The collapse of many important fish stocks around the world has now been widely interpreted as a blatant example of a failure of management to sustain a natural resource. Environmentalists compare the practice of bottom trawling for ground fish with the clear-cutting of forests, long considered an unsustainable way of managing terrestrial resources. The comparison implies that solutions to the management of marine fisheries might be found in “sustainable” practices on land. This could be a sensible approach since we naturally tend to seek answers to complex problems by observing practical experience in other jurisdictions or environments. But can we really draw lessons from the management of terrestrial environments for those in the ocean?

We shall argue that the differences are more important than any similarities – differences in the way marine systems respond to change, differences in the way we attempt management and especially, differences in how we might use the “terrestrial” concept of sustainability in relation to the seas. These factors have important implications for the effective application of scientific understanding to management of marine resources. Further, there are significant differences in the institutional frameworks within which management measures may be shaped.
The natural vegetation on land – trees or perennial grasses – have long time scales. Regeneration of forests can take decades to centuries. One potential concern with global warming is that plant communities could not adapt to the relatively rapid latitudinal shift in temperature and so maintain optimal conditions for growth. This is not really a problem in the sea. The base of the food web, phytoplankton, have lifetimes of days not decades. The top of the marine web, fish, mainly live for a few years, although some in the deep sea live for decades. We see great cycles in the natural abundance and geographic location of sardines and anchovy, with periods of a few decades. We also have witnessed dramatic switches in the abundance of major ground fish stocks. On Georges Bank off New England, cod are replaced by dogfish and mackerel. Off Newfoundland crustaceans became abundant after the cod went. These switches can have great economic consequences; especially they have great impact on the fishing communities. Yet these large rearrangements in species composition appear to be ecologically acceptable responses, utilizing alternative pathways within the upper levels of the ecosystem. There is little evidence of any significant effects on basic productivity.

Thus, unlike terrestrial systems, marine communities appear to be much more adaptable to natural and human pressures at time scales of decades. It is the consequent versatility in fish stock composition that creates the most intransigent management issue: the “ratchet” effect. When the abundance of a stock increases, the fishing capacity goes up. But when, later, the stock decreases, the effort stays the same, usually with disastrous consequences for the stock and the economy. This general sequence occurs on top of a trend for “improved” gear technology. The critical scientific problem is to distinguish between these two causes; natural environmental variability and changes in effort, fishing boats and gear. The time scale of natural changes in the sea – a few decades – is comparable to the economic scales of human adaptation; specifically the “lifetime” of a fishing vessel. This is why the “ratchet” works. It is this resonance in time scales that makes the attribution of cause to the quasi-cycles in stock abundance more than a purely scientific problem – and very different from forest management!

We tend to put fisheries in the general category of natural resource management along with forestry. This is particularly inappropriate, not only because of the time scale problem already discussed, but also because we consider the sea as “the common heritage of mankind” with a lack of any ownership for the sea, the sea bed, and the fish. Unlike the case on land, the resources and physical characteristics of the ocean and seabed typically are considered to be either res communis, belonging to the public, or res nullius, belonging to no one. In either situation, the absence of private rights to a scarce resource, such as fish, often leads to the well-known “tragedy of the commons”; a phrase coined by Garrett Hardin in 1969. It should be remembered that this concept arose not from forestry but from farming. During the 17th and 18th centuries, the establishment of long-term property rights in land, and their allocation by owners to tenant farmers, became the sustainable solution to an over-exploitation of the commons.

A comparison with farming suggests two options that can be considered generically as American and European. In the. former, market forces have led to very large farms often owned by even larger corporations who necessarily take a long term view. Such farms are, typically, very dull aesthetically but financially efficient. The “European” alternative is to maintain a traditional landscape, geographically and culturally. This is aesthetically pleasing but requires central support by subsidy and import controls. Each approach is a solution for a sector of the economy which, although significant politically, is not critical for highly industrialized countries.

In Europe and North America, fisheries are even less critical economically but highly visible culturally. Yet on both continents we try to have it both ways – to require economic efficiency and expect cultural continuity. It is not surprising this leads to failure. In some cases we appear to legislate specifically for that outcome. Attempts to implement programs of marketable property rights in fish, through such measures as ITQ’s (individually tradable quotas) have been subject to moratoria in countries like the United States. These quotas are recognized to aggregate or integrate fishing effort into larger management blocks that necessarily take a longer term view but may deny independence to individual fishers; as well as being likely to decrease the number of boats and people employed. At present we regard the fishers, rather than the fish, as the endangered species. As the costs of enforcement of present policies increase and the fish stocks decline, it will be interesting to see whether free-market forces begin to trump the proponents of cultural preservation. Certainly in countries such as Iceland or New Zealand, where the fishing economy is critical to national economic production, we have seen institutional changes in the direction of property rights and market allocations.
The European agricultural solution often results in part-time farmers. This is not feasible in open sea fishing given the nature of the work and the substantial capital depreciation. It may be successful in near shore fisheries for high priced shellfish. The logical outcome for all these problems seems to be fish farming. In northern Europe, the rearing of salmonids has converted an expensive delicacy into a supermarket commodity comparable to chicken. It may seem that, when the open sea has become bereft of directly edible fish, it will then supply an enhanced source of protein for the fish farms, from small rapidly growing fish further down the food web (industrial fishing). This form of “enclosure” is an obvious consequence of our inability to evolve a management protocol for the open sea. Ironically such a combination – harvesting at lower trophic levels to feed higher level farmed stocks – could still expose us to the consequences of the greater natural flexibility in marine ecosystems; such as having an abundance of “jellies” rather than small fish at the top of the food web.

Thus focusing on sustainability, especially of individual fish stocks, ignores the natural variability at decadal scales. Attempting to damp out these inter-annual trends may even exacerbate the oscillations, particularly by compounding them with economic processes at the same time scales. We need to understand the natural physical and ecological causes of these ”cycles”. And then devise sufficiently long term management to ameliorate rather than amplify the economic consequences.