Rethinking Fisheries Management
by Dr. Gary Sharp
Abstract and Text of Presentation given in Brisbane, Australia at the Second World Fisheries Congress, August, 1996.
by Gary D. Sharp, California State University, Monterey Bay and Center for Climate/Ocean Resources Study
(www.fao.org/WAICENT/)The recent decades’ catastrophes in ocean fisheries are among many signs of lack of societal will in resource management contexts. (FAO – trends.htm)
Although abundant theory, and sometimes adequate information from fisheries activities exist, continuous surprises and stock failures provides impetus to revise not only the basic theory of resource management, but even the philosophies of conventional fisheries management practice.
Gross perturbations of ecosystem structures due to fishing have often been denied. (TrophicPyram.gif).
(See ref. at Sharp’s Site). Habitat degradation and losses, along with declining natural biodiversity define the principal issues of anadromous and estuarine species. Uncertainties of context-free fisheries stock assessments form the bases of legal contentions. Pitting government science against industry lawyers is clearly ineffective. Beyond CPUE, Yield-per-Recruit, VPA, and their associated faulty assumptions, necessary information need to be defined and integrated into ecosystem-wide monitoring, (Horta-1991.html) resource assessments(physics.html), and management processes. (See ref. at Sharp’s Site). We have a global crisis needing revolution, not consensual fiddling. (www.panda.org)
Formulation of an Appropriate Fisheries
The "innocent until proven guilty" legal philosophy has resulted in the systematic reduction of most of the natural resources in the developed world, and the chaotic exploitation of natural resources in the undeveloped world, threatening their elimination.
Critical habitat degradations and losses define the principal issues of anadromous and estuarine species. In less sophisticated settings usually associated with but certainly not limited to developing nations, general absence of information along with the underlying ignorance of and about coastal subsistence fishers can only lead to despair for natural resources, and dwindling environmental quality.
Another important issue is that of maintaining biodiversity in natural populations (c.f. Oceanography 9(1) 1996).
For most exploited fisheries we simply have no idea what levels of diversity ever existed within the exploited populations, particularly the losses of diversity that may have occurred during the recent "swarming" of fishing fleets over the global oceans. Significant efforts to measure and understand genetic issues has not been adequately funded. Few studies have ever been funded that have permitted researchers the luxury of large enough samples, collected over several years, to provide the statistical Power needed to reject any complex null hypothesis. A few tens or a hundred individuals sampled from each area is not a sufficient statistical sample for any rigorous study, for more than inferential or taxonomic purposes. An important related management problem is that the "inconvenience" of complex stock structures has in most cases been assumed away, as data from ever broader ranging fisheries are merged to produce population biomass estimates, from which most fisheries are managed.
To date, few or no fisheries management plans include environmental contexts.
Physical variations that affect all living resources are well defined from basic physiological ecology. Interdependencies of ecosystem components can be resolved from food web structure studies and population energetic dynamics, i.e. fat content and reproductive status at size/age (c.f., Carpenter et al. 1994, Schülein, et al. 1995, Parrish et al. 1986).
Only within the last decade and half has it been possible to openly discuss the consequences of fishery independent causalities such as climate-driven oceanographic processes that affect fluctuations of the major pelagic fish stocks (c.f., Sharp and Csirke 1983, Csirke and Sharp 1983).
Few resource management success stories will prove capable of coping with dwindling, or highly variable resource bases that do not include understanding of natural environmental patterns and responses of living resources to these variations.
Lastly, there is the issue of where to best apply meaningful resource management regulations.
The limited success of direct regulatory manipulation of fishing effort in many cases can be attributed to other, often unregulated sectors of the industry, i.e., markets. In recent years the focus amongst environmental activist groups on market places has been much more effective than conventional negotiated effort limitations, treaties, or state-managed catch prohibitions. Perhaps there is a lesson to be learned.
From at least the mid 1970s to present, I and my colleagues at the (www.fao.org/WAICENT) Fisheries Department of the Food and Agriculture Organization (FAO – fishery.htm) in Rome set about compiling various arguments that might provide bases for the reorganization of fisheries science in support of the elusive "rational" management of the world’s fisheries resources. We have attempted to reduce the assumptions common to fisheries modeling in support of fisheries management, a result of the equilibrium-based approach. (Bakun et al. 1982, Caddy 1983, Caddy 1993, Caddy and Gulland 1983, Caddy and Sharp 1986, Sharp 1981, Sharp 1988, Csirke 1995, Csirke and Sharp 1983, Sharp and Csirke 1983). Fisheries research and related management passed from early empirical observations through the post WW II period of theory development, and on to the mathematicization of basic ecological and population biology concepts that evolved throughout the last century (c.f. May et al 1979). Many of the period’s steps, and mis-steps, are described in Sharp (1995). What follows is a terse and personal review of the sequences of events that led me (and many colleagues) to make a very strong effort to reset the ideas and thinking of the world’s fisheries managers. I make no claim to "original" thinking in this problem area.
At the 1988 American Fisheries Society symposium in Toronto, Canada, there was a day-long tribute to the late Professor F.E.J. Fry entitled From Environment to Fish to Fisheries. I was invited to speak at a concurrent symposium on fisheries mathematical modeling. During my talk I admonished those attending the modeling session to quit isolating themselves, to take immediate advantage of the Fry symposium, to leave the room and learn from Fry’s colleagues about the predictive powers of physiological ecology. I am an advocate of similar cause-response, system oriented research and interpretations of empirical physiological ecologists, i.e., the late Professors Wrigler and Fry. I cannot condone the guessing or parameterization that has become the hallmarks of context free ocean fisheries stock assessments (Ricker 1975, Gulland 1983).
Dichotomies abound in fisheries science.
On one hand, agency population dynamicists hold their statistical training out as a license to criticize any and every empirical study made in the attempts to organize a cause-effect, or simple stimulus-response framework for applications in fisheries management. They have, somehow, as a group convinced themselves that anything they agree to accept as an assumption, for the sake of solving messy mathematical equations, is justified, even if these "principles" do not fit empirical observations (c.f. Finlayson 1994). What if they were wrong? Well, then it is always easy enough to "adjust" the parameters, or restate their conclusions in hind-sight, such that the ranges of possible solutions encompassed any new findings.
Sensitivity analysis has long been in vogue as a "cheap" substitute for direct experimentation.
It remains a puzzle what that once the fisheries modelers construct and adopt another "convention" that contradictory empirical observations can, and likely will be ignored. That is not science. That is theology (per Dayton 1979).
Unvalidated, "consensus truths" are, of course, "the enemy" in the real world of scientific endeavor.
Many empiricists and disbelievers suffer constant lashes from many such truth-by-consensus, pseudo-scientific conventions. This behavior is rampant in the competition for funds and recognition amongst so-called "peers". The problem is not unique to fisheries science, but is rife in natural resource research issues, particularly the "Global Warming" debate and its associated "peer-driven" funding grabs.
Dread Factors seem to drive funding for modern research effort.
Global Warming and the attendant doom-and-gloom scenarios have never fared well against historical knowledge. Some "facts" needing reconciled are that the peak warming that ended the recent Ice Age was reached about 9,000 years ago. We are well advanced into the next Ice Age (Dean et al. 1984, Overpeck 1996). That well recognized Warm period also corresponds to the advent of human civilization. The cooling trend since, has been punctuated by several warm and cool epochs, many of which brought civilization to its knees.
For example, the Medieval Warm (node5.html)period (from about 600-1180 AD) was a period of relative self-sufficiency over most of Europe, Asia, and the Americas. With the onset of the so-called Little Ice Age (william-the-conqueror.html) (AD1180 to ~1780-1850) European civilization was in constant flux, and human populations fell due to plagues, famines, and wars, as concentration of resources shifted, newly blessed regions were identified, and then fought over for those limited resources. In fact, a comparison of historical records and modern research results, there is abundant historical information that suggests that Global Warming, is NOT a bad thing. Rapid changes in climate, i.e., local, regional and global regime changes, commonly occur over short periods, less that a decade, or several decades (e.g., Allen and Anderson 1993, Dean et al. 1984). Such dynamic shifts are important to the periodic renewals of entire ecosystems, in which production systems change, predators are minimized, nutrients recharged, and the Darwinian Play is acted out. Climate-driven fish population blooms and collapses serve similar function, as long as adequate genetic plasticity, and broad habitat access is retained.
This brings me to my principal point.
If we are ever to accomplish Sustainable Resource Management it is imperative that there be full incorporation of the transitory nature of climate, and the cascade of ecological responses (e.g., Allen and Anderson 1995, Carpenter et al. 1994) in forecasts. Related observations provide a basis for rehabilitation of our science, as well as reclamation of scientific credibility. While there is always a place for modeling, in defining data needs, it is more important to consider known sequences of events, processes, and consequences, within defined context.
Assumptions: the basis of the apparent contextual chaos
Wrong concepts and assumptions are rampant in fisheries models.
Production Modeling assumes that removal of adult fishes leaves "space" within the niche for more younger fish of the subject species. An intrinsic compensatory increase in basic population production is assumed. This underlies the fallacy of constant (or varying) "Carrying Capacity" and related "Fishing-Up" dualities. To physiological ecologists, the assumptions makes very little sense. Carrying capacity is not a species concept, it is a system concept. Clearly, a truncated, younger population will certainly "grow" at a greater average rate than an older, age-distributed population, on an aggregated per unit basis. That is a common thread of living systems, and physiological ecology (as per Ulanowitz 1986). However, decrementation of larger members of an oceanic population does not automatically "release" either niche space, or resources, to smaller, younger age classes of only that population. The first, immediate options go to competitors, usually of different species (except in the case of Arctic lakes, and similarly constrained systems (c.f., Johnson 1981).
Within a Production Model’s assumptions also lies an assumption invoking the conventional fishery Stock and Recruitment (S/R) concept, disguised as one more blur.
Consider also the disconnect within the older and prerecruit populations that takes place when Biomass and Fishing Effort are the sole contributing information to this approach. For most pelagic species, these are fundamentally wrong assumptions (c.f., Koslow 1992, Sharp 1981, 1995).
Coastal, pelagic-spawning fish populations characterize the more productive fishes.
Effective positive contributions resulting from decreases in the larger adults to the population mostly derive from primary environmentally determined ecological interactions. The science problem is to identify direct mechanism(s) that result(s) in increased survival of eggs and larvae through stages that share little or nothing with their parents. Once gametes are released into the sea live, one invokes changes in intra- and inter-specific competition (Carpenter et al. 1994), or the consequences of cannibalism (Sharp 1981). Assuming these do not matter seems inadequate to explain regime changes, and often well coordinated timing of changes that occur over entire ecosystems, across and amongst oceans (Sharp and Csirke 1983, Crawford, et al. 1991).
Where is the necessary differentiation and "understanding" provided by the context-free, biomass management approach?
How can such an approach be useful in explaining changes in either population (size-age) structures; or the ecological cascade that results from an expected decrease in the predation rates due to harvesting the larger adults (c.f., Sharp, et al. 1983)? It is difficult to identify many aquatic species that are self-limiting, given naturally heterogeneous habitat (i.e., access to refugia, continuous environmental variation, behavioral plasticity’s, and subsequent ecological responses), or natural environments that fulfill to any reasonable degree the usual assumptions. It is nearly impossible to find supportive data for many conventional (perhaps convenient is a better term) fishery modeling assumptions, except for fissional, monoclonal closed-cultures of yeast or Tetrahymena, that both consume and poison their local environments simultaneously.
Asking Questions and Getting No Answer
Convergence on the concept of management for near-constant fishable stock biomass during the 1960-1980s was misleading, initiating inappropriate reactions once a fishery system began a regime change.
Sustainable management practices and adaptability have been subject to much recent rhetoric (Walters and Collie 1988, Kesteven 1996, Steele 1996, Pauly 1996), yet no one is really being heard over the "chanting priesthood" (per Hilborn, 1992) to deliver the obvious messages. Few deny that the "well-managed" Atlantic cod has fallen victim of management by consensus. Hard sought credibility is lost, and "Truth is Emergent" (Sharp 1995).
One fundamental criteria for validating scientific research is that if a question is asked repeatedly, and no predictive answer appears from the approaches taken, it is probably a wrong question.
The quest for a direct S/R relation is a good example of this type of problem. Sharp (1981, 1995) described the details of dichotomies between observed and expected life histories for different fishes.
North Sea plaice (Pleuronectes platessa), provide a nearly flat recruitment record, with a few lows and highs over the century-long records. I am amazed that any direct Stock and Recruitment concept might even be proposed from such information.
What is the linking mechanism between adult numbers, or biomass, and recruitment, particularly for nearly constant recruitment – with occasional highs and lows? Well documented examples arguing against these sorts of processes abound (c.f., Koslow 1992, Sharp et al 1983). In studies of the Wadden Sea as a nursery ground for the plaice and other commercial species Rauck and Zijlstra (1978), and their associates, describe the pelagic plankton egg and pre-feeding stages of plaice. Once feeding begins, larval transformation and settlement out of the plankton onto the bottom is induced. Where they settle out, and what they encounter up until they have settled has little or nothing to do with the behavior, numbers, or conditions of their parents, after the gametes are cast into the sea.
Why invoke an S/R relation? What is the source of persistence of this "conventional wisdom"? Why does this myth persist?
Is this fishery science’s analog for the Arthurian quest for the "Holy Grail"? Neill, et al. (1994) apply Fry’s physiological stimulus-response paradigms in a recent re-evaluation of fish recruitment, including plaice, providing invigorating insights into fishes and their ecologies. Empirical concepts work, at all levels of integration.
Forgetting to ask, "Why ?" is a major flaw in stock assessment paradigms.
It is often the case in resource management issues. Recognition of the "managed" and unmanaged declines of fishable stocks, and the inadequacies of conventional fishery model data, should make a bit more acceptable my earlier arguments against prevailing conventional "wisdoms" (reviewed in Sharp 1995).
A growing body of evidence indicates that the prime variables that impose the strongest variations, particularly those that enhance population recruitment, are driven by environmental variability, including ecological interactions, rather than inherent population properties.
This does not, however, exonerate historically bad resource management. It is critically important to address the damage done by over-capitalized fisheries, and related poor management decisions and practices, in quick order, by creating a new framework, for sustainable resource management practices. That must start with a clear definition of what is, and what is not sustainable.
- Business as usual, either fishing, or management, is not sustainable.>
- "Sustainability" does not include any of the following:
- Open access fisheries;
- Constant high levels of catch from season to season or year to year;
- Economic guarantees; or
- Single species management.
- Reduction of total expenditures of nonrenewable energy per unit catch, i.e., greater true energetic and economic efficiencies from selection of appropriate technologies, including minimization of redundancies;
- Creation of better, more inclusive methods for assessing resource status, i.e., monitoring whole contexts, including economics along with ecological and environmental measures;
- Redefining resource population health in realistic, measurable terms, e.g., monitoring of energy content and reproductive status by size and age, through well sampled catch aged to monthly birth dates via daily increments, and associated measurements of fat content and gonadal status;
- Real commitment to better methods of regulating fisheries production. e.g. market-based production management, rather than only direct effort based management;
- Enhancement and coordination of catch, processing, and transport into a system that can be controlled at any stage, for optimal economic return from varying resource bases and often changing markets, i.e., adaptive integration of the entire industry;
- Monitoring and control of the entire global market outlet system, to ensure most effective maintenance of resource bases, through vertical integration of environmental information, including status indicators of local and regional resources, resource demands, and economic indicators for global market places;
- Return to appropriate, sustainable technologies, (related to 1.) and
- Addressing the issues of cultural support collapses due to recent evolution toward 280+ day per year offshore vessel activities.
New Syntheses – Empirical Thinking:
Beginning a New Awareness
While I will be the first to agree that future states of living resources may remain truly unpredictable, or in many cases only marginally forecastable, there is a very realistic need for understanding of the full set of processes that can and will affect each fishery, within the lifetime of any investment.
Empirical evidence shows, depending upon the region of interest, that there are many patterns and quasi-cycles that repeat themselves over decadal to century time scales, and in specific cases such as El Niño-Southern Oscillation (ENSO) phenomenon, short-term ecological perturbations are significant.
Therein lies the basic issue. An equilibrium conceptual approach to modeling fisheries cannot provide the necessary insights that will allow both long term conservation and short term, efficient exploitation of the major living aquatic resources in the face of continuous environmental change.
Typical X-Y plots from fisheries data or models, with "best fit" lines, ALWAYS underestimate the good and overestimate the bad. Fitting averages through time series has similar logical consequences. Good decision making needs to account for well-documented prognoses about the whole system.
The question is not how to project or forecast one population, but for system production changes of meaningful magnitudes?
What has not worked is modeling fisheries via elegant applications of mean expectations, or worse, through inappropriate Monte Carlo simulations, claiming mathematical rigor, but generating logical chaos. Patterned sequences are the rule for most events and climatic processes, ranging from daily and seasonal patterns, onward through quasi periodic climate processes (c.f., Sharp 1995). This does not imply that each event or process is identical, but only that each follows some unifying pattern. Hence, only certain one-way sequences are likely, as in the case of changes in state or during long term trends.
Observed regime (or system) state changes occur on either ENSO or longer time scales, and are either continuous, patterned cycles, or abrupt apparent shifts.
These system changes are due to crossing of unknown thresholds, that result in immediate shifts in ecological processes. Defining these thresholds, and tracking changes in time are important to revitalization of fisheries management, and regaining scientific credibility. This can be best accomplished through whole-ecosystem monitoring (Loeb and Rojas 1988, Shelton 1992, Sharp and McLain 1993). We’ve work to do.
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