Fingerlings and other lings
With the accelerating growth of fish consumption, more and more attention and efforts are being dedicated to the development of fish farming, both marine and freshwater. To produce fish of edible size, in most cases fish farmers populate their ponds or fish cages with young stages of the preferred fish species.
In the wild the process starts as fertilised eggs develop into – although most eggs do not survive to maturity even under the best conditions. They are beset with threats, from changes in water temperature or oxygen levels to flooding with wrong sort of water, sedimentation that can cover the eggs with a layer of mud, and then there are disease and predation.
Well, who doesn't like eggs? Then, there is the caviar. Traditionally, the term caviar refers only to roe from wild sturgeon in the Caspian and Black Seas (Beluga, Ossetra and Sevruga caviars). Depending on the country, caviar may also be used to describe the roe of other fish such as salmon, steelhead, trout, lumpfish, whitefish, other species of sturgeon, and even carp.
Assuming the eggs make it to become hatchlings and then fry as they can feed by themselves and fingerlings as they develop scales and working fins, they have already fought their way past a myriad of hazards to get this far.
Unsurprisingly, most fingerlings are typically about the size of human children’s fingers –hence the name. The juvenile stage lasts until the fish reach their final form and start feeding on the regular food typical of their species. ...
In aquaculture the process typically begins with the stocking of fry, and these can come captured from the wild or have been bred. Whatever their origin, they are indispensable and the means of obtaining them influences directly farm production. With erratic supply, there will be undesirable interruptions in the production of the succeeding stages.
The production of marketable fish begins with the stocking of fry or juveniles into a rearing environment that assures optimum and rapid growth to allow harvest in the shortest possible time. However, there is little or no guarantee that adequate numbers of fry can be captured and stocked in the time corresponding to optimum production conditions. The fish farmer then naturally turns to other means of obtaining his stock. By simulation of the conditions necessary for the reproduction of his fish, the farmer can spawn the fish in captivity. Successful spawning is only the beginning, however, the eggs must hatch, and these reared successfully to fry stage. The spawning, hatching, and early rearing present a path well filled with obstacles, for example quality of water with dissolved oxygen, feed of the proper nutritive composition and particle size, low resistance to diseases, and so on. A good appreciation of all these factors is needed for successful production of fish.
The ultimate goal of the fish farmer is to produce fish that meet both his needs and the market demand. Through artificial propagation, the farmer can select for desirable characteristics such as rapid growth and resistance to disease. By hybridisation and selection, these goals can be achieved if the farmer dedicates enough time and patience.
If one looks at production of eggs, larvae, and fry that is carried out on the farm itself, the major problems are obtaining a sufficient number of eggs, a good hatching rate of these eggs, and good survival and growth of the larvae obtained. In nature, there is very high mortality at these stages, and a lot of attention and effort is needed to overcome these difficulties.
To practice reproduction and fry production, a certain investment in equipment, infrastructure (ponds, tanks, water supply), and trained labour is needed. These costs can be considered a part of overall production costs of marketable fish.
But things are, as usual, not so straightforward. Firstly, the ratio between the fish captured from the wild and those produced by aquaculture is constantly changing in favour of the farmed ones. Thus, nowadays, there are almost twice as much farmed fish as captured ones of commercial size. If such trend keeps going, we could soon reach three or four times more of farmed fish.
However, humanity's many thousands years of experience with nature teaches that no trend goes forever. In general, depending on countless factors, sooner or later, trends tend to collapse with louder or lesser noise. Prosperous populations suffer from breakdowns due to various diseases, some resulting from their density. Human populations have their own methodology: wars and mass murder such as the Holocaust.
Well, as they say: hope for the best and prepare for the worst. Fish farmers, we've got you in mind.
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