Introduction

Michael H. Glantz

Environmental and Societal Impacts Group National Center for Atmospheric Research* Boulder, CO 80307, USA

During the past decade there has been considerable speculation about the possible consequences of a global warming of the atmosphere for terrestrial ecosystems. One of the latest surveys of such impacts was undertaken by the US Environmental Protection Agency (EPA) at the request of the US Congress in its search for policy options with respect to the possible anthropogenically induced climate change (US EPA, 1989). While freshwater ecosystems and two estuarine ecosystems (Apalachicola Bay in Florida and San Francisco Bay in California, USA) were included in this recent EPA survey, marine ecosystems were not. A more recent assessment undertaken by Working Group II of the Intergovernmental Panel on Climate Change (IPCC, 1991) generated some speculation about possible climate change impacts on fish population and on aquatic life.

This volume, Climate Variability, Climate Change, and Fisheries, addresses the potential implications for fisheries and societies of the regional impacts of a global warming of the atmosphere. Fisheries case studies were selected for investigation of the responses to changes in their environment. While most of these changes related to biological factors (that is, changes in the abundance of a fish population), some case studies related to abiotic factors, focusing on changes in the availability of fish (that is, a loss of access to commercially exploited fish stocks because of unilateral extensions by nations of their fishing jurisdictions). This study began with the identification of fisheries around the world (see Fig. 1.1) that have undergone changes in availability and abundance, with a preference for fisheries affected by such changes in the past few decades. Some of the cases, however, are

* The National Center for Atmospheric Research is sponsored by the National Science Foundation.

classic ones (e.g., the collapse and reappearance of the Far Eastern sardine). Each chapter provides the general historical background of the fishery, the problems (or prospects) faced as the result of a natural or human-induced change in availability or abundance, and a set of possible lessons to societies that are directly or indirectly dependent on the exploitation of specific living marine resources.

Gulf of Mexico Shrimp

Maine Lobster

Great Lakes Sea Lamprey

Atlantic Menhaden

Polish Long-distance Trawlers

Peruvian Anchoveta & Chilean Sardine

Mexican Oysters

California Sardine

Pacific Northwest Salmon

Indian Ocean Tuna

Pacific Sardine Alaska King Crab

Fig. 1.1 Location of fisheries case studies. Adapted from Athelstan Spilhaus, "Whole Ocean Map," cited in Cousteau, 1981.

Gulf of Mexico Shrimp

Peruvian Anchoveta & Chilean Sardine

Mexican Oysters

Maine Lobster

Great Lakes Sea Lamprey

Atlantic Menhaden

Icelandic Cod Wars

Atlanto-Scandlan Herring North Sea Herring

Polish Long-distance Trawlers

California Sardine

Indian Ocean Tuna

Pacific Northwest Salmon

Pacific Sardine Alaska King Crab

Fig. 1.1 Location of fisheries case studies. Adapted from Athelstan Spilhaus, "Whole Ocean Map," cited in Cousteau, 1981.

The approach taken is referred to as "forecasting by analogy." This is an attempt to forecast society's ability to respond to the consequences of yet-unknown environmental changes that might occur in the future, by looking at societal responses to recent environmental as well as societal (e.g., legal) changes. Some of these changes have been long-term, low grade and cumulative, while others have been short-term and abrupt. This method of "forecasting" regional responses to the regional impacts of global climate change on the abundance or availability of living marine resources has been used in the absence, at this time, of reliable computer-generated regional climate impacts scenarios about the next several decades.

Many studies have already been undertaken on various aspects of the effects of anthropogenic and environmental factors on the viability of specific living marine resources under contemporary climatic conditions (e.g., Troadec, 1990). Clearly, a good base of information is available with which to begin an assessment of the possible regional and local implications of a global atmospheric warming of a few degrees Celsius, as projected by general circulation modeling output. There are also many researchers whose expertise would place them in a good position to address questions about the interrelationship between global changes and fisheries, once they become aware that their research is relevant to global climate change issues.

