substantial gaps in our understanding of the dynamics of marine ecosystems, there is compelling evidence that changes in both the physical climate of the sea and fishing have had large influences on the composition and dynamics of many marine ecosystems (e.g., Sherman, 1991; Chapter 6). Again, distinguishing between effects of physical changes and those of fishing (more broadly, exploitation of natural resources) was the central issue in our evaluation of the causes of recent declines in certain marine mammals (Steller sea lions, harbor seals, and fur seals) and seabirds (red- and black-legged kittiwakes, sea ducks, and murres) over various expanses of the Bering Sea and adjacent regions. A critical difference exists between these two kinds of potential causes of change in the Bering Sea ecosystem. Changes in the physical climate of the sea occur largely, although not completely, independent of human control, whereas exploitation of natural resources is directly carried out by humans and theoretically can be controlled (in practice, control often is extremely difficult). This difference potentially allows fisheries to be managed with attention to evaluating rigorously the consequences of the exploitation (e.g., Peterson, 1993). This has been called adaptive management (McAllister and Peterson, 1992; Walters and Hilborn, 1986). Under well- designed fishing regulations (based on hypotheses about ecological causation), adaptive management of fisheries can become an extremely powerful tool for improving our understanding, not only of the impacts of fishing but also of the basic functioning of marine ecosystems (Holling, 1993). Clearly, the potential for adaptive management of the Bering Sea fisheries has not been adequately applied to develop the necessary understanding of the role of fishing in contributing to ecosystem changes. These would especially include the disturbing declines in many important marine mammals and seabirds. Much of the research on the Bering Sea ecosystem to date has followed the traditional reductionist path of trying to understand the mechanisms that drive the dynamics of this ecosystem on various spatial and temporal scales. Such an approach has obvious value. Elucidating fundamental interactions among components of the physical and biological environment appeals to a large majority of scientists and promises the capacity to understand and perhaps predict. Such research on basic processes should continue, but it should be complemented by assessments of the effects of manipulating the system through fisheries- management practices. This effort must include the provision of resources sufficient for research to follow up with evaluations of how variations in fishing affected the functioning of the system. It also must examine the ecosystem's ability to sustain populations of key component species. For example, the recent establishment of no-fishing buffers around important colonies of seabirds and marine- mammal haulouts provides opportunities for exactly the sort of experimental adaptive management that is required. However, there has been no experiment or dedicated research to assess the role of fishing in declines of certain Important marine mammals and seabirds. The U.S. National Marine Fisheries Service (NMFS) regulations of fishing were not designed with experiment in mind, and little research support was provided to evaluate the effects of these
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252 The Bering Sea Ecosystem changes in fishing practices. This is a wasted opportunity to realize an important aspect of adaptive management; learning through rigorous evaluation of the consequences of management interventions. These oversights must be corrected to achieve confident stewardship and sustainable use of the living resources of this ecosystem. To be effective, the adaptive management actions and research goals to be addressed through intervention in fishing practices must be jointly planned by fisheries scientists, bird and wildlife biologists, oceanographers, fisheries managers, and the users of the natural resources on both sides of the Bering Sea. In using adaptive management to evaluate the role of fishing in the ongoing declines of valued marine mammals and seabirds, any changes in regulation and management of fishing must be carefully crafted. They should include tests of specific hypotheses that relate to critical aspects of the species' ecology in the proper physical context. For example, while average abundance of important forage fishes such as pollock may remain high even with intense fishing when considered over the complete Bering Sea basin, dramatic depletion of certain size (age) classes at certain times and in certain places is likely to occur as a result of commercial fishing in this system. The creation, evolution, movement, and transformation of those depleted patches will depend on both physical and biological processes. Those local depletions may correspond with the seasons and locations where food limits one or more important consumers of these forage fishes. For example, the need for abundant food of high nutritive value around rookeries or other important foraging areas to nourish parents or independent young may well present a conflict between fishing and sustained production of some marine mammals and seabirds. Design of adaptive fisheries management to test the relationship of local fishing to successful passage through potentially critical life history stages must be achieved through collaboration. The collaboration should take place among scientists of several disciplines and fisheries managers, so that the management actions taken match the relevant biological time and space scales. Thus experts on marine mammals and seabirds must participate early in the design of the management plan, and agree that the plan is an appropriate test of the most important hypotheses. The study plan developed must recognize relevant physical transport and mixing processes as