Numbers of Mediterranean fish vary from year to year: gluts occur, but dearth is so frequent that it is unwise to make fish protein more than a supplement to a subsistence diet. The nutritional usefulness is greatly increased by drying and salting. Even in times of glut, and assuming very favourable conditions for fishing, total yields cannot have made an important contribution to the protein needs of even small ancient populations, compared with cereal or legume staples (see food and drink). They did, however, play a significant role in diversifying a diet based on those staples, which was important both nutritionally and culturally in the classic Mediterranean pairing of staple and ‘relish’—Gk. opson. Salted or pickled fish was the opson par excellence, and widely available for use in small quantities.
To the producer, this demand gave the catch the economic status of a cash crop, and enabled the secondary purchase of more protein than could easily have been acquired through consuming the fish. On this base of widely disseminated eating of fish‐pickle, the fisherman could rely on a more lucrative market in fresh fish, which could fetch high prices. This combination of ready availability of fish opsa with the opulent associations of fresh fish prized by the connoisseur underlies the great prominence of fish in the Athenian comic tradition. What had been characteristic of Athens became a feature of most towns in the Hellenistic and Roman periods; study of the amphorae reveals the scale and complexity of the trade in garum (as the pickle came to be known), while the competitive consumption of the exquisites of high society provided a continuing stock of anecdote about colossal prices and singular specimens. The fisherman became a type of opportunism and poverty.
Fishing in the open sea was chancy and hazardous, but essential for the most prized fish. Many local markets were supplied from the rocky shores. The fisheries of the once extensive wetland lagoons of the Mediterranean coasts were the easiest to develop artificially, because they were sheltered, shallow, and had controllable inlets and outlets, and systematic pisciculture grew from their management. Both archaeological and literary evidence shows the extent to which Roman pisciculture developed, and the elaboration of fishponds for both fresh and salt‐water fish. Processing plants for making pickle were also built on a grand scale, from the early Hellenistic period in the Black (Euxine) Sea area, and in the Roman period on the coasts of southern Spain and Mauretania. This economy depended on, and is an indicator of, a developed interdependence of markets in the Mediterranean.
See meals; oppian.