Fish and plants! Archaeobotanical analyses in a roman tub

Archaeobotanical analyses provided interesting information about a Roman tank (1st cent. BC – 1st cent. AD) discovered in Modena (Emilia Romagna, Northern Italy). The tank must have been shielded by a hedge of Buxus sempervirens (720 seeds/13l, first Italian recovery, combined with good pollen %). The recovery of few archaeozoological finds let suppose that the tank was used for fish farming and this hypothesis is supported by some particular vegetal findings. The presence of Ceratophyllum sp.pl. (with 1382 achenes/13l, traces of pollen and leaf spinule), combined with Myriophyllum spicatum (29 achenes/13l), suggests a suitable habitat for fish farming; hornwort and watermilfoil, that must have formed a thick “carpet” on the bottom of the tank, are excellent to support fish eggs in fish farm. Furthermore, the recovery of many mericarps (110/13l) of Pastinaca sativa is peculiar; parsnip was used by Romans in cooking and as a medicinal and mellipherous plant as well (Apicio 3,21; Columella VI, 17.8, 33.1; IX, 4.5; Plinio XI 3.14; XII 7.1-2; XIX 62, 88-89). This plant presents an interesting peculiarity in this context: it is rich with normal butyric acid (of fermentation) in the form of octyl ester. Butyric acid is used for its strong smell as additive in fishing baits, even if it is not clear how this molecule turns out to be so attractive for fishes. Parsnip mericarps identified in the tank therefore could suggest baiting practices of fishes. Hydrophytes comprehensively show an environment consistent with the supposed use of the tank: Cerathophyllum sp.pl., Myriophyllum spicatum, Ranunculus subgen. Batrachium, Lemna minor/gibba, taxa quite tolerant to human disturbance, indicate stagnant waters rich in nourishing substances (condition confirmed also by algae of the genus Tribonema between NPPs) and limestone and characterised by some summer heating.