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Is the fall of Nile perch bad for Lake Victoria?

By Gerald Tenywa

Added 26th August 2017 02:08 PM

In an aquatic survey conducted between 1999 and 2002, there were about 1.6 million tonnes of Nile Perch. But this reduced to about 800,000 tonnes this year.

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In an aquatic survey conducted between 1999 and 2002, there were about 1.6 million tonnes of Nile Perch. But this reduced to about 800,000 tonnes this year.

For the first time, the Nile Perch, which established itself as a dominant fish in Lake Victoria about four decades ago, has lost the top position to the smaller fish species.

New Vision interacted with experts during the Great Lakes conference at Entebbe regarding the factors leading to the ‘coup’ in the lake, as well as the implications.

It came! It saw! It conquered! Julius Caesar’s words (Veni vidi vici) fit well in the Nile perch’s story in Uganda, only that something spectacular has just happened to the conqueror.

The Nile Perch dominance is no more. Tables have turned in favour of the small fish, such as mukene and Nkejje, also known as Haplochromines, according to Anthony Munyaho, the director of research at the National Agricultural Research Organisation (NARO).

The predating Nile perch was introduced by the colonialists into Lake Victoria about 60 years ago to get rid of the small fish, which were also referred to as trash fish. It thrived and has been the springboard for the fish export industries that were surrounding the lake in the three countries — Uganda, Kenya and Tanzania.

“There has been a silent coup,” Munyaho said, “These small fish were the dominant species when the Nile perch was introduced in the lake.

It overwhelmed them and became the king of the lake. But from our aquatic survey on Lake Victoria, we can now declare that the small fish have returned to be the most abundant.”

Munyaho made the remarks during the recent Great Lakes Conference at the Imperial Resort Beach Hotel, Entebbe.

The event was organised by the environment ministry, together with the UK-based The Nature Conservancy.

In an aquatic survey conducted between 1999 and 2002, there were about 1.6 million tonnes of Nile Perch. But this reduced to about 800,000 tonnes this year.

“It means that Nile Perch has reduced by half,” Munyaho said.

He attributed the reduction in stocks to over-fishing and said that the changing environmental conditions have helped the small fish to wrestle down the giant one.

Should we celebrate or cry?

Richard Kimbowa, the director of Uganda Coalition for Sustainable Development, said he does not know whether to celebrate or cry about the depletion of the Nile perch.

“From an economic view, it is bad to deplete the Nile perch,” Kimbowa said.

“It is a source of foreign exchange for the country as well as employment.”

However, he added that the Nile perch is not blameless. It caused a decline of the ecological diversity of the lake as most of the small fish were under predation.

Nevertheless, he pointed out that the future remains uncertain as the lake is changing as a result of environmental conditions.

“Is the Nile perch going to become extinct? Will the fish survive the changing environmental conditions?”

The Nile perch (lates niloticus) and the Nile tilapia (oreochromis niloticus) are native species to Lake Albert. The Nile perch was introduced into Lakes Kyoga and Victoria basins in the mid-1950s, but its presence in Lake Victoria was first noted in the 1960s.

However, it took more than 10 years to get fully established in the new ecosystem.

“The Nile perch is big. It grows up to 200kg, but the biggest fish caught in most of Uganda’s water bodies is about 40kg,” he says.

“The big fish are few and localised (stay in restricted areas) where there is no poaching. So the average weight of fish where there is free access to the lake is about 5kg.

Is the economy in trouble?

The Nile perch has for the last two decades been the hottest item in terms of fish export to the European Union.

However, the high demand for Nile Perch and its attractive revenue have worked against East Africa’s most charismatic fish species.

“As a result, most fish factories set up to export Nile perch closed in recent years, meaning Uganda no longer gets limited foreign exchange from fish,” Munyaho said.

According to President Yoweri Museveni, illegal fishing has caused enormous loss to the country, noting that out of the 21 fish factories that were operational 10 years ago, only eight are operating today.

“The 21 factories were processing a total of 36,614 tonnes of fish per year, worth $144m (about sh517.3b). Today, the surviving factories earn only $123.1m (about sh441.5b). They were employing 5,600 permanent workers, and the ones surviving today are employing 2,200 permanent workers,” Museveni said.

In neighbouring Kenya, only one factory remains operational out of 17 that were previously churning out fish for export.

Protect the catchment

Although the catching of Nile perch has declined, we have not seen an extinction of the Nile perch, according to Munyaho.

This means that if fishing pressure on the lake is reduced, the Nile perch will thrive again in Lake Victoria and help to revive the economy.

As the catchment gets degraded and unsustainable farming in the catchment takes its toll on the lake, most conservationists say the lake is dying. Munyaho differs with this popular view.

“It is an overstatement to say that Lake Victoria is dying,” he said, “Lake Victoria is a big basin; it is only about a metre from the lakeshore that is polluted.

Fish breeds on the shores, but Nile Perch prefers the deep water, where it lays eggs, but sometimes, the young drift to the lakeshores.”

Munyaho added that it is important to protect the wetlands and promote sustainable agriculture that curtails runoff and silting of the lake.

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