It is important to note that forecasting by analogy is not an attempt to assess the direct effects of a climate change on the biological aspects of living marine resources. A few such research efforts have already been undertaken (e.g., Bakun, 1990; Bardach & Santerre, 1981; Frye, 1983; Sharp & Csirke, 1983; Shepherd et al., 1984; US Department of Energy (US DOE), 1985; Fisheries, 1990). Fish populations are influenced by many elements of their natural environments during all phases of their life cycles. Subtle changes in key environmental variables such as temperature, salinity, wind speed and direction, ocean currents, and strength of upwelling, as well as those affecting predator populations, can sharply alter the abundance, distribution, and availability of fish populations. Human activities can also affect the sustainability of these populations through, for example, the application of a variety of different management schemes or new technologies, each of which could have a different (either beneficial or adverse) consequence for the state of the fishery, years, if not decades, into the future.

Interactions within the marine environment are acknowledged to be extremely complex. The proposed sustained global warming of the atmosphere adds to that complexity. An obvious environmental effect of a global warming would be changes in sea surface temperatures, which, in turn, would have an effect on fish populations during all life stages. However, as a recent DOE report noted, "the production of fish biomass in the oceans is governed by interactions among numerous physical, chemical, and biological processes" (US DOE, 1985, p. 97), not just temperature. Surprises, that is, counter-intuitive responses of marine organisms, should not be ruled out. According to the DOE report (US DOE, 1985, p. 98), "Whatever C02-induced climate-fisheries interactions occur on a global scale, there will be local areas or specific fisheries that display the opposite effects." Figures 1.2a and 1.2b depict in a generalized way some of the complexities associated with the direct and indirect effects of climate on the marine environment and on the life stages of fish populations. Thus, the relationship between climate change and fisheries will not be easy to define and most likely will have to depend, at least for the near future, on generalizations derived from case-by-case assessments of past and present experiences. Such assessments can provide first approximations or "guesstimates" about how fisheries might (not will) respond to climate-related environmental stresses, until we improve our understanding about how a global climate change will manifest itself in the regional marine environment.

There has been considerable speculation about what a warming of the atmosphere by several degrees Celsius will do to regional climate and to human activities presently attuned to that climate. The basis for that speculation comes mainly from various atmospheric general circulation model (GCM) outputs as a result of sensitivity studies associated with the equivalent of a C02 doubling. Speculation about future climate regimes has also been drawn from historical analogues such as the Medieval Optimum (about ad 800-1100) and the Little Ice Age (about 1550 to 1850), and from other paleoclimate analogues including the Al-tithermal (4,000-8,000 years ago), and epochs tens of thousands as well as millions of years ago when the earth's atmosphere was much warmer than it is at present.

Other approaches to gain a glimpse of the future have also been pursued. For example, composites of the warmest Arctic summers

DIRECT EFFECTS INDIRECT EFFECTS

abiotic biotic

DIRECT EFFECTS INDIRECT EFFECTS

abiotic biotic

Fig. 1.2a Major climatic pathways affecting the abiotic environment of fishes.

Increased atmospheric CO2 directly affects climate and dissolved CO2. CO2 indirectly affects seawater temperature, salinity, ice cover, turbulence, and currents. All of these abiotic effects have biotic consequences (US DOE, 1985).

Fig. 1.2a Major climatic pathways affecting the abiotic environment of fishes.

Increased atmospheric CO2 directly affects climate and dissolved CO2. CO2 indirectly affects seawater temperature, salinity, ice cover, turbulence, and currents. All of these abiotic effects have biotic consequences (US DOE, 1985).

have provided analogues to global warming based on the view that a global warming will be greatest in the polar regions (e.g., J├Ąger & Kellogg, 1983). Even the various advanced GCMs yield somewhat divergent pictures of temperature and precipitation changes that will result from a warmer earth, especially when one compares their regional projections in detail (e.g., Schlesinger & Mitchell, 1987). This raises the troubling question about which GCM to use for climate-related impact analyses.

There is also considerable disagreement about how a global average warming might translate into climate changes (i.e., temperature and precipitation) at the regional and local levels. At present the spatial resolution of general circulation models of the atmosphere is too coarse for the generation of regional scenarios that can be useful for reliable and credible social impact assessment. In addition, none of these GCMs as yet has defined an effective oceanic component. This, however, has in no way hindered speculation about regional and local climate changes and their socioeconomic impacts. In the absence of such scenarios, we have relied on the historical record in an attempt to forecast societal responses to climate change by analogy.

