Nepedia
Back to Discover
Advanced Reader
💻

Fish hatchery

technology Maturity 5-7 Next article →

A fish hatchery is a specialized facility used for the artificial breeding, hatching, and rearing of aquatic animals. These facilities focus primarily on finfish and shellfish, such as salmon, shrimp, oysters, and scallops. The main goal is to produce larval and juvenile stages of these species. These young animals are then transferred to on-growing systems, like fish farms, to reach a harvestable size. This process supports the global aquaculture industry, which was valued at approximately US$98.4 billion in 2008.

Shrimp hatchery
Shrimp hatchery

While China dominates this market, hatcheries also play vital roles in conservation and small-scale farming.

The production process begins with broodstock conditioning. Broodstock are the adult animals used for breeding. To prepare them for spawning, workers keep them in flow-through tanks. These tanks provide optimal light, temperature, salinity, and food. This conditioning helps develop the animals' gonads, which are the organs that produce eggs and sperm. High levels of lipid reserves in the mother are especially important for egg quality. Good nutrition ensures that the larvae have a better chance of survival once they hatch.

Colorado Pikeminnow spawn 05-25-05 (62)
Colorado Pikeminnow spawn 05-25-05 (62)

Next, the hatchery must induce spawning to collect gametes. Spawning is the release of eggs and milt, which is the sperm from males. Sometimes, hatcheries rely on natural seasonal cycles. Other times, they use manual stripping to extract gametes. For fish, this involves stroking the animal under the pectoral fins to release eggs and milt.

Workers can also use environmental manipulation. For example, thermal shock involves alternating cool and warm water to mimic natural changes. Chemical injection using hormones is another method to trigger spawning. Once collected, eggs are washed to remove bacteria and then fertilized. To maintain genetic diversity, workers often use milt from several different males.

After fertilization, the tiny larvae enter the nursery stage. Nurseries are areas designed to rear larvae into juveniles. These can be land-based tanks or sea-based systems. For fish, the nursery is usually closely associated with the hatchery. For shellfish, nurseries often exist separately.

Scotland Inchnadamph Assynt Hatchery
Scotland Inchnadamph Assynt Hatchery

Maintaining high water quality is essential for juvenile survival. Feeding is also a massive task. Many species require live prey, such as rotifers or Artemia nauplii, to grow. Because producing this live food is labor-intensive, it is one of the largest costs for a hatchery.

CapilanoRiverRegPark-salmonhatchery
CapilanoRiverRegPark-salmonhatchery

Shellfish follow a unique developmental path involving a settlement phase. After hatching, the larvae swim freely in the water. They eventually look for cues like water flow, temperature, or chemical signals from adults. These signals tell them where to find a suitable substrate, or a surface to attach to. Once they settle and undergo metamorphosis, they are known as spat.

These spat are then moved to on-growing facilities to complete their growth.

Hatcheries provide several critical benefits to the aquaculture industry. First, they allow for out-of-season production. By conditioning broodstock, hatcheries can extend the natural spawning season. They can also source stock from the opposite hemisphere to ensure a steady year-round supply. Second, hatcheries allow for genetic improvement. Through selective breeding or hybridization, scientists can improve growth rates, disease resistance, and survival.

RV Celtic Explorer, Galway Bay, Ireland
RV Celtic Explorer, Galway Bay, Ireland

Finally, hatcheries reduce the need to catch wild juveniles. In 2008, aquaculture provided 46% of the total food fish supply, or about 115 million tonnes. Using hatchery-reared juveniles is a more sustainable way to meet growing food demands.

Despite these benefits, hatcheries face complex challenges. Genetic issues are a major concern. If a hatchery uses too few adults, it can lead to inbreeding depression. Additionally, hatchery-reared fish may have less genetic diversity than wild populations. If these fish escape into the wild, they might affect the genetics of native species. There are also environmental concerns regarding fish farms, such as disease prevalence and the impact of supplemental feed. Managing these biological and economic factors is a key part of modern aquaculture science.

638 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (9)
File:Global thinking.svg
Global thinking.svg
File:Alaminosjf403.JPG
Alaminosjf403.JPG
File:Scotland Inchnadamph Assynt Hatchery.jpg
Scotland Inchnadamph Assynt Hatchery.jpg
File:Trawer Hauling Nets.jpg
Trawer Hauling Nets.jpg
File:CapilanoRiverRegPark-salmonhatchery.jpg
CapilanoRiverRegPark-salmonhatchery.jpg
File:RV Celtic Explorer, Galway Bay, Ireland.jpg
RV Celtic Explorer, Galway Bay, Ireland.jpg
File:Colorado Pikeminnow spawn 05-25-05 (62).JPG
Colorado Pikeminnow spawn 05-25-05 (62).JPG
File:Fish Packed in Ice.jpg
Fish Packed in Ice.jpg
File:Shrimp hatchery.jpg
Shrimp hatchery.jpg
More to explore

🔗 What's this?

Concepts mentioned in this article

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.