🔗 Share this article

Fish species that make mammoth journeys through freshwater systems are confronting a multifaceted threat from dams, pollution, and overfishing preventing them from reaching their spawning sites.

Examples including the Himalayan mahseer and goonch catfish are among thirty flagship species which have now been selected for global conservation by the United Nations in a new study.

"These aquatic species provide for countless numbers of communities worldwide, so for societies, they're incredibly vital," said a co-author biologist on the assessment.

A panel of global researchers assessed over 15,000 species of migrating freshwater species – which make up half of all fish species – and determined their abundance had fallen by an staggering 81% in the past 50 years.

The researchers argued that for too long, this class of species has been neglected but "represent an essential part of people's livelihoods."

Excessive Harvesting and Environmental Degradation

The shorter list is consists of fish that are both at risk and also valued culturally for worldwide societies.

"As an instance, the golden mahseer is an iconic fish of the Himalayas. Numerous people in that region esteem that fish for cultural and spiritual reasons that extend well past monetary values," commented a conservation specialist who worked on the study.

Like many fish on the roster, it is facing two major dangers: overfishing and environmental destruction.

"Habitat loss involves things like obstructions that divide a waterway, and can change the natural flow regime of a river, which causes fish not being able to connect to their spawning grounds," the expert said.

Obstruction to migratory routes is an challenge that is especially prevalent in Europe, where fish face a barrier to their paths frequently.

Often the barriers are minor structures that are redundant and could be eliminated, said an conservation charity lead.

But the cumulative consequence on migratory fish is enormous: "It can have a profound impact in terms of the resources fish are using to pass the [barriers]."

That leaves them more susceptible to illness. They're more prone to get eaten. They will breed in suboptimal locations."

Back from the Brink

Most species will cross national borders on their extensive journeys. This demands coordinated work between states to address these issues and ensure the restoration of local populations, said a report contributor.

The international conservation agreement is a worldwide United Nations convention signed in 1979 which commits nations to collaborate to conserve migratory species of many kinds.

The UN is now proposing that the thirty fish species be listed to the convention at its annual meeting in the coming years.

The Saiga antelope is an example of a species that has benefited from being protected under the treaty.

Following a population crash, an international conservation team was established and since then numbers have recovered significantly.

"Conservation efforts has traditionally been on some of the more visible species, such as big cats," stated a senior UN official.

She said it was now the opportunity of river fish to gain from coordinated action.