Brief case studies of the Atlantic sturgeon, sustained medieval fisheries on Lake Constance, and development of intense commercial fishing for Atlantic cod identify themes and issues for an environmental history of medieval European fisheries, history as if nature matters. An interactive metabolic model for the interplay of autonomous cultural (i.e. socially learned) and natural forces provides an analytical framework for handling diverse local and regional experiences and impacts of medieval Europeans with aquatic ecosystems. Traditional historical methods fit together with interdisciplinary evidence from archaeology, archaeozoology, historical climatology, and aquatic ecology in a search for understandable consilience. Some developments during roughly 500–1500 CE may foreshadow present-day global fisheries crises.

A survey of post-Pleistocene hydrologies and living aquatic ecologies identifies key variables which shaped fish communities in European and surrounding waters into Roman times. Provides a basic introduction to key ecological concepts such as habitats, food webs, predator–prey relations, ecological ‘guilds’, and environmental tolerances of fishes. Signs of localized negative effects of Roman consumption on especially inshore and estuarine Mediterranean fishes were, however, mostly effaced following late antique disintegration of classical cultures in the West.

Late medieval Europeans extended exploitation of fish stocks to marine frontiers previously little affected by intense human predation. Driven by demand since the twelfth century and supported by waves of innovative capture and preservation methods, herring fisheries in the North Sea and Baltic fed millions of northern Europeans with the largest medieval catches known. Stockfish (naturally freeze-dried cod) from arctic Norway went from a regional subsistence product c.1100 to an export trade profiting fishers and merchants alike. Elsewhere entrepreneurs caught, preserved, and exported pike and other fish from the eastern Baltic, hake and conger from the Channel approaches and Bay of Biscay, and migratory bluefin tuna off Sicily and the Gulf of Cadiz, all for consumption a thousand and more kilometers away. Transforming local abundances for distant tables at unprecedented scale drove new capitalized forms of organization and market behaviour. Consumers, merchants, and fishers saw fish as economic objects disconnected from any familiar nature and free for competitive exploitation. Yet besides prospects of infinite abundance the new frontier fisheries posed risks, and not simply those of hazardous access or human conflict. Heavily fished local stocks of herring successively crashed to commercial insignificance when further stressed by environmental changes in the pulsating arrival of the Little Ice Age. But the almost accidental discovery of virgin cod stocks off Newfoundland in the 1490s confirmed the mythic belief that abundance always lay over the next horizon. Thoughts of limits vanished at the eve of modernity.

Fearing shortage of culturally significant fish, medieval societies reacted in several ways. In a culture of markets, scarce supply motivates sellers to demand and/or buyers to offer more for the commodity: anecdotes from the twelfth century and serial prices from the thirteenth indicate fish prices rising even past 1350. Ownership of the productive resource itself could capture some of those sellers’ gains, not to mention the prestige and power medieval society associated with landownership: elite acquisition of fishing rights had begun with early creation of private lordships, but by and after the twelfth century it also promised income from direct exploitation or from leasing operations to artisans (depriving local subsistence fishers). In contrast, relict and then emergent claimants to public authority could gain by regulating resource exploitation ‘for the public good’. From the 1200s onwards kings, territorial princes, and self-governing communes asserted control over fishing rights and activities, first on acknowledged public waters (large rivers, coastal waters) and eventually over practices and uses of private natural waters. The chapter explores grounds for regulating fisheries as a ‘public’ resource to allocate their value, settle disputes, ensure consumer safety, and occasionally to encourage what might now be called ‘sustainable’ uses within recognizable limits. Like the artisanal fisheries toward which they were directed, these cultural measures retained close ties between local natural ecosystems and consumers of fish.

Artisan fishers broke the early medieval pattern of subsistence fishing. Participants in Europe’s medieval ‘Commercial Revolution’, artisans made their living by catching fish to sell on a local market. Evidence of such people appears around 1000 CE in commercially precocious northern Italy but also in England, France, the Rhineland, and elsewhere. Commonly they arose at or near emerging towns, where skilled subsistence fishers might offer a surplus catch to other non-agricultural specialists. The chapter examines the social position of these household-based fishers, their traditional small-scale technologies, and the collective organizations (guilds) used to manage their human and environmental relations. It then turns to the urban markets where these men and their wives provided fresh fish from nearby waters. In larger towns professional fishmongers consolidated catches from various regional habitats, while communal concern for a safe and abundant supply caused municipal authorities to regulate market dealings. By the late twelfth century the interplay of seasonal demand (Lent) and supply (runs of migratory fish) coupled with cultural criteria of taste and quality shaped fish prices. Whether in great cities like Venice or Paris or small towns on the Castilian plateau or English coast, local markets offered consumers the regional fish they ate.

For centuries up to about 1000 CE, and in many settings also long thereafter, medieval Europeans ate almost exclusively the fishes available in their nearby waters, fresh or marine. Predominant technologies and institutional arrangements could not easily or safely move fish or fish flesh more than a few days from the point of capture. Peasant households with local knowledge of seasonally available stocks took fish ‘for their own table’. Local communities with de facto access to waters defended customary uses on what later writers would call fisheries commons. Much better documented, however, were those subordinates obligated to supply fish for the tables of their social superiors and masters. For some this was routine labour service, but for a few it was full-time employment and expertise. Small gear handled by individuals could provide family subsistence, while crew-served equipment targeting seasonal concentrations served the larger demands of ruling elites. Depending on the fish variety and season, short-term preservation methods (salting, drying, smoking) might keep a catch edible for short-run future use. Local and regional variations on these practices were ubiquitous.

As the Middle Ages drew to a close, however, a rising share of Europeans were eating fish from systems other than their natural local waters. By 1500 around Paris, for instance, elite menus featured carp and headless codfish, while lesser folk made do with herring and haddock. Beside the Mediterranean, Valencia was receiving millions of Atlantic sardines and hake, while Romans could get herring from the North Sea, Norwegian cod, and tuna from Sicily. Both cultured carp and fishes from Europe’s economic frontiers changed Europeans’ relations with aquatic nature.

Carp aquaculture colonized nature, creating artificial habitats to rear an organism alien to western Europe. Late fifteenth- and early sixteenth-century financial records and instructional manuals from east-central Europe detail an original and distinctive European mode for farming fish. Those practices provide a benchmark to identify and trace their creation in twelfth- to thirteenth-century France – where the carp was a late invader – and subsequent spread eastwards of the innovation. Human-controlled aquaculture created thousands of local ecological revolutions across interior Europe, providing inland elites with a steady source of live fresh fish, serving as a vehicle of elite power over subjected nature and people, and replacing indigenous ecosystems with private anthropogenic habitats tailored for domesticated, soon also feral, invaders. For contemporary writers fish had become objects of human agency.

How and why Europeans evidently ate fish during the medieval millennium as revealed in traditional verbal records, archaeological remains of fish in human waste deposits, and biochemical traces of fish proteins in human skeletal remains. Christian teachings allowed fish during regularly recurring religious taboos on mammal and bird meats. Medical teachings inherited from classical Greco-Roman culture and further elaborated by Muslim and later Christian physicians both advised and constrained fish consumption, as did some folk beliefs. All social ranks recognized fish consumption, especially that of certain large or impressive fishes, as marking high status, wealth, and power. Hence medieval demand for fish was highly stratified. Medievals fished for household subsistence and eventually some people caught fish for sale to other consumers.

The concluding chapter reiterates discovery of medieval fisheries as a series of interlocking specific experiences of cultural interaction with aquatic nature and the underlying importance in those narratives of drivers both cultural and natural in origin. It then turns to implications which arise when contradictory medieval legacies of overexploitation, recognition of limits, expectation of human control, and belief that abundance always lies just beyond physical or technological frontiers are viewed from the perspective of a present-day global fisheries crisis.

The high-medieval demographic and economic growth in which fishers and their customers shared had detectable environmental consequences. Prevailing agricultural practices plus increased human and other wastes damaged river systems and polluted both flowing and still waters. Contemporaries were aware of some such effects; others emerge only in modern scientific archaeology. Rulers and others blamed perceived declines in the quantity and quality of fish on overfishing. Present-day studies of long-running assemblages of fish remains detect local depletion of favoured varieties and shrinking average size of more common species. Some fishes (eel) and some fisheries (for herring) of previously limited importance increased their contribution to European diets. An exotic species, common carp, hitherto present in Europe only in the lower Danube, spread westwards into waters made warmer and siltier by human activities. In large thirteenth-century assemblages (but with regional variations), more accessible herring, eel, codfishes, and small cyprinids become dominant. Not all change had human origin; natural dynamics also played a role. High medieval centuries saw the crest, then decline, of climatic warming, with concomitant regional differences in precipitation, seasonality, riverine and estuarine hydrology, and even shifts in stratification and water chemistry of the Baltic. Changed habitats let heat-tolerant fishes spread west, while a herring-dominated regime in the Baltic peaked and slowly yielded to greater presence of cod. Knowingly or not, humans and animals had to adapt.