Fish farming has been around for over 100 years, with the first commercial fish farms occurring in 1853. The first commercial fish farm produced rainbow trout. While the operation was not a massive endeavor, it wasn’t long before fish farming had become a commercial success. By the early 1950s, large scale commercial operations geared towards food production.
Many fish have been able to be farmed, providing consistent fish as food for decades. It’s estimated that about half the world’s consumption of fish is due to animals being produced on fish farms. But what exactly is a fish farm? And can all fish be farmed? Today we’re finding out if walleye, a favorite North American fish, can be farmed or not. Farm Raised
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What is a Fish Farm?
A fish farm is an establishment that creates artificial environments to raise fish for pond stocking and consumption purposes. There are several different methods of fish farming, ranging from enclosures placed in natural environments, to man-made waterways meant to house populations of fish that are being raised.
Classic Fry Farming
Classic fry farming is the oldest method of fish farming, where sportfish species are raised from eggs in captivity, but are then released back into the wild. Typically, these juvenile fish are released into streams, or into ponds and lakes meant for sport fishing primarily.
Cage Systems
Cage systems are most often used for saltwater fish that need larger areas to be raised, utilizing cages in offshore environments. These cages contain fish that are fed until they reach the optimal size for harvesting, when they are then removed for food production. These run the highest risk of farmed fish being released into the wild accidentally, and as such there are more restrictions in place for them.
Irrigation Ditch and Pond Systems
When you think of a fish farm, this is most likely the method of farming that comes to mind. Irrigation ditches are filled with fish that are artificially fed, and the waste that these fish produce is used as fertilizer for farmers’ fields. On a larger scale, fish are farmed using a pond, either naturally existing or manmade, and the ecosystem is self-sustaining, but monitored to foster growth when needed.
A version of the pond system exists called composite fish culture that allows both farmed fish and native fish to coexist in the same pond. Farmed fish are selected based on coexistence, and competition for food is reduced through selective stocking.
Integrated Recycling Systems
This is perhaps the most complex version of fish farming available today. In this fish farming method, large plastic tanks are positioned in a greenhouse. Near these plastic tanks there are hydroponic beds. Waste water from the fish tanks is circulated from the fish tanks into the hydroponic beds to provide nutrients that allow the plants to thrive.
Popular Species of Farmed Fish
The most popular species of fish for farming are:
- Carp
- Catfish
- Cod
- Salmon
- Tilapia
- Trout
Fish farming is a complex industry, with more options available than just the four listed above. There are many different systems in each type of fish farming, allowing for the production of sportfish and fish for consumption.
The Walleye’s Preferred Habitat
Walleye are freshwater fish that can be found in lakes and rivers in most of North America. Their range, since introduction into non-native waters, begins as far south as Georgia and Alabama, stretching north into Canada and the Arctic. Walleye can be found from coast to coast.
No matter what kind of water they’re in, walleye prefer rock or gravel bottoms, with high turbidity in the water. During the spring, especially during spawning season, walleye like to inhabit shallow waters, usually no more than 15 feet in depth. In rivers, that depth is normally about 2 feet. During the summer, when temperatures rise, they move to deeper water to escape the higher water temperatures. This is when they’re slowest, as well. Then, as temperatures cool slightly in the beginning of fall, activity increases again. When temperatures become too cool, walleye will become dormant once again, reserving their energy for the winter to come.
In rivers, walleye prefer a strong current and fast moving waters with slower areas for resting. Often, walleye will sit in these slow moving pools and wait for prey to float downriver to them. When living in lakes and ponds, walleye will occupy waters near where waters are fed, like the mouths of creeks and rivers. They’ll also cruise the lake just above the bottom, looking for prey in weed beds and in shallow waters.
What Walleye Like to Eat
In the wild, walleye like to eat nearly anything smaller than they are. They’re predatory in nature, and will follow their food through bodies of water as needed. Juvenile walleye will eat small invertebrates and small fish like fathead minnows and fry of other fish species. Larger, adult walleye, will eat fish smaller than themselves. They prefer yellow perch and minnows, but will eat any fish they can eat, as they have been caught with numerous species in their stomachs.
When fish and insects are scarce, walleye will resort to eating snails, crayfish, frogs, and small mammals that are unlucky enough to find themselves in the water. While walleye are effectively predatory bottom feeders, they differ from other bottom feeders like catfish, who will eat nearly anything presented to them.
Are Walleye Able to Be Raised in Captive Conditions?
Walleye are able to be raised in captive conditions at this point in time, though, with less success than that of other fish. They can be raised in cages, tanks, or ponds, but have much higher maintenance needs than that of many other farm-raised fish. Additionally, there are issues in terms of viability when raising walleye on farms.
For one thing, walleye are highly predatory. They need to feel that they are chasing their prey, and won’t blindly eat anything given to them. Because of this, they don’t tend to fare well in captive conditions. If they are doing well, they’re highly expensive to keep, unless living in a natural environment where prey is readily available, such as a composite fish culture. This dietary restriction makes them fairly prohibitive to raise in captive conditions.
What’s more is the spawning behaviors of walleye. While they can be coaxed into spawning in areas that they’re not familiar with, it’s something that’s not easily done. Walleye return to the same spawning grounds year after year. This need to migrate can create adverse conditions when spawning grounds aren’t accessible to the fish.
Additionally, walleye are highly photosensitive, needing specific habitat requirements to truly thrive. If they are not given an area with deep enough waters to hide from light, or waters that are high in turbidity, they won’t feed and they certainly won’t spawn. This can be circumvented by raising them in ponds and lakes, but the ecosystem has to be set up accordingly for them to thrive.
Farm-Raised Walleye on the Horizon
While they have highly specialized needs and habitats, walleye farming seems to be on the horizon with developments made in recent years. Farms that are working with walleye have been able to produce 14-inch fish in the span of 12 months, meaning that raising fry is not an issue. The real boundary that presents itself with farm-raised walleye is their spawning. Walleye only produce one clutch of eggs per year. Because of this, it’s difficult to maintain a population and continue to produce walleye without some form of genetic modification. For now, while walleye can be farm-raised, it doesn’t look to be financially promising until more breakthroughs are had.
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Sources
- Fish Farms | Fish Farming Information and Resources
- Raising Walleye
- Midwest turns hungry eyes toward farmed walleye
- Walleye and saugeye growing successfully indoors « Global Aquaculture Advocate
- lakescientist.com Walleye
- Walleye – Freshwater Fish of America
- nwf.org Walleye
- Walleye: Everything You Ever Wanted to Know