Description

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Context:

Recently, National Green Tribunal (NGT) had issued notice to the Centre
because the centre planned to use 2 invasive fish species, Gambusia Affinis (Mosquitofish) and Poecilia Reticulata (Guppy), for mosquito control in water bodies in India.
There are also concerns that the release of these species into local water ecosystems can potentially cause ecological harm.

Invasive Fish Species

Species	Common Name	Purpose	Native Range	IUCN Status
Gambusia Affinis	Mosquitofish	Used for biological mosquito larvae control	Native to the Mississippi River Basin, USA	Least Concern
Poecilia Reticulata	Guppy, Millionfish, Rainbow Fish	Used for mosquito larvae control	Native to Northern South America and Caribbean	Least Concern

Characteristics of Invasive Fish Species

Gambusia Affinis (Mosquitofish)

Purpose: A biological agent for mosquito larvae control.
An adult Mosquitofish consumes 100-300 mosquito larvae per day.
Habitat: Found in freshwater and tolerates brackish water with high salinities.
Adaptability: Can survive in low oxygen
Reproduction: Viviparous (gives birth to live young).
Invasiveness: Considered one of the 100 worst invasive alien species by the International Union for Conservation of Nature (IUCN).
Historical Use: Introduced to India in 1928 during British rule for mosquito control.

Poecilia Reticulata (Guppy)

Purpose: Also used for controlling mosquito larvae.
Habitat: Found in shallow pools and streams.
Invasiveness: Although widely used for mosquito control, it poses a threat to native biodiversity.

States Involved in Fish Release

Fish Species	States Where Released
Gambusia Affinis (Mosquitofish)	Assam, Arunachal Pradesh, Gujarat, Karnataka, Maharashtra, Rajasthan, Tamil Nadu, Uttar Pradesh, Odisha, Punjab, Andhra Pradesh.
Poecilia Reticulata (Guppy)	Maharashtra, Karnataka, Punjab, Odisha.

Concerns Regarding Invasive Fish Species

Invasive Species Definition:
- Non-native organisms spread rapidly and harm local ecosystems.
- They always outcompete indigenous species, leading to ecological damage.
Ecological Impact:
- Threat to Native Fish: Invasive species like the Mosquitofish and Guppy compete for food and habitat, which can lead to food scarcity for indigenous fish species.
- Biodiversity Loss: These invasive species can cause the decline or extinction of native species by altering the natural balance of the ecosystem.
- Ecosystem Disruption: The introduction of non-native species disrupts food chains and can have cascading effects on the entire aquatic ecosystem.

Examples of Other Invasive Species in India

Flora	Fauna
Lantana camara	African Catfish (Clarias gariepinus)
Parthenium hysterophorus	Tilapia (Oreochromis mossambicus)
Prosopis juliflora	Giant African Snail

Concerns Raised by the NGT

Biodiversity Risks: The release of Gambusia Affinis and Poecilia Reticulata in multiple states poses significant risks to local biodiversity.
Widespread Distribution: Both species have already been released in several regions, leading to concerns over their uncontrolled spread and potential damage to the environment.

Conclusion

The National Green Tribunal (NGT) has raised important questions regarding the ecological consequences of using invasive fish species like Gambusia Affinis (Mosquitofish) and Poecilia Reticulata (Guppy) for mosquito control. While these species are effective in controlling mosquito larvae, their potential to disrupt local ecosystems and outcompete native species raises significant environmental concerns.

Source:

Deccanherald

Practice Question:

Q. With reference to the use of invasive fish species for mosquito control, consider the following statements:

The National Green Tribunal (NGT) has raised concerns about the ecological harm caused by releasing Gambusia Affinis (Mosquitofish) and Poecilia Reticulata (Guppy) into local water bodies.
Gambusia Affinis and Poecilia Reticulata are both native to India and have been used historically for mosquito control.
The introduction of these fish species has caused no significant impact on native fish populations or biodiversity in the affected states.

Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (a)
Explanation:
Statement 1 is correct: The NGT has indeed raised concerns about the ecological consequences of using invasive fish species like Gambusia Affinis and Poecilia Reticulata for mosquito control, particularly regarding their impact on local ecosystems and biodiversity.
Statement 2 is incorrect: Both Gambusia Affinis and Poecilia Reticulata are non-native species to India. They were introduced to the country for mosquito control purposes.
Statement 3 is incorrect: The introduction of these species has caused significant ecological harm, including threats to native fish populations and biodiversity due to their invasiveness.