“Soon there won’t be any fish in the seas”, “overfishing is irreversible”, “are there still fish in the sea?” 

When it comes to fish consumption, we come across many such statements – but do they reflect reality? Throughout the last few decades, we have been fishing all over the planet, carelessly destroying habitats, using narrow-sighted practices and technologies. To understand how the fishery industry operates, we need to understand how the international community allots the waters and in whose favour.

Coastal countries control a so-called exclusive economic zone [EEZ], where they hold sovereignty on the commercial use. This area represents about 41 % of all oceanic waters and provides the majority of the global catch. Outside of this region, on the high seas, there are no governmental regulations and only a handful of countries make use of it. Marine life however, does not care about our arbitrary division of the seas and especially migratory species can be found in both shallow and open waters. Depleting the resources in the open ocean, where these species often gather in large numbers to breed, causes a severe impact on the fish stock and threatens the livelihoods of coastal fishery which relies on the fish to come back. In this article, we look at the main challenges global fishery is overcoming by using holistic data and applying new technologies. We highlight two main initiatives that can drastically improve our marine ecosystems on a global scale, increase revenue from fishing, ensure that we can continue to rely on this food source, allow for a fairer distribution of the global catch between regions at different stages of development and to top it off, ensure a flourishing marine wildlife! 

A global map showing the high seas (blue) and national exclusive economic zones (green), which stretch 220 miles off coastlines. Source: PLOS BIOLOGY

The lack of data

In this article we consider two key perspectives on data indicating sustainability of fishery: The human fishing activity and the natural fish stock

The human fishing activity can roughly be categorized in the following two types of activity when excluding fish farms:

– The countless small trawlers operated by coastal inhabitants, often in less developed regions which roam their EEZs to make a living.

Large factory ships controlled by a handful of countries, capable of sweeping huge areas and equipped to prepare the catch ready-for-sale on board.

As each country can set their own rules and policies on fishing, until recently, only limited information has been  available on the total amount of vessels, the size of the catch, the actual health of the fishing grounds and its profitability. Moreover, as a lot of data regarding human fishing activity has not even been collected on a state level, gathering data on the global scale seemed quite impossible. This doesn’t solely apply to the scattered coastal fishing, where one presumes that gathering data is not the fisher’s priority. Until 2018, there was hardly any information on which countries are fishing with which trawler in what open seas. In some cases, this data has even been purposely suppressed as  the example of the Damanzaihao shows.

Furthermore, only about half of the world’s natural fish stock is being monitored scientifically. When a stock is being monitored, it can yield crucial information on its health and regeneration rate, allowing for better stock management and preventing overfishing. To understand the global marine fishing industry, scientists had to rely on many assumptions on both the human fishing activity and the natural fish stock. Now, if your primary information has as many holes as trawlers’ nets, making sound recommendations on an economic, environmental and social level would be quite… fishy.

To summarize the lack of information:

 Human Fishing activity

Natural fish stock

Amount, location and productivity of ships 

Monitored fish stock

Size of the catch per ship, country and globally

Health of Fish stock

Social and economic benefits

Historical development

 Filling the data gap

A 2018 study by Enric Sala et al. gathered – for the first time – enough data from satellite imagery and combined it with machine learning in a way that allowed them to gather almost real-time information on the following aspects of high seas fishery:

  • Where and if a trawler is fishing
  • Which stock it is depleting
  • Under which Flag the vessel operates

Unlike other studies, Sala and his team did not only highlight the evident and long-known environmental damage – they also compared the satellite data with the fishing industry’s revenue to review the economic and social benefits. It turns out, high seas fishery is not only destroying natural habitats, disrupting natural migratory patterns and impeding regeneration of fish stock – it also burns a whole lot of government money. While high sea fishery only amounts for 8% of total global fishing revenue, it`s profitability is “artificially propped up by an estimated $4.2 billion in government subsidies” which is more than twice the economic profit before subsidies. Although subsidies are based on educated estimates and are not backed by actual figures, it raises the question of what purpose high sea fishery still has– from an environmental, social and economic perspective.