Fig. 1.2b Major biotic processes affecting fish production and the abiotic factors that modify these processes. The four major hypotheses concerning control of fishery abundance are related to the major processes controlling production and mortality of early life history stages: reproductive output, starvation, predatory (including cannibalistic) losses, and transport losses. To represent an actual fishery environment, several such interlocking diagrams would be needed to depict multiple species (US DOE, 1985).

Fig. 1.2b Major biotic processes affecting fish production and the abiotic factors that modify these processes. The four major hypotheses concerning control of fishery abundance are related to the major processes controlling production and mortality of early life history stages: reproductive output, starvation, predatory (including cannibalistic) losses, and transport losses. To represent an actual fishery environment, several such interlocking diagrams would be needed to depict multiple species (US DOE, 1985).

Since regional climatic changes that might be associated with a global warming are not yet well understood, there is a need to produce information that will be of value regardless of the magnitude (or direction) of those changes. In this regard, forecasting by analogy might be viewed as providing a win/win approach (as opposed to win/lose) to researchers as well as policymakers. It underscores the value of improving our understanding about how societies respond to environmental stress. It provides decisionmakers with baseline information about how well societies have responded to the consequences of past environmental changes, even in the absence of an anthropogenically induced warming of the atmosphere. Whether the atmosphere warms, cools or stays as it has been for the past several decades, it is important to improve our understanding of the interactions between human activities and climate variability. The information gathered in these and other forecasting by analogy studies around the globe (e.g., Glantz, 1988; Antal & Glantz, 1988; Magalhaes & Neto, 1989; Ninh et al., 1991) can be used to develop ways to mitigate the societal impacts of a variable climate at the regional level.

Analogies have been used to perform a variety of functions, some of which are as follows: (1) For general education: analogies can be used to educate nonspecialists about some aspects of a complex situation by making reference to a different situation about which they already have some information. (2) To educate researchers: more sophisticated analogies can be identified to enable researchers to better understand changes in processes, interrelationships, and sensitivities that might conceivably accompany a global warming. (3) To parameterize complex processes: analogues are used in numerical modeling where there is a need to include important processes related to atmospheric circulation in the model. As a result, there are simple "base" analogies that can be used to generate information about "target" analogies, or at least serve as adequate place holders in the models until those processes become better understood. (4) To forecast future states of systems, such as the atmosphere or society: while an analogy may be used for any one of a variety of purposes, a troublesome use is to forecast a state of the atmosphere or of society several decades into the future. It can, however, be used to make other kinds of projections about the nature of different types of societal responses to cope with a variety of plausible (but not necessarily probable) future regional climatic changes. (5) To generate policy options or responses: plausibility of a physical or societal analogy is not a sufficient condition for use by policymakers, because several plausible but contradictory policies could be formulated based on different analogues drawn from the same pool of ob jective scientific information. Analogies, however, can be used to identify policy needs in order to eliminate shortcomings in societal responses to environmental change. (6) To fulfill a psychological need: when confronted by unknown situations, analogies can provide us with a feeling of understanding. They provide a first step toward knowing or at least considering the unknown.

Using analogies to gain a glimpse of the future can be advantageous in several ways. Analogies provide a wealth of detail, an ease of communication. Yet, analogies can be developed without a need to provide all details; they can be presented from the perspective of an individual, a sector, a level of government, etc. Even when they are not consistent, they could serve to illuminate different aspects of the future. Also, analogies are conducive to communication, thereby inviting questions and discussions about what can or cannot be told about the future.

To summarize, analogies are an integral part of both physical and social science research with regard to the global warming issue (Glantz, 1991). Analogies are useful heuristic devices that can enhance our understanding. Almost every aspect of the global warming dialogue, from the projection of future production of ra-diatively active trace gases to the effects of global warming on society, must be explicitly recognized as having been based on analogy. Given the current state of uncertainty surrounding the implications for atmospheric processes, the environment, and societies of an increased loading of the atmosphere with radiatively active trace gases, it is essential that we examine the analogies we use.

