{"id":238591,"date":"2026-01-10T23:14:18","date_gmt":"2026-01-10T23:14:18","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/238591\/"},"modified":"2026-01-10T23:14:18","modified_gmt":"2026-01-10T23:14:18","slug":"it-survives-in-sewers-breathes-out-of-water-and-devours-the-eggs-of-native-fish-the-african-catfish-is-advancing-through-rivers-in-asia-south-america-and-europe-like-a-silent-biological-plague","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/238591\/","title":{"rendered":"It survives in sewers, breathes out of water, and devours the eggs of native fish: the African catfish is advancing through rivers in Asia, South America, and Europe like a silent biological plague"},"content":{"rendered":"

Capable of breathing out of water and producing up to millions of eggs, the African catfish is spreading through tropical rivers, causing local extinctions and worrying scientists.<\/p>\n

The advance of the African catfish is not remarkable for its size or appearance, but for the profound consequences it causes wherever it arrives. This is an extremely resilient, opportunistic, and adaptable fish, capable of surviving in environments where most native species simply cannot exist. This combination transformed the Clarias gariepinus It is one of the most problematic invasive species in tropical and subtropical river systems in recent decades.<\/p>\n

Originally distributed throughout much of Africa and the Middle East, the African catfish was introduced to other continents primarily through aquaculture, commercial fishing, and poorly planned animal protein production projects. From these introductions, it escaped into urban rivers, lakes, and canals, where it began to compete fiercely with local species.<\/p>\n

A fish that defies the limits of aquatic physiology.<\/p>\n

What makes the African catfish so dangerous is not just its predatory behavior, but its unusual biology. <\/p>\n

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Unlike most fish, it possesses an accessory respiratory organ that allows it to absorb oxygen directly from the air. In practice, this means it can survive for hours \u2014 and in some cases days \u2014 out of water, as long as its skin remains moist.<\/p>\n

This capability allows it to traverse flooded terrain, sewage canals, agricultural areas, and even urban stretches during periods of heavy rain. In tropical regions, records show individuals moving between isolated bodies of water, something impossible for native fish restricted to gill respiration.<\/p>\n

Furthermore, the African catfish tolerates extreme levels of pollution. It survives in waters with very low dissolved oxygen and a high organic load. presence of domestic sewage and industrial waste. Degraded environments, which would act as natural barriers for other species, become dispersal corridors for this fish.<\/p>\n

Explosive reproduction and numbers that explain the advance.<\/p>\n

The true driver of the invasion lies in reproduction. Adult female African catfish can produce, in a single reproductive cycle, between 100 and over 1 million eggsdepending on the size of the animal and environmental conditions. <\/p>\n

In favorable systems, with warm water and abundant food, the survival rate of juveniles is high.<\/p>\n

Reproduction occurs opportunistically, often associated with floods and rainy periods, when flooded areas function as natural nurseries. <\/p>\n

Under these conditions, the offspring grow rapidly and reach sexual maturity in a few months, creating successive cycles of population growth.<\/p>\n

This pattern explains why, in asome rivers of Asia and South AmericaIn the region, the density of African catfish increased abruptly in less than a decade, replacing entire communities of native fish.<\/p>\n

Generalist predator and destroyer of natural nurseries.<\/p>\n

The most serious ecological impact is on its diet. The African catfish is an extreme generalist predator. It consumes aquatic insects, crustaceans, mollusks, amphibians, small mammals, waterfowl, and, above all, fish.<\/p>\n

One of the most destructive behaviors is the direct predation of eggs and larvae of other species. By invading shallow areas used as spawning grounds, the catfish eliminates entire generations before the native fish even have a chance to grow. This effect is silent, but devastating.Populations collapse without large, visible mass deaths.<\/p>\n

Studies document local extinctions and abrupt declines in biodiversity in rivers where the African catfish has become dominant, especially in systems already strained by pollution, dams, and water withdrawal.<\/p>\n

From aquaculture to the global environmental problem.<\/p>\n

The expansion of the African catfish population is directly linked to its popularity in aquaculture. It grows quickly, accepts low-cost feed, tolerates high stocking densities in tanks, and exhibits good feed conversion. <\/p>\n

These characteristics led to its deliberate introduction into countries in Asia, South America, and even parts of Europe.<\/p>\n

The problem arises when breeding systems fail, floods break through ponds, or illegal dumping occurs. Once in its natural environment, control becomes extremely difficult. Unlike other invasive species, the African catfish does not depend on clean water or preserved habitats to establish itself.<\/p>\n

In urban areas, it finds refuge in highly degraded canals, storm drains, and rivers, functioning as a kind of “winner” in the face of environmental collapse.<\/p>\n

Why is control so difficult?<\/p>\n

Eradicating the African catfish after its establishment is virtually impossible. Traditional fishing methods rarely reduce populations effectively, as the species reproduces too quickly. Physical barriers also fail. since the fish is able to move across land under favorable conditions.<\/p>\n

Furthermore, the use of aquatic pesticides or selective poisons faces severe environmental risks, as it would affect remaining native species. In many countries, current strategies are limited to containment, monitoring, and attempts to prevent new introductions.<\/p>\n

The scientific consensus is clear: prevention is far more effective than trying to control it afterward. Once established, the African catfish permanently alters the ecological dynamics of the invaded ecosystems.<\/p>\n

A silent symbol of modern ecological collapse.<\/p>\n

The rise of the African catfish illustrates a pattern that is becoming increasingly common across the planet. Highly adaptable species thrive in degraded environments created by human activity, while specialized organisms disappear. Polluted rivers, open sewers, and urban canals cease to be dead zones and become territories dominated by resilient invaders.<\/p>\n

More than just a problematic fish, the African catfish acts as a biological indicator of environmental imbalance. Where it dominates, something fundamental has already been lost in the ecosystem.<\/p>\n

The expansion of this species across Asia, South America, and Europe shows that… biodiversity crisis<\/a> It doesn’t only occur in remote forests or coral reefs, but also in rivers that cross cities, farmlands, and industrial areas. And, in this scenario, the invasion happens silently, generation after generation, egg after egg.<\/p>\n","protected":false},"excerpt":{"rendered":"Capable of breathing out of water and producing up to millions of eggs, the African catfish is spreading…\n","protected":false},"author":2,"featured_media":238592,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[121022,121023,121024,61,60,121025,121026,82,263],"class_list":{"0":"post-238591","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-wildlife","8":"tag-avanco-do-bagre-africano","9":"tag-bagre-africano","10":"tag-bagre-africano-se-espalha-por-rios-tropicais","11":"tag-ie","12":"tag-ireland","13":"tag-praga-biologica","14":"tag-praga-biologica-silenciosa","15":"tag-science","16":"tag-wildlife"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/238591","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=238591"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/238591\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/238592"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=238591"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=238591"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=238591"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}