What Early Fish Culturists Learned About Hatching and Rearing Fish

The story of artificial fish culture is largely a story of hard-won lessons. Through most of the nineteenth century, the people who tried to hatch fish eggs and raise the fry to a useful size were working without manuals, without trained predecessors to consult, and often without a clear idea of why what they were doing was failing. What they left behind in their published accounts is a remarkably candid record of confusion, costly mistakes, and occasional insight.

A practice older than it looked

By the time American and European practitioners began writing seriously about fish culture in the 1860s and 1870s, the practice had roots stretching back centuries, though those roots had repeatedly been forgotten and rediscovered. Practical Trout Culture (1876) notes that Chinese writers as early as 2,100 B.C. described laws regulating when fish spawn could be taken, and that a Jesuit missionary named Father Duhalde, writing in 1735, described Chinese merchants gathering spawn from the Yangtse-kiang each May, with country people stretching mats and hurdles across the river current to catch the drifting eggs for sale.

Whether this constituted fish culture in any modern sense was contested. Modern Fish Culture in Fresh and Salt Water records that at the Berlin Fisheries Exposition of 1880, the author put the question directly to knowledgeable Chinese attendees and concluded that their work amounted to placing twigs in water to catch adhesive spawn, then moving those eggs to other waters and leaving them. The eggs were protected while they developed and used to stock depleted waters, but beyond that there was little systematic management. The same source describes this as a rude attempt, and notes that the practice had not meaningfully improved.

In medieval Europe, the honour of inventing the first purpose-built hatching box is generally attributed to Dom Pinchon, a monk of the Abbey of Reome, who worked sometime in the fourteenth century. Both Fish Culture: Its Origin and Progress and American Fish Culture credit this attribution to the French writer M. Jourdier (and in some sources, Baron Mongaudry's archival discoveries). Pinchon's boxes had wicker-work ends and sand-covered bottoms, with small excavations made in the sand to hold the eggs. A gentle stream of water ran through continuously. As Fish Culture notes, the method was in its essentials not far removed from what practitioners were still doing in the nineteenth century.

The art then lapsed for several centuries. It was revived, apparently independently, by Lieutenant Jacobi, a German gentleman, who published detailed accounts in the Hanover Magazine in 1763 to 1765. According to Fish Culture, Jacobi constructed long oaken boxes with fine gratings at the top and ends, filled them partially with gravel, mixed ripe spawn from females with milt from males, deposited the fertilised eggs in the gravel, and placed the whole box in a clear running stream. He left incubation to nature and reportedly succeeded with several freshwater species including salmon and trout. Practical Trout Culture remarks that his plan, with little alteration, remained in use at the time of writing.

The French revival of the mid-nineteenth century is credited in Fish Hatching and Fish Catching to two fishermen of Bresse, Gehin and Remy, who observed that mature eggs from certain fish could be expressed from the body with slight pressure, and grasped what might be done with that fact. Their work drew government attention in France and eventually spread the practice across Europe and to North America.

Extending the method from salmon to other species

Fish Hatching and Fish Catching describes how artificial culture was gradually extended from one species to another: first salmon, the most commercially valuable; then trout; then shad and whitefish; then lake trout, herring, perch, bass, striped bass, and sturgeon. With each extension, practitioners discovered that methods working well for one species often failed badly with another. The same source notes that salmon, trout, lake trout, and shad showed the greatest promise for purely artificial manipulation, while other varieties required a subsidiary approach in which natural processes were assisted and protected rather than replaced entirely.

This point about species-specific requirements turns out to be one of the central lessons of the entire period. The early practitioners operated as though successful technique with brook trout should transfer directly to whitefish or salmon. It did not.

The whitefish problem

The most detailed account of learning this lesson the hard way comes from the author of Pisciculture, writing from his own published record in Forest and Stream dated Clarkston, June 29, 1874. In November 1869, with assistance from Seth Green, he placed 50,000 whitefish ova in hatching troughs supplied with spring water at 47 degrees Fahrenheit. He was already hatching brook trout successfully in the same setup and expected the whitefish to behave similarly. Within two weeks, nine-tenths of the eggs had turned white and become worthless.

Green came to his assistance and, on careful inspection, found that a small proportion still showed signs of vitality. His advice was to remove the viable eggs individually. The result was approximately 2,000 hatched fish by January 15th, but the troubles were only beginning. The young whitefish behaved nothing like young trout. The moment they emerged they darted off rapidly, whereas newly hatched trout were inactive, sustained by a large umbilical sac that kept them for about sixty days without any external food. The whitefish had only a very small appendage, absorbed in roughly fifteen days. Moving quickly and requiring food almost immediately after hatching, they escaped through the meshes of the wire cloth used to contain them and were lost.

