A fish hatchery (Fish hatcheries) is a place where large numbers of fish eggs are artificially fertilized and fry and are hatched in an enclosed environment.
Fish hatcheries can increase a fish population quickly in the wild only 2% of the eggs survive (versus 80% using a hatchery). Some hatcheries raise the fry until they reach adulthood and have commercial value; others release the fry into the wild with the intent of building up the wild stock.
For fish culture, it is necessary to ensure the supply of suitable sized good quality fish seed in sufficient quantities. The main source fish seeds are spawn produced in government and private hatcheries, and some collected from rivers.
The seed collected from natural breeding grounds have many problems such as the inclusion of seed of predatory fishes or disease. Wild seed is collected and handled in crude and unscientific methods that can potentially lead to large scale mortality during transportation from collection centers to nursery ponds and also in the nursery ponds after release.
Therefore, emphasis should be placed on expansion of hatchery facilities to supply high-quality fish seed required to support aquaculture development.
The hatchery phase is often the aspect that limits aquaculture expansion. Water environments that may be adequate for adult fish may not be sufficient for breeding, fish eggs and hatchlings. Any number of environmental factors can cause adults to become infertile.
Fish eggs and baby fish are a favorite food for some predators like frogs, turtles and other fish. Some adult fish even eat smaller fish and eggs of their own species. Fish hatcheries resolve these problems.
The entire life cycle of the aquaculture (figure 1), from egg to market-size product, is completed in a production line composed of these stages:
Hatchery: Parental brood stock produces high quality hybrid fry.
Nursery: Young fry are raised to juveniles.
Grow-out: Juveniles are raised to market size product.
Processing Plant:Processing and packaging of fish fillets.
Support & service: Ensuring supply of feed, disease control, etc.
Marketing: Distribution to local and foreign markets.
Needs for Fish Hatcheries
A fish hatchery is a facility designed to raise fish. It provides an optimum environment for fish eggs to develop and hatch by maintaining proper water temperature and oxygen levels, and providing adequate food supplies and safety from predators.
A fish hatchery works to raise baby fish and prepare them for release in another environment for various reasons, as well as for food
One purpose of a fish hatchery is to raise a certain kind of fish in order to stock a lake or pond for fishing. Certain types of fish, such as trout and salmon, are favorites among fisherman.
Sometimes, in a popular fishing hole, the fish are harvested too quickly to allow them to breed and grow. A fish hatchery provides a safe haven until the fish are mature enough to be caught.
Another reason that a certain fish may be raised in a fish hatchery is for environmental conservation. Every animal has its place in the ecosystem.
Sometimes, human activity makes it impossible for fish to breed or causes them to disappear from a body of water altogether. A fish hatchery can reintroduce mature, healthy fish to a previously inhabited body of water where they will maintain the ecosystem by doing their part in the food chain.
A fish hatchery may also be used to farm fish for human food consumption. Hatching and raising fish for food has many advantages for humans and the environment.
First, because of pollution, many wild fish are contaminated with dangerous pollutants such as mercury and polychlorinated biphenyls (PCBs). Consuming these pollutants is hazardous to human health. Farm raised fish contain lower levels of contaminants, which helps to reduce this risk. Raising fish in a hatchery also helps to relieve the environmental pressures in an area due to over-fishing.
Read Also : Guide to Proper Fish Pond Management
Purposes of Fish Hatchery
1. Fish farms
Fish farms use hatcheries to cultivate fish to sell for food or ornamental purposes, eliminating the need to find the fish in the wild, and even providing some species outside of their natural season. They raise the fish until they are ready to be eaten or sold to aquarium stores.
2. Fish stocking
Other hatcheries release the juvenile fish into a river, lake or the ocean to support commercial, tribal, or recreational fishing or to supplement the natural numbers of threatened or endangered species, a practice known as fish stocking.
Some fish hatcheries are used to mitigate the effects of development, such as construction of a dam, hydroelectric plant or water diversion.
3. Ornamental fish
The ornamental fish industry uses fish hatcheries to produce fish for the aquarium fish trade; this has helped to limit the overharvesting of native fish populations both in fresh and salt water ecosystems.
4. Hatchery Requirement
The efficient operation of a fish hatchery depends on a number of factors. Among these are suitable site selections, soil characteristics, and water quality.
Adequate facility design, water supply structures, water source, and hatchery effluent treatment must also be considered
5. Site Selection
Water quality is among the most critical of considerations during site selection. This is of equal importance to both fresh and saltwater resources. Listed in figure 2 are water quality ranges required during various hatchery production phases.
Hatchery water requires significant pre-treatment inclusive of solids removal, disinfection, carbon filtration, and binding of heavy metals.
Hatchery design needs to be scaled in proportion to required post larvae (PL) production for grow-out. Species with seasonal availability of brood stock or spawning capabilities require larger infrastructure because facilities are not in continuous production. Hatchery sizing should be based upon species and production requirements.
6. Water Quality
It determines to a great extent the success or failure of a fish cultural operation. Physical and chemical characteristic such as suspended solids, temperature, dissolved gases, ph, mineral content and the potential danger of toxic metals must be considered in the selection of site of a suitable water source.
Read Also : Guide to Proper Techniques of Fish Culture
7. Temperature
No other single factor affects the development and growth of fish as much as water temperature. Metabolic rates of fish increase rapidly as temperatures go up.
Many biological processes such as spawning and egg hatching are geared to annual temperature changes in the natural environment. Each species has a temperature range that it can tolerate, and within that range it has optimal temperatures for growth and reproduction.
These optimal temperatures may change as a fish grows. Successful hatchery operations depend on a detailed knowledge of such temperature influences.
The temperature requirements for a fish production program should be well defined, because energy must be purchased for either heating or cooling the hatchery water supply if unsuitable temperatures occur.
First consideration should be to select a water supply with optimal temperatures for the species to be reared or, conversely, to select a species of fish that thrives in the water temperatures naturally available to the hatchery.
It is important to remember that major temperature differences between hatchery water and the streams into which the fish ultimately may be stocked can greatly lower the success of any stocking program to which hatchery operations may be directed.
Within a hatchery, temperatures that become too high or low for fish impart stresses that can dramatically affect production and render fish more susceptible to disease. Most chemical substances dissolve more readily as temperature increases; in contrast, and of considerable importance to hatchery operations, gases such as oxygen and carbon dioxide become less soluble as temperatures rise.
8. Dissolved Gases
Nitrogen and oxygen are the two most abundant gases dissolved in water. Although the atmosphere contains almost four times more nitrogen than oxygen in volume, oxygen has twice the solubility of nitrogen in water.
Therefore, fresh water usually contains about twice as much nitrogen as oxygen when in equilibrium with the atmosphere. Carbon dioxide also is present in water, but it normally occurs at much lower concentrations than either nitrogen or oxygen because of its low concentration in the atmosphere.
All atmospheric gases dissolve in water, although not in their atmospheric proportions; as mentioned, for example, oxygen is over twice as soluble as nitrogen. Natural waters contain additional dissolved gases that result from erosion of rock and decomposition of organic matter.
Several gases have implications for hatchery site selection and management. Oxygen must be above certain minimum concentrations.
Other gases must be kept below critical lethal concentrations in hatchery or pond water. As for other aspects of water quality, inappropriate concentrations of dissolved gases in source waters mean added expense for treatment facilities.
Fish Hatchery Pollutants
Generally, three types of pollutants are discharged from hatcheries: (l) pathogenic bacteria and parasites; (2) chemicals and drugs used for disease control; (3) metabolic products (ammonia, feces) and waste food. Pollution by the first two categories is sporadic but nonetheless important.
If it occurs, water must be sterilized of pathogens, disinfected of parasites, and detoxified of chemicals. Standby detoxification procedures should be in place before the drug or chemical is used.
The third category of pollutants — waste products from fish and food — is a constant feature of hatchery operation, and usually requires permanent facilities to deal with it. Two components — dissolved and suspended solids — need consideration.
Dissolved pollutants predominantly are ammonia, nitrate, phosphate, and organic matter. Ammonia in the molecular form is toxic, as already noted. Nitrate, phosphate, and organic matter contribute to eutrophication of receiving waters.
For the trout and salmon operations that have been studied, each kg of dry pelleted food eaten by fish yields 0.032 kg of total ammonia, 0.087 kg of nitrate, and 0.005 kg of phosphate to the effluent (dissolved organic matter was not determined separately).
The feed also contributes to Biological Oxygen Demand (BOD), commonly used as an index of pollution; it is the weight of dissolved oxygen taken up by organic matter in the water.
More serious are the suspended solids. These can, as they settle out, completely coat the bottom of receiving streams. Predominantly organic, they also reduce the oxygen contents of receiving waters either through their direct oxidation or through respiration of the large microbial populations that use them as culture media.
For the trout and salmon hatcheries mentioned above, each pound of dry feed results in 0.3 kg of settle able solids — that part of the total suspended solids that settle out of the water in one hour. Most of these materials have to be removed from the effluent before it is finally discharged. Typically, this is accomplished with settling basins of some type.
Operating Principles for Fish Hatchery Management
Hatchery management and reform will generally proceed from the following hatchery premise: The ideal hatchery removes as many random mortality effects as possible without having any other influence on the natural life or experience of native fish and their habitats.
The hatchery premise has five main components that managers shall strive to incorporate into hatchery programs:
Removing random mortality occurring in the natural environment;
Simulating selective mortality operating in the natural environment;
Minimizing artificial selection;
Providing fish rearing and training experiences to reduce unnatural behaviors; and
Minimizing ecological impacts associated with hatchery operations (e.g., competition and predation associated with release location and number, pathogen transfer and amplification, pollutants, passage barriers, over harvest of weak stocks in mixed stock fisheries).
Success moving toward the premise in subsection (1) will be largely dependent on funding, research, program type, and facility or operating flexibility.
Hatchery program management plans shall be developed and implemented in consultation and cooperation with management partners and the public, and in coordination with native fish conservation policy plans at local and regional scales.
Hatchery programs shall be managed to provide optimum fishery and conservation benefits, based on the best available scientific information. Most programs will contribute toward fish management objectives primarily by raising fish for harvest while minimizing the impact on, or benefiting, fish that spawn naturally.
Hatchery facilities shall be operated to maximize fish quality and minimize adverse impacts to watersheds, consistent with fish management objectives, applicable permits and agreements.
Monitoring and evaluation shall be adequate to measure progress toward fish management and hatchery program objectives, contain risks within acceptable limits, and provide feedback for adaptive management.
In summary, originally devised to mitigate for fish production lost through development and supply the demand for fishing from an expanding human population, fish hatcheries have been criticized for producing poor quality or genetically inferior fish.
Several researchers have raised concerns about hatchery fish potentially breeding with wild fish. Hatchery fish may in some cases compete with wild fish. There is debate among the scientific community regarding the risks and benefits of hatchery programs.
Proving negative (or positive) effects of hatchery programs on wild fish is challenging due to numerous other environmental and anthropogenic factors that simultaneously affect fish.
In the United States and Canada, there have been several salmon and steelhead hatchery reform projects intended to reduce the possibility of negative impacts from hatchery programs. Most salmon and steelhead hatcheries follow up to date management practices to mitigate potential risks.
A fish hatchery is a place where large numbers of fish eggs are artificially fertilized and fry and are hatched in an enclosed environment.
Fish hatcheries can increase a fish population quickly but in the wild only 2% of the eggs survive (versus 80% using a hatchery).
Some hatcheries raise the fry until they reach adulthood and have commercial value; others release the fry into the wild with the intent of building up the wild stock. The hatchery phase is often the aspect that limits aquaculture expansion.
Generally, three types of pollutants are discharged from hatcheries:
(l) Pathogenic bacteria and parasites;
(2) Chemicals and drugs used for disease control;
(3) Metabolic products (ammonia, feces) and waste food.
Pollution by the first two categories is sporadic but nonetheless important.The third category of pollutants — waste products from fish and food — is a constant feature of hatchery operation, and usually requires permanent facilities to deal with it.
Operating Principles for Hatchery Management outline the standard operating procedure for successful hatchery.
Terms Associated With Fish Hatchery
Aquaria species: means those fish commonly sold in the pet store trade for use in home aquaria. “Aquaria” are any tanks, pools, ponds, bowls or other containers intended for and capable of holding or maintaining live fish and from which there is no outfall to any waters of this state.
Brood stock:means a group of fish, generally from the same population that are held and eventually artificially spawned to provide a source of fertilized eggs for hatchery programs.
Disease: means problems caused by infectious agents, such as parasites or pests, and by other conditions that impair the performance of the body or one of its parts.
Fish Hatchery: means a facility at which adult brood-stock are held, or where eggs are collected and incubated, or where eggs are hatched, or where fish are reared.
Hatchery produced fish:means a fish incubated or reared under artificial conditions for at least a portion of its life.
Hatchery production system:means the fish, facilities and operations associated with collecting, spawning, incubating, rearing, distributing and releasing hatchery produced fish.
Hatchery Program: means a program in which a specified hatchery population is planted in a specified geographical location.
Native fish: means indigenous to Oregon, not introduced. This includes both naturally produced and hatchery produced fish.
Naturally produced: means fish that reproduce and complete their full life cycle in natural habitats.
Natural production system: means the fish and environment associated with completing the life-cycles of naturally produced fish populations.
Production: means the number fish raised in a hatchery or resulting from natural spawning and rearing in freshwater, estuarine, or ocean habitats; also used in reference to harvest.
Propagation of fish: means the spawning, incubating, and/or rearing of fish by a human for sale, release or other uses.
Random mortality:means fish mortality that generally does not affect the genotypic or phenotypic traits of fish populations.
Selective mortality:means fish mortality that generally affects the genotypic and phenotypic traits of fish populations.
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