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Science in support of fishery management
Ocean & Coastal Management 39 (1998) 151—166
Science in support of fishery management: New approaches for sustainable fisheries L.S. Parsons*, H. Powles, M.J. Comfort Department of Fisheries and Oceans, 200 Kent Street, Ottawa, Ont., Canada K1A 0E6
Abstract Uncertainty will always be part of managing marine ecosystems, and resource conservation must be based on explicit recognition of this fact coupled with suitable mechanisms for dealing with uncertainty. Science programs in Canada’s Department of Fisheries and Oceans are evolving to meet the challenges of resource conservation in a context of increasing pressure for access to resources and declining public funding. Studies of stock dynamics in an ecosystem context and of the links between variations in environmental conditions and stock productivity are helping to reduce uncertainty about long-term production potential. New forms of cooperative relationships between government, industry, universities and the general public are contributing to better knowledge of marine systems and to development of consensus views on conservation requirements for fishery resources. The precautionary approach to conservation has been adopted and use of marine protected areas will be expanded to complement other conservation approaches. ( 1998 Elsevier Science Ltd. All rights reserved.
1. Introduction Canada faces tremendous challenges in conservation and management of its fishery and oceans resources. The Minister for Fisheries and Oceans, supported by the Department of Fisheries and Oceans, must work to ensure conservation of over 200 stocks of more than 60 marine species in 3 oceans, and thousands of anadromous stocks. Pressure from the fishing industry for access to resources is constantly increasing, as some important traditional stocks have declined in abundance and as development of a world market in seafood has contributed to increasing value of catches at dockside. The Minister must also ensure that resources are allocated in an
*Corresponding author. Tel.: 001 613 993 0850; Fax: 001 613 990 2768. 0964-5691/98/$19.00 ( 1998 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 4 - 5 6 9 1 ( 9 8 ) 0 0 0 2 1 - 0
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orderly and equitable way between a variety of competing user groups, including aboriginal groups, commercial fishers and recreational anglers. These increasing demands must be met at a time when public funding for fisheries management, as for other government activities, is declining. Fisheries science and fisheries management operate in a world where uncertainty is the norm rather than the exception. Despite the remarkable progress made during this century in understanding the dynamics of marine stocks and ecosystems, uncertainty about the current status and future trajectory of marine systems remains a major constraint to ensuring long-term sustainability of the fisheries. The role of science in fisheries management is primarily to identify and, where possible, to reduce uncertainty — to allow fishers, industry and fishery managers to plan their activities, and to ensure conservation of marine resources so that future generations can realise the same benefits as we do. Marine ecosystems are sometimes subject to large-scale changes. Productivity trends for cod and lobster, the two most important fished species in Atlantic Canada, over the past 30 years provide an example of such changes (Fig. 1). Landings of cod have declined to close to zero since the early 1990s, as fisheries have been closed following collapses of the major stocks. Prior to the declines landings increased in the late 1970s and early 1980s as stocks rebuilt following the extension of Canadian
Fig. 1. Trends in Atlantic cod and lobster landings 1960—1994.
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jurisdiction over the 200-mile economic zone. No less remarkable is the fact that between the mid-1970s and the early 1990s lobster landings increased by a factor of three, and today remain well above the long-term average landings during the 20th century. Scientific analyses indicate that lobster stocks are very heavily exploited, indeed overexploited over parts of their range in Atlantic Canada. The increase in lobster landings may be partly due to increased fishing effort and to the extension of fishing areas, but analyses indicate that the increase is mainly due to improved survival of young lobsters to commercial size, as a result of unknown, but widespread environmental factors (release of predation by the reduced groundfish stocks is one hypothesis for the increase in lobster abundance, widely credited by fishermen, but the lack of overlap between the distributions of lobster and commercial groundfish suggests that this factor may not be of primary importance). The increase in landings of lobster and other shellfish in Atlantic Canada has compensated in some ways and some areas for the decreases in groundfish landings. Total landed value of all Atlantic fisheries in 1995 was the highest on record and many communities which have access to shellfish resources have experienced prosperity in recent years. However communities dependent on groundfish have been subject to hardship, and it remains to be seen whether dependence on a reduced number of primary species will introduce instability into the fishery. The cod and lobster landings trends (which in this case are a reasonable proxy for abundance trends) are a result of complex interactions between environmental factors and factors related to fishing. In both cases, the relative importance of the different factors underlying the great changes are currently unclear, but are the subject of intensive research. The important point is that these changes were not predicted and could not have been predicted with the state of knowledge at the time. We must improve our understanding of the dynamics of exploited stocks in order to improve our forecasting capability, and we must develop robust mechanisms to ensure that resources will be protected even in the face of uncertainty. Fishery science focusses on two main activities: the assessment of the current status of stocks and ecosystems, and forecasting of future potential production. Each step has its own particular sources of uncertainty. Assessments of current status are primarily based on estimation procedures and as is well known estimation in the marine environment is fraught with tremendous difficulties. Forecasting requires knowledge of how ecosystem level processess affect stock processes such as mortality, recruitment, growth and reproduction, as well as a sense of how the ecosystem may change in future. Such process studies address another very difficult set of scientific problems. To compound the scientific difficulties, fishers and the public are not hesitant to express a need for increasing levels of accuracy and precision in assessments of resource status. This paper outlines some current approaches to study and management of marine systems which are aimed at reducing uncertainty and its effects on resource management. We describe some recently initiated research programs in areas critical for improving estimates of abundance of marine stocks, improving understanding of the relationships between environmental variability and biological processes, and improving understanding of multispecies interactions and how they affect fishery
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productivity. We also discuss mechanisms for ensuring participation of industry, universities and the public in resource conservation, and other approaches to managing uncertainty in the marine environment, including the use of marine protected areas as a conservation and management tool. It should be noted that we have not attempted to cover the role of the social sciences in fisheries resource conservation in this article, but have concentrated on the biological aspects of fisheries science.
2. Improving resource assessments 2.1. Improving the accuracy and precision of abundance estimates 2.1.1. Estimates based on fishery information A key variable in models used to estimate abundance from fishery information is mortality of the target species. Total mortality can be partitioned into mortality due to fishing and mortality due to natural factors (senescence, predation, starvation, disease). Estimating mortality in fish stocks has proved to be one of the most difficult exercises in fisheries science, particularly natural mortality which can be expected to vary with changes in environmental conditions or in abundance of predators and prey. The Department of Fisheries and Oceans has initiated a multidisciplinary project to examine in detail the factors contributing to mortality of Atlantic cod over the past 15 years, during which time most stocks essentially collapsed. It is known that mortality of cod was very high during the 1980s and that the stock collapse followed this period of very high mortality. There has been considerable discussion — indeed there has been controversy — over the reasons for the high mortality, in particular over the relative contributions of fishing and of changes in the ecosystem [1]. Overfishing was a principal cause of the collapse, in that harvests were well above levels consistent with resource conservation. However the extent to which changes in production conditions in the marine environment also contributed to the collapse is increasingly becoming clear (this is discussed later in this paper). A number of factors could have contributed to increased cod mortality, both fishing and natural mortality. Fishing mortality is made up of mortality due to reported landings and due to ‘‘non-catch’’ sources such as discarding at sea, fish killed by trawls but not brought aboard the vessel, and unreported landings. Landings data may have been subject to error through misreporting, and there is evidence that several of the non-catch factors, notably discarding at sea and misreporting of landings, increased their contribution to fishing mortality in the years preceding the stock collapse. As part of the cod mortality project scientists are working to improve the information on these factors by conducting intensive interviews with fishers to determine the extent of misreporting and non-catch mortality. Natural mortality could be influenced by such factors as starvation, predation, and environmental stress. Again, there are indicators of changes in biological characteristics of cod stocks and in environmental conditions which could have contributed to increased natural mortality. For example, it has been shown that growth rate of cod,
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Fig. 2. Decline in weight at age of Atlantic cod, ‘‘northern cod’’ stock (NAFO Subdivisions 2J3KL).
as measured by weight at age, declined substantially in many areas of the Canadian Atlantic in the years preceding the stock collapse [2, 3] (Fig. 2). The decline in weight at age was also reflected in a decrease in condition factor or plumpness of cod [2, 3]. Condition of cod normally reaches its annual maximum in the fall, when fat reserves have been laid down to permit survival through the winter when food is scarce and conditions are severe. The observed decline in fall condition has been hypothesised to put cod at risk from increased natural mortality during the winter and early spring. Other possible sources of increased mortality are discussed later in this paper. Research is being conducted on each of the factors which could have contributed to increased mortality in cod over the past 15 years. Once better data are obtained on the various potential contributing factors, these will be related in a set of mathematical models which should help to determine the relative contributions of each. New knowledge of the influence of different factors on fish mortality will help in future to track changes in mortality, to relate these to ecosystem changes, and to improve our confidence in estimates of abundance of harvested fish species.
2.1.2. Estimates based on fishery-independent information The Department is also conducting a program of research aimed at improving hydroacoustic estimates of fish abundance. Acoustic techniques have been used for many years to assess the distribution and the abundance of fish in the sea, both by fishers and by scientists. Technology is advancing constantly in this field and systems now available have overcome some of the problems which have affected acoustic estimates in the past. The utility of modern acoustic methods for assessing the abundance of exploited fish was dramatically shown during a study which was part of the Department’s
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Northern Cod Science Program [4, 5]. In June 1990 an acoustic survey of the continental shelf off eastern Newfoundland found the largest school of cod ever documented in Canadian Atlantic waters, covering an area of roughly 20]30 km and containing an estimated 500 000 t of cod. In subsequent years, smaller schools of cod were found in the same area, which appeared to be part of a predictable pathway for the annual migration from the edge of the shelf to inshore waters. However, in 1993 and 1994 very few cod were found in this area. In 1993 almost the only cod found in the acoustic survey were far to the east and south, beyond Canada’s 200-mile limit. In 1994 no high-density schools of cod were found over the area surveyed although some scattered low density concentrations were located. Detailed information on smallscale distribution and behaviour of cod was also provided by this series of acoustic surveys: z springtime feeding migrations from the edge of the continental shelf to nearshore waters followed predictable ‘‘migration pathways’’ defined by relatively warm water temperatures; z cod spawned in dense shoals featuring midwater spawning columns made up of pairs of individuals; z migrating aggregations became fragmented when prey concentrations (capelin or shrimp) were encountered. In summary, these annual acoustic surveys succeeded in locating a predictable concentration of this important species, provided estimates of abundance, tracked the rapid decline in biomass which occurred from 1990 to 1994, and provided several hypotheses about the reasons for the decline in abundance which can be tested with further research. The overall goal of the enhanced research program on hydroacoustics is to improve the direct measurement and estimation of fish stocks. As part of this national multidisciplinary, multi-institute program work is being undertaken on improving species identification from acoustic surveys (to resolve a particularly important source of uncertainty in present acoustic work), on developing new technologies for acoustic abundance estimation, and on measurement of distribution and abundance of fish through collaboration between scientists and fishing fleets. The program has recently begun and is expected to bring together a wide range of expertise from government and industry and from disciplines including fisheries science, oceanography, engineering and commercial fishing. 2.2. Environmental variability and fishery productivity To improve our ability to forecast potential fishery productivity we must understand the effects of environmental variability on fisheries. Environmental or climatic factors affect many processes underlying fishery productivity: migration and distribution, the survival of young fish until recruitment to commercial sizes and growth rates. Much work has been done over the years on specific environmental factors such as temperature or wind and how they influence specific biological processes. Another approach, in which important results have recently been obtained and to which increasing research effort is being directed, is the study of the effects of large-scale
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Fig. 3. Relationship between the Aleution low pressure index (‘‘Climate index’’) and all-nation catches of all salmon species in the North Pacific Ocean.
environmental changes on overall production in large fished ecosystems. This work suggests that marine systems can experience shifts in production regimes between favourable and unfavourable for a given species or group of species. This general conclusion would have broad implications for fisheries science, suggesting that rebuilding stocks and maintaining them at some theoretical fixed production level may not be attainable objectives. Stability in fishery production is not a realistic goal, and sustainability does not equal stability of catch. A good example comes from the North Pacific. A recent study [6] has demonstrated that over a 70-year period there has been a close relationship between total catch of all North Pacific salmon species and a climate index related to the overall biological productivity of the North Pacific (Fig. 3). The results suggest that conditions over this large oceanic area shifted from ‘‘favourable’’ to ‘‘unfavourable’’ for salmon production in the mid-1940s and from ‘‘unfavourable’’ to ‘‘favourable’’ in the late 1970s. Changes in salmon catches by a factor of 2—3 times were observed concurrent with these shifts in production regimes. Several other studies in the North Pacific using different analytical approaches have found similar results [7] and more recently it has been shown that species other than salmon have experienced variations in abundance or in recruitment which correspond to the same shifts in environmental conditions [8—10]. In the northwest Atlantic similar processes are doubtless at work. The collapse of northwest Atlantic groundfish stocks followed some years of anomalously harsh environmental conditions [11], as represented by mean annual sea temperatures at a station off St. John’s Newfoundland (Fig. 4). Low temperatures have been observed
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Fig. 4. Integrated 0—175 m water temperature at Station 27 on the Grand Banks of Newfoundland.
since the mid-1970s and more particularly in the late 1980s and early 1990s. At the same time, the thickness and extent of the cold intermediate water layer found at depths between 50 and 150 m over much of Canada’s Atlantic offshore region, increased substantially, and minimum temperatures in this layer declined, with the result that wide areas of bottom habitat were covered with water much colder than in previous years [11]. The extent of the relationship between the groundfish decline and the harsh environmental conditions, and what processes might be acting, are the subject of ongoing research. Cold temperatures alone are unlikely to have directly influenced groundfish production but environmental changes associated with the period of cold temperatures could well have had an effect. The cold climatic conditions have been associated with a number of system-level changes suggesting that groundfish productivity may have been affected: declines in abundance of capelin (an important prey species for a range of predatory fish in the region), a southerly shift in the distribution of Arctic cod into areas where the Atlantic cod were once abundant, the declines in Atlantic cod condition factor noted above, changes in distribution of Atlantic cod. Off Newfoundland and Labrador groundfish species which were not the target of fisheries or which were only lightly fished have declined in abundance, further suggesting that environmental conditions have become unfavourable for groundfish [12]. Severe environmental conditions may indicate an ‘‘unfavourable’’ production regime for cod and other groundfish which in combination with the excessive fishing which is known to have occurred during this same period could have substantially accounted for the stock collapse. Such variations between high production and low production regimes must become part of our expectations for fishery production, and have to be explicitly factored into the process of establishing conservation limits.
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2.3. Multispecies interactions — stock dynamics in an ecosystem context Forecasting of potential fishery productivity also requires better knowledge of interactions between species. It has always been recognised that fished species live in complex ecosystems but for the purposes of resource assessment ‘‘system’’ factors were generally assumed to be constant and models were built based only the dynamics of the particular species of interest. With the great changes we have seen recently in abundance of our important fished species and in the ecosystems they inhabit it has become evident that credible stock assessment work will have to explicitly account for system-level changes. Multispecies systems are very complex to model. Research on these interactions has increased in recent years and will be continued with a view to giving us more confidence in our ability account for past changes and forecast future stock trends. A good example of this kind of research is recent work on the role of seals as predators on fish in the Atlantic region of Canada. There are three important species: harp seals, which migrate seasonally into Canadian waters, grey seals which are less abundant but resident year round, and harbour seals which are less abundant again. Seal populations have been growing rapidly over the last two decades [13]. For example, the total harp seal population has more than doubled since the early 1980s (Fig. 5) and in 1995 was estimated to be growing at 5% per year. Considerable research has been done since 1990 to allow estimation of the consumption of fish by harp and other seals. A wide range of studies has been undertaken to model consumption, including diet studies, studies of the bioenergetic requirements of the seals (to estimate consumption rates), seasonal distribution of fish and seals, and abundance and age structure of the seal population. The results to date indicate that in areas
Fig. 5. Estimated abundance of harp seals off Canada’s Atlantic coast.
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Fig. 6. Estimated consumption of prey by harp seals in Arctic and in Canadian Atlantic waters, and total catches of all fish species in Canadian Atlantic waters.
where the Canadian commercial fishery operates harp seals have consumed over 3 000 000 t of prey per year in recent years, compared with 1 000 000 t or less of fish taken in commercial fisheries (Fig. 6). Major prey species for harp seals are capelin and Arctic cod, but substantial quantities of other species are also consumed. There is potential for considerable impact on fisheries, particularly at a time when a number of other factors may also have been operating to increase mortality of groundfish. Regarding Atlantic cod specifically, recent estimates are that harp and gray seals are consuming of the order of 90 000 t per year east of Newfoundland and Labrador, 70 000 tons per year in the Gulf of St. Lawrence, and 17 000 tons per year east of Nova Scotia. The fish consumed are typically small so the number of individuals represented by these figures would be very large. These numbers are similar to the commercial fishery catches in the last years before fisheries were closed in 1992. There is no evidence to suggest that seal predation was a major factor in the collapse of groundfish stocks, but it is plausible that consumption rates of this magnitude could have an adverse impact on rebuilding of stocks which are presently severely depleted. Seals consume small fish whose survival to maturity will be essential for stock rebuilding. Work is continuing to allow us to build more precise, accurate models of interactions between seals and cod. 3. Resource conservation – institutional changes In response to the collapse of Atlantic groundfish stocks a number of stringent conservation measures have been implemented, the closure of most Atlantic groundfish fisheries being the most visible. The fishery on the northern cod stock was the
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first to be closed, in 1992, and since then most of our Atlantic cod stocks have been closed to fishing, along with many stocks of other species of groundfish. In 1995 more than 23 groundfish stocks were closed to fishing. Other measures have also been implemented: a prohibition on discarding fish caught (discarding had been shown to be a major source of unrecorded fishing mortality in the years before the groundfish closures), institution of more comprehensive conservation-oriented annual harvesting plans, increase in mesh size and mandatory use of square mesh, and institution of small fish protocols. Following these stringent conservation measures the most recent annual report on status of groundfish stocks has indicated that the decline of stocks has been stopped [14]. Recruitment from these very low stock levels will be necessary to rebuild abundance levels and it is not possible to predict how long this will take. In addition to these stringent measures, a number of changes have been made in the ways scientific information is being collected and used, and the ways that conservation measures for our fishery resources are being developed. Fishers and industry are becoming much more involved in the collection of information needed to improve the accuracy and precision of stock assessments, and in determining what measures need to be taken to ensure resource conservation. A major step towards a central role for industry in resource conservation was the creation of the Fisheries Resource Conservation Council in 1993. The FRCC presently has 5 members from universities and 8 from the fishing industry (as well as delegates from the 6 provinces and territories participating in Atlantic fisheries and ex officio members from the Department of Fisheries and Oceans). It is mandated by the Minister of Fisheries and Oceans to recommend conservation measures for Atlantic fish resources. The Council considers the scientific assessments of stock status produced by DFO scientists and also conducts public consultations at which people from industry, aboriginal groups and the public at large can contribute their information and opinions on resource status and conservation. The Council has worked mainly on Atlantic groundfish stocks to date, and has succeeded in providing conservation advice based on a broad consensus view of stock status [15, 16]. Consensus recommendations were a noteworthy achievement since the recommendations have meant closure of fisheries supporting the economy of large regions of Canada. The fishing industry has considerably increased its contribution to data gathering over the past 5—10 years. Observer programs on vessels at sea have existed for many years in the larger vessels of our offshore fleets, but recently these have been expanded to include a range of fleets including some of the smaller ‘‘midshore’’ vessels. Dockside monitoring programs have been initiated in a number of fisheries to verify landings data which were formerly based on logbooks and purchase slips. Both these programs are funded directly by industry and the data are made available for resource assessment. In the last three years agreements have been signed with fleets for contributions to stock assessment programs, for example in the Pacific sablefish fishery, the southern Gulf of St. Lawrence snow crab fishery, and the Atlantic offshore fishery for the Stimpson surf clam. In each case fishers have contributed enough funds to cover most of the expanded field and laboratory work needed to provide stock assessments of the detail and precision required to ensure a sustainable fishery under heavy exploitation pressure. Some of these agreements have had problems related to competing interests
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in the fishery, but over the long term these should be resolved and this sort of industry-science partnership will increasingly be a part of research programs on exploited species. Fishers and industry have become more directly involved in research on stock status through closer collaboration with scientists. This has happened in a number of ways, notably through the formation of the Fishermen/Scientists Research Association (FSRA) in Nova Scotia. Through this association fishers are provided with courses on monitoring of stock status and of environmental variables, and they in turn provide monitoring data to scientists for use in stock assessments. In recent years scientists have made considerable efforts to ensure that the results of stock assessments and related research are communicated in forms which can be understood and used by fishers and the general public, notably through the series of Stock Status Reports which describe the state of each commercially exploited stock in the Atlantic region.1 Perhaps the best example of industry-science partnership is the sentinel surveys which have been monitoring status of groundfish stocks. These are very restrictedscale fisheries which resemble commercial fisheries in some respects and which are run by fishers’ associations with funding from government. The objective is to provide information on distribution, abundance and biological characteristics of groundfish stocks for which commercial fisheries have been closed due to stock depletion. The programs are jointly designed by scientists and fishers and they not only allow collection of data and information essential for scientific assessment of stock status but allow fishers to maintain their own monitoring of stock status during the closures. In 1995 some 500 fishers were occupied in sentinel fisheries at 114 locations throughout Atlantic Canada.
4. Marine protected areas – a new approach to conservation Most of the advances and new approaches described above might be characterized as improvements to a traditional model for management. New ways of understanding our marine environment and commercial stocks are being developed, and new forms of industry—government collaboration are developing which allow those who benefit from commercial exploitation of resources to become more directly involved in research and in conservation. Following the unprecedented decline in abundance of some of our most important resources, and recognising that uncertainty is a fact of life in fisheries management, a new approach to conservation has been developed. A precautionary approach to resource conservation [17] has been adopted by the Department of Fisheries and Oceans, consistent with the approach Canada sought in negotiating the UN
1 See, for example, references 2 and 3. Stock Status Reports on Canadian stocks are available from the Canadian Stock Assessment Secretariat, Fisheries and Oceans, 200 Kent Street, Ottawa, Ontario, Canada K1A OE6.
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Convention on Straddling Stocks and Highly Migratory Species. Under the precautionary approach resource conservation is the first priority. In the 1980s fishery resources were seen as basically resilient and understanding of these resources was thought to be adequate to predict future production. We have learned at great cost that resources are more fragile than previously thought. As a consequence the approach has changed to erring on the side of caution when there is uncertainty about resource status and prospects. ‘‘Conservation first’’ has become the guiding principle which must override all other considerations. The addition of marine protected areas to our suite of conservation and management measures would represent a concrete way of implementing the precautionary approach and would represent a significant shift in our resource conservation strategy. Marine protected areas can act as a safeguard against uncertainty and can provide opportunities for further understanding of marine ecosystems. Protected areas are being used in several parts of the world as a conservation tool, complementing other management approaches. Research, primarily conducted on tropical ecosystems, shows that for some species marine protected areas can be an effective management tool for replenishing stocks. The establishment of marine-protected areas in temperate ecosystems would provide further opportunity to conduct research on their efficacy in these ecosystems. Marine-protected areas are not a new or revolutionary concept. Prior to the technological advances which allowed us to fish longer and deeper, as well as mine or drill for oil at great depths, there were de facto ‘‘protected’’ areas or refugia which were not accessible to exploitation and which thus acted as the cushion against declines due to environmental factors and exploitation of stocks [18]. A new Oceans Act outlining Canada’s overall approach to oceans management and giving the Department of Fisheries and Oceans a lead coordination role for all oceans activities was passed by Canada’s Parliament early in 1997. The centrepiece of the Oceans Act is a new Oceans Management Strategy for stewardship and sustainable development of all oceans resources. In the text of the Oceans Act the Oceans Management Strategy is only loosely framed, but provision is made for broad consultation among the many oceans interests and stakeholders that will lead to complete definition of the Strategy. The Act does call for immediate development of three pillars of the Oceans Management Strategy: z integrated management of ocean, coastal and estuarine resources, including a system of integrated coastal zone management (ICZM); z a national system of marine environmental quality guidelines to measure our effectiveness in protecting the marine environment; z a national system of marine protected areas. The Oceans Act provides a mechanism for establishing marine protected areas for a variety of purposes including: z conservation and protection of commercial and non-commercial fisheries resources, including marine mammals and their habitats; z conservation and protection of endangered or threatened marine species and their habitats; z conservation and protection of unique habitats; and
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z conservation and protection of marine areas of high biodiversity or biological productivity; The mechanism outlined in the Oceans Act for establishment of protected areas is the ability to promulgate regulations that will describe the area geographically, describe zones within it, and limit the activities that may take place in that area, or in each of the zones. This range of mechanisms for establishment of marine protected areas covers the spectrum of requirements. It provides for the obvious need for protection of specific areas critical to life stages of particular species such as spawning areas or juvenile nursery areas. It also provides for broader protection for areas of high biodiversity or high productivity, recognizing the responsibility of this Department not only for commercially exploited species but for all marine species within the Minister’s mandate. This approach supports adoption of an ecosystem approach when establishing marine protected areas. Marine protected areas established under the Oceans Act can then fit into a larger array of marine protected areas such as those established as representative of marine regions (i.e. marine parks) or for the protection of marine birds. The design and nature of a marine-protected area will be dependent on its ultimate purpose [19]. The flexibility in the Oceans Act will allow us to design marine protected areas that include a full spectrum of protection; from those that are protected from all forms of exploitation to multiple use areas. The essential element is a clear identification of the purpose of a marine protected area and a plan to accomplish that purpose. The use of marine protected areas is not restricted to use as a fisheries management tool although there is evidence to suggest that for some species they can be quite effective. In existing marine protected areas and reserves from coral reefs to temperate kelp forests, greater abundance of exploitable species and larger, more fecund individuals have been observed [18]. In addition, protected areas or refugia have been shown to preserve natural genetic diversity where fishery based selection operates to decrease diversity. More important than the role of marine protected areas as a fishery management tool is their role as a broad conservation tool. Marine protected areas allow us to implement the precautionary principle in a concrete way [20]. By integrating marine protected areas into our conservation and management regimes, we provide ourselves with an ‘‘insurance policy’’ against the effects of intensive exploitation and environmental fluctuations. They can effectively act as a hedge against the uncertainty we all recognize in marine systems. Marine protected areas or marine protected area systems, if designed correctly, can maintain the ecosytems and their functions for which we continue to seek a better understanding. Marine protected areas can also serve the purpose of preserving genetic diversity by acting as refugia for small or depleted sub-stocks of exploited species that might otherwise be removed from the gene pool, thus reducing genetic richness and vigour of the stock as a whole. Marine protected areas are not a panacea for all that ails marine ecosystems. There is little to be done if external effects continue to degrade habitats or if management
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approaches do not reflect ecosystem functions. Nor are marine protected areas a last resort, to be turned to when all else fails. Experience and scientific principles support the view that general and precautionary action would be a valuable addition to standard fisheries management [21]. Their effectiveness will be fully realized when anchored in a broad integrated resource management framework and in overall conservation goals. The Oceans Act provides for this broad planning framework and gives a legislative basis for establishing marine protected areas as part of that planning framework.
5. Conclusions Uncertainty will always be part of managing marine ecosystems. Resource conservation must be based on explicit recognition of this fact coupled with suitable mechanisms for dealing with uncertainty. The precautionary approach and the use of other new approaches such as marine protected areas are elements of a more robust management system which can help to ensure resource conservation when uncertainty is great. Active participation and support of people who benefit from ocean resources, who have specialized knowledge of the oceans, and who have a vital stake in the future of ocean resources — fishers, scientists, the Canadian public — are essential for development and respect of the conservation measures which will ensure sustainable fisheries despite uncertainty. Continuing improvements to our knowledge of ocean resources and particularly of the dynamics of fished stocks in an ecosystem context are an essential basis for resource conservation. Science is our principal tool for ensuring that our knowledge is as good as it can be. We must put these elements together into an overall conservation framework which will ensure that benefits from our fishery resources are better realised today and for future generations.
6. Acknowledgements This paper is based on work of scientists at Canada’s Department of Fisheries and Oceans, who maintain the tradition of excellence essential for conservation of ocean resources. We are grateful to Kathryn Bruce, Helen Joseph, Gerry Swanson and an anonymous referee for comments on the manuscript, and to Jennifer Vollrath for preparation of figures. This paper is based on a presentation by L. S. Parsons to the Coastal Zone Canada Conference, Rimouski, Quebec, August 1996.
References [1] See, for example, International Council for the Exploration of the Sea, Cod and Climate Change, ICES Marine Science Symposia 1993;198:693. [2] Anon. Northern cod (2J3KL). DFO Atlantic Stock Status Report 96/45E. Department of Fisheries and Oceans, St. John’s, Newfoundland, 1996:6pp.
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[3] Anon. Cod in the northern Gulf of St. Lawrence. DFO Atlantic Stock Status Report 96/53. Department of Fisheries and Oceans, Mont-Joli, Que´bec, 1996:8pp. [4] Anon. Northern Cod Science Program, Final Report 1990—1995. Department of Fisheries and Oceans, St. John’s, Newfoundland, 1995:67pp. [5] Rose GA. Cod spawning on a migration highway in the north—west Atlantic. Nature 1993;366:458—461. [6] Beamish RJ, Bouillon DR. Pacific salmon production trends in relation to climate. Canadian Journal of Fisheries and Aquatic Sciences 1993;50:1002—1016. [7] Hare SR, Francis RC. Climate change and salmon production in the Northeast Pacific Ocean. Canadian Special Publication in Fisheries and Aquatic Sciences 1995;121:357—372. [8] Beamish RJ, Bouillon DR. Marine fish production trends off the Pacific coast of Canada and the United States. Canadian Special Publication in Fisheries and Aquatic Sciences 1995;121:585—591. [9] Hollowed AB, Wooster WS. Decadal-scale variations in the eastern subarctic Pacific: II. response of Northeast Pacific fish stocks. Canadian Special Publication in Fisheries and Aquatic Sciences 1995;121:373—385. [10] Ware DM, McFarlane GA. Climate-induced changes in Pacific hake (Merluccius productus) abundance and pelagic community interactions in the Vancouver Island upwelling system. Canadian Special Publication in Fisheries and Aquatic Sciences 1995;121:509—521. [11] Anon. State of the Ocean: Northwest Atlantic. DFO Atlantic Fisheries Stock Status Report 96/41E. Department of Fisheries and Oceans, Dartmouth, Nova Scotia, 1996:7pp. [12] For example see Bowering WR, Brodie WB, Morgan MJ. Changes in abundance and distribution and certain population parameters of American plaice off Newfoundland during 1972—1994, with implications for fisheries management. North American Journal of Fisheries Management 1996;16:747—769. [13] Anon. Report on the status of harp seals in the northwest Atlantic. DFO Atlantic Fisheries Stock Status Report 95/7. Department of Fisheries and Oceans, St. John’s, Newfoundland, 1995:4pp. [14] Anon. Overview of the status of Canadian managed groundfish stocks in the Gulf of St. Lawrence and in the Canadian Atlantic. DFO Atlantic Fisheries Stock Status Report 96/40. Department of Fisheries and Oceans, Ottawa, Ontario, 1996:11 pp#10 annex pp. [15] FRCC, 1994 Conservation Requirements for Atlantic Groundfish—Report to the Minister of Fisheries and Oceans. Fisheries Resource Conservation Council, Ottawa, Ontario, 1993:70 pp#appendices. [16] FRCC, Conservation, Come Aboard. 1996 Conservation Requirements for Atlantic Groundfish — Report to the Minister of Fisheries and Oceans. Fisheries Resource Conservation Council, Ottawa, Ontario, 1996:109 pp # appendices. [17] FAO, Precautionary approach to fisheries. Part 1: Guidelines on the precautionary approach to capture fisheries and species introductions. FAO Fisheries Technical Paper Part 1, 1995;350:52pp. [18] Dugan, JE, Davis GE. Aplications of marine refugia to coastal fisheries management. Canadian Journal of Fisheries and Aquatic Sciences 1993;50:2029—2042. [19] Ticco PC. The use of marine protected areas to preserve and enhance marine biological diversity: a case study approach. Coastal Management 1995;23:309—314. [20] Agardy MT. Advances in marine conservation: the role of marine protected areas. Trends in Ecology and Evolution 1994;9:267—270. [21] Ballantyne WJ. The practicality and benefits of a marine reserve network. In: Gimbel KL, editor. Limiting Access to Marine Fisheries: Keeping the Focus on Conservation. Centre for Marine Conservation/World Wildlife Fund, Washington DC, 1994.
Science in support of fishery management: New approaches for sustainable fisheries L.S. Parsons*, H. Powles, M.J. Comfort Department of Fisheries and Oceans, 200 Kent Street, Ottawa, Ont., Canada K1A 0E6
Abstract Uncertainty will always be part of managing marine ecosystems, and resource conservation must be based on explicit recognition of this fact coupled with suitable mechanisms for dealing with uncertainty. Science programs in Canada’s Department of Fisheries and Oceans are evolving to meet the challenges of resource conservation in a context of increasing pressure for access to resources and declining public funding. Studies of stock dynamics in an ecosystem context and of the links between variations in environmental conditions and stock productivity are helping to reduce uncertainty about long-term production potential. New forms of cooperative relationships between government, industry, universities and the general public are contributing to better knowledge of marine systems and to development of consensus views on conservation requirements for fishery resources. The precautionary approach to conservation has been adopted and use of marine protected areas will be expanded to complement other conservation approaches. ( 1998 Elsevier Science Ltd. All rights reserved.
1. Introduction Canada faces tremendous challenges in conservation and management of its fishery and oceans resources. The Minister for Fisheries and Oceans, supported by the Department of Fisheries and Oceans, must work to ensure conservation of over 200 stocks of more than 60 marine species in 3 oceans, and thousands of anadromous stocks. Pressure from the fishing industry for access to resources is constantly increasing, as some important traditional stocks have declined in abundance and as development of a world market in seafood has contributed to increasing value of catches at dockside. The Minister must also ensure that resources are allocated in an
*Corresponding author. Tel.: 001 613 993 0850; Fax: 001 613 990 2768. 0964-5691/98/$19.00 ( 1998 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 4 - 5 6 9 1 ( 9 8 ) 0 0 0 2 1 - 0
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orderly and equitable way between a variety of competing user groups, including aboriginal groups, commercial fishers and recreational anglers. These increasing demands must be met at a time when public funding for fisheries management, as for other government activities, is declining. Fisheries science and fisheries management operate in a world where uncertainty is the norm rather than the exception. Despite the remarkable progress made during this century in understanding the dynamics of marine stocks and ecosystems, uncertainty about the current status and future trajectory of marine systems remains a major constraint to ensuring long-term sustainability of the fisheries. The role of science in fisheries management is primarily to identify and, where possible, to reduce uncertainty — to allow fishers, industry and fishery managers to plan their activities, and to ensure conservation of marine resources so that future generations can realise the same benefits as we do. Marine ecosystems are sometimes subject to large-scale changes. Productivity trends for cod and lobster, the two most important fished species in Atlantic Canada, over the past 30 years provide an example of such changes (Fig. 1). Landings of cod have declined to close to zero since the early 1990s, as fisheries have been closed following collapses of the major stocks. Prior to the declines landings increased in the late 1970s and early 1980s as stocks rebuilt following the extension of Canadian
Fig. 1. Trends in Atlantic cod and lobster landings 1960—1994.
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jurisdiction over the 200-mile economic zone. No less remarkable is the fact that between the mid-1970s and the early 1990s lobster landings increased by a factor of three, and today remain well above the long-term average landings during the 20th century. Scientific analyses indicate that lobster stocks are very heavily exploited, indeed overexploited over parts of their range in Atlantic Canada. The increase in lobster landings may be partly due to increased fishing effort and to the extension of fishing areas, but analyses indicate that the increase is mainly due to improved survival of young lobsters to commercial size, as a result of unknown, but widespread environmental factors (release of predation by the reduced groundfish stocks is one hypothesis for the increase in lobster abundance, widely credited by fishermen, but the lack of overlap between the distributions of lobster and commercial groundfish suggests that this factor may not be of primary importance). The increase in landings of lobster and other shellfish in Atlantic Canada has compensated in some ways and some areas for the decreases in groundfish landings. Total landed value of all Atlantic fisheries in 1995 was the highest on record and many communities which have access to shellfish resources have experienced prosperity in recent years. However communities dependent on groundfish have been subject to hardship, and it remains to be seen whether dependence on a reduced number of primary species will introduce instability into the fishery. The cod and lobster landings trends (which in this case are a reasonable proxy for abundance trends) are a result of complex interactions between environmental factors and factors related to fishing. In both cases, the relative importance of the different factors underlying the great changes are currently unclear, but are the subject of intensive research. The important point is that these changes were not predicted and could not have been predicted with the state of knowledge at the time. We must improve our understanding of the dynamics of exploited stocks in order to improve our forecasting capability, and we must develop robust mechanisms to ensure that resources will be protected even in the face of uncertainty. Fishery science focusses on two main activities: the assessment of the current status of stocks and ecosystems, and forecasting of future potential production. Each step has its own particular sources of uncertainty. Assessments of current status are primarily based on estimation procedures and as is well known estimation in the marine environment is fraught with tremendous difficulties. Forecasting requires knowledge of how ecosystem level processess affect stock processes such as mortality, recruitment, growth and reproduction, as well as a sense of how the ecosystem may change in future. Such process studies address another very difficult set of scientific problems. To compound the scientific difficulties, fishers and the public are not hesitant to express a need for increasing levels of accuracy and precision in assessments of resource status. This paper outlines some current approaches to study and management of marine systems which are aimed at reducing uncertainty and its effects on resource management. We describe some recently initiated research programs in areas critical for improving estimates of abundance of marine stocks, improving understanding of the relationships between environmental variability and biological processes, and improving understanding of multispecies interactions and how they affect fishery
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productivity. We also discuss mechanisms for ensuring participation of industry, universities and the public in resource conservation, and other approaches to managing uncertainty in the marine environment, including the use of marine protected areas as a conservation and management tool. It should be noted that we have not attempted to cover the role of the social sciences in fisheries resource conservation in this article, but have concentrated on the biological aspects of fisheries science.
2. Improving resource assessments 2.1. Improving the accuracy and precision of abundance estimates 2.1.1. Estimates based on fishery information A key variable in models used to estimate abundance from fishery information is mortality of the target species. Total mortality can be partitioned into mortality due to fishing and mortality due to natural factors (senescence, predation, starvation, disease). Estimating mortality in fish stocks has proved to be one of the most difficult exercises in fisheries science, particularly natural mortality which can be expected to vary with changes in environmental conditions or in abundance of predators and prey. The Department of Fisheries and Oceans has initiated a multidisciplinary project to examine in detail the factors contributing to mortality of Atlantic cod over the past 15 years, during which time most stocks essentially collapsed. It is known that mortality of cod was very high during the 1980s and that the stock collapse followed this period of very high mortality. There has been considerable discussion — indeed there has been controversy — over the reasons for the high mortality, in particular over the relative contributions of fishing and of changes in the ecosystem [1]. Overfishing was a principal cause of the collapse, in that harvests were well above levels consistent with resource conservation. However the extent to which changes in production conditions in the marine environment also contributed to the collapse is increasingly becoming clear (this is discussed later in this paper). A number of factors could have contributed to increased cod mortality, both fishing and natural mortality. Fishing mortality is made up of mortality due to reported landings and due to ‘‘non-catch’’ sources such as discarding at sea, fish killed by trawls but not brought aboard the vessel, and unreported landings. Landings data may have been subject to error through misreporting, and there is evidence that several of the non-catch factors, notably discarding at sea and misreporting of landings, increased their contribution to fishing mortality in the years preceding the stock collapse. As part of the cod mortality project scientists are working to improve the information on these factors by conducting intensive interviews with fishers to determine the extent of misreporting and non-catch mortality. Natural mortality could be influenced by such factors as starvation, predation, and environmental stress. Again, there are indicators of changes in biological characteristics of cod stocks and in environmental conditions which could have contributed to increased natural mortality. For example, it has been shown that growth rate of cod,
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Fig. 2. Decline in weight at age of Atlantic cod, ‘‘northern cod’’ stock (NAFO Subdivisions 2J3KL).
as measured by weight at age, declined substantially in many areas of the Canadian Atlantic in the years preceding the stock collapse [2, 3] (Fig. 2). The decline in weight at age was also reflected in a decrease in condition factor or plumpness of cod [2, 3]. Condition of cod normally reaches its annual maximum in the fall, when fat reserves have been laid down to permit survival through the winter when food is scarce and conditions are severe. The observed decline in fall condition has been hypothesised to put cod at risk from increased natural mortality during the winter and early spring. Other possible sources of increased mortality are discussed later in this paper. Research is being conducted on each of the factors which could have contributed to increased mortality in cod over the past 15 years. Once better data are obtained on the various potential contributing factors, these will be related in a set of mathematical models which should help to determine the relative contributions of each. New knowledge of the influence of different factors on fish mortality will help in future to track changes in mortality, to relate these to ecosystem changes, and to improve our confidence in estimates of abundance of harvested fish species.
2.1.2. Estimates based on fishery-independent information The Department is also conducting a program of research aimed at improving hydroacoustic estimates of fish abundance. Acoustic techniques have been used for many years to assess the distribution and the abundance of fish in the sea, both by fishers and by scientists. Technology is advancing constantly in this field and systems now available have overcome some of the problems which have affected acoustic estimates in the past. The utility of modern acoustic methods for assessing the abundance of exploited fish was dramatically shown during a study which was part of the Department’s
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Northern Cod Science Program [4, 5]. In June 1990 an acoustic survey of the continental shelf off eastern Newfoundland found the largest school of cod ever documented in Canadian Atlantic waters, covering an area of roughly 20]30 km and containing an estimated 500 000 t of cod. In subsequent years, smaller schools of cod were found in the same area, which appeared to be part of a predictable pathway for the annual migration from the edge of the shelf to inshore waters. However, in 1993 and 1994 very few cod were found in this area. In 1993 almost the only cod found in the acoustic survey were far to the east and south, beyond Canada’s 200-mile limit. In 1994 no high-density schools of cod were found over the area surveyed although some scattered low density concentrations were located. Detailed information on smallscale distribution and behaviour of cod was also provided by this series of acoustic surveys: z springtime feeding migrations from the edge of the continental shelf to nearshore waters followed predictable ‘‘migration pathways’’ defined by relatively warm water temperatures; z cod spawned in dense shoals featuring midwater spawning columns made up of pairs of individuals; z migrating aggregations became fragmented when prey concentrations (capelin or shrimp) were encountered. In summary, these annual acoustic surveys succeeded in locating a predictable concentration of this important species, provided estimates of abundance, tracked the rapid decline in biomass which occurred from 1990 to 1994, and provided several hypotheses about the reasons for the decline in abundance which can be tested with further research. The overall goal of the enhanced research program on hydroacoustics is to improve the direct measurement and estimation of fish stocks. As part of this national multidisciplinary, multi-institute program work is being undertaken on improving species identification from acoustic surveys (to resolve a particularly important source of uncertainty in present acoustic work), on developing new technologies for acoustic abundance estimation, and on measurement of distribution and abundance of fish through collaboration between scientists and fishing fleets. The program has recently begun and is expected to bring together a wide range of expertise from government and industry and from disciplines including fisheries science, oceanography, engineering and commercial fishing. 2.2. Environmental variability and fishery productivity To improve our ability to forecast potential fishery productivity we must understand the effects of environmental variability on fisheries. Environmental or climatic factors affect many processes underlying fishery productivity: migration and distribution, the survival of young fish until recruitment to commercial sizes and growth rates. Much work has been done over the years on specific environmental factors such as temperature or wind and how they influence specific biological processes. Another approach, in which important results have recently been obtained and to which increasing research effort is being directed, is the study of the effects of large-scale
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Fig. 3. Relationship between the Aleution low pressure index (‘‘Climate index’’) and all-nation catches of all salmon species in the North Pacific Ocean.
environmental changes on overall production in large fished ecosystems. This work suggests that marine systems can experience shifts in production regimes between favourable and unfavourable for a given species or group of species. This general conclusion would have broad implications for fisheries science, suggesting that rebuilding stocks and maintaining them at some theoretical fixed production level may not be attainable objectives. Stability in fishery production is not a realistic goal, and sustainability does not equal stability of catch. A good example comes from the North Pacific. A recent study [6] has demonstrated that over a 70-year period there has been a close relationship between total catch of all North Pacific salmon species and a climate index related to the overall biological productivity of the North Pacific (Fig. 3). The results suggest that conditions over this large oceanic area shifted from ‘‘favourable’’ to ‘‘unfavourable’’ for salmon production in the mid-1940s and from ‘‘unfavourable’’ to ‘‘favourable’’ in the late 1970s. Changes in salmon catches by a factor of 2—3 times were observed concurrent with these shifts in production regimes. Several other studies in the North Pacific using different analytical approaches have found similar results [7] and more recently it has been shown that species other than salmon have experienced variations in abundance or in recruitment which correspond to the same shifts in environmental conditions [8—10]. In the northwest Atlantic similar processes are doubtless at work. The collapse of northwest Atlantic groundfish stocks followed some years of anomalously harsh environmental conditions [11], as represented by mean annual sea temperatures at a station off St. John’s Newfoundland (Fig. 4). Low temperatures have been observed
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Fig. 4. Integrated 0—175 m water temperature at Station 27 on the Grand Banks of Newfoundland.
since the mid-1970s and more particularly in the late 1980s and early 1990s. At the same time, the thickness and extent of the cold intermediate water layer found at depths between 50 and 150 m over much of Canada’s Atlantic offshore region, increased substantially, and minimum temperatures in this layer declined, with the result that wide areas of bottom habitat were covered with water much colder than in previous years [11]. The extent of the relationship between the groundfish decline and the harsh environmental conditions, and what processes might be acting, are the subject of ongoing research. Cold temperatures alone are unlikely to have directly influenced groundfish production but environmental changes associated with the period of cold temperatures could well have had an effect. The cold climatic conditions have been associated with a number of system-level changes suggesting that groundfish productivity may have been affected: declines in abundance of capelin (an important prey species for a range of predatory fish in the region), a southerly shift in the distribution of Arctic cod into areas where the Atlantic cod were once abundant, the declines in Atlantic cod condition factor noted above, changes in distribution of Atlantic cod. Off Newfoundland and Labrador groundfish species which were not the target of fisheries or which were only lightly fished have declined in abundance, further suggesting that environmental conditions have become unfavourable for groundfish [12]. Severe environmental conditions may indicate an ‘‘unfavourable’’ production regime for cod and other groundfish which in combination with the excessive fishing which is known to have occurred during this same period could have substantially accounted for the stock collapse. Such variations between high production and low production regimes must become part of our expectations for fishery production, and have to be explicitly factored into the process of establishing conservation limits.
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2.3. Multispecies interactions — stock dynamics in an ecosystem context Forecasting of potential fishery productivity also requires better knowledge of interactions between species. It has always been recognised that fished species live in complex ecosystems but for the purposes of resource assessment ‘‘system’’ factors were generally assumed to be constant and models were built based only the dynamics of the particular species of interest. With the great changes we have seen recently in abundance of our important fished species and in the ecosystems they inhabit it has become evident that credible stock assessment work will have to explicitly account for system-level changes. Multispecies systems are very complex to model. Research on these interactions has increased in recent years and will be continued with a view to giving us more confidence in our ability account for past changes and forecast future stock trends. A good example of this kind of research is recent work on the role of seals as predators on fish in the Atlantic region of Canada. There are three important species: harp seals, which migrate seasonally into Canadian waters, grey seals which are less abundant but resident year round, and harbour seals which are less abundant again. Seal populations have been growing rapidly over the last two decades [13]. For example, the total harp seal population has more than doubled since the early 1980s (Fig. 5) and in 1995 was estimated to be growing at 5% per year. Considerable research has been done since 1990 to allow estimation of the consumption of fish by harp and other seals. A wide range of studies has been undertaken to model consumption, including diet studies, studies of the bioenergetic requirements of the seals (to estimate consumption rates), seasonal distribution of fish and seals, and abundance and age structure of the seal population. The results to date indicate that in areas
Fig. 5. Estimated abundance of harp seals off Canada’s Atlantic coast.
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Fig. 6. Estimated consumption of prey by harp seals in Arctic and in Canadian Atlantic waters, and total catches of all fish species in Canadian Atlantic waters.
where the Canadian commercial fishery operates harp seals have consumed over 3 000 000 t of prey per year in recent years, compared with 1 000 000 t or less of fish taken in commercial fisheries (Fig. 6). Major prey species for harp seals are capelin and Arctic cod, but substantial quantities of other species are also consumed. There is potential for considerable impact on fisheries, particularly at a time when a number of other factors may also have been operating to increase mortality of groundfish. Regarding Atlantic cod specifically, recent estimates are that harp and gray seals are consuming of the order of 90 000 t per year east of Newfoundland and Labrador, 70 000 tons per year in the Gulf of St. Lawrence, and 17 000 tons per year east of Nova Scotia. The fish consumed are typically small so the number of individuals represented by these figures would be very large. These numbers are similar to the commercial fishery catches in the last years before fisheries were closed in 1992. There is no evidence to suggest that seal predation was a major factor in the collapse of groundfish stocks, but it is plausible that consumption rates of this magnitude could have an adverse impact on rebuilding of stocks which are presently severely depleted. Seals consume small fish whose survival to maturity will be essential for stock rebuilding. Work is continuing to allow us to build more precise, accurate models of interactions between seals and cod. 3. Resource conservation – institutional changes In response to the collapse of Atlantic groundfish stocks a number of stringent conservation measures have been implemented, the closure of most Atlantic groundfish fisheries being the most visible. The fishery on the northern cod stock was the
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first to be closed, in 1992, and since then most of our Atlantic cod stocks have been closed to fishing, along with many stocks of other species of groundfish. In 1995 more than 23 groundfish stocks were closed to fishing. Other measures have also been implemented: a prohibition on discarding fish caught (discarding had been shown to be a major source of unrecorded fishing mortality in the years before the groundfish closures), institution of more comprehensive conservation-oriented annual harvesting plans, increase in mesh size and mandatory use of square mesh, and institution of small fish protocols. Following these stringent conservation measures the most recent annual report on status of groundfish stocks has indicated that the decline of stocks has been stopped [14]. Recruitment from these very low stock levels will be necessary to rebuild abundance levels and it is not possible to predict how long this will take. In addition to these stringent measures, a number of changes have been made in the ways scientific information is being collected and used, and the ways that conservation measures for our fishery resources are being developed. Fishers and industry are becoming much more involved in the collection of information needed to improve the accuracy and precision of stock assessments, and in determining what measures need to be taken to ensure resource conservation. A major step towards a central role for industry in resource conservation was the creation of the Fisheries Resource Conservation Council in 1993. The FRCC presently has 5 members from universities and 8 from the fishing industry (as well as delegates from the 6 provinces and territories participating in Atlantic fisheries and ex officio members from the Department of Fisheries and Oceans). It is mandated by the Minister of Fisheries and Oceans to recommend conservation measures for Atlantic fish resources. The Council considers the scientific assessments of stock status produced by DFO scientists and also conducts public consultations at which people from industry, aboriginal groups and the public at large can contribute their information and opinions on resource status and conservation. The Council has worked mainly on Atlantic groundfish stocks to date, and has succeeded in providing conservation advice based on a broad consensus view of stock status [15, 16]. Consensus recommendations were a noteworthy achievement since the recommendations have meant closure of fisheries supporting the economy of large regions of Canada. The fishing industry has considerably increased its contribution to data gathering over the past 5—10 years. Observer programs on vessels at sea have existed for many years in the larger vessels of our offshore fleets, but recently these have been expanded to include a range of fleets including some of the smaller ‘‘midshore’’ vessels. Dockside monitoring programs have been initiated in a number of fisheries to verify landings data which were formerly based on logbooks and purchase slips. Both these programs are funded directly by industry and the data are made available for resource assessment. In the last three years agreements have been signed with fleets for contributions to stock assessment programs, for example in the Pacific sablefish fishery, the southern Gulf of St. Lawrence snow crab fishery, and the Atlantic offshore fishery for the Stimpson surf clam. In each case fishers have contributed enough funds to cover most of the expanded field and laboratory work needed to provide stock assessments of the detail and precision required to ensure a sustainable fishery under heavy exploitation pressure. Some of these agreements have had problems related to competing interests
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in the fishery, but over the long term these should be resolved and this sort of industry-science partnership will increasingly be a part of research programs on exploited species. Fishers and industry have become more directly involved in research on stock status through closer collaboration with scientists. This has happened in a number of ways, notably through the formation of the Fishermen/Scientists Research Association (FSRA) in Nova Scotia. Through this association fishers are provided with courses on monitoring of stock status and of environmental variables, and they in turn provide monitoring data to scientists for use in stock assessments. In recent years scientists have made considerable efforts to ensure that the results of stock assessments and related research are communicated in forms which can be understood and used by fishers and the general public, notably through the series of Stock Status Reports which describe the state of each commercially exploited stock in the Atlantic region.1 Perhaps the best example of industry-science partnership is the sentinel surveys which have been monitoring status of groundfish stocks. These are very restrictedscale fisheries which resemble commercial fisheries in some respects and which are run by fishers’ associations with funding from government. The objective is to provide information on distribution, abundance and biological characteristics of groundfish stocks for which commercial fisheries have been closed due to stock depletion. The programs are jointly designed by scientists and fishers and they not only allow collection of data and information essential for scientific assessment of stock status but allow fishers to maintain their own monitoring of stock status during the closures. In 1995 some 500 fishers were occupied in sentinel fisheries at 114 locations throughout Atlantic Canada.
4. Marine protected areas – a new approach to conservation Most of the advances and new approaches described above might be characterized as improvements to a traditional model for management. New ways of understanding our marine environment and commercial stocks are being developed, and new forms of industry—government collaboration are developing which allow those who benefit from commercial exploitation of resources to become more directly involved in research and in conservation. Following the unprecedented decline in abundance of some of our most important resources, and recognising that uncertainty is a fact of life in fisheries management, a new approach to conservation has been developed. A precautionary approach to resource conservation [17] has been adopted by the Department of Fisheries and Oceans, consistent with the approach Canada sought in negotiating the UN
1 See, for example, references 2 and 3. Stock Status Reports on Canadian stocks are available from the Canadian Stock Assessment Secretariat, Fisheries and Oceans, 200 Kent Street, Ottawa, Ontario, Canada K1A OE6.
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Convention on Straddling Stocks and Highly Migratory Species. Under the precautionary approach resource conservation is the first priority. In the 1980s fishery resources were seen as basically resilient and understanding of these resources was thought to be adequate to predict future production. We have learned at great cost that resources are more fragile than previously thought. As a consequence the approach has changed to erring on the side of caution when there is uncertainty about resource status and prospects. ‘‘Conservation first’’ has become the guiding principle which must override all other considerations. The addition of marine protected areas to our suite of conservation and management measures would represent a concrete way of implementing the precautionary approach and would represent a significant shift in our resource conservation strategy. Marine protected areas can act as a safeguard against uncertainty and can provide opportunities for further understanding of marine ecosystems. Protected areas are being used in several parts of the world as a conservation tool, complementing other management approaches. Research, primarily conducted on tropical ecosystems, shows that for some species marine protected areas can be an effective management tool for replenishing stocks. The establishment of marine-protected areas in temperate ecosystems would provide further opportunity to conduct research on their efficacy in these ecosystems. Marine-protected areas are not a new or revolutionary concept. Prior to the technological advances which allowed us to fish longer and deeper, as well as mine or drill for oil at great depths, there were de facto ‘‘protected’’ areas or refugia which were not accessible to exploitation and which thus acted as the cushion against declines due to environmental factors and exploitation of stocks [18]. A new Oceans Act outlining Canada’s overall approach to oceans management and giving the Department of Fisheries and Oceans a lead coordination role for all oceans activities was passed by Canada’s Parliament early in 1997. The centrepiece of the Oceans Act is a new Oceans Management Strategy for stewardship and sustainable development of all oceans resources. In the text of the Oceans Act the Oceans Management Strategy is only loosely framed, but provision is made for broad consultation among the many oceans interests and stakeholders that will lead to complete definition of the Strategy. The Act does call for immediate development of three pillars of the Oceans Management Strategy: z integrated management of ocean, coastal and estuarine resources, including a system of integrated coastal zone management (ICZM); z a national system of marine environmental quality guidelines to measure our effectiveness in protecting the marine environment; z a national system of marine protected areas. The Oceans Act provides a mechanism for establishing marine protected areas for a variety of purposes including: z conservation and protection of commercial and non-commercial fisheries resources, including marine mammals and their habitats; z conservation and protection of endangered or threatened marine species and their habitats; z conservation and protection of unique habitats; and
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z conservation and protection of marine areas of high biodiversity or biological productivity; The mechanism outlined in the Oceans Act for establishment of protected areas is the ability to promulgate regulations that will describe the area geographically, describe zones within it, and limit the activities that may take place in that area, or in each of the zones. This range of mechanisms for establishment of marine protected areas covers the spectrum of requirements. It provides for the obvious need for protection of specific areas critical to life stages of particular species such as spawning areas or juvenile nursery areas. It also provides for broader protection for areas of high biodiversity or high productivity, recognizing the responsibility of this Department not only for commercially exploited species but for all marine species within the Minister’s mandate. This approach supports adoption of an ecosystem approach when establishing marine protected areas. Marine protected areas established under the Oceans Act can then fit into a larger array of marine protected areas such as those established as representative of marine regions (i.e. marine parks) or for the protection of marine birds. The design and nature of a marine-protected area will be dependent on its ultimate purpose [19]. The flexibility in the Oceans Act will allow us to design marine protected areas that include a full spectrum of protection; from those that are protected from all forms of exploitation to multiple use areas. The essential element is a clear identification of the purpose of a marine protected area and a plan to accomplish that purpose. The use of marine protected areas is not restricted to use as a fisheries management tool although there is evidence to suggest that for some species they can be quite effective. In existing marine protected areas and reserves from coral reefs to temperate kelp forests, greater abundance of exploitable species and larger, more fecund individuals have been observed [18]. In addition, protected areas or refugia have been shown to preserve natural genetic diversity where fishery based selection operates to decrease diversity. More important than the role of marine protected areas as a fishery management tool is their role as a broad conservation tool. Marine protected areas allow us to implement the precautionary principle in a concrete way [20]. By integrating marine protected areas into our conservation and management regimes, we provide ourselves with an ‘‘insurance policy’’ against the effects of intensive exploitation and environmental fluctuations. They can effectively act as a hedge against the uncertainty we all recognize in marine systems. Marine protected areas or marine protected area systems, if designed correctly, can maintain the ecosytems and their functions for which we continue to seek a better understanding. Marine protected areas can also serve the purpose of preserving genetic diversity by acting as refugia for small or depleted sub-stocks of exploited species that might otherwise be removed from the gene pool, thus reducing genetic richness and vigour of the stock as a whole. Marine protected areas are not a panacea for all that ails marine ecosystems. There is little to be done if external effects continue to degrade habitats or if management
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approaches do not reflect ecosystem functions. Nor are marine protected areas a last resort, to be turned to when all else fails. Experience and scientific principles support the view that general and precautionary action would be a valuable addition to standard fisheries management [21]. Their effectiveness will be fully realized when anchored in a broad integrated resource management framework and in overall conservation goals. The Oceans Act provides for this broad planning framework and gives a legislative basis for establishing marine protected areas as part of that planning framework.
5. Conclusions Uncertainty will always be part of managing marine ecosystems. Resource conservation must be based on explicit recognition of this fact coupled with suitable mechanisms for dealing with uncertainty. The precautionary approach and the use of other new approaches such as marine protected areas are elements of a more robust management system which can help to ensure resource conservation when uncertainty is great. Active participation and support of people who benefit from ocean resources, who have specialized knowledge of the oceans, and who have a vital stake in the future of ocean resources — fishers, scientists, the Canadian public — are essential for development and respect of the conservation measures which will ensure sustainable fisheries despite uncertainty. Continuing improvements to our knowledge of ocean resources and particularly of the dynamics of fished stocks in an ecosystem context are an essential basis for resource conservation. Science is our principal tool for ensuring that our knowledge is as good as it can be. We must put these elements together into an overall conservation framework which will ensure that benefits from our fishery resources are better realised today and for future generations.
6. Acknowledgements This paper is based on work of scientists at Canada’s Department of Fisheries and Oceans, who maintain the tradition of excellence essential for conservation of ocean resources. We are grateful to Kathryn Bruce, Helen Joseph, Gerry Swanson and an anonymous referee for comments on the manuscript, and to Jennifer Vollrath for preparation of figures. This paper is based on a presentation by L. S. Parsons to the Coastal Zone Canada Conference, Rimouski, Quebec, August 1996.
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