There are, however, problems with the use of analogies. First of all, the reason behind making the analogy must be made clear or the analogy will be viewed as either irrelevant, misapplied, or misleading when judged from other perspectives. Secondly, there may be a tendency to "strain" an analogy; one must not read more into it than is there; one must not downplay or ignore important dissimilarities; one must remember that an analogy will not be a perfect replication of what might be expected. Thirdly, sometimes we are forced to make analogies that are inappropriate for cultural or historical reasons. Finally, plausible but mutually inconsistent scenarios can be developed (see, for example, Jamieson, 1988).

Scenarios about future worlds based on human experience have the political and social credibility that computer-generated see-

narios lack. Decisionmakers who have been directly involved in problems generated by climatic anomalies of the recent past have already been using that experience as a guide to dealing with current issues. Such experience is being passed on to future decisionmakers, just as the experiences of the 1930s US Great Plains drought or the California sardine or Peruvian anchoveta collapse have been (and continue to be) carried from one generation to the next.

Some atmospheric scientists have argued that the climate of the future will not be like the climate of the past. Therefore, they contend that the past cannot be seriously considered as a useful guide to the future. However, societal responses to regional climate in the near future will most likely be similar to societal responses to the climate-related environmental changes of the recent past. Recent societal responses to variable climatic conditions might provide useful insights into how best to cope with such conditions at least in the near future. Forecasting society's ability to cope with the impacts of climatic variations and change can be achieved through this method. Researchers can identify strengths and weaknesses, successes and failures in the way societies have responded to events that are most likely to recur in the future. Societies can then reduce the weaknesses while capitalizing on the strengths to mitigate those impacts in the future.*

This volume presents a set of case studies from around the world representing a variety of fisheries. Although given some broad guidelines, each contributor to this volume was allowed considerable flexibility in his or her approach to develop the case studies and to identify possible insights into potential societal responses to global warming.

Wooster's chapter on the Alaska king crab discusses the development and collapse of this important fishery. It also identifies management responses to the collapse with the expectation that there are lessons for fisheries managers responding to the impacts of global warming in the Gulf of Alaska/Bering Sea region.

* For example, a recent study (Glantz, 1988) using the forecasting-by-analogy approach assessed 10 North American case studies. Five of the climate-related environmental changes considered have occurred since the first workshop was held in June 1987.

The California sardine fishery has become part of American folklore as a result of the writings of John Steinbeck. Ueber and MacCall describe this classic case of a fishery collapse. The chapter underscores an improvement in the way living marine resources are managed. It also shows how the collapse of the California sardine fishery spawned the rapid development of major fisheries in South Africa and in Peru.

Miller and Fluharty's chapter is centered on the regional implications of the 1982-83 El Nino-Southern Oscillation (ENSO) event and focuses on the difficulties of separating economic pressures on fish populations from environmental ones. Their study also points out how a decline in one area can be accompanied by a sharp increase in fish landings in other adjacent regions.

Condrey and Fuller investigated the history of the Gulf shrimp fishery. They view this fishery as a classic example of an open-access fishery which has been allowed to expand beyond the point of maximum long-term economic benefit. A resource that had been viewed as limitless has in recent decades been threatened by fishing pressures as well as habitat destruction and occasional low streamflow in the Mississippi River.

Although Atlantic menhaden have been uncommon as a food fish, they have several industrial uses. Feingold points out in her chapter that society has had a direct effect on the fortunes of the menhaden fishery as a result, for example, of zoning laws that govern the location of processing plants, of intentional changes in coastal and estuarine habitats, and of increased demands for menhaden-based products.

Everyone associates lobsters with the US State of Maine. In fact, the lobster has been "immortalized" by serving as a graphic design on Maine's license plate. Acheson has reviewed the lobster industry during its decline in the first half of the twentieth century in order to identify possible lessons for changes in lobster availability or abundance that might be associated with global warming.

