In Rome considerable trade was done in the sale of young fish for stocking waters. In China the commerce in fish eggs was on a vast scale and extremely lucrative. The Jesuit missionary Du Halde writes, “Le gain va souvent au centuple de la dépense, car le Peuple se nourrit en partie de Poissons.”[739]
The method, however, of both the Chinese and the Romans was to gather eggs, already naturally fertilised, lying at the bottom of, or adhering to weeds in, the water. The Chinese went farther by employing special traps of hurdles and mats to bar the rivers and catch the eggs deposited on these.
During the long interval between the Roman Empire and the eighteenth century, we note little or no progress in the rearing of fish, although preserves became numerous in Italy and France. Kings and nobles were zealous and jealous in making and maintaining artificial ponds. Charlemagne the Great personally ordered the repairing of old and digging of new ponds. By sales from their vivaria, and by heavy royalties from their fisheries the religious communities amassed large revenues.
Towards the end of the Middle Ages new methods to counter the scarcity universally prevalent, despite the teaching in the thirteenth century of Peter of Vescenza, were eagerly sought. Dom Pinchon, a monk of the Abbey of Réome, seems the first to have conceived the idea of artificially fecundating the eggs of trout. He pressed out in turn the milt of a male and the eggs of a female into water, which he then agitated with his finger. He placed the resulting eggs in a wooden box, with a layer of fine sand on the bottom, and a willow grating above and at the two ends. The box till the moment of hatching was immersed in water flowing with a gentle stream.
The process—described in a manuscript dated 1420, but not published till about 1850—naturally led to no practical results. Consequently Pinchon’s claim to be the father of modern Pisciculture—a term first used some three hundred years after his death—can hardly be sustained. His discoveries interest only from a historical point of view.
The middle of the eighteenth century witnessed an improvement on Pinchon’s plan. In Sweden (where the care taken to protect fish even prohibited the ringing of bells at the spawning season) the bream, perch, and mullet attach their eggs either to rocks, or twigs of pine.
Lund shut up males and females for three or four days in three boxes, furnished with twigs of pine, etc. (on which the fish spawned), and pierced with little holes to allow the entrance of water. He succeeded at his first attempt in raising from 50 female bream, 3,100,000 fry; from 100 perch, 3,215,000 fry; and from 100 mullet, 4,000,000 fry.
Jacobi of Westphalia, the first real inventor of practical fecundation by artificial means, experimented on trout and salmon for sixteen years before attaining definite success.
He pressed in turn the eggs and milt into a vase half filled with water which he kept gently stirred with his hand. The fertilised eggs were at once placed in a grated box inside a larger chest, in which Jacobi had inserted at the sides and at the top fine metallic gratings to allow the easy flow in and out of water over the sand or gravel lying at the bottom. The apparatus was set in a trench by the side of a brook, or, better still, in an artificial channel into which springs were led. The young fish after hatching lived for three or four weeks on their umbilical sac, and were then passed into a reservoir.
By these simple means Jacobi, who for his services was granted by England a pension for life, solved the problem of protecting fertilised eggs against their enemies, and yet of leaving them in surroundings not unlike those of Nature. The experiment, as far as it went, succeeded admirably.