well. One set of adaptive management actions may not suffice to test all the important hypotheses, several management interventions may be needed. Some disruption of historical patterns of commercial fishing will necessarily occur in this process, but adaptive management is the most rigorous, efficient, and effective means of evaluating the effects of these fisheries on the broader ecosystem. Other indirect methods of testing for the effects of various fishing practices will perpetuate the piecemeal efforts of the past, and will not dramatically improve our understanding of the relationships until a great deal more money has been spent and critical time for restoration has passed. Manipulation of the fisheries using a well-crafted design, together with funding for ecological evaluation of impacts, represents the best way to address these unanswered questions. It is important to keep in mind that fishing includes commercial, subsistence, and recreational fishing, and that all of them to varying degrees affect each other and the exploited organisms. There are several additional research needs of high priority. One is the need for a better, more complete retrospective analysis of the Bering Sea ecosystem and certain of its key components. This analysis is especially critical for pollock, because of continuing uncertainty over whether its present high abundance is a relatively recent phenomenon, or whether the
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Gaps In Knowledge and Recommendations 253 absence of pollock fishing before about 20 years ago gives a false impression of relatively low pollock biomass in earlier years. The relationship between adult and ~ ~~ abundances also needs to be understood better. - ~ - ~ ~ ~ .. ~. . . .. .. . . . .. Juvenile pollock Resolution ot these and similar unanswered bump Mu ~= ~c Mar; `;v~npv=~vn or one Bering pea ecosystem 's critical to ~1~:_ ~ 41~_ ._1~- _ _1~ - _= ^_ __ _ ~ ~ u~uc~vra~u~g ~c Up o~ top predators to prey resources and Questions concerning natural versus human-caused fluctuations in species abundance ~- --O The present monitoring of the Bering Sea ecosystem is inadequate to understand, let alone predict, biological changes within it. In fact, there is no ecosystem monitoring. Only a few components of the system are monitored at all, with insufficient attention to the broader context of the ecosystem. We have little or no quantitative information on such critically important prey species as capelin, sand lance, smelts, squids, and myctophids. Understanding and managing an ecosystem without basic knowledge of the prey base on which the predator species depend is virtually impossible. Both conceptual and mathematical models of the structure and function of the Bering Sea ecosystem must be developed and verified by comparison with field fiats tn arlv~nce ~1 _ _ _ 1~ , 1 ~, ~, ~. ~ ~1 ~ ur~uers~analng or me ecosystem, lo TOCUS rurtner research on the most sensitive issues and to guide adaptive management decisions. r ~ ~ ~.= ~= ~___ ~4, _ _ ___ ~^ ~ TV VIA ~ ~ AVER-Vat ~11~ TV Such models are also necessary to design proper ecosystem monitoring, Waco cannot be so extensive as to provide information on all elements of the system. A sensible ecosystem monitoring strategy must be model-driven. For example, a selection of specific seabirds and marine mammals may serve well as indicators of the forage prey base of the entire ecosystem in a much more cost-efficient and biologically meaningful way than direct monitoring of all prey populations. Monitoring a shallow-diving seabird such as a kittiwake and a deep-diving seabird such as a murre might be one tool, for example, to monitor offshore pelagic forage fish. Such suggestions need to be more completely developed to cover the most important aspects of the ecosystem. At present, there is no archive of information about the various databases that do exist on certain aspects of the Bering Sea ecosystem. The sources and contact people for each database need to be identified and compiled in a fashion that permits potential users to access data. This is not to suggest that vast resources be spent in the creation of a comprehensive database on the Bering Sea. In the modern era of distributed computing and information highways, such an effort is not necessary. Ultimately, the use of geographic information system technologies to achieve integration through data overlays on various scales of time and space should be encouraged to move closer to the integration required for an ecosystem perspective. Long-term monitoring of Important physical and biological components of the Bering Sea ecosystem must be established to permit analyses of observed changes in the system and their causes. The short-term perspective of almost all available data sets contrasts sharply with what is known about the longer-term nature of many important climate changes and the population dynamics of many long-lived organisms. Instead of initiating necessary long-term monitoring, some of the most important long-term records are being abandoned, with grave Implications for understanding and management of the system as a whole. For example, a long-term (30-year) program of monitoring juvenile fur seal survivorship was abandoned in 1988 and should be reinitiated. Other long-term monitoring programs need to be established through reference to good conceptual models of the ecosystem. ~. ~ . ~. ~