McGoodwin's chapter on the Mexican oyster fishery evaluates societal responses to adverse changes in the availability of har-vestable mollusks along Mexico's south Sinaloan coast. Changes in demographics in this region since the turn of the century have made traditional responses to losses in oyster productivity no longer viable. McGoodwin suggests ways that local fishermen can maintain a degree of flexibility in response to potential environmental changes that might accompany a climate change.

The Great Lakes, considered the "fifth coast" of North America (along with the Atlantic, Pacific, Caribbean and Arctic; for a discussion of this concept see Ashworth, 1987), is the geographic field of research by Regier and Goodier. They investigated the history of the sea lamprey in the Great Lakes as a possible analogue to some unpredictable consequences of global warming. Just as an ecosystem can be caused to undergo serious restructuring with an intrusion of a parasitic species, climate-related environmental changes can also prompt ecosystem restructuring.

Bailey and Steele assessed the North Sea herring, one of the world's most important living marine resources that has supported major fisheries in many northwest European countries for centuries. Their chapter addresses the role of environmental changes as well as the role of perceptions held in management organizations and the fishing industry in this stock's collapse in the mid-1970s.

A Soviet contribution was provided by Krovnin and Rodionov, scientists at the Ail-Union Research Institute of Marine Fisheries and Oceanography (VNIRO) in the USSR. Their study focused on changes in Atlanto-Scandian herring during the warmer decades of the the 1920s and 1930s. They suggest that a global warming might be favorable for the development of the Atlanto-Scandian herring fishery.

The next two chapters are somewhat different in that they are not based on changes in the physical environment but in the political setting in which fisheries must operate. The first of these by Glantz uses the Anglo-Icelandic conflicts (several of which were referred to as the Cod Wars) as a surrogate for societal responses to changes in the availability of cod. Iceland and UK came into conflict over the exploitation of this valuable resource as a direct result of a series of unilateral extensions by Iceland of its territorial waters between 1952 and 1976.

Russek's chapter assesses the impacts of the creation and implementation of the 200-mile exclusive economic zones (EEZs) by coastal nations worldwide. Poland's long-distance fishing industry was forced to adjust to this precipitous shock or face extinction. This chapter documents how Poland's fleet managed to survive a loss in availability of living marine resources that resulted from international legal decisions.

The history of the Far Eastern sardine fishery extends back at least to the early 1600s. Kawasaki reports on the rise and collapse and rise again of this fishery. The chapter discusses the impacts of these changes in abundance of the Far Eastern sardine population not only in Japan but in Korea and the USSR as well. He notes that coastal communities dependent on the exploitation of this fish population should prepare for the eventuality of yet another decline. He also compares some aspects of this fishery with those of California and Peru.

Caviedes and Fik address the implications of ENSO events for fisheries along the western coast of South America. They conclude that ENSO has a clear and major impact on regional fisheries, specifically the anchoveta in Peruvian waters and the sardine along the Chilean coast. They also highlight the importance of improving ENSO forecasts so that fisheries could be better managed in the face of this recurrent environmental change. Caviedes and Fik suggest a need for regional cooperation in the management of the fisheries of these two countries.

In the final case study, about western Indian Ocean tuna, Sharp discusses the development of the tuna fishery around the Seychelles Plateau. He assesses why this fishery thrives, while similar fisheries in other oceans in recent decades have either been marginally successful or have failed. He then compares the development of the tuna fisheries of the Seychelles and the Maldives.

The concluding section presents a summary of the highlights of each of the case studies and serves as an "executive summary." The information in this section has been drawn from the chapters, as prepared by the contributing authors, with the general findings prepared by Glantz and Feingold.

As a final comment on the forecasting by analogy approach, it is important to note that the purpose of looking back is neither to identify the exact types of climate changes that societies must prepare for nor is it to put emphasis on the most recent aberrations of climate as the most likely forecasts of future climate. The purpose is to determine how flexible (or rigid) societies are or have been in dealing with climate-related environmental changes. We must be aware of past events but we must not get drawn into preparing for them. Societies everywhere have already shown the propensity to prepare for the last climate anomaly by which they were affected. However, such anomalies seldom seem to recur in the same place, with the same intensity, or with the same societal impacts. Decisions today must take into consideration the need to maintain as much flexibility as practicable in the face of future unknowns.

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