March 17, 2020

Editor's Note - Black Swans and Aquaculture

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A Black Swan is an event that is rare, unpredictable and has profound and disruptive impacts, something random with a large deviation from normal. The current global disease pandemic caused by the novel coronavirus is an exemplary Black Swan event. An influential book published in 2007 on the subject of Black Swans, written by Nassim Nicholas Taleb, was subtitled “the impact of the highly improbable.” In 2012, the US National Intelligence Council published Global Trends 2030: Alternative Worlds that identified eight Black Swans, with a severe pandemic disease outbreak topping the list. New terms like flattening the infection curve and social distancing have entered popular lexicon.

How has the coronavirus outbreak affected aquaculture? Looking broadly, and given that the outbreak originated in China, it has highlighted the premier importance of China as the world’s largest aquaculture producer and both the largest seafood importer and exporter in the world. The pandemic has impacted both supply and demand for seafood products. Severe disruptions in global seafood supply chains have occurred. Farmed imports to China of shrimp from Ecuador, India and Indonesia, salmon from Norway and Chile, pangasius from Vietnam have declined due to reduced demand. Exports of farmed tilapia from China have been severely curtailed. Hubei Province, the center of the pandemic, is the core area of production of red swamp crayfish and harvests have been delayed or limited by mandatory lock-downs. Given the abrupt reduction in overall demand in China, prices are collapsing and farmers from countries exporting to China are likely not to stock or at least reduce stocking densities in the short term. Certainly the livelihoods of millions of small- and medium-scale producers worldwide have been jeopardized. Perhaps this global event will lead to a reconfiguration of global supply chains that favor local production.

One of the main features of the coronavirus is that it is a zoonotic disease, meaning that it can cause disease in people and animals. Similar to the SARS disease outbreak, it is thought that the virus passed to humans from virus-carrying bats or pangolins in a live animal market in Wuhan. Such markets are common in China and many other places in the developing world.

Wet markets for live seafood are also common but there is no evidence of a link between such markets and this virus outbreak. Here is where aquaculture and live seafood marketing have a good story to tell in that the risk of disease transfer between live farmed fish, shrimp and other farmed seafood to humans is negligible. This is not to say that contact with fish, shellfish and crustaceans will not cause disease in humans. So-called “fish handlers disease” is caused by Mycobacterium marinum and every year there are clusters of disease and even death from consumption of raw shellfish contaminated with Vibrio vulnificus, but there are no examples diseases of a viral etiology passing from fish to humans.

Of course, disease pandemics are quite familiar to producers of farmed fish and shrimp around the world. The history of shrimp farming is essentially the story of boom-and-bust cycles in response to various diseases that have travelled around the world, some of them caused by viruses and others (more recently) by pathogenic bacteria. Unregulated transfers of aquatic organisms have been a major factor in global fish and shrimp disease pandemics, indicating — as it does with the coronavirus pandemic — the extent of our global interconnectedness. The proposed behavioral responses to the pandemic are analogous to good sanitary practices and biosecurity that are effective in aquaculture as well.

Although the recent focus of attention has been the worldwide impacts of the coronavirus pandemic, one of the other Black Swans that could have profound direct and indirect effects on aquaculture identified in the 2013 National Intelligence Council report was climate change occurring at a more rapid pace than currently expected. A recent book, Discerning Experts, by Naomi Oreskes et al., explains how (and more importantly, why) scientists have been underestimating the pace of climate change. Oceans have warmed more and ice sheets and glaciers are melting faster than previously predicted, indicating that the rate of projected sea level rise is likely underestimated and we may be approached or have already passed irreversible tipping points. The time window for adaptation and building resilience may be closing faster than anticipated. The current global mobilization to counter the threat of the coronavirus pandemic is in some ways encouraging, suggesting that it should be possible to mobilize similarly to address the existential threat of rapid climate change.

Stepping back further from highly disruptive Black Swan events, we are now living in an age of disruptive technologies and approaches in aquaculture. In contrast to the profoundly negative effects of Black Swan events, these relatively small disruptive innovations can create incremental, generally positive shifts in the ways aquaculture is practiced. In the realm of feed ingredients, oils from algae, single-cell protein meals from various fermentation and other biotechnology processes, and insect meals are rapidly increasing the scale of production to fill the future gap in the need for fishmeal and fish oil. Nutraceuticals, phytobiotics and probiotics are now part of the ever-expanding list of ingredients in feeds to enhance aquatic animal health. Camera-based feeding systems for salmon are now standard. Hydrophone-based feeding systems for shrimp have significantly changed the way shrimp are now fed, with both approaches achieving improved efficiency and less waste. New technologies like computer vision and machine learning are allowing accurate estimation of fish appetite. Underwater robots and drones are cleaning nets, inspecting cages and monitoring fish health and growth. The Internet of Things is linking communication, computing and big data. All of these are examples of a new wave of “precision aquaculture” that represents the leading edge of innovation in aquaculture. In contrast to Black Swan events like the coronavirus pandemic, disruptive innovations in aquaculture represent desirable changes that can contribute to sustainability and greater food security.
— John A. Hargreaves, Editor-in-Chief

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About John A. Hargreaves

World Aquaculture - Editor in Chief. Aquaculture expert with 40 years of experience in research, teaching, and development. Freelance consultant on commercial aquaculture and international development projects.

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