The following November, 1870, the same practitioner tried again with another 50,000 ova from the Detroit River. This time he used a finer wire cloth, which kept the fish in their troughs. James W. Milner, U.S. Deputy Fish Commissioner, visited the hatchery, and 100 of the young fish were taken away for separate study while the remaining approximately 3,000 stayed in the hatching boxes. The goal was to find out what artificial food would sustain whitefish fry through their critical early weeks. Seth Green himself had not yet worked this out. Every food tried failed. All the fish died within four weeks despite constant attention.

The lesson was stated plainly in Pisciculture: a practitioner must know not just how to hatch a species, but the period of self-sustenance of the newly hatched fish, and what natural food it requires once that period ends. Applying trout methods to whitefish had failed because the two species have fundamentally different early-life requirements.

The question of when to hatch

A second major problem concerned timing. Early practitioners sometimes pushed to hatch eggs as quickly as possible, apparently assuming that earlier hatching gave the young fish more time to grow. The author of Pisciculture challenged this directly, drawing on a trout-rearing experiment from 1872. He had set aside about 2,500 brook trout ova in hatching boxes and arranged them so that when hatched, the fry could move directly into a small adjacent pond about 14 by 45 feet and two feet deep. The eggs received little attention over winter, hatched late, and were observed swimming actively around April 1st, with their yolk sacs almost entirely absorbed.

Those roughly 2,000 fish were then left entirely unfed and uncared for until September 15th, by which point they had grown to a size the author said he had never seen equalled. He reported not seeing a single dead fish among them. The pond was fed by spring water at about 55 degrees Fahrenheit, and the author concluded that the fish had fed on animalcule (small organisms) naturally present in the water.

He contrasted this with earlier attempts in the same water following Seth Green's published methods, feeding young trout on curdled milk and chopped liver. Those fish had done considerably worse. His question was pointed: if fish were hatched by December, months before natural food was available in the water, could they survive past the period of yolk-sac absorption? His experience suggested they could not, and that hatching fish too early in cold water, long before conditions in a pond could support them naturally, was a significant source of unexplained losses.

The salmon ova experiment noted in the same source reinforces the point about conditions after hatching. Some 30,000 California salmon ova sent through Professor Baird and the U.S. Fish Commissioner were distributed in Michigan in October 1873. The batch placed under Commissioner Jerome at the State Hatchery at Pokagon measured six to seven inches by the time of the author's visit, while those left with another culturist in nearby streams reached only four to six inches and were in poorer condition. The difference was attributed to the quality and constancy of care after hatching, not to the hatching process itself.

Artificial impregnation and the handling of spawn

Practical Trout Culture gives considerable attention to the mechanics of fertilising eggs outside the body of the fish, a process at the centre of all artificial culture. The table of contents of that work lists the key questions practitioners were working through: how to distinguish ripe males and females, how to capture them without damage, how to manage the impregnating process, and crucially, the causes of failure and their remedies. M. Vrasski's experiments on the theory of impregnation are mentioned as an area of active investigation.

The same work notes with some feeling that the Collins Patent Roller Spawning Race, which allowed spawn to be taken without the operator wetting their hands, represented what seemed at the time to be the practical limit of labour-saving and health-saving apparatus. The handling of spawn was physically demanding work done in cold water at awkward seasons, and devices that reduced direct hand contact were genuinely valued.

Practical Trout Culture also acknowledges the limitations of the knowledge available when its authors began. Every misfortune they suffered, they write, could be traced either to their own ignorance or to their own neglect. For neglect they offered no excuse. For ignorance, they noted simply the great want of facilities for instruction that existed at the time. Only two original American works on fish culture had appeared before theirs, both written after the authors had already entered the practice.

The slow accumulation of reliable knowledge

Fish Hatching and Fish Catching claims, with obvious pride, that its authors had a hundredfold more experience in fish culture than any other persons in the country at the time of writing, and that by them or under their control the most important inventions and discoveries had been made. This was a field still young enough that individual practitioners could make genuine contributions simply by attempting things systematically and recording what happened.

Practical Trout Culture is candid about how quickly the field was moving. New theories, it notes, would often be accepted that rendered old ones baseless or even ridiculous. New inventions might further simplify the manual labour involved. The science was in its infancy. The advice offered was offered in that spirit: here is what we know now, which is more than was known five years ago, and less than will be known five years hence.

What comes through most clearly in reading these sources together is how much of what early fish culturists learned came from their mistakes rather than their successes. Whitefish escaped through wire meant for trout. Young fish starved because they were hatched weeks before their natural food existed. Feeding methods that worked for one species killed another. Each failure, documented and published, added something to the collective understanding. The hatching box that Dom Pinchon built in the fourteenth century, the gravel-filled oaken box that Jacobi placed in a German stream in the 1760s, and the wire-cloth troughs that a Michigan practitioner adjusted in 1870 after losing his whitefish through the wrong mesh size all represent the same slow process: people trying something, observing carefully what happened, and adjusting.