Concerns rise over decline of indigenous fish species in Pokhara

Pokhara, often referred to as the ‘Garden City of Lakes’ in Nepal, boasts a picturesque landscape adorned with nine lakes. Each of these lakes, including the renowned Fewa, holds significant ecological value, contributing to a well-balanced and diverse ecosystem within the valley. The Lake Cluster of Pokhara Valley, which includes all nine lakes, have been designated as a Ramsar site, recognizing their global importance as wetland areas.

As a world-renowned wetland, the lakes in Pokhara host a rich array of aquatic plants and animals. Among these, fish play a pivotal role as indicators of the overall ecosystem health. However, recent trends indicate a diminishing importance of these lakes in sustaining connections with indigenous plants and insects. The decline in the number of local fish species within these lakes has been alarming. Notably, vital plants like Lotus are experiencing a sharp decline, contributing to the proliferation of polluted vegetation such as water hyacinth, which covers the lake's surface.

Compounding these ecological concerns is the shift in the economic activities of local communities. In the past, residents were engaged in the trade of indigenous and medicinally valued fishes like Baam, Bhittye, Fageta, and Shahar. However, this traditional practice is undergoing a transformation, with hybrid fish varieties like Nile Tilapia and Mahur replacing the high-value indigenous species.

“The significance of the fish in these lakes today has been reduced to merely a business,” said Birendra Dhakal, a local resident of Rupa Lake, expressing his concerns over the noticeable invasion of unnecessary plants and hybrid fishes in the lake.

Dhakal’s sentiments echo those of many residents around the lakes of Pokhara, all deeply troubled by the threat to the indigenous species of fish and medicinal plants and various other aquatic life in the lake’s watershed area. Rajan Jalari, a seasoned fisherman from Fewa Lake, highlighted the surprising surge in the number of hybrid fishes in the lake over recent years. Raja, who belongs to the Jalari community engaged in fisheries for generations, said he too has no option but to sell hybrid varieties like Nile Tilapia which don’t fetch good prices. “To break free from relying on selling hybrid varieties, I am contemplating setting up my own fish cage in the lake. This way, I hope to nurture local fish varieties,” he shared.

According to local fishermen, nearly all the lakes in Pokhara and surrounding areas have seen proliferation of hybrid varieties, particularly Nile Tilapia. The presence of Tilapia has had a detrimental impact on the native fish species, creating competition for both food and habitat. The prolific breeding capacity of Nile Tilapia has affected indigenous varieties in lakes in Pokhara.

Jhalak Jalari, who leads the Begnas Fisheries Association, said Nile Tilapia now constitutes nearly half of the total fish population in the lakes. “This number might increase further in the days to come,” Jhalak added.

The concern over the decline in local fish populations is not only shared by the locals but is also substantiated by the Fisheries Research Station,Pokhara. According to the station, it has been hatching a high number of fish fries belonging to local species such as Rahu, Sahar and Naini, etc, and releasing them into the lakes every year. “However, the population of these local fish varieties is not growing as expected,” said Dr Akbal Husen, the Fishery Scientist and Chief of the Fishery Research Station, Pokhara.

Dr Husen attributed slow growth of local fish population to the lack of plankton in the water which serves as both food and a crucial habitat for the hatch of local fishes. “The presence of a large number of exotic fish, particularly Nile Tilapia, exacerbates the issue. As a hybrid fish, Nile Tilapia poses a threat by preying on small fishes, including fries, and competes for food with other fish species,” he said.

He said enhancing plankton levels in the water by maintaining a pollution-free environment and avoiding pesticide use in the watershed area is one of the solutions to mitigate this problem.