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254 The Bering Sea Ecosystem A major field research program is required to develop the necessary basic understanding of how the physical conditions of the Bering Sea interact with the biological system to drive changes in ecosystem dynamics. There has been a substantial research commitment to achieving an oceanographic, process-based understanding of the eastern boundary current systems of upwelling. In other ecosystems, these upwelling systems are critical to production of important ecosystem goods and services. However, mechanistic understanding of the roles of climate and physical oceanographic forcing relative to the predominantly buoyancy-driven currents of the critical green belt of the Bering Sea is incomplete. This basic oceanographic research is central to developing the conceptual and mathematical models for focusing research, monitoring, and managing of this system. A data rescue and archiving project should be initiated immediately to preserve endangered ecological information that has been collected by individuals and institutions within the borders of the former Soviet Union. The breakdown of institutional structures within Russia and the republics threatens the loss of valuable information on components of the Bering Sea ecosystem along the Asian coast. In this region of the Bering Sea, there has been virtually no research by U.S. scientists. Furthermore, many data records that complement U.S. information are also known to be in files within the former Soviet Union, often in such forms as hand-written notes. Further basic research on ecosystem dynamics is needed to address convincingly whether ecological science can predict or even explain how a perturbation to an ecosystem cascades through that system. The characteristics of an ecological system that will allow confident prediction or explanation of cascading impacts should be identified. These questions need to be addressed in marine pelagic ecosystems, where little, if any, research has ever taken a broad perspective involving the dynamics of complete ecosystems. Research is also needed to integrate traditional knowledge of indigenous peoples into the body of scientific knowledge on the Bering Sea, to achieve both better scientific understanding and better resource management. The traditional knowledge of native communities and the acquired knowledge of fishermen and hunters represent valuable sources of information and understanding. Ecological research on the meaning of sustainability is necessary to address the question of how to define sustainability under conditions of dynamic natural change in ecosystems. This is an especially challenging question in ecosystems undergoing substantial changes in response to major climate shifts, which force biological responses. Management decisions concerning the Bering Sea ecosystem that affect many stakeholders both within the region and in other parts of the world are made by local, state, regional, tribal, national, and international entities. Good institutional structures should be designed to coordinate the activities of these entities such that the views of all stakeholders can be heard, the likely effects of alternative actions can be made known, and decisions can be reached. In addition, research is necessary to design specific management regimes and regulatory tools (such as area management, co-management, or individual transferable quotas) that are acceptable to the stakeholders, enforceable, and capable of changing individual behavior such that the intended objectives for resource use can be achieved. Improved knowledge of the ecosystem will have little effect on resource use unless there are overall management structures that can implement effective policies and overall communication structures that can facilitate exchange of knowledge
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Gaps In Knowledge and Recommendations 255 and understanding among different stakeholders. These considerations led the committee to make the following recommendations. RECOMMENDATIONS Research Adaptive Management One research recommendation includes and influences all the others, and that is the first one on adaptive management and monitoring. Humans have exploited the Bering Sea ecosystem for hundreds of years, at least, but because of environmental variability and the lack of adaptive (experimental) approaches to management, our understanding of the system remains meager. This problem is not unique to the Bering Sea; it is common to many if not all problems of natural resource management (see, for example, NRC, 1996 for a discussion of this problem with respect to salmon in the Pacific Northwest.) · An adaptive or experimental approach should be taken to all management actions concerning the Bering Sea ecosystem. Despite the committee's conclusions that the cascade hypothesis is a plausible explanation for at least some of the changes observed in the Bering Sea over the past 50 years and that the only significant human activity that could have affected the Bering Sea ecosystem is fishing, much remains unknown about the ecosystem and its functioning. Regulated human activities such as fishing provide some of the best possible vehicles for experimentation and improving understanding, as do protective activities mandated by the Endangered Species Act and the Marine Mammal Protection Act. It is therefore of critical importance that such activities and related regulations be designed such that information can be gained from them wherever possible. In addition to information already required, such as catch statistics, regulations should be implemented on an adaptive basis wherever possible. For example, no-fishing zones have been established adjacent to 43 sea lion rookeries, but some people, including members of this committee, believe that they are too small. Therefore, the National Marine Fisheries Service should reexamine the size of the no-fishing zones based on actual foraging ranges and habits of juveniles. In particular, no-fishing zones of various sizes should be implemented in a controlled way. As another example, the committee suggests that experimental fishing (and perhaps even overfishing in some carefully selected and limited areas) would be of value. Thus, in a few selected areas, one might set catch limits on pollock and some Catfish species above the level estimated to be sustainable, with carefully designed experimental monitoring of a variety of ecological factors, including those mentioned in the - recommendations that follow.
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256 Research to hnprove Understanding of the Ecosystem The Bering Sea Ecosystem Two of the most important questions about the functioning of the Bering Sea ecosystem concern pollock, which appears to be an important (keystone) species in the ecosystem (Bakkala, 1993; chapters 4 and 6), and the effects of sea ice, which has a major influence on the oceanography of the eastern Bering Sea shelf (Coachman, 1986; Ohtani and Azumaya, 1994; Chapter 3), and hence on the life of bottom-dwelling and nearshore species such as crabs, Catfishes, and herring. Research on the more general questions about the ecosystem should keep these two questions in mind. The committee recommends research on the following questions. · What are the nature and causes of the dynamics of pollock in the northeastern Pacific and Bering Sea over the past 50 years? Understanding this broad question can be approached by asking a number of more specific questions: a. Is the cascade hypothesis a plausible scenario for ecosystem dynamics? To answer this question, models would be useful. Is it possible to model energetics and energy transfers to arrive at a result that is consistent with the cascade hypothesis, with experience in other ecosystems, and with the available data? What is the effect of releasing zooplankton from predation? To what degree are alternative states of ecosystem organization stable? How likely is the organization to return to its previous state or to some other state? b. What are the short- and long-term effects of commercial fishing on the structure and dynamics of the Bering Sea ecosystem? Short-term effects might be investigated through adaptive management of the fishery, as described in the first research recommendation. Longer- term effects could be investigated through modeling and through comparisons with other large ecosystems, in addition to the continued, controlled collection of relevant data about fishing and its effects. Important questions include the effects of removing commercial species on their predators, their competitors, and their prey. In each case, information about substitutability is unportant, e.g., would their predators switch to other food sources and would their prey be eaten by their competitors? How does fishing affect the distributions of various species? How wide- ranging are its effects, e.g., how does fishing off Attu Island affect distributions and abundances of species in Norton Sound? - c. What are the roles of top-down and bottom-up forcing in the Bering Sea ecosystem? Do commercial, subsistence' and recreational fishery effects tend to be top-down and environmental effects bottom-up? How do such effects manifest themselves? d. What are the relationships between juvenile pollock and other forage species (e.g., capelin and Pacific sand lance) in the ecosystem? How do they organize the time and space dynamics of the top-level predators such as birds and marine mammals (and human fishers)? Answering this question would require studies of at-sea ecology of marine mammals and birds. More information is needed on the foraging locations and diets of marine mammals, especially pinnipeds. Long-term information on the distribution and abundance of seabirds at sea would be valuable to help understand foraging patterns and their relationships to oceanic productivity and the distribution and abundance of plankton and small fish. Finally, focused time series studies of the geographic and spatial distributions (and variability) of macrozooplankton are needed. This information is needed to study and understand the behavior of larger invertebrates,
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Gaps In Knowledge and Recommendations 257 and the vertebrates (including pollock) that rely on them and on zooplankton as a significant part of their diet. · What is the role of ice in structuring the Bering Sea ecosystem? This general question encompasses many questions about the eastern Bering Sea shelf resources, in particular those concerning crabs, Catfishes, and herring, and their population dynamics. They are all influenced by bottom temperatures, which in turn are influenced by sea ice. More specific questions include the following: a. What are the habitat requirements of various commercial invertebrates (especially crab species) and demersal finfishes (especially Catfishes and herring)? It would be valuable to know the habitat preferences and requirements (if any) of these species, and the relationship of fishing activities to their occupation of various habitats. A habitat and distribution atlas would be helpful. b. How did the seasonal and interannual dynamics of ice affect the collapse of the eastern Bering Sea king crab fishery? Would it have been possible to manage the fishery so as to avoid the collapse? · What are the periodicities of ecosystem changes? Much of this information can be obtained by analysis of existing data and by extrapolation from other related systems, but most will require long-term study. In some cases, the information is already being collected, and financial and administrative support is needed for continued study. Information is needed on the periods of physical changes such as the position of the Aleutian Low, ocean circulation changes, and sea surface temperatures. Better and longer-term information is needed on the distribution and abundance of marine mammals, seabirds, fish, benthic invertebrates, and plankton. · How do lower trophic levels of the ecosystem interact? Better understanding of the lower levels of food webs is needed, especially trophic roles and dynamics. Planktivorous birds (and fishes, if their place and time of collection are carefully documented) can be used to monitor at least the surface distribution and abundance of various planktonic species. · What are the structure and functioning of the "green belt?" It is important to understand the green belt better, to know the degree to which it supports productivity of various parts of the Bering Sea ecosystem, and to know more about the physical and biological features that make it more productive than other parts of the Bering Sea. Does it serve as an important source of biological production for the eastern, central, and western Bering Sea? Does it provide a connection between those areas; i.e., do changes in the green belt affect the various areas in a related way? · How well are the management and institutions of the Bering Sea structured to address problems and provide appropriate management solutions? The committee recommends detailed study of these institutions (for the reasons described in more detail in Chapter 7); the important questions to ask about each institution would include:
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258 The Bering Sea Ecosystem · the geographic area under its purview; · the resources and activities under its purview; · the basis for its authority; · the legislative mandate or other operational objectives · its basic operational procedures; · its source and level of funding; and · any implicit or explicit links between it and other organizations in research, planning, ~ , or operations. This information would help to develop understanding of the areas and types of regulation. Answers to these questions could help answer other questions, such as whether the North Pacific Fishery Management Council should be given more or less centralized authority or whether it should be restructured, and whether the Magnuson Fishery Conservation and Management Act, the Marine Mammal Protection Act, and the Endangered Species Act are compatible with a program of research and management with an ecosystem perspective. Management and Institutional Recommendations Institutions The committee identified four basic problems that need to be solved to achieve proper management of the Bering Sea ecosystem: the lack of knowledge and inherent limitations on understanding and predictability, incomplete specification of management objectives, lack of appropriate domestic institutional structures through which to make and implement coordinated management decisions on either side of the Bering Sea, and the Innited ability to coordinate domestic management with users and management agencies of other nations. The committee recommends the following steps to address these problems (described in detail in Chapter 71: · Improve the coordination of the complete web of institutional structures that make management decisions concerning resource use in the Bering Sea. · Coordinate the philosophy and objectives of laws dealing with management in the Bering Sea ecosystem. · Improve processes and institutions to coordinate the implementation of major federal acts relating to resource use in the ecosystem, and federal-state and international management. ~ Develop a research program to increase understanding of the Bering Sea ecosystem (keeping international issues and cooperation in mind), to fulfill the research needs identified by the committee to help future policy makers solve both short-term management and longer-term ecological problems.
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Gaps In Knowledge and Recommendations Specific Action to Reverse Declines in Marine Manunals and Birds 259 To reverse declines in marine mammals and birds, broaden the distribution of fishing effort in space and time, especially for pollock. As described in Chapter 6, there is a significant likelihood that concentrated fishing for pollock in some places at some times can have an adverse effect on availability of food for marine mammals and birds, especially juveniles. Therefore, fishing over wider areas and over longer periods is likely to improve the food supply for these animals, and is extremely unlikely to have adverse effects. The intent of this recommendation is not to increase total catches, and some areas should probably still be closed to fishing for conservation of fish, bird, and mammal populations. As with all management actions, if this one is adopted, it should be done on an adaptive basis. TO FUTILE The Bering Sea ecosystem, like all ecosystems, has been affected by natural fluctuations since time immemorial. Like most ecosystems, it has been affected by human activities since prehistory, but especially within the past 200 years as commercial exploitation developed. Thus, the recent changes that we see today should not be thought of as perturbations of a "pristine" ecosystem, but as part of a pattern of change affected by a complex array of natural and human influences. The complexity of the influences on the ecosystem makes understanding and management difficult, but some things are clear. First, environmental change will continue to occur in the future. Second, significant human exploitation of a single species can affect not only that species but many other species as well. In other words, there are connections among ecosystem components. Finally, the total productivity of the ecosystem has a limit, which means that human use of living resources will affect the ecosystem to some degree. Those three conclusions imply that unexpected events will continue in the future and that they will be larger as living resources are more heavily exploited. It also follows that actions with respect to single species will have complex consequences that will be hard to predict. Simply changing exploitation rates on a single species-pollock, for example-is unlikely to have easily predictable effects on other ecosystem components-marine mammals, for example. To operate successfully within this complex system, management strategies must be based on long-term data on physical and biological phenomena and must be adapted as we learn more about the structure and functioning of the ecosystem. A better understanding of institutional and socioeconomic factors will also be needed. Finding a balance between human uses of the region's many resources and maintaining other desired aspects of the ecosystem, such as high productivity of marine mammals or a particular composition of fish communities, will be an ongoing challenge.
Representative terms from entire chapter: