EnvironmentScience

Fishermen blame aquaculture for diminishing wild fry population

Alexandria-born fisherman Ali Mohsen has seen his profits ebb and flow with the tide. The salty septuagenarian spent his youth plying the coastal lagoons of the Nile Delta. He recalls a time before the Aswan High Dam when sardines churned the muddy shallows near Rosetta, and glows while describing the bountiful hauls during his two decades on a commercial trawler.

These days the white-haired mariner leaves the fishing to his sons. But his family has fallen on hard times, as the nets are rarely full and their boats must venture further afield. The total catch of Egypt's Mediterranean fishing fleet has been in decline for nearly a decade. As fish become more elusive, desperate fishermen are resorting to mist nets, poison and even dynamite to even the odds.

But it is not just the poachers who are depleting Egypt’s seas. Mohsen accuses aquaculture projects of stripping coastal waters to seed their nurseries with wild fry. He claims the aquaculture sector's reliance on wild-caught seed reduces supplies of wild fish that would otherwise fill fishermen's nets.

“Every fish they take means one less for us fishermen,” he says.

Egypt’s aquaculture — the farming of aquatic organisms — sector has grown exponentially since the 1980s and now accounts for over 750,000 tons of finfish a year, or about 65 percent of the country’s total fish production. While freshwater hatcheries have been extremely successful in captive spawning programs, supplying nearly 100 percent of the fry used to seed aquaculture projects, marine hatcheries have lagged far behind.

“The main source of seed for our marine hatcheries is still wild fry,” says Mohamed Abdel Razek Eissa, director of aquaculture at the National Institute for Oceanography and Fisheries. “Last year, the government collected over 80 million fry from estuaries along the Mediterranean coast to be used as seed for mariculture projects.”

Mullet, known locally as bouri, accounts for the vast majority of wild-caught fry. Collection stations on Egypt's Mediterranean coast also gather a small amount of seabass (qarous) and sea bream (denis) fry, as well as broodstock.

Mullet aquaculture has a long pedigree in Egypt. The popular table fish was traditionally reared in small enclosures known as hosha. Commercial farming of mullet in Egypt began in 1961. Today the country is the world leader in mullet aquaculture, producing over 250,000 tons a year.

Egyptian mullet aquaculture has relied on the collection of wild seed since the practice began in the 1920s. Each year, the General Authority for Fish Resources and Development, the state agency responsible for fisheries oversight, issues permits for fry collection at some dozen designated sites along the Mediterranean coast and Gulf of Suez. The fry are collected from estuaries using seine nets and sold directly to licensed fish farms, or transported to state nurseries where they are reared and sold as fingerlings. The authority sets the prices and establishes a quota for purchases.

The collection of wild fry as seed for aquaculture has long been a source of contention among environmentalists and fishermen, who deem the practice a threat to natural fisheries. The meteoric growth of aquaculture in the 1990s, and with it the rate of fry collection, led to a number of confrontations with authorities. Many of Egypt's 200,000 fishermen view the government-backed seed collection program as support for wealthy fish farm owners at the expense of poorer fishing communities.

“It was fine to collect wild mullet fry when there were only a few fish farms,” says Mohsen. “But now there are thousands. They have the technology to breed mullet in hatcheries, but it's easier and cheaper to take the fry from the sea.”

Magdy Saleh, a retired official from the general authority and a leading expert in mullet production, has heard all the arguments. Yet he is skeptical, claiming statistical data demonstrates that the practice has only a negligible effect on wild stocks.

“The capture of mullet fry for aquaculture is a very old business that has been going on since 1926,” he says. “It has never been proven that organized or managed aquaculture of mullet seed can affect the total production of mullet in the country, especially as the seed is going to be used in aquaculture and it's going to be mullet at the end of the day.”

Saleh explains that mullet is a species that has survived for millions of years by playing a numbers game, pitching high fecundity against natural losses due to disease and predation. The amount of fry collected is just a fraction of the number produced.

“Each adult female can produce up to four million eggs a year,” he says. “In the wild you may lose 99 percent of these, but in captivity the mortality rate is much lower. So if you are raising mullet in captivity you are in essence helping the species rather than depleting its stocks.”

According to Saleh, for every million fry collected in estuaries to seed aquaculture projects, about 40 percent will die before maturity in nurseries, while “losses by predation alone in the wild may exceed 75 percent.”

Eissa of the National Institute for Oceanography and Fisheries disputes these figures, arguing that in practice, no more than 50 percent of fry survive the live capture process, while up to 70 percent live to maturity if left in the wild. The main reason for the low captive survival rate, he says, is insufficient acclimatization.

“The mortality rate is high because people often collect the fry from saline water and stock them directly into freshwater ponds,” he says. “Millions of fry just go to waste.”

One study found that up to 96 percent of the transported fry die within the first week if transferred directly to freshwater ponds. Gradual acclimatization over six to eight hours can reduce losses to below 10 percent, but only a handful of operators appear to follow the guidelines.

The live capture mortality rate is assumed to be highest in the significant black market that has evolved as an alternative to the General Authority for Fish Resources and Development's stocking program. The low quota and perceived high price of government mullet seed has led many aquaculture projects to seek unlicensed suppliers. Moreover, restrictions that prohibit aquaculture on reclaimed agricultural land mean that nearly half of all fish farms must depend entirely on illegal sources for their required seed.

The general authority's records show that 75–150 million mullet fry are collected each year. It is estimated that for every fry captured legally, another three are caught illegally.

Reliance on the collection of wild seed is a result of both economic considerations and technological barriers to hatchery production, explains Saleh. Of the three main commercial species of mullet in Egypt, thin-lipped grey mullet is relatively easy to breed in a hatchery environment, but the other two require complex hormone treatment and broodstock preparation.

A USAID-funded hatchery program in the early 1990s managed to produce about a million fry of flathead grey mullet annually, but at 15 times the cost of wild-caught fry. Production eventually shifted to other species with lower rearing costs and higher market value.

“Even in the United States, commercial production of mullet seed is difficult,” says Saleh. “All the hatcheries set up in Italy a few years ago went bankrupt and closed, so this is not a local problem.”

In 2010, fish farm managers were alerted to a proposed government ban on the practice of collecting wild fry as seed, requiring all aquaculture projects to use hatchery-raised fry by 2013. The general authority appears to have shelved the moratorium due to budgetary constraints and inadequate hatchery facilities.

Egypt's three state-run marine hatcheries have a combined annual capacity of three million fry from mostly captive broodstock, while private hatcheries produce no more than a million fry a year. Production is geared to high-value species such as seabass and sea bream, and any shift to mullet would likely entail enormous financial losses.

The government is mulling a proposal for a large hatchery in Sinai with an annual capacity of 10 million fry, but any additional production is expected to support the growing market for seabass and sea bream culture. Saleh says it is still too technologically demanding and economically impractical to produce large quantities of mullet seed under controlled conditions.

Wild seed will continue to form the basis of mullet culture “until captive breeding is developed to commercial levels,” he says. “There is really no scientific evidence that wild fry collection is harmful to the environment, so there is nothing urging us to start artificial propagation in a hatchery.”

The focus instead, say experts, should be to stamp out illegal fry collection and educate fish farmers on ways of reducing the high seed mortality due to transport and inadequate pond preparation.

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