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Scientists emphasize disease control in booming aquaculture sector

  • The World Organisation for Animal Health held a conference in Santiago, Chile, focused on aquatic animals
  • Compared with land animals, little is known about diseases of aquatic animals.
  • Yet experts are looking to aquaculture to support human food security in the coming years.

SANTIAGO, Chile — At its last global conference, held in April in Santiago, Chile, the World Organisation for Animal Health (known as OIE) focused on aquatic animals. The reason? Experts estimate that if the planet’s human population continues to increase as projected, the world will need to double its food production by 2050. The oceans, and aquaculture in particular, are seen as a main source for meeting this need.

“For the past decade, fishing of native animals has stabilized while aquaculture has increased enormously,” Monique Eloit, the OIE’s director-general, told Mongabay Latam. However, information about the health of aquatic animals is poor compared with that of land animals. According to Eloit, this gap must be addressed to secure the food supply for the coming decades.

Insufficient data

Around 60 percent of human pathogens and three-quarters of first-emerging infectious diseases are of animal origin. Among these are bird flu strain H5N1, rabies, tuberculosis, the Ebola virus, and foot-and-mouth disease.

Since aquaculture is the fastest-growing food source, “it is likely that we will face greater health risks and challenges,” Eloit said. She recommended taking steps to improve disease management, biosecurity and the responsible use of antimicrobials.

OIE conference in Santiago, Chile, in April. Image courtesy of OIE.

To achieve these objectives, the OIE has been making efforts to gather information on aquatic-animal diseases and the measures being taken to prevent them. One such initiative involves the creation of a database on the use of antimicrobial agents in animals, mainly antibiotics. However, the aquatic-animal production sector has contributed considerably less data than the land-animal production sector, Eloit said.

She said this is in part because businesses lack of transparency when reporting their use of antibiotics. “The industry must really understand that it can no longer avoid that question. It can no longer be ignored,” Eloit said.

Giant clams grow in floating ocean cages in the Solomon Islands, circa 2001. Image by Mike McCoy/WorldFish Center.

But more importantly, many countries have not institutionalized data collection, she said, and they are the entities that will need to generate more and better information, with the OIE serving as an adviser. “We cannot do it alone because we have limited powers,” Eloit said, adding that the countries “must organize themselves and ask for our support if they need it.”

At this point, however, the evaluation is still deficient. The OIE has a global program called Performance of Veterinary Services (PVS) that supports and advises countries to strengthen their national veterinary services and improve animal health. Although 140 countries have joined the program to improve their land-animal production sectors, only 13 have done so to strengthen their aquaculture and fisheries sectors.

The disadvantages of aquaculture

While the OIE conference was taking place in Chile’s capital, residents in the south of the country demonstrated in favor of expanding the country’s largest aquaculture industry: salmon.

Chile is the world’s second-largest salmon producer (Norway is the biggest). However, a growing chorus of civil society actors, including fishermen, scientists and conservation professionals, have criticized this leadership because of the environmental impacts of various salmon cultivation operations. Among these is the generation of low-oxygen “dead zones” in the sea.

Giant clam husbandry in the Solomon Islands, circa 2001. Image by Mike McCoy/WorldFish Center.

Alicia Gallardo, director of the National Fisheries Service (Sernapesca), the Chilean government agency responsible for ensuring the protection of hydrobiological resources and their environment, said her office has applied “a very strict rule.”

In 2007, an outbreak of infectious salmon anemia (ISA) occurred, which Gallardo described as “the worst health crisis in the history of the national salmon industry and that left more than 15,000 people unemployed.” At the time, she said, “there was no animal health area established within Sernapesca. So we have been taking foreign regulations and applying them at the highest level.”

Yet 12 years after the ISA crisis, health problems persist in the salmon aquaculture industry. In 2016, 9,000 tons of dead salmon were dumped into the Chiloé Sea, intensifying a red tide outbreak that caused unprecedented fish mortality and a deep social and economic crisis. In 2018, almost 700,000 salmon escaped from breeding cages. The consequences remain unknown, but according to scientific predictions the escape could put populations of native species at risk.

