{"id":4091,"date":"2026-04-16T09:52:00","date_gmt":"2026-04-16T09:52:00","guid":{"rendered":"https:\/\/climatevdo.com\/?p=4091"},"modified":"2026-04-20T19:53:38","modified_gmt":"2026-04-20T19:53:38","slug":"from-carp-to-hippos-43-of-large-freshwater-animal-species-spread-far-beyond-native-ranges","status":"publish","type":"post","link":"https:\/\/climatevdo.com\/?p=4091","title":{"rendered":"From carp to hippos, 43% of large freshwater animal species spread far beyond native ranges"},"content":{"rendered":"
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From fish and turtles, to hippos and crocodiles, about 43% of all known large freshwater animal species have been deliberately introduced into ecosystems outside their native ranges, a recent study<\/a> finds<\/span>.<\/p>\n

Most species were introduced to boost fisheries, food security or tourism, but many have had unintended consequences for local wildlife, habitats and people.<\/p>\n

Fengzhi He, the study\u2019s co-author, told Mongabay this research stemmed from his earlier work documenting where large freshwater animal species, weighing more than 30 kilograms (66 pounds), occur globally. He noticed many were present outside their native ranges.<\/p>\n

\u201cI realized the complex interactions between alien freshwater megafauna and people and started this project together with our colleagues,\u201d said He, a freshwater ecologist at the Chinese Academy of Sciences\u2019 Northeast Institute of Geography and Agroecology.<\/p>\n

Of the 216 known large freshwater animal species, 93 have been introduced in rivers, wetlands and lakes outside their native ranges, the study found. These introductions span 142 countries and regions.<\/p>\n

Most introductions were to improve fisheries and aquaculture. For example, large fish like common carp (Cyprinus carpio<\/em>) have been introduced to more than 100 countries, while African catfish (Clarias gariepinus<\/em>) are now in more than 30 countries. \u201cTheir introductions have been documented for many years in some regions and have become an important part of local aquaculture,\u201d He said.<\/p>\n

Species like the Siamese crocodile (Crocodylus siamensis<\/em>), Nile crocodile (Crocodylus niloticus<\/em>) and spectacled caiman (Caiman crocodilus<\/em>) have been introduced in China for leather farming. Certain turtles, river stingrays<\/a>, crocodilians and large fishes have been introduced for the pet trade.<\/p>\n

Many introduced animals, while bringing benefits, have also harmed the local wildlife and communities. For example, Nile perch (Lates niloticus<\/em>), introduced in Lake Victoria for fisheries, caused dramatic declines<\/a><\/span> in many small native fish, leading to economic hardship and reduced food security for local people, He said.<\/p>\n

Similarly, hippos introduced in Colombia boosted tourism, but they also pose a safety risk for people living or working nearby, He added.<\/p>\n

\u201cWe noticed that the detrimental impacts posed by alien freshwater megafauna often affect people who neither introduce freshwater megafauna nor benefit from their introduction,\u201d He said, adding that it\u2019s important to consider different groups of people when assessing impacts of introduced species.<\/p>\n

Overall, the researchers found that the benefits of introduced species are better documented than their harms.<\/p>\n

\u201cIt is probably because benefits, including enhanced food supply, provision of materials, pet trade, and recreational fishing, can be relatively easy to observe and measure. For example, data on economic activities is often available in published financial reports,\u201d He said. \u201cHowever, measuring detrimental [impacts], particularly complex indirect impacts that affect social interactions and human health, often requires more effort and long-term monitoring.\u201d<\/p>\n

The authors expect that large animal introductions for aquaculture, the pet trade and recreational fishing will continue to grow, making it essential to understanding their likely impacts.<\/p>\n

Banner image: <\/em><\/strong>The British introduced the Nile perch to Lake Victoria\u2019s waters. Image by Global Environment Facility via\u00a0<\/em>Flickr <\/a>(CC BY-NC-SA 2.0<\/a>).<\/em><\/p>\n

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From fish and turtles, to hippos and crocodiles, about 43% of all known large freshwater animal species have been deliberately introduced into ecosystems outside their native ranges, a recent study finds. Most species were introduced to boost fisheries, food security or tourism, but many have had unintended consequences for local wildlife, habitats and people. Fengzhi […]<\/p>\n","protected":false},"author":1,"featured_media":4092,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"class_list":["post-4091","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-nature-biodiversity"],"_links":{"self":[{"href":"https:\/\/climatevdo.com\/index.php?rest_route=\/wp\/v2\/posts\/4091","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climatevdo.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/climatevdo.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/climatevdo.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/climatevdo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4091"}],"version-history":[{"count":1,"href":"https:\/\/climatevdo.com\/index.php?rest_route=\/wp\/v2\/posts\/4091\/revisions"}],"predecessor-version":[{"id":4093,"href":"https:\/\/climatevdo.com\/index.php?rest_route=\/wp\/v2\/posts\/4091\/revisions\/4093"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/climatevdo.com\/index.php?rest_route=\/wp\/v2\/media\/4092"}],"wp:attachment":[{"href":"https:\/\/climatevdo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4091"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/climatevdo.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4091"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/climatevdo.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4091"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}