Graph showing the profitability of open seas fishery without subsidies. In large parts, fishing activity is highly unprofitable. As expected, the profitability on open seas fishery is higher when in proximity to land. However, it is not unanimously the case as the surrounding parts of South America show. With a lack of profitability, destroying entire populations, and with it ecologic diversity, trawler fishery makes little sense. Image: Sala et al.

A 2020 study published by Ray Hilborn et al. shows the progress that managed fish stocks made over the last twenty years. The research team built a network of collaborators in countries and regions throughout the world, inputting their data on valuable fish populations. About 880 fish stocks are now included in the database, giving a much more comprehensive picture of the health and status of fish populations worldwide. It highlights the increasing number of managed fisheries and their observable, positive effect on replenishing fish stocks. Hilborn particularly highlights the Peruvian example of anchovy stocks which have been constantly improving over the last 50 years since their dramatic decline. While overharvesting still occurs, it is happening in only 20% of managed fisheries while the rest is within the maximum sustainable yield. The authors conclude that managing fish stock has been successful and should be expanded to more regions. It remains unclear how the stocks are monitored and whether monitoring only happens on EEZ or open oceans as well. Our assumption based on the available data remains that the monitored stocks are within EEZ only.

Banning or Managing?

Narrowing the information gap has brought both rapid progress and hope back to the fishing industry. It offers a feasible solution to protect marine biodiversity and could even be economically beneficial to various marine stakeholders. However, as both sides are converging the gap on their respective core information (supply and demand), their solutions are diverging.

Enric Sala et al. propose a global ban on high seas fishery. This would allow the fish to replenish, eliminate an economically questionable industry and allow for a fair, natural distribution of increasing fish stocks that migrate back into the EEZ. Previous cases on fishing bans taken by countries bordering the arctic have already shown promising results. The proposal would still have to work through major issues:

  • How to enforce it?
  • How to track compliance?
  • What are the penalties?
  • How could the social and capital impacts be cushioned?

Compliance can now be monitored with the new tracking methods introduced in the study. Enforcement, penalties and the social and capital impacts, however, have not yet been thought through and in a tense trade war between the strong world powers, an agreement and implementation of such a ban seems to have little chance.

Ray Hilborn et al. propose expanding the success of fishery management onto a global scale. Applying successful management methods to the remaining half of the global catch would allow for a holistic view on the supply of fish, protect the industry and generate a positive environmental impact by reducing CO2 emissions via effective resource allocation. Moreover, such management could ensure that fishing techniques are less harmful to the environment. Still, there are open questions to be answered:

  • Which management approach works best?
  • Who holds control over the allocation?
  • How will fair distribution be defined?
  • How can this approach be incentivized cross-culturally?

Although a lot of progress has been made, industry experts agree that there is no “one-size-fits-all management approach”. The fact that most of the management efforts have been done on a private based collaborative effort allows the solution to bypass potential political turmoil but might face barriers when it comes to incentives.


There is still a lot to be done before the consumer can sit back, relax and enjoy a carefree tuna, anchovy or salmon. Sure, there are labels and certifications that have already contributed a lot to sustainable fishing. Websites like seafoodsource.com or mcsuk.org also give the consumer the opportunity to see which seafood is already out of the water – sustainability wise. The great news is that we have been able to realize significant progress and the challenge is being viewed on a global basis. Properly managed fish stocks are replenishing, destructive trawlers are being stopped and monitored and collaboration on progress does not seem out of reach anymore. We are looking at the challenge from many different perspectives and are respecting the various demands from all stakeholder groups to make sure the raging fire is not just passed on to the next generation but can be extinguished and marine life can thrive again..

We would like to read your opinion on which of the proposed approaches would work and why? Where do you see potential or obstacles? Or do you even see different possibilities? Do you disagree with any of the viewpoints or do you have other good news?

Tell us why in the comments below or leave a comment here on facebook.