Catfish has white, mild-tasting meat and is sold both fresh and frozen, most often as steaks, skinless and boneless fillets and fillet strips, and as whole dressed fish. They tend to be processed immediately after being delivered live to a plant so freshness tends to be high. Stocks of catfish tend to be lowest during February or March, usually pushing prices higher then usual. Some processors have been known to abuse sodium tripolyphosphate solution, soaking catfish fillets in it to add moisture and weight, resulting in an inferior product and buyers should avoid fillets that are brown or gray in color. Catfish from ponds containing a certain type of algae will have an off flavor, so buyers recommend making sure the processor conducts regular taste tests before harvest.
Channel catfish are North America’s most abundant catfish species, and is the official fish of Kansas, Missouri, Iowa, Nebraska, and Tennessee. They are distinctive from other catfish due to their deeply forked tail and spotted body. They can grow to weigh more than 50 pounds; however, most are caught weighing up to 10 pounds. Most are between 12 to 24 inches long, although the largest recorded was 52 inches in length and weighed 58 pounds. Interestingly, catfish never stop growing; the older it is, the larger it will be.
Channel catfish spawn in the late spring or early summer. Males select nest sites in dark, secluded areas. Females deposit a gelatinous yellow egg mass at the bottom of the nest of 3,000 to 50,000 eggs, which the male guards for about a week until the eggs hatch. If the female comes near the nest after fertilization, she will eat the eggs. Fry remain in the nest with the father for another week. After another two to three weeks, the juveniles go their own way. They reach maturity in two or three years in captivity, and three to six years in the wild. The average lifespan of a catfish is 15 to 20 years.
Catfish are sometimes referred to as the “swimming tongue” because of their keen sense of taste. They have taste buds all over their external body surface, and inside their mouth, and as such, do not have scales. When the receptors are stimulated, particularly by amino acids released by prey, catfish barbells (whiskers) will move to orient the fish towards their food. They prey on a variety of foods, including terrestrial insects, minnows, shad, frogs, sunfish, crawfish, and freshwater drum. Large freshwater fish, such as flathead catfish and muskies, are predators to channel catfish.
Channel catfish are native to the southeastern United States and North America – ranging from the Gulf Coast states through the Mississippi Valley, north to Canada, and south to Mexico. They are now found nationwide as the species has been introduced into non-native rivers and lakes for sport fishing. As of 2017, channel catfish have been introduced in over 35 different countries primarily for aquaculture cultivation. In the wild, channel catfish inhabit freshwater, but are also known to survive in brackish water. They prefer clear water habitats with gravel, sand, or rubble bottoms in streams, lakes, and ponds. They will also tolerate mud-bottomed habitats.
Science & Management
A study done by the Virginia Institute of Marine Science running from 2010 to 2014 tested the use of various traps as an alternative means to commercially fish for catfish in tidal rivers, allowing bycatch and smaller catfish to escape. Traps made of coated wire mesh and steel rods, equipped with an entry funnel were fished alongside three strings of trotlines. The gear was proven to be a good improvement over trotline operations.
Hybrid catfish, a cross of channel and blue catfish, generally have better growth, higher survival rates, and better meat yield than purebred catfish; however, they are not easy to breed. The US Department of Agriculture (USDA) along with the Agricultural Research Service (ARS) in Mississippi study catfish nutrition, genetics, and management practices to produce a better catfish. Research includes improving hybrid embryo production and developing a method to identify poor quality eggs before they hatch. DNA markers for channel and blue catfish are being developed to determine genetic diversity, produce purebred populations, and identify markers associated with important traits (such as resistance to disease). The relationship between gene expression, catfish growth, and immune function is also being studied.
Channel catfish are one of the most economically valuable aquaculture species in the United States – with consumption steadily increasing over the last two decades. Catfish are primarily raised in the Gulf Coast states and southeastern US with the majority being raised in Mississippi, Arkansas, Alabama, and Louisiana.
While there is no national oversight agency for aquaculture in the US, management of US-based farms is considered to be strong and there are extensive regulations in place regarding predator controls, therapeutant use, and disease management. Permitting varies by state with numerous federal agencies providing some degree of oversight. These include:
The United States Department of Agriculture (USDA) – which is responsible for coordinating national aquaculture policy and providing industry with research, information, and extension services;
The Environmental Protection Agency (EPA) – which regulates waste discharge from aquaculture facilities;
The Fisheries and Wildlife Service (FWS) – which regulates the introduction and transport of fish; and,
The Food and Drug Administration (FDA) – the FDA’s Center for Veterinary Medicine is responsible for approving and monitoring the use of drugs and medicated feeds used in the aquaculture industry.
The FDA is also authorized to detain a import product that appears to be out of compliance with US food safety laws. As part of its regulation of aquaculture imports, the FDA requires all producers exporting to the US use a Hazard Analysis and Critical Control Points (HACCP) plan. The HACCP plan identifies and defines proper management and monitoring systems to ensure that only safe products enter the market. If the owner of the import fails to submit evidence that their product is in compliance, or cannot bring the product into compliance, the FDA refuses admission of the product. Between November 2005 and June 2013 the FDA refused 99 shipments of channel catfish from China due to noncompliance and concerns regarding veterinary drug residue and unsafe food additives.
The EPA determines permitting standards for controlling effluent load from aquaculture facilities. These effluents are subject to control by the National Pollution Discharge Elimination System (NPDES) of the Clean Water Act – which only applies to concentrated aquatic-animal production (CAAP) facilities. Most US catfish farms do not fall under the designation of a CAAP and are therefore exempt from federal NPDES permitting. In most catfish production states there is no required permitting for effluent discharge, but most discharge is infrequent and only occurs during periods of excessive runoff. Additionally, US-based farmers implement several best management practices to help improve water quality and reduce environmental impacts.
The Chinese government has invested heavily in channel catfish aquaculture and is making efforts to comply with global standards for environmental protection and food safety. Despite new financial investments and legislation as well as inspecting, licensing, monitoring, and educational assistance initiatives, there are significant issues regarding management and regulatory enforcement of catfish farms in China particularly at the provincial and local levels.
Chinese water quality regulations and effluent management are established and addressed by a number of national aquaculture-related laws in China including:
The Fisheries Law (2004) – which address the legal framework for wild and farmed fisheries;
The Water Law (2002) – which regulates the development, utilization, allocation, and management of water resources;
The Environmental Protection Law (1989) – which provides provisions on environmental impact assessment requirements; and,
The Law on the Prevention and Control of Water Pollution (1984) – which works to prevent and control pollution of water bodies
In addition to these national laws, provinces and regions may establish their own water quality and effluent laws; however, monitoring, inspection, and enforcement of these laws is lacking and as such, most farmers have not taken measures to comply with these regulations. Under guidance of the Ministry of Agriculture, the Chinese Bureau of Fisheries coordinates aquaculture enforcement – with enforcement being carried out by the Fisheries Law Enforcement Command of China. These enforcement agencies are regionally fragmented and there is little available evidence of monitoring and compliance data. The Ministry of Agriculture is also responsible for the licensing of aquaculture facilities in China, but due to the rural and small-scale nature of catfish farms, it is challenging for the Ministry to license each farm.
Numerous Chinese government agencies are involved in enforcing food safety regulations and significant financial investment has been made to improve food and drug safety. Despite these efforts, policies and investments are not translating to regulatory action at the provincial and local levels. Enforcement efforts are considered to be ineffective and repercussions for breaches in these regulations are often minor and not implemented.
Channel catfish are native to the southeastern United States and by law are the only ones that can be marketed as “catfish” in the U.S. Southeast Asian governments are currently promoting fish farming using rice field ponds to alleviate environmental pressure from the dense fish farms along the Mekong River. Chinese fish farmers have started to grow and export channel catfish, but conservation groups haven’t assessed the farms yet for environmental impacts, according to the Seafood Choices Alliance.
-United States: Channel catfish are raised in large clay ponds on converted agricultural land, primarily in Mississippi, Alabama, Arkansas, and Louisiana. These manmade freshwater ponds are self-contained and get high marks from environmental groups because they discharge little waste and have limited chemical use. The New England Aquarium notes that harvest from the ponds is year-round with the use of a large mesh seine so the only fish caught are market-size. Although the ponds are self-contained and produce little waste, the regulation of catfish farm effluent disposal isn’t strong and the disposal isn’t closely monitored. Heavy rainfall can cause ponds to overflow, releasing effluent into neighboring watersheds.
-Southeast Asia: Suspended cages and ponds are used to grow tra. Since ponds tend to be further from waterways, pond culture is considered less polluting than cages and fenced areas. Ponds can also be a way to effectively recycle nutrients and organic matter. Tra are grown in net cages along rivers in Vietnam, Thailand, and China with little government regulation of the farming operations, according to the Environmental Defense Fund. Waste from the cages that pack Vietnam’s Mekong Delta is discharged directly into waterways, adding to the already poor water quality in the region.
Catfish farms draw predatory birds, which have been killed legally and illegally by farmers. In the United States, the National Wildlife Research Center has experimented with nonlethal methods to scare away double-crested cormorants, including robotic alligators and lasers, but nothing has resulted in a lasting solution. The Institute also cites evidence of increasing antibiotic resistance among tra, posing a threat to human health.
Channel catfish are omnivores that are fed mostly grain-based vegetarian diets. Tra grow quickly with feed containing low fish meal content, usually pellets made from inexpensive locally-caught bycatch, juveniles, and trash fish. In Vietnam, the trend is toward grain-based feeds like the ones used by American farmers.
Escapes and Introduced Species
Tra is one of two catfish species native to Southeast Asia and is the hardier of the two, enabling them to be raised in higher densities. Risk to Wild Stocks: Since channel catfish are native to the U.S., escapes are not an ecological problem, according to the Environmental Defense Fund.