These diamonds are a fishery manager’s best friend

A blog of Bridge Environment

Have you heard that all marine fisheries are doomed? After a study he published with co-authors in 2006, Boris Worm, a professor at Dalhousie University, claimed “if the long-term trend continues, all fish and seafood species are projected to collapse within my lifetime -- by 2048.” Anyone who has paid any attention to news reports over the past decade will realize this claim is not the first or the only that fisheries management is failing, although it may be the most extreme.

Don’t believe everything you hear. Some of these doom and gloom pronouncements may have elements of truth in them, but they all do a disservice to fisheries management because they seem to suggest that there is a right answer, usually a plea for a general decrease in fishing pressure or a call for a specific technique, most often a closed fishing area. In today’s blog, I hope to convince you that there is no such thing as a right answer, but that there is an effective process for coming up with good solutions. I’m sure it won’t surprise you that this process does not include doom and gloom pronouncements. Instead, it focuses on two inherent attributes of fisheries: their uncertainty and the differences of opinion among stakeholders on objectives.

The key to uncertainty is recognizing and characterizing it in terms that are relevant to stakeholders and policy-makers. I have already discussed uncertainty extensively and encourage you to review previous blog postings if this subject is of interest. Today I will focus on conflicting objectives. To start, I need to reiterate a point from the rocket science approach to fisheries. When setting catch limits, rarely can I give advice about the implications of an annual quota in isolation. A seemingly irresponsibly high quota might end up meeting the economic needs and be part of a sustainable plan if it is paired with commitments to set low quotas in the future. Conversely, many seemingly reasonable quotas may be wildly irresponsible if the quota will remain the same in subsequent years even if there is evidence of stock decline. In short, to understand the implications of fisheries quotas, we need to analyze the whole system.

There are a few key objectives that come up in the design of most quota-setting systems. Let’s start with two fairly simple ones—high catches versus constant catches—and simplify matters by assuming that we have exceptional information so that there is no uncertainty. Even in this simple case, small-scale and large-scale fishing groups are likely to have distinct objectives. The small-scale operations probably have a greater need for regular catches on a daily, weekly, or at least monthly basis. Subsistence fishers, those who catch food for their households, would be a good example. By contrast, a large corporate fishing operation may be in a position to weather ups and downs in catches even over months or years. In general, constancy of catches is beneficial to all fishing-related businesses, from the fishermen themselves, who have better economic conditions with consistent income, to restaurants and fish markets, which benefit from having a consistent supply of seafood. Nevertheless, fishing operations will vary in their tolerance of catches that vary from one month or one year to the next, and the size of the operation will influence that tolerance.

Fig. 1--Diamond of high catch peformance.
Stock and flow are policy choices.
Performance: Green = high, Red = low.

Recall from the blog that compared fish, water, and methane that we can think of many environmental systems as a stock and a flow. We have choices for the target stock level (in this case, number of fish left in the ocean) and the characteristics of the flow (in this case the shape of our quota-setting policy combined with the productivity of the fish stock). These policy options can be represented in a diamond shape, which when used properly can be a fisheries manager’s best friend. Like the gemstone diamond, this one has color. We can represent performance based on a given objective, ranging from high performance in green to poor performance in red. The colors change across the surface of the diamond, call that its cut. When it comes to average catches, we get best performance from fisheries that have intermediate stock levels (Fig. 1). Too few fish and the population will suffer from a lack of reproductive output. Too many fish and much of the potential productivity will be “lost” to the ecosystem. When we consider that the productivity of a stock varies from one year to the next, it turns out that highly responsive policies provide higher average catches than more constant ones because they keep the population from drifting even temporarily to sizes that would be less productive (again, Fig. 1). The details of how quickly performance drops and the exact location of the peak—the color and cut of the diamond—will vary based on ecological factors, but the general attributes are consistent across fisheries.

Fig. 2--Diamond of constant catch performance.

Constant catches respond very differently to various policies. This objective is influenced exclusively by the flow properties, as shown in Fig. 2. Note that the best policies for average catches are the worst for constancy. We could find some happy medium somewhere near the middle of the diamond. However, because fishing operations have different tolerances for unpredictable catches, they will not agree on where this happy medium lies. Smaller scale operations, which require regular catch and income, will prefer policies pretty far to the left while larger scale operations will want somewhat more responsive policies because they are willing to trade off some fluctuations in catches in order to catch more fish overall.

Fig. 3--Diamonds of ecosystem function (top)
and sustainability (bottom).

In real-life, the situation is more complicated. We have groups that care about the ecosystem function of the fish population. These groups include conservation organizations as well as people who have an interest in other aspects of the same ecosystem, for example fishing operations that target a predator of the fish in question. When we consider ecosystem function, a high stock will be of paramount importance (Fig. 3, top). This conflicts with the high catch performance because the productivity that is “lost” to the ecosystem as far as catches are concerned provides benefits elsewhere. Although less important, natural flows (neither too high nor too low) will be best for maintaining ecosystem services (Fig. 3, top). Once again, the nuances of these performance results, the color and cut of this diamond, will vary depending on ecological conditions.

Uncertainty also plays a key role. The performances in terms of average and constancy of catch, above, are based on the assumption that we know the long-term productivity of the stock. In reality, the majority of stocks lack even an educated estimate of productivity. For the rest, the estimates range from moderately to highly uncertain. The most recent two blog posts have made the point that sustainability can be achieved, even in the face of uncertainty, through responsive management, light fishing (and thus a high stock size), or a combination of both. Thus, the sustainability of various fisheries policies drops from a peak on the upper right portion of the policy diamond to a minimum on the bottom left (Fig. 3, bottom). Sustainability affects everyone who has an interest in fisheries, but once again this diamond’s color and cut depend on social, economic, and ecological characteristics.

Together, these four objectives: high catches, constant catches, ecosystem functions, and sustainability, capture the majority of concerns various groups have about quota-setting policies. Unfortunately, they give conflicting advice. The right answer will differ among groups depending on their social and economic circumstances and how much they value each of these objectives. Thus, we do a disservice anytime we present a ‘right’ answer. Doing so is simply a way of justifying one’s own preference by treating it as if it was an objective finding of science. We can do better by presenting the trade-offs to everyone involved in the management arena. These diamonds do exactly that. When interest groups are better informed about the consequences of long-term policies, like quota-setting rules, they will have more investment in their design and application. Of equal importance, when groups are more informed about the trade-offs that their opponents face, they are more likely to work constructively and devise long-lasting solutions.

As always, your comments are appreciated.

Best,

Josh

Does it take a dictator to manage a fishery?

A blog of Bridge Environment

Last week, I wrote about successful and sustainable fisheries management as conducted by indigenous tribes in the Lower Klamath River basin in northern California. The evidence suggests that these groups maintained sustainable salmon catches and a stable human population by limiting their consumption of salmon. From a societal perspective, there was most likely a positive feedback loop at play. Stable catches led to predictable food sources and trade goods, which in turn allowed people to plan for and develop strong and stable institutions. At the same time, strong and stable institutions must have been necessary to enforce fishing practices that to the self-discipline that let so many salmon escape. I didn’t mention this last week, but these tribes believed that the giant redwood trees in the area were embodiments of their ancestors’ spirits and kept an eye on them to make sure they behaved well. Enforcement was also severe. In the same way that stable catches promoted the development of strong institutions, strong institutions promoted stable catches.

King Kamehameha of Hawaii

The situation was similar in pre-European-contact Hawaii. Complex regulations were made by rulers and their spiritually-associated fisheries managers, called konohiki. Regulations limited catches in certain areas or closed certain fisheries based on a wide range of rationales, including: early indications of a developing shortage, an approaching feast and its food requirements, and access by the powerful to rich fishing grounds. In concert, these regulations aided sustainability through responsiveness to early signs of depletion and by limiting consumption, the two paths to sustainability discussed last week. Like the California tribes and their salmon fishery, Hawaiians bolstered the fisheries rules through regulations and strict enforcement (a common punishment for fisheries violations was being thrown off a cliff to one’s death). Once again, stable fisheries promoted strong social institutions and those strong institutions promoted stable fisheries.

Cuba serves as a modern example. Strong institutions there have led to unusually healthy marine environments (although not without ongoing problems), a phenomenon described by Jaws author Peter Benchley. Religion is not a part of their system, but an authoritarian government surely has contributed.

San hunter

This brings up the fascinating question: do we need authoritarian rule to have a sustainable environment? There are examples of people who managed natural resources without social hierarchies. The San (Bushmen) of the Kalahari Desert and aborigines of Australia both have classless societies without the concepts of ownership, and have lived in balance with their natural environments for millennia. However, they are not necessarily good examples for us to follow. Both societies are severely limited by water supply and many of their cultural practices are centered around finding and sharing water during droughts. Their social systems, including clan-based matching for marriages, promotes reliance on each other for support when scarcity hits one area but not another. Trade already promotes the spread of risk across areas in our modern society, plus our environmental issues are increasingly global and so not ones we can address by making the world more interconnected.

I leave this blog with a question to you, interested reader (or two): can we address the environmental challenges of our time with our modern institutions? On a global level, the United Nations lacks much authority. In an increasing number of countries, governments are turning to democracy, which usually lacks the sort of authoritarian structure that was used to good effect in northern California, Hawaii, and Cuba. Nevertheless, I hold hopes in two somewhat conflicting directions. I have faith in the ability for resource users to grasp the challenges we face and embrace proactive solutions. This is a major emphasis of our work at Bridge Environment. I also believe we could move in a direction of stronger environmental institutions. It seems to me there would be significant costs of doing so, but that environmental crises may prompt us to move in this more authoritarian direction. I would rather see us move towards co-management with involved resource users, but recognize that the second would be preferable to devastation. I hope to hear your thoughts on the matter.

Thoughtfully yours,

Josh

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Traditional fisheries management: Was it rocket science?

I have previously described the insight for fisheries that comes from rocket science, in the form of missile guidance systems. Unlike many fisheries, missile guidance systems identify a clear target, monitor progress towards hitting the target, and, most importantly, make decisive corrections the minute evidence suggests the trajectory is off. The decisive corrections are the biggest difference between missile guidance and fisheries management systems.

The benefit of decisive adjustments is robustness, the quality that for me defines sustainability. Fisheries managed in this manner can sustain healthy stocks and productive catches even when scientific information is highly uncertain or even wildly optimistic. The cost of decisive adjustments is unpredictable catches. Certain fishing operations might be able to weather days, months, or even years of low catch quotas, when environmental conditions or inadvertent excessive catches drive the stock below target levels. However, most fishing operations, including subsistence, artisanal, and small-scale commercial fleets as well as processors and distribution chains, have a strong preference for predictable catches. For them, an alternative path to sustainability is to set conservative catch quotas, which need not be adjusted so decisively.

The above conclusions about fisheries are based on theory. It would be reassuring if there were some evidence that these approaches work to sustain real-world fisheries. Such evidence is tricky to obtain. True proof of sustainability would require centuries, or at least many decades, of consistent management practices during which time fisheries remained healthy. Modern fisheries are not suitable for this analysis because of major technological advancements and the paucity of traditional management systems (meaning that current management is inconsistent with practices from even the recent past). Fortunately, there are traditional cultures where we know something of their fisheries management practices and whether they sustained healthy fisheries. In these cases, we do have evidence that spans centuries to test the concept of rocket science-based fisheries management.

Not all indigenous people were conservation-minded stewards of their natural resources. There are many cases of extinction that can be attributed to overhunting, and some cases where entire societies collapsed, most likely from resource use that failed to recognize limitations or failed to adapt to changes in those limitations. Collapse: How Societies Choose to Fail or Succeed, a thoughtful book by Jared Diamond, details many such cases.

My favorite example of a society which clearly succeeded is the collection of indigenous tribes that lived along the Lower Klamath River in northern California. Their success is described in detail by Arthur McEvoy in The Fisherman’s Problem: Ecology and Law in the California Fisheries, 1850-1980, and under-read gem for anyone interested in fisheries. The tribes sustained healthy salmon fisheries for centuries, and salmon was their principle food source. The strength and splendor of their culture was something to behold, from ornate art to a stable and invincible society. Unable to conquer them, the U.S. Government offered them unusually beneficial treaty terms for Native American tribes, terms that give them substantial say today over water use throughout the entire Klamath River Basin.

Studies of indigenous tribes in what is now the State of California show an interesting pattern. Salmon and acorns (and the deer they supported) were the staple food throughout the State prior to European contact, and there is a strong correlation between the supply of these resources and the pre-contact human population density. In most of the State, the human population was in balance with the available resources. Two groups were exceptions to this rule. One lived along the Santa Barbara Channel, where the human population was unusually dense due to the southerly aspect of the coast, which provides sheltered and reliable access to marine fisheries and thus an additional food source. The other groups lived in the Lower Klamath, and maintained human populations that were smaller than what the resources could provide.

This was no small feat. In the sciences of ecology and economics, the norm is for populations to fully utilize resources. Nature and people thrive when they can and, in doing so, tend to use up what is available. Maintaining a smaller human population would require purposeful underutilization of resources. The specifics of traditional fisheries management in the Lower Klamath included exclusive use of a large fishing weir to catch salmon. The construction of the weir did not begin until after the salmon run started and a priest had blessed it, a process that took 10 days. The weir was then dismantled after 10 days of fishing. Salmon that passed through before or after the weir was in operation escaped upstream. These practices meant that salmon truly was underutilized.

Recall that this strategy is one of the two options to achieve sustainability. And did it succeed! The tribes of the Lower Klamath developed their strength and splendor primarily off of healthy salmon runs managed sustainably for centuries. Their purposeful “waste” of fishing opportunities led to great benefits to society, and serve as proof that a rocket science-based framework can lead to healthy and well-managed fisheries. The feat of the Lower Klamath tribes was even more notable because they managed these salmon runs without the use of formal science. In contrast, we regularly sidestep managing data-poor fisheries under the belief that data is necessary to manage. Clearly we can do better, and a rocket science-based approach will be crucial.

Until next week,

Josh