The OIE says it recognizes that biological stress caused by bad environmental or farming practices contributes negatively to the health status of an animal population. “Advances in breeding practices will be important to improve the health of aquatic animals,” Eloit said.

Gallardo pointed out that Sernapesca is augmenting control measures out of an awareness that, as a leading country in Latin America, Chile has the responsibility to promote “adequate biosecurity and sustainability practices.” One such practice is surveillance through technology that allows difficult-to-access salmon production centers to be controlled. “While we cannot have an army of inspectors, we are incorporating remote inspection, which is probably the way to approach production centers that are far away,” Gallardo said.

Salmon cages in Chile. Image by Daniel Casado.

She said her agency is also promoting small-scale aquaculture.

For Liesbeth van der Meer, director of the marine conservation NGO Oceana in Chile, that’s the only kind of aquaculture that should operate. “Native species like oysters and mussels, which can be cultivated, are adapted to our ecosystem and do not harm the environment,” she said. “The aquaculture that we believe can feed the world is the one that is concerned with maintaining ecosystem balance and that is developed on a small scale by the coastal communities themselves.”

When it comes to food security, “salmon only feeds a small elite class that eats the orange fish,” van der Meer said. “What is going to have the greatest impact on feeding the world is the recovery of fish populations.”

But small-scale aquaculture is not free of health problems, and influencing this is one of the OIE’s greatest challenges.

Challenges and investing in science 

Aquaculture is a diverse sector in which large companies and small producers converge, the latter representing an important labor force. This is why one of the biggest challenges is not only addressing the private sector, which has large farming centers, but also, and above all, the small centers, Eloit said. Larger centers tend to be very well informed, and have tools and laboratories, while small centers “are not necessarily concerned with complying with international health standards” because they do not export products but feed a local or regional market, Eliot said.

The second challenge is for countries that want to start a more industrial production to consider all the sanitary measures from the beginning. “This is a problem because we often imagine that it is enough to have the fish in the water and we have little awareness of safety measures and environmental protection,” Eloit said. In fact, in much of the world, biosecurity measures are not applied in aquaculture, so the OIE emphasizes the need to find a way to communicate its advantages.

Small-scale purse seine fishers target squid and cuttlefish in Vietnam circa 2009. Image by David Mills/WorldFish Center.

Even so, Eloit said she feels confident in a bright future for aquatic animal health “because we have seen presentations from countries that invest enormously, even though they are not developed countries.”

Raul Avendaño, principal investigator of Chile’s Interdisciplinary Center for Aquaculture Research (INCAR) and director of the Aquatic Organisms Pathology and Aquaculture Biotechnology Laboratory at Andrés Bello University in Santiago, said that “at present, science is an impressive engine of new proposals and solutions to health problems,” which is why “the aquaculture industry and regulatory bodies should seek support from researchers.”

As an example Avendaño pointed to new vaccines that have proven very effective in controlling pathogens in aquatic animals. However, in Chile he noted that “the investment in science and technology is low and does not exceed 0.4 percent of the GDP, while in OECD [Organisation for Economic Co-operation and Development] countries they have an average contribution of 2.4 percent.” For that reason, good projects tend to run out of funding, he said, forcing “professionals who carry out research in diseases to compete for the allocation of resources, rather than collaborating.”

Recently, the Chilean government’s Strategic Investment Fund contributed $16.7 million and the salmon industry’s Salmon Technological Institute another $697,000 to generate knowledge associated with the main pathogen that threatens the salmon industry.

Although this is an important sum, Avendaño said, “it remains to be seen whether this investment is sufficient, since the studies were carried out in a period of no more than 16 months and science requires more time to generate knowledge in an area that was not considered a priority in 30 years.”

This story was first published in Spanish on Mongabay Latam on April 22, 2019.

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