Invasive Species
According to the International Union for Conservation of Nature (IUCN), 14 of the world’s 100 worst invasive alien species are found in Turkey. These species pose serious threats to native ecosystems, biodiversity, and local livelihoods.
The species identified in Turkey include:
Mosquitofish (Gambusia holbrooki)
Comb Jelly (Mnemiopsis leidyi)
Veined Rapa Whelk (Rapana venosa)
Israeli Carp / Prussian Carp (Carassius gibelio)
Zebra Mussel (Dreissena polymorpha)
Water Hyacinth (Eichornia crassipes)
Killer Algae (Caulerpa taxifolia)
Rainbow Trout (Oncorhynchus mykiss)
Crucian Carp (Carassius carassius)
Mozambique Tilapia (Oreochromis mossambicus)
Nutria (Myocastor coypus) – also known as “water monkey” in Turkish
Red-Eared Slider Turtle (Trachemys scripta elegans) – often referred to as the Singapore Turtle
Black Rat (Rattus rattus)
African Catfish (Clarias gariepinus)
The most dangerous invasive species in our region are listed below:
FISH
Eastern Mosquitofish (Gambusia holbrooki)
Originally introduced from America in the 1930s to fight mosquitoes, this small fish has spread across many Turkish water bodies. Its rapid reproduction and aggressive nature have threatened native fish, amphibians, and aquatic invertebrates, especially endemic species like Aphanius.
Prussian Carp (Carassius gibelio)
Native to Asia, this carp was introduced for fish stocking but quickly spread. It reproduces quickly, competes with local species, and has caused native species to disappear in many lakes and reservoirs.
Rainbow Trout (Oncorhynchus mykiss)
Brought from North America for fish farming, it has spread into wild rivers and lakes. It outcompetes native trout and affects other aquatic life due to its strong predatory behavior.
Big-Scale Sand Smelt (Atherina boyeri)
Though native to seas, it became invasive in freshwater environments. It spreads quickly and disrupts food chains, mainly by feeding on zooplankton.
Redbelly Tilapia (Coptodon zillii)
Introduced for aquaculture and weed control, this herbivore alters local plant life and affects spawning habitats of native species.
AQUATIC PLANTS
Brown Beetle Grass (Diplachne fusca)
A fast-spreading grass found near dams and rice fields. While sometimes used for erosion control, it disrupts native agriculture and spreads aggressively.
INVASIVE LAND PLANTS
Black Locust (Robinia pseudoacacia)
Initially used in landscaping, this tree spreads quickly and dominates natural forests. Its nectar-rich flowers impact local pollination patterns.
Giant Pigface (Carpobrotus acinaciformis)
A popular ornamental plant, now invasive along coasts. It displaces native species, especially in sandy habitats.
Tree of Heaven (Ailanthus altissima)
Known for its rapid growth, this tree releases toxins that prevent other plants from growing, making it a serious forest invader.
MAMMALS
Black Rat (Rattus rattus)
Originally from India, spread via ships. Found across Turkey, it spreads disease and damages crops and property.
BIRDS
Rose-Ringed Parakeet (Psittacula krameri)
First recorded in Ankara in 1976, this bright green bird has now spread to many cities. It competes with native birds and damages crops.
MARINE SPECIES
Elongated Pufferfish (Lagocephalus sceleratus)
Arrived via the Suez Canal. Extremely toxic to humans and harmful to marine life, especially mollusks. Its presence has grown, especially in the Aegean and Mediterranean.
Upside-Down Jellyfish (Cassiopea andromeda)
Also migrated via the Suez Canal. Causes skin irritation and impacts coastal tourism.
Nomad Jellyfish (Rhopilema nomadica)
Feeds on shrimp and fish larvae, disrupting food chains. Large swarms cause problems for swimmers and fishers.
White-Spotted Jellyfish (Phyllorhiza punctata)
Consumes large amounts of zooplankton, impacting other marine species.
Dusky & Marbled Spinefoot (Siganus luridus & Siganus rivulatus)
Herbivorous and venomous, they damage native marine plants and pose risks to fishers. Still valuable in local fisheries.
Oilfish (Ruvettus pretiosus)
Contains toxins that can cause serious digestive issues in humans. Its consumption is banned in some countries.
OTHER SPECIES
Stinging Hydroid (Macrorhynchia philippina)
Forms painful stings in shallow waters. Common in the Mediterranean.
Blotchfin Dragonet (Callionymus filamentosus)
A venomous fish now found in the Mediterranean. Less dangerous but still invasive.
This growing list of invasive species highlights the urgent need for monitoring and control programs to protect Turkey’s unique biodiversity and